13th AxionWIMP conference (Patras workshop)

14 May 2017, 17:00 → 19 May 2017, 18:30 Europe/Athens

Hotel MAKEDONIA PALACE (Thessaloniki, Greece)

The 13th Patras Workshop on Axions, WIMPs and WISPs will be held in Thessaloniki (Greece ) from May 15th to 19th, 2017. This workshop is aiming to continue the rich and successful series, reviewing recent theoretical advances, laboratory experiments, novel ideas as well as astrophysical and cosmological results in the fields of axions, WIMPs and WISPs. Participation by young scientists is encouraged. A poster session is scheduled and an award is foreseen.

For early registration until Friday 31/3/2017 a conference fee of 350 Euros is foreseen. For late registration the fee increases to 400 Euros.
More details on the workshop are given on the conference webpage:
http://axion-wimp2017.desy.de/

Sunday 14 May

Registration (up to 20:30 h)

Welcome Reception

Monday 15 May

Registration (up to 12:30 h)

Session 1

Convener: Dr Axel Lindner (DESY)

1 Welcome

Speaker: Prof. Konstantin Zioutas (U. of Patras)

Slides 1)_13_PATRAS_WORKSHOP_welcome_K_Zioutas.pptx

2 Gravitational self-interactions of a degenerate quantum scalar field

Axions (and axion-like particles) produced by the vacuum realignment mechanism in the early universe form a highly degenerate Bose gas and are a cold dark matter candidate. Dark matter axions thermalize as a result of their gravitational self-interactions when the photon temperature reaches approximately 500 eV. When thermalizing, the axion fluid undergoes Bose-Einstein condensation, a quantum process. A formalism is introduced to help calculate the outcome of this process.

Speaker: Prof. Pierre Sikivie (University of Florida)

Slides 2)_Thessaloniki2017_Sikivie.ppt

3 The NA64 experiment at CERN SPS

In this talk, we will report the results of our direct search for sub-GeV dark photons (A') which might be produced in the reaction e Z -> e Z A' via kinetic mixing with photons by 100 GeV electrons incident on an active target in the NA64 experiment at the CERN SPS. The A's would decay invisibly into dark matter particles resulting in events with large missing energy. No evidence for such decays was found with 2.75x10^9 electrons on target [1]. We set new limits on the gamma-A' mixing strength and exclude the invisible A' with a mass <100 MeV as an explanation of the muon g-2 anomaly. The future prospects and physics program of the NA64 experiment will be briefly presented. [1] NA64 collaboration, Phys. Rev. Lett. 118, 011802 (2017)

Speaker: Dr Paolo Crivelli (ETH Zurich, Institute for Particle Physics)

Slides 3)_Patras17_NA64_Crivelli.pdf

4 New ideas on the axion search experiment via topological Casimir Effect

We propose a new table-top experimental configuration for the direct detection of dark matter axions. Different from most experimental setups found in literature on direct dark matter axion detection, which relies on $\dot{\theta}$, we found that our system is in principle sensitive to a static theta as a result of the nontrivial topological features of the Maxwell system. We explain some connections to Aharonov Bohm effect and Witten effect. Talk is mostly based on recent arxiv 1702.00012.

Speaker: Prof. Ariel Zhitnitsky (University of British CXolumbia)

Slides 4)_zhitnitsky.pdf

5 Status of the HAYSTAC Experiment

Dark matter axions may be detected by their resonant conversion to photons in a tunable microwave cavity permeated by a strong magnetic field. This talk will give an overview of the design and operational experience of HAYSTAC (Haloscope At Yale Sensitive to Axion CDM), which incorporates a dilution refrigerator and Josephson parametric amplifier and has thus achieved a system equivalent noise temperature of only twice the Standard Quantum Limit. First results will be presented, which exclude axion models a factor of ~2.3 above the benchmark KSVZ model over the mass range 23.55-24.0 μeV. These are the first limits within the axion model band in the 10-100 μeV mass decade. Finally, I will discuss our R&D oriented to significantly increase the detector sensitivity through application of a squeezed-vacuum state receiver, higher Q cavities, distributed Bragg reflectors, and photonic band-gap resonators. This work was supported by NSF Grants PHY-1306729 and PHY-1362305, Heising-Simons Foundation Grant 2014-182, and U.S. DOE Contract DE-AC52-07NA27344. M. Simanovskaia is supported by the NSF Graduate Research Fellowship Grant DGE-1106400 and the Berkeley Fellowship.

Speaker: Ms Maria Simanovskaia (UC Berkeley)

Slides 5)_SimanovskaiaPatras2017.pdf

Coffee break

Session 2

Convener: Prof. Pierre Sikivie (University of Florida)

6 Storage Ring EDM Search and Polarimeter Concept Development for Electron EDM Measurements

The storage ring EDM method can be used to study the electron EDM at the 10^-29 e.cm level provided there is a high sensitivity electron spin polarimeter available at 15 MeV/c, the electron magic momentum. In this study, we present the feasibility results on a polarimeter concept we developed specifically for the storage ring electron EDM measurement. The idea of using Compton backscattering method as an electron spin analyzing tool is described. The cross section and analyzing power is calculated for both transverse and longitudinal electron spins. The requirements of 8.9 keV high intensity light source as the analyzing tool for the electron spin measurement are also discussed. This work was supported by IBS-R017-D1-2017-a00.

Speaker: Dr Seongtae Park (CAPP/IBS)

Slides 1)_PATRAS2017_Park.pdf

7 Looking for low-mass WIMPs with TREX-DM

The Weakly Interacting Massive Particles, which appear in supersymmetric extensions of the Standard Model, are one of the strongest candidates to form the Dark Matter of the Universe. The lack of a positive signal during the last 30 years in the search of “standard WIMPs“, during which the experimental efforts have reached remarkable levels of sensitivity, and the lack of proof of supersymmetry in the data of LHC so far, have made attractive the lower end of the WIMP mass. Looking for low-mass WIMPs (< 10GeV) requires the use of light elements and a low energy threshold, aspects for which the current experiments are not optimized. We propose another experiment to look for low-mass WIMPs, TREX-DM. TREX-DM is a gas time projection chamber (TPC) equipped with novel micromesh gas structures (Micromegas) readout planes. The detector will hold, in the fiducial volume, ~20 litres of pressurized gas up to 10 bar, which corresponds to approx. 0.300 kg of Ar at 10 bar, or alternatively 0.160 kg of Ne. The energy threshold foreseen is well below 0.4~keVee and the expected background level is better than 10 counts keV-1 kg-1 d-1 , according to the screening of all the components of the detector. Based on the background model, for a level of the order of 1 count keV-1 kg-1 d-1, TREX-DM could give competitive results in the search for low mass WIMPs. The experiment has recently been approved by the Underground Laboratory of Canfranc (Laboratorio Subterráneo de Canfranc) and is expected to be commissioned by the end of the current year. We will report on the status of the project.

Speaker: Dr Theopisti Dafni (Universidad de Zaragoza)

Slides 2)TDAFNI_patras2017_other.pptx

8 Searching for galactic axions through magnetized media: The QUAX proposal

We present a proposal to search for QCD axions with mass in the 200 μeV range, assuming that they make a dominant component of dark matter. Due to the axion–electron spin coupling, their effect is equivalent to the application of an oscillating rf field with frequency and amplitude fixed by the axion mass and coupling respectively. This equivalent magnetic field would produce spin flips in a magnetic sample placed inside a static magnetic field, which determines the resonant interaction at the Larmor frequency. Spin flips would subsequently emit radio frequency photons that can be detected by a suitable quantum counter in an ultra-cryogenic environment. This new detection technique is crucial to keep under control the thermal photon background which would otherwise produce a too large noise. (On the behalf of the QUAX collaboration)

Speaker: Giuseppe Ruoso (INFN - LNL)

Slides 3)_ruoso-patras.pdf

9 Anomalous gauge U(1), 't Hooft mechanism, and "invisible" axion from string

We can consider two continuous parameters, one is the MI-axion direction and the other the phase of anomalous U(1) gauge transformation. If the anomalous U(1) gauge boson obtains mass by absorbing the MI-axion at the compactification scale, one continuous parameter remains, which describes a global symmetry. This corresponds to the 't Hooft mechanism in gauge theory that if one scalar VEV breaks both a gauge symmetry and a global symmetry then the gauge symmetry is broken and a global symmetry survives. This is a good PQ symmetry and can give the axion decay constant around 10^{11} GeV, without any gravity spoil of the PQ symmetry.

Speaker: Prof. Jihn E. Kim (Kyung Hee University)

Slides AThessaloniki.key.zip

10 Fermi-LAT and NuSTAR as stellar axionscopes

I will present some recent results on the Fermi-LAT and Nustar potential to probe axion like particles (ALPs) produced in stars. The case of massive ALPs will also be included.

Speaker: Dr maurizio giannotti (Barry Universtiy)

Slides 5)_Maurizio_Giannotti.pptx

Lunch

Session 3

Convener: Igor Tkachev (INR RAS)

11 Phenomenology of Majorons

An overview of the phenomenology of majorons (and familons) as dark matter and in connection with lepton flavor violation.

Speaker: Julian Heeck (Université Libre de Bruxelles)

Slides 1)_heeck_majoron.pdf

12 ALPs Effective Field Theory and Collider Signatures

We study the leading effective interactions between the Standard Model fields and a generic singlet CP-odd (pseudo)Goldstone boson. Two possible frameworks for electroweak symmetry breaking are considered: linear and non-linear. For the latter case, the basis of leading effective operators is determined and compared with that for the linear expansion. Associated phenomenological signals at colliders are explored for both scenarios, deriving new bounds and analyzing future prospects, including LHC and High Luminosity LHC sensitivities. Mono- Z, mono-W, W-photon plus missing energy and on-shell top final states are most promising signals expected in both frameworks. In addition, non-standard Higgs decays and mono-Higgs signatures are especially prominent and expected to be dominant in non-linear realizations.

Speaker: Ms Rocío del Rey Bajo (UAM)

Slides 2)_PATRAS_R_delRey_ALP_Collider.pdf

13 Constraints to axion physics from Globular Clusters: an update

New evolutionary models of low-mass stars that include axion productions due to Primakoff, Bremsstrahlung and Compton scattering are presented. These set of models has been used to calculate isochrones, luminosity functions (LFs) and synthetic colour-magnitude (CM) diagrams to be compared with their observational counterparts, i.e. LFs and CM diagrams of Galactic Globular Clusters stars. Based on these comparisons, updated constraints to both the axion-photon and axion-electron couplings are provided.

Speaker: Dr Oscar Straniero (INAF (Istituto Nazionale di Astrofisica))

Slides 3)_straniero_2017.pptx

14 Search for hidden-photon Dark Matter with FUNK

It has been proposed that an additional U(1) sector of hidden photons could account for the Dark Matter observed in the Universe. When passing through an interface of materials with different dielectric properties, hidden photons can give rise to photons whose wavelength is related to the mass of the hidden photons. In this contribution, we report on measurements covering the visible and near-UV spectrum that were done with a large, 14 m^2 spherical metallic mirror and discuss future dark-matter searches in the eV and sub-eV range by application of different electromagnetic radiation detectors. (The talk will be given on behalf of the FUNK collaboration.)

Speaker: Ralph Engel (Karlsruhe Institute of Technology (KIT))

Slides 4)_Engel-FUNK-PATRAS-2017.pdf

15 CULTASK, Axion Experiment at CAPP in Korea

CAPP’s flagship axion experiment, CULTASK has been built on a low vibration facility at Munji campus of KAIST in Korea. We have so far installed 4 dilution refrigerators with two 8T superconducting magnets, which allow us to explore axion mass range of 2~2.5 GHz and 1.35~1.6 GHz, respectively. A resonant cavity (10 cm OD) with a sapphire tuning rod driven by piezoelectric actuator system was successfully cooled down below 30 mK and showed very high unloaded Q-factor (~120,000) even under 8T magnetic field. RF receiver employs 1K HEMT amplifier out of the cavity, but the design is flexible enough to replace it with SQUID amplifier when R&D is completed soon. I will present the status and possibly the very first data of CULTASK and our future plans. I will also discuss about the progress of our R&D projects, development of superconducting cavities and SQUID amplifiers.

Speaker: Dr Woohyun Chung (IBS/CAPP)

Slides 5)_Woohyun_Chung_PATRAS_2017_final.pdf

16 Structure Formation Simulations with Axion Dark Matter

Nonlinear structure formation with axion dark matter can be studied with cosmological simulations using different initial conditions (in the case of axion minicluster formation) and/or new computational methods to capture wave-like phenomena close to the de Broglie wavelength (in the case of ultralight axions). Some approaches for such simulations will be described and first results presented.

Speaker: Prof. Jens Niemeyer (University of Goettingen)

Slides 6)_Patras2017_Niemeyer.pdf

Coffee break

Session 4

17 Hunting magnetic monopoles and more with MoEDAL at the LHC

Speaker: Dr Vasiliki Mitsou (IFIC - CSIC / Valencia Univ.)

Slides 1)_Mitsou-MoEDAL.pdf

18 SUSY DM predictions for Direct Detection Experiments, the LHC and future colliders

We perform a fit of various SUSY models (with a WIMP DM candidate) to experimental data from LHC searches, astrophysical data, low-energy and flavor observables. Based on this analysis we give predictions for the propects of Direct Detection experiments, ongoing LHC searches and future colider searches. We stress the complementarity of the various searches to determine the nature of DM.

Speaker: Dr Diego Martinez Santos (GAIN and Universidade de Santiago de Compostela)

Slides dms_wisps_wimps_n_shrimps.pptx

19 Dark Sector Searches using exotic Higgs Boson Decays in the ATLAS Collaboration

This Dark Sector search in the ATLAS collaboration uses Higgs boson exotic decays as a possible portal to such new phenomena. Use is made of the Standard Model (SM) decay to four leptons: H-->ZZ*-->4l The current analysis is sensitive to the possible existence of "Dark Sector" or "Hidden Sector" vector boson ("Zd") or pseudoscalar boson ("a") that is beyond the SM: H-->ZZd-->4l (electrons and muons) H-->Za-->4l ( models suggest that this is mainly to muons) Analysis results from the full Run 2 dataset (36 inverse fb from 2016) and (20 inverse fb from 2015) will be presented.

Speaker: Oliver Keith Baker (Yale University)

Slides 3)_baker-patras2017.pdf baker-patras2017.pptx

20 Axion – MCs and FRBs

Speaker: Igor Tkachev (INR RAS)

Slides 4)_Tkachev.pdf

21 Detection of Fe-57 14.4 keV Axions by Coherent Inverse Primakoff Conversion in Single Crystal Detectors

Axions can be emitted in the M1 transition of Fe-57 in the Sun. The width of the 14.4 keV axion spectrum is Doppler broadened to about 5 eV (FWHM). The angular size of the region of the Sun responsible for axion production subtends an angle of approximately 0.05 deg., which means the Sun is a nearly monochromatic point source of 14.4 keV axions and ideally suited for coherent Bragg conversion by the inverse Primakoff effect in single crystal detectors. The region of the sky where the Bragg condition is satisfied for a particular reciprocal vector can be visualized as an annular ring with an angular width on the order of 0.01 deg. whose center is the projection of the reciprocal vector on the sky. It takes the Sun on the order of 10-20 seconds to cross one of these Bragg rings, leading to a very distinctive time-dependent counting rate. Both the flux from the Sun and the cross section for coherent conversion are insensitive to the axion mass so long as the mass of the axion is much less than its energy. We estimate that with oriented detectors like SuperCDMS and CUORE it will be possible to establish an upper bound on the product of the coupling of axions to nuclei and to photons one or two orders of magnitude better than current limits.

Speaker: Prof. Richard Creswick (University of South Carolina)

Slides 5)_axion-wimp2017_-_Creswick.pdf

22 Status of the Cosmic Axion Spin Precession Experiment (CASPEr)

The Cosmic Axion Spin Precession Experiment (CASPEr) uses nuclear magnetic resonance (NMR) techniques to search for spin precession induced by ultralight axion dark matter. I will discuss recent experimental progress, including a new experimental mode based on zero- to ultralow-field (ZULF) NMR.

Speaker: Dr John Blanchard (Helmholtz-Institut Mainz)

Slides Blanchard_CASPEr-Patras2017-for-upload.pdf

Tuesday 16 May

Session 5

Convener: Oliver Keith Baker (Yale University)

23 Axions and ALPs: a very short introduction

Axions were originally predicted as a dynamical solution to the strong CP problem. Axion like particles are also a generic prediction of many high energy physics models including string theory. Theoretical models for axions are reviewed, giving a generic multi-axion action with couplings to the standard model. Axion cosmology motivates the existence of several distinct populations of axions behaving as coherent condensates, or relativistic particles. Light, stable axions are a mainstay dark matter candidate. Axions can also contribute to the dark energy density and provide natural inflaton candidates. Axions can also be produced in the lab as virtual particles (force-mediators) or directly, and can contribute to stellar cooling. Constraints on axions from the well-known photon coupling, as well as other portals, are briefly reviewed, including model-independent gravitational constraints. Finally, axions and the ``fuzzy DM’’ model are briefly discussed.

Speaker: Dr David Marsh (Cambridge)

Slides 1)_marsh_patras.pptx

24 Terrestrial effects on DM-e scattering

Speaker: Prof. Chris kouvaris (University of southern Denmark)

Slides thessaloniki_Kouvaris.key

25 An Improved Signal Model for Axion Dark Matter Searches

To date, most direct detection searches for axion dark matter, such as those by the Axion Dark Matter Experiment (ADMX) microwave cavity search, have assumed a signal shape based on an isothermal spherical model of the Milky Way halo. Such a model is not capable of capturing contributions from realistic infall, nor from a baryonic disk. Modern N-Body simulations of structure formation can produce realistic Milky Way-like halos which include the influences of baryons, infall, and environmental influences. An analysis of the Romulus25 N-Body simulation shows that the axion signals from MW-like halos are narrower than the SHM by nearly a factor of two, which has important implications for cavity searches. An improved signal shape and an account of the relevant halo dynamics are also given.

Speaker: Mr Erik Lentz (University of Washington)

Slides EWL_Patras_5_16_17.pdf

26 First axion dark matter search with toroidal geometry

We report the first axion dark matter search with toroidal geometry. Exclusion limits of the axion-photon coupling gaγγ over the axion mass range from 24.7 to 29.1 µeV at the 90% confidence level are set through this pioneering search. Prospects for axion dark matter searches with larger scale toroidal geometry are also given.

Speaker: Byeong Rok Ko (IBS/CAPP)

Slides 4)_Ko_ByeongRok.pdf

Coffee break

Session 6

Convener: Prof. Ariel Zhitnitsky (University of British CXolumbia)

27 Direct Dark Matter Searches with LUX and LZ

The Large Underground Xenon (LUX) experiment recently completed the data-taking phase of its search for direct evidence of dark matter. The detector is instrumented as a dual-phase liquid xenon (LXe) time projection chamber (TPC), providing energy measurement, position information in 3D, and single-scatter event identification. LUX has obtained the world leading spin-independent exclusion limit over a wide range of WIMP (Weakly Interacting Massive Particle) masses, excluding cross sections above 0.11 zb for M(WIMP)=50 GeV/c2 (90% CL). For spin-dependent interactions, cross sections above 1.6E-41 cm2 and 5E-40 cm2 are also excluded for M(WIMP)=35 GeV/c2 (90% CL) for neutron and protons interactions respectively. Paramount for the LUX results was the extensive calibration of the detector electron and nuclear response. For the electron recoils, 83mKr and CH3T sources dissolved in the xenon were used to measure the electric field uniformity and the signal dependence with the position of interaction, both aspects critical to define the active volume of the detector. The nuclear response was calibrated in situ using a collimated beam of monoenergetic 2.45 MeV neutrons from a deuteron-based generator. Besides detailing the analysis leading to the LUX results, we will also present the LUX-ZEPLIN (LZ) detector, a LXe dark matter detector featuring more than 5 tons of target material in the fiducial region (from a total of 10 tons of xenon). It will be installed at the same facilities used by LUX. The experiment aims to improve in 3 years of livetime (starting with commissioning in 2020) the WIMP-nucleon spin-independent sensitivity by a factor of 50.

Speaker: Dr Alexandre Lindote (LIP)

Slides PATRAS2017_ALindote

28 ABRACADABRA, A Search for Low-Mass Axion Dark Matter

ABRACADABRA is a proposed experiment to search for ultralight (10e-14 - 10e-6 eV) axion dark matter. When ultralight axion dark matter encounters a static magnetic field, it sources an effective electric current that follows the magnetic field lines and oscillates at the axion Compton frequency. In the presence of axion dark matter, a large toroidal magnet will act like an oscillating current ring, whose induced magnetic flux can be measured by an external pickup loop inductively coupled to a SQUID magnetometer. The readout circuit can be broadband or resonant and both are considered. ABRACADABRA is fielding a 10-cm prototype in 2017 with the intention of scaling to a 1-m^3 experiment. The long term goal is to probe QCD axions near the GUT-scale. In this talk I will review the design, sources of noise, and sensitivity of the experiment. I will also discuss the proposed 10-cm prototype.

Speaker: Prof. Reyco Henning (University of North Carolina at Chapel Hill)

Slides ABRA_PATRAS2017_Henning.pdf

29 Inferences on the Axion Mass through the Maximum Entropy Principle

We present a formulation of the Maximum Entropy Principle (MEP) that has provided a precise theoretical determination of the Higgs boson mass, within the context of the Standard Model. Motivated by this result we use MEP to infer the axion mass, taking into account a generic low energy effective theory with an axion-neutrino interaction, in addition to the typical axion-eletromagnetic field interaction. Under the assumption that the axion decay into a pair of photons and also into pairs of neutrinos, we construct, from its branching ratios, the Shannon entropy function associated to an initial ensemble of axions. Two cases are considered for inferring the mass of the axion if it can decay into all the three neutrinos, in addition to photons. The first assumes MEP fixes all the free parameters, and leads to the infered interval 0.1 eV<$m_{A}$<0.2 eV for the axion mass. The second assumes that only the axion mass is fixed by MEP, and leads to the interval 0.1 eV<$m_{A}$<6.3 eV, taking into account a DFSZ type model with right-handed neutrinos plus the astrophysical bounds on the axion mass. Both mass intervals are derived using the mass squared differences determined by the data on the neutrinos oscillations, along with cosmological bound on the sum of the neutrinos mass. Moreover, MEP determines a viable dark matter candidate light axion if it is allowed to decay into photons and the lightest neutrino only.

Speaker: Prof. Alex G. Dias (Universidade Federal do ABC)

Slides alexdias-patras2017.pdf

30 GPS and the search for Axions

GPS, an excellent tool for geodesy, may serve also particle physics. In the presence of Earth’s magnetic field, a GPS photon may be transformed into an axion. The proposed experimental setup involves the transmission of a GPS signal from a satellite to another satellite, both in low orbit around the Earth. To increase the accuracy of the experiment, we evaluate the influence of Earth’s gravitational field on the whole quantum phenomenon. There is a significant advantage in our proposal. While the geomagnetic field B is small, the magnetized length L is very large, resulting into a scale (BL)2 orders of magnitude higher than existing or proposed reaches. The transformation of the GPS photons into axion particles, will result in a dimming of the photons and even to a “light shining through the Earth” phenomenon.

Speaker: Argyris Nicolaidis

Slides GPS_Axions_11-5-2017.ppsx

31 CAPP18T: Dark matter axion search experiment using 18T 7cm bore diameter high Tc superconducting magnet

We present progress of developing axion dark matter search experiment using 18T and 7cm bore diameter high Tc superconducting (HTS) magnet at the Center for Axion and Precision Physics laboratory. This CAPP18T experiment is designed to probe resonance frequency range of 3.5GHz to 4.2GHz which is equivalent to the dark matter axion mass range of 14 ueV to 17 ueV sensitive to the KSVZ coupling. In this presentation, we will cover the progress of overall experimental design, the HTS magnet development at SuNAM Co. Ltd, progress in cryostat design, magnet shielding and cancellation, and essential components of the experiment.

Speaker: Prof. Jonghee Yoo (KAIST/IBS)

Slides YooPATRAS2017.pdf

Lunch

Excursion

Wednesday 17 May

Session 9

Convener: Laura Baudis

32 WIMP overview

Speaker: Bernard Sadoulet

Slides Patras_170517.Sadoulet.pdf

33 How to save the WIMP?

Speaker: Mr Stefan Vogl (Technische Universitaet Muenchen)

Slides PATRAS.pdf

34 CAPP optical magnetometer station for GNOME

The Global Network of Optical Magnetometers to search for Exotic physics (GNOME) is an experiment to search for transient events of axion domain walls based on a novel scheme: synchronous measurements of high precision optical magnetometer signals from multiple stations around the Earth. This collaboration now consists of more than 10 magnetometer stations located geologically well apart from each other. One of them, the CAPP is a newly joined station at Daejeon, South Korea and expects to start the operation of an optical magnetometer for GNOME by the end of 2017. We present initial setup and characterization of the atomic magnetometer at CAPP station.

Speaker: Dr Yun Chang Shin (Center for Axion and Precision Physics)

Slides 3)_2017_PATRAS_YUN.pdf

35 Status and commissioning of the KATRIN experiment

The goal of the KArlsruhe TRItium Neutrino experiment (KATRIN) is to investigate the neutrino mass with a sensitivity of 0.2 eV/c^2 by a high-resolution and high-statistics measurement of the end-point region of the tritium beta-spectrum. The beta-electrons start in the windowless gaseous tritium source and go into a differential and a cryogenic pumping section. These components magnetically guide the beta-electrons, while reducing the tritium flow to a negligible level. The energy of the beta-electrons is then analyzed by two electrostatic spectrometers based on the MAC-E filter technique and detected by a multi-pixel silicon semiconductor detector. At the experimental site at the Karlsruhe Institute of Technology (KIT), all major components have arrived by summer 2015 and the complete beam line has been assembled. The inauguration of the full beam line, the "FirstLight", took place in October 2016 and was followed by a FirstLight+" commissioning campaign, that finished in December 2016. This talk gives an overview of the current status of the KATRIN experiment, the recent "FirstLight+" campaign and the upcoming steps towards the first tritium measurements planned for the beginning of 2018.

Speaker: Dr Philipp Chung-On Ranitzsch (IKP, WWU Münster)

Slides 4)_Ranitzsch_Patras.pptx

Coffee break

Session 10

Convener: Dieter H. H. Hoffmann

36 Current Status of the ADMX Experiment

The Axion Dark Matter eXperiment (ADMX) is a DOE "Generation 2" direct-detection dark matter project searching for axions in the few to 10s of microeV mass range. It uses a large (100+ liter) RF cavity inserted in an 8 Tesla solenoid magnet to resonantly convert primordial axions to detectable microwave photons. Over the last decade the ADMX experiment has undergone multiple upgrades including the installation of a new, high-power, dilution refrigerator. As a result of these upgrades the ADMX experiment is now operating with unprecedented sensitivity (down to pessimistic DFSZ axion-photon couplings). Here I will present on overview of the ADMX experiment as well as present some preliminary results from our most recent data run. This work was supported by DOE Grants DOE grant DE-SC00098000, DOE grant DE-SC0011665, DE-AC52-07NA27344, DE-AC03-76SF00098, the Heising-Simons Foundation, and the Lawrence Livermore National Laboratory, Fermilab and Pacific Northwest National Laboratory LDRD programs. SQUID development was supported by DOE grant DE-AC02-05CH11231.

Speaker: Dr Gianpaolo Carosi (Lawrence Livermore National Laboratory)

Slides Patras_ADMX_Overview_May2017_Carosi_final.pdf Patras_ADMX_Overview_May2017_Carosi_final.pptx

37 ADMX Haloscope R&D

The Axion Dark Matter eXperiement (ADMX) is a direct-detection axion dark matter search which has successfully completed searches between 1.9 and 3.7 μeV down to the KSVZ photon-coupling strength limit. The current upgrades will allow ADMX to detect axions with even the most pessimistic couplings in this frequency range. In order to expand the mass reach of the Haloscope detector, ADMX is conducting extensive research and development of microwave cavity technology. Multiple prototype development programs include periodic post arrays, multi-vane cavities, in-phase coupled cavities, partitioned cavities, superconducting hybrids, and exotic waveguide-like cavies. Additional studies include techniques for mode identification and mode-mixing suppression, as well as advanced simulations and optimization. The various projects are in different phases of analysis, fabrication, and/or testing. The current status, near term objectives, projected sensitivities, and theoretical considerations will be presented. This work was supported by DOE Grants DOE grant DE-SC00098000, DOE grant DE-SC0011665, DE-AC52-07NA27344, DE-AC03-76SF00098, the Heising-Simons Foundation, and the Lawrence Livermore National Laboratory, Fermilab and Pacific Northwest National Laboratory LDRD programs. SQUID development was supported by DOE grant DE-AC02-05CH11231.

Speaker: Ian Stern (University of Florida)

Slides ADMX_Haloscope_R&D_Stern_final.pdf

38 Probing ultralight axion dark matter with gravitational-wave detectors

The ultralight axion with mass around 10^{-22} eV is a candidate of dark matter. A distinguishable feature of the ultralight axion is oscillating pressure in time, which produces an oscillation of gravitational potentials. The oscillating potentials can, in principle, be detected by gravitational-wave detectors. I will discuss the detectability of the ultralight axion dark matter through the gravitational interaction.

Speaker: Mr Arata Aoki (Kobe University)

Slides 3)_Patras_Aoki.pdf

39 The ORGAN Experiment: status of the experiment and novel resonator design

At the University of Western Australia we are commissioning a haloscope designed to probe for high mass axions (frequencies greater than 15 GHz) with an initial search focused around 26.6 GHz, in order to perform a direct test of a claimed result suggesting axions at 110 micro-eV. After this, we will move to a wider range of the axion parameter space to test predictions of many theoretical models. The experiment underwent its pathfinding run in December 2016, and is in preparation for the next stage. We discuss the design and results of the pathfinding run of the experiment, as well as the future planned stages. This will include a discussion of novel resonator design proposals based on dielectric materials such as Bragg reflectors, and other structures. These technologies will be implemented in the future stages of the ORGAN experiment, which has recently received funding to conduct a seven year axion haloscope search.

Speaker: Mr Ben McAllister (University of Western Australia)

Slides Patras2017.pdf

40 Status and perspetives of DAMA/LIBRA

The DAMA/LIBRA set-up (about 250 kg highly radiopure NaI(Tl)) is currently in data taking at the Gran Sasso National Laboratory of the I.N.F.N. in its phase2. This experiment is dedicated to the investigation of Dark Matter (DM) particles in the galactic halo mainly by exploiting the model independent Dark Matter annual modulation signature. DAMA/LIBRA collected in its first phase data over 7 annual cycles corresponding to an exposure of 1.04 ton $\times$ yr (DAMA/LIBRA--phase1). The DAMA/LIBRA--phase1 and the former DAMA/NaI data (cumulative exposure $1.33$ ton $\times$ yr, corresponding to 14 annual cycles) give evidence at 9.3 $\sigma$ C.L. for the presence of Dark Matter particles in the galactic halo on the basis of the model independent DM annual modulation signature by using highly radio-pure NaI(Tl) target. In this talk some new recent analyses performed on the released data will be presented as well as perspectives of the present phase-2. Future perspectives of the experiment will also be addressed.

Speaker: Dr Riccardo Cerulli (INFN-LNGS)

Slides 5)_Cerulli_Patras_2017.pdf

Lunch

Poster

41 A systematic effective operator analysis of semi-annihilating dark matter

Semi-annihilation is a generic feature of dark matter theories stabilized by symmetries larger than Z2. It contributes to thermal freeze out and cosmic ray signals, but is irrelevant for direct and collider searches. We use an effective operator approach to make the first model-independent study of the associated phenomenology, enumerating all semi-annihilation operators up to dimension 6, plus leading terms at dimension 7. We find that when the only light states charged under the dark symmetry are dark matter, the model space is highly constrained. If there can be additional light, unstable "dark partner" states the possible phenomenology greatly increases, at the cost of additional model dependence in the new particle decay modes. We find that for semi-annihilation to electrons and light quarks, the thermal relic cross sections can be excluded for dark matter masses up to 100 GeV, but significant model space for semi-annihilating dark matter remains.

Speaker: Dr Andrew Spray (Institute for Basic Science)

42 Axion's mass from lattice QCD

We determine the topological susceptibility and the thermodynamical equation of state for temperatures relevant for the axion production in the early Universe. We use lattice QCD with dynamical fermions. We point out several difficulties in these calculations and address them by introducing novel techniques. Assuming the standard QCD axion scenario and no topological defects we obtain a lower bound on the axion's mass. The talk summarizes the results of doi:10.1038/nature20115.

Speaker: Kalman Szabo (Forschungszentrum Juelich)

43 Chiral Primordial Gravitational Waves from the Axion-Gauge Couplings

An inflationary universe predicts vacuum fluctuations of space-time, called primordial gravitational waves, whose power spectra have tiny amplitudes and parity-symmetric features. Intriguingly, however, it is known that the axion-gauge coupling, motivated by string theory, could occur the particle production of gauge fields during inflation so that it provides the parity-violated gravitational waves testable in future gravitational wave experiments. In this talk, we suggest a new mechanism of providing chiralities of gravitational waves sourced by the axion-gauge couplings from string theory. The gravitational waves predicted by our model could be observable by future space-based interferometers such as BBO and DECIGO experiments.

Speaker: Mr Ippei Obata (Department of Physics, Kyoto University)

44 Dark-Sector Photo-Magnetic Coupling Studies

We report the results of studies showing that temperature dependent photo-luminescence is the likely source of unexpected large background rates in afterglow searches for dark sector phenomena. Using this information, we examine the possibility of a room temperature afterglow search that automatically eliminates this background. Finally, without this background, we discuss a modest search effort that would explore the chameleon afterglow half-life range: 0.1 ≤ T1/2 ≤ 200 second, corresponding to the photon coupling constant range: ~3×10^13 ≤ βγ ≤ ~3×10^14.

Speaker: Dr James "Jim" Boyce (The College of William & Mary and Jefferson Lab)

45 Frequency tuning system and RF receiver setup of CULTASK experiment

CAPP at IBS has started an experiment for searching for axions, employing a method suggested by P. Sikivie. I will present the current set up of CAPP’s axion detector, which includes cryogenics with 3He/4He dilution refrigerator that could cool down cavities to 30mK, development of a high Q-factor pure metal cavity with a sapphire tuning rod driven by piezoelectric frequency tuning system, and a complete RF receiver chain with low noise amplifiers. I will also present the recent test of quantum-limited amplifiers at CAPP.

Speaker: Mr Doyu Lee (IBS/CAPP, KAIST)

46 Impact of axions on the minimum mass of Core Collapse Supernova progenitors

In this project we include axions on stellar evolution models, adopting the current stringest constraints for their coupling to photons and electrons. We obtain that the minimum stellar mass of Core Collapse Supernova (CCSN) progenitors is shifted up by nearly 2 Mo. Although theoretical and observational uncertainties do not allow us to impose reliable constraints to axions properties based on this result, it may be in tension with the observed minimum mass of CCSNe progenitors.

Speaker: Prof. Inma Dominguez (Universidad de Granada)

47 Magnetoresistance in copper at high frequency in high magnetic field

In halo dark matter axion search experiments, microwave cavities are employed to detect signal from the axion-photon conversion. To enhance the conversion power and reduce the noise level, cavities are typically placed in strong magnetic fields at sufficiently low temperatures, respectively. Axion mass is allowed in a broad range (1 ueV ~1 meV), whereas current cavity-based experiments are designed to explore relatively low mass regions. As search for higher mass axions requires higher frequency microwave cavities, understanding cavity properties at high frequencies in extreme conditions is deemed necessary. In this poster, we present a study of the magnetoresistance of copper using a cavity with a resonant frequency of 12.9 GHz in magnetic fields up to 15 T at the liquid helium temperature, 4.2 K.

Speaker: Mr Saebyeok Ahn (Korea Advanced Institute of Science and Technology (KAIST), Center for Axion and Precision Physics research (CAPP), Institute for Basic Science (IBS))

48 Measurement of $^{144}\rm{Pr}$ beta-spectrum with Si(Li) detectors for the purpose of determining the spectrum of electron antineutrinos.

Measurements of the beta spectra of $^{144}\rm{Ce}$ and $^{144}\rm{Pr}$ are necessary for the successful implementation of a search for neutrino oscillations in a sterile state with artificial antineutrino source $^{144}\rm{Pr}$. The $^{144}\rm{Ce}-^{144}\rm{Pr}$ target with a thickness of about 1 $\mu\rm{g~cm^{-2}}$ is deposited on the Mylar substrate and is covered with 200 Å of palladium. The $^{207}\rm{Bi}$ and $^{144}\rm{Ce}-^{144}\rm{Pr}$ sources are located 14 mm from the Si(Li)-detector with a diameter of 16 mm and a thickness of 7 mm. The performed measurements allow to establish the response function of Si(Li) detector and to determine the concentration of $\alpha$-, $\beta$- and $\gamma$-active impurities in the target.

Speaker: Prof. Alexander Derbin (Petersburg Nuclear Physics Institute)

49 Microwave Resonator R&D in Support of the HAYSTAC Experiment

The axion is a leading cold dark matter (CDM) candidate and may be detected by its resonant conversion to a monochromatic RF signal in a tunable microwave cavity permeated by a strong magnetic field. The Haloscope At Yale Sensitive To Axion CDM (HAYSTAC) experiment is both a test bed for innovative cavity and amplifier concepts and a data pathfinder for the 5-25 GHz range. This poster will highlight several innovations that help resolve the challenges posed by microwave cavities in the 5-25 GHz range. These include using distributed Bragg reflectors to maximize the Figure-of-Merit QC^2 in higher-harmonic cavity modes and employing photonic band gap resonators or slotted cavities to eliminate the forest of TE modes, particularly problematic in higher-harmonic mode operation at high frequencies. This work was supported by NSF Grants PHY-1306729 and PHY-1362305, and Heising-Simons Foundation Grant 2014-182. M. Simanovskaia is supported by the NSF Graduate Research Fellowship Grant DGE-1106400 and the Berkeley Fellowship.

Speaker: Ms Maria Simanovskaia (UC Berkeley)

50 Recent results and future plans for the MAJORANA DEMONSTRATOR

The MAJORANA DEMONSTRATOR (MJD) is a 44-kg array of low-background germanium detectors of which 30kg is made from detectors enriched to 88% in 76Ge. MJD is operating a mile underground in the Sanford Underground Research Laboratory in Lead, SD. Its main purpose is to search for the neutrinoless double-beta decay of 76Ge and to demonstrate the technical feasibility of a tonne-scale Ge-based neutrinoless double-beta decay experiment. It is also capable of direct searches of a variety of dark matter candidates and other physics beyond the Standard Model. In this talk I will review the motivation, design and construction of the MJD, as well as recently published results for a the search for bosonic dark matter using commissioning data taken in 2015. I will also discuss the current status of MJD and conclude with a discussion of future plans for MJD and a proposed tonne-scale Ge-based experiment, LEGeND.

Speaker: Prof. Reyco Henning (University of North Carolina at Chapel Hill)

51 Search for solar axions using resonant absorption by 83Kr nuclei

A search for resonant absorption of the solar axion by $^{83}\rm{Kr}$ nuclei is continued with the krypton proportional counter at the Baksan Neutrino Observatory. Such an absorption should lead to the excitation of low-lying nuclear energy level of $^{83}\rm{Kr}$: $A + ^{83}\rm{Kr} \rightarrow ^{83}\rm{Kr}^* \rightarrow ^{83}\rm{Kr} + \gamma~ \rm{(8.41 keV)}$. The obtained model independent upper limit on the combination of isoscalar and isovector axion-nucleon couplings $|g_3 - g_0|\leq 8.4\times 10^{-7}$ leads to a new upper limit on the hadronic (KSVZ) axion mass of $m_{A}\leq 65$ eV (95\% C.L.) with the generally accepted values $S$=0.5 and $z$=0.56. The resonant absorption of the Primakoff solar axions leads to constraint on the axion–photon coupling and axion mass $g_{A\gamma}\times m_A \leq 6.3\times 10^{-17}$ that corresponds to the upper limit on KSVZ axion mass $m_{A}\leq 14.3$ eV. For solar axions produced by Compton and bremsstrahlung like processes the limit on axion-electron coupling and KSVZ axion mass are $g_{Ae}\times m_A \leq 1.8\times 10^{-9}$~eV and $m_A\leq 98$ eV, correspondingly (all at 95\% C.L.).

Speakers: Prof. Alexander Derbin (Petersburg Nuclear Physics Institute), Dr Valentina Muratova (Petersburg Nuclear Physics Institute)

52 Substructure of fuzzy dark matter halos and constraints from gravitational lensing

Using the semi-analytic GALACTICUS code modified for fuzzy dark matter (FDM), we study the statistics of halo substructure in the FDM model. We find that compared to cold dark matter, FDM halos have much less substructure. The compact cores in the center of subhalos are stable with regard to classical tidal stripping, leading to a peak in the subhalo mass function (SHMF) at roughly the mass of the cores. Including mass loss of the core due to quantum tidal stripping, the peak in the SHMF becomes less significant. For higher FDM particle masses the peak is still visible. Based on the semi-analytic realizations of FDM halos, we then compute the lensing power spectrum of substructure. With upcoming ALMA measurements this could potentially put a tight constraint on the mass of FDM particles.

Speaker: Xiaolong Du (University of Goettingen)

Session 7

Convener: Prof. Yannis Semertzidis (CAPP/IBS and KAIST)

53 CUORE and axions

Speaker: Prof. Frank Avignone (University of South Carolina)

Slides 1a)_Patras_13.pptx 1b)_Patras_13.pptx.pdf

54 Axion Detection with Cavity Arrays

We demonstrate that a cavity built of an array of elementary harmonic oscillators with negative mutual couplings exhibits a dispersion curve with lower order modes corresponding to higher frequencies. Such cavity arrays help to achieve infinitely large mode volumes with high resonant frequencies, where the mode volume for the composed array scales proportional to the number of elements, but the frequency remains constant. This gives an advantage over simultaneous averaging over the same number of independent cavities (giving the same scaling law), as the proposed approach requires only one measurement system. The negatively coupled cavity array may be realised by magnetically coupling coils, where the sign of next-neighbour coupling (set by chirality of adjacent elements) sets the dispersion curve properties of the resonator array medium. The principle is demonstrated by determining the dispersion relation for a one dimensional array of coils, configured as re-entrant cavity resonators. We will also discuss cavity arrays employing some features of left handed metamaterials and how these features may boost axion sensitivity. The presentation is based on arXiv:1703.07207

Speaker: Dr Maxim Goryachev (University of Western Australia)

Slides 2)_maxim_goryachev.pdf

55 A Radio Astronomy Search for Cold Dark Matter Axions

The search for axions has gained ground in recent years, with laboratory searches for cold dark matter (CDM) axions, relativistic solar axions and ultra-light axions the subject of extensive literature. In particular, the interest in axions as a CDM candidate has been motivated by its potential to account for all of the inferred value of $\Omega_{DM} \sim 0.26$ in the standard $\Lambda CDM$ model. Indeed, the value of $\Omega_{DM} \sim 0.26$ could be set by a universal value of the CDM axion mass. We investigate the possibility of complementing existing axion search experiments with radio telescope observations in an attempt to detect axion conversion in astrophysical magnetic fields. Searching for a CDM axion signal from a large-scale astrophysical environment provides new challenges, with the magnetic field structure playing a crucial role in both the rate of interaction and the properties of the emitted photon. However, with a predicted frequency in the radio band (200MHz - 200GHz) and a distinguishable spectral profile, next generation radio telescopes may offer new opportunities for detection. If we consider observations at $\sim 500$MHz using the planned SKA1-mid telescopes, the limiting sensitivity is expected to be $\sim 0.04$mK. This compares with a signal temperature of $\sim 0.005$mK using SKA Phase 1 telescopes and up to $\sim 0.2$mK using a collecting area of (1km)$^2$ as planned for Phase 2.

Speaker: Ms Katharine Kelley (ICRAR-UWA)

Slides Patras_17_May.pptx

Coffee break

Session 8

Convener: Prof. Marc Schumann (Univertity of Freiburg)

56 Search for low-mass dark matter with the CRESST experiment

CRESST is a multi-stage experiment directly searching for dark matter (DM) using cryogenic $\mathrm{CaWO_4}$ crystals. Previous stages established leading limits for the spin-independent DM-nucleon cross section down to DM-particle masses below $1\,\mathrm{GeV/c^2}$. Furthermore, CRESST performed a dedicated search for dark photons (DP) which excludes new parameter space between DP masses of $300\,\mathrm{eV/c^2}$ to $700\,\mathrm{eV/c^2}$. In this contribution we will discuss the latest results based on the previous CRESST-II phase 2 and we will report on the status of the current CRESST-III phase 1: in this stage we have been operating 10 upgraded detectors with $25\,\mathrm{g}$ target mass each and enhanced detector performance since summer 2016. The improved detector design in terms of background suppression and reduction of the detection threshold will be discussed with respect to the previous stage. We will conclude with an outlook on the potential of the next stage, CRESST-III phase 2.

Speaker: Dr Holger Kluck (Institute of High Energy Physics (HEPHY))

Slides 1)_2017-05-16_Patras_LowMassDMwithCresst_Kluck.pdf

57 The halo-independent approach as a moment problem: profile likelihoods with a continuum of nuisance parameters

Halo-independent methods in the analysis of WIMP detection data have up to now provided separate constraints for specific integrals of the WIMP velocity distribution, and have assumed separate velocity distributions for the modulated and unmodulated rates. This has hindered the statistical interpretation of the results and has restricted the analysis to the comparison of experiments. I have recast the halo-independent approach as a moment problem, thus obtaining a proper statistical interpretation, including a profile likelihood with a continuum of nuisance parameters. This has extended the scope of the method to questions beyond the mere comparison of experiments. As a first example of the new method, I show a halo-independent estimate of the unmodulated signal corresponding to the DAMA annual modulation, including proper confidence levels, for spin-independent interactions under the assumption of a velocity distribution that is isotropic in the galactic reference frame.

Speaker: Prof. Gondolo Paolo (University of Utah)

Slides 2017e-Thessaloniki.pdf

58 Searching for weakly-coupled, long-lived particles with NA62

Fixed target experiments are a particularly useful tool in the search of very weakly coupled particles in the MeV-GeV range, which are of interest, e.g. as Dark Matter mediators. The NA62 experiment at the CERN SPS is currently taking data to measure the rare decay K->pi \nu \bar{\nu}. Owing to the high beam-energy and a hermetic detector coverage, NA62 also has the opportunity to directly search for a plethora of long-lived beyond-the Standard Model particles. We will detail on status and prospects of these searches

Speaker: Babette Döbrich (CERN)

Slides bd_PATRAS_2017.pdf

59 Searching for Axion Like Particles using Spin Polarized Noble Gases and Other Methods

Exotic spin dependent interactions can be meditated by ALPs(Axion Like Particle). Not only ALPs are possible candidates for dark matter, but also they might provide the most promising solution to the strong CP problem. Furthermore, recently, various models of new physics beyond the standard model have been studies in which new massive particles such as axion, familon, and majoron, etc. were theoretically introduced. Many of these exotic new interactions are spin dependent. For these interactions to be detected, the source or the probe particles have to be spin polarized. Spin polarized neutron beam, atom beam or noble gases are good probes to detect these new interactions. We used spin rotation of polarized neutrons in liquid Helium to search for spin-velocity dependent new interactions[1]. The new upper bound we obtained is more than 7 orders of magnitude more stringent than the existing laboratory constraints for interaction ranges below 1 m. We proposed to use $^3$He atom beams to search for three types of new interactions[2]. Using the atom beam method, sensitivities on three different types of spin dependent interactions could be improved by as much as $10^2$ to $10^8$ over the current experiments at the millimeter range. We Searched for New Spin- and Velocity-Dependent Interactions by spin relaxation of polarized $^3$He Gas[3]. Using the best available measured $T_2$ of polarized $^3$He gas atoms as the polarized source and the Earth as an unpolarized source, we obtain constraints on two new interactions. We present a new experimental upper bound on possible vector–axial-vector (VVA) type interactions for ranges between 1 and $10^8$ m.\\ \textbf{References}\\ 1.{H.Yan},M.W.Snow,A New Limit on Possible Long-Range Parity-odd Interactions of the Neutron from NeutronSpin Rotation in Liquid $^{4}He$, \textbf{Physical Review Letters},\textbf{110},082003(2013). 2.H. Yan, G. A. Sun, J. Gong, B. B. Pang, Y. Wang, Y. W. Yang, J. Zhang, Y. Zhang, Probing the short range spin dependent interactions by polarized $^{3}He$ atom beams, \textbf{European Physical Journal C}, 10/2014; 74(10). 3.{H.Yan},G.A.Sun,S.M.Peng,Y.Zhang,C.Fu, H.Guo, B.Q.Liu, Searching for New Spin- and Velocity-Dependent Interactions by Spin Relaxation of Polarized 3He Gas , {\bf Physical Review Letters},115,182001(2015).

Speaker: Haiyang Yan (China Academy of Engineering Physics)

Slides 3He_patras.pdf 3He_patras.pptx

60 Searches for Axion-Like Particles with NGC1275: Current and Future Bounds

Axion-like particles (ALPs) can induce localised oscillatory modulations in the spectra of photon sources passing through astrophysical magnetic fields. Ultra-deep \emph{Chandra} observations of the Perseus cluster contain over $5 \times 10^5$ counts from the central NGC1275 AGN, and represent an extraordinary dataset for ALP searches. In this talk I will describe how we used these to search for spectral irregularities from the AGN. No irregularities were found at the ~30% level, allowing us to place leading constraints on the ALP-photon mixing parameter $g_{a\gamma\gamma} \simeq 1.5 - 3.5 \times 10^{-12} {\rm GeV}^{-1}$ for $m_a \lesssim 10^{-12} {\rm eV}$, depending on the magnetic field realisation along the line of sight. I also discuss prospects for improving these bounds, with the ATHENA X-ray Observatory, due for launch in 2028.

Speaker: Mr Nicholas Jennings (University of Oxford)

Slides 5)_Patras_Talk_Jennings.pptx

Thursday 18 May

Session 11

Convener: Bernard Sadoulet

61 ATLAS / LHC

Speaker: Prof. Iain Bertram (Lancaster University)

Slides Patras_DM_IainBertram_2017_Final.pdf

62 XENON

Speaker: E. Aprile

Slides Aprile_Patras.pdf

63 Probing a new WISP model with laboratory experiments

Existing experiments looking for Axion (like-particles) and Hidden Photons are in the stage of major updates, and many other new proposals are also foreseen to start in the near future. The sensitivity will increase significantly and therefore, seems timely to put under the microscope more complex models than the usual one new particle picture (ALP-photon or HP-Photon). We work on a model with a coupling between HP and ALP and a kinetic mixing between HP and photons. This model was firstly introduced to naturally accommodate the puzzling observation of a 3.55 keV line seen in several cluster of galaxies. We obtain oscillation probabilities between the three particles in vacuum and analyse the sensitivity to the model of optical precision experiments such as LSW and vacuum polarisation.

Speaker: Dr Paola Arias (Universidad de Santiago de Chile)

Slides Arias.pdf

Coffee break

Session 12

Convener: Frank Avignone

64 Latest Developments of the CAST-CAPP/IBS Detector Project at CERN

Lino Miceli Presenting for the CAST Collaboration and external collaborators In 2016, the CAST-CAPP/IBS Detector, a joint effort between the CERN Axion Solar Telescope (CAST) collaboration [1] and the Center for Axion and Precision Physics Research (CAPP/IBS) [2], demonstrated for the first time that a cold DM axion search with the haloscope [3] technique is feasible in a large dipole magnet. The project is now moving towards the installation and operation of multiple rectangular cavities inside one of the bores of the CAST magnet, with the goal of reaching significant sensitivity at an axion mass of ~ 23 eV. Progress towards this new phase of the project will be reported. [1] CAST Collaboration, K. Zioutas et al., Phy. Rev. Lett. 94 (2005) 121301. [2] http://capp.ibs.re.kr/html/capp_en/ [3] P. Sikivie, Phys. Rev. Lett. 51, 1415 (1983).

Speaker: Dr Lino Miceli (IBS Center for Axion and Precision Physics)

Slides 1a)_2017-05-18_PATRAS-XIII__LMiceli.pptx 1b)_2017-05-18_PATRAS-XIII__LMiceli.pdf

65 The CAST Experiment: Status report

The CAST (Cern Axion Solar Telescope) experiment has been looking at the Sun for more than a decade now in its quest of observing a signal coming from the conversion of the axions in the telescope's magnetic field. Such a signal has not been observed thus allowing the collaboration to set only an upper limit to the axion - photon coupling constant in the parameter space. The final results will be presented as well as a new set of detectors that are looking into the dark sector. The new detectors, currently in operation, are KWISP which is directly sensitive to the chameleon coupling to matter, INGRID which is probing the chameleon coupling to photons and CAST - CAPP that is looking for dark matter axions. Also an additional dark matter axion detector, the RADES system, will be installed this year. While the search of axions is now limited to ones that are constituents of the galactic halo, the experiment continues to look at the Sun in an effort to see a signal of solar chameleons which are created in the Sun's tachocline via Primakoff effect and are particle candidate constituents of the dark energy in the Universe.

Speaker: Dr Marin Karuza (university of Rijeka)

Slides 2)_patras_mk_2017.pdf

66 DEAP-3600

Speaker: Thomas McElroy

Slides ThomasMcElroy_Patras17.pdf

67 GeV galactic center excess

Speaker: Nils Håkansson

Slides 4)_PATRAS.pdf

68 Search for axions in streaming dark matter

Streaming axion DM may be the better source for their discovery than the isotropic DM. Because, a large flux enhancement can take place, temporally, due to gravitational lensing when the Sun and/or a planet are aligned with the stream. Of interest are axion miniclusters, in particular, if the solar system has trapped one during its formation. Wide-band axion antennae fit this concept, but also the proposed fast narrow band scanning. A network of detectors can provide full time coverage (and large axion mass acceptance). Other DM searches may profit from this proposal.

Speaker: Dr Antonios Gardikiotis (University of Patras)

Slides 5a)_Search_for_streaming_DM_axions_or_other_exotica2.pptx 5b)_Search_for_streaming_DM_axions_or_other_exotica.pdf

69 Multiple-cell cavity for axion dark matter search

In axion dark matter searches using microwave cavity detectors, multiple-cavity design is typically considered to make an optimal use of a given magnet volume to explore higher frequency regions. We introduce a new idea, referred to as multiple-cell cavity, which provides various benefits including larger volume usage, simpler experimental setup, and easier phase-matching mechanism. In this talk, the conceptual design of this new idea and experimental feasibility using a double-cell cavity are presented.

Speaker: SungWoo YOUN (CAPP/IBS)

Slides Patras2017_YOUN.pptx

Lunch

Session 13

Convener: Wolfgang Funk

70 ShiP proposal

Speaker: Eric van Herwijnen

Slides Patras_EVH_2017.pdf Patras_EVH_2017.pptx

71 IAXO

Speaker: Dr Igor Irastorza (Universidad de Zaragoza)

Slides 2)_Irastorza_IAXO_.pptx

72 Dark Matter Results from First Data of the PandaX-II Experiment

The Particle and astrophysical Xenon (PandaX) project is a series of xenon-based ultra-low background experiments in the China JinPing underground Laboratory (CJPL) targeting the unknown physics of dark matter and neutrinos. The first and second stage experiments (PandaX-I and II) both utilize dual-phase xenon time projection chamber (TPC) to carry out direct search for the dark matter particles. PandaX-II, a half-ton scale experiment, is currently under operation, and produced leading limits on dark matter-nucleon spin independent and spin dependent scattering cross sections in 2016. In this talk, I shall present an overview of the PandaX project and the results from the first data of the PandaX-II experiment.

Speaker: Mr Andi Tan (University of Maryland, College Park, USA)

Slides Patras2017_Andy.pdf

73 Search for the Dark Photon with the PADME experiment at LNF

Massive photon-like particles are predicted in many extensions of the Standard Model with a hidden sector where dark matter is secluded. They are vector bosons mediating the interaction between dark matter particles and can be produced in scattering of ordinary particles through a faint mixing to the photon. Most of the present experimental constraints on this “dark photon” (A’) rely on the hypothesis of dominant decays to lepton pairs. The PADME experiment will search for the e+e−→γA’ process in a positron-on-target experiment, assuming a decay of the A’ into invisible particles of the hidden sector. The positron beam of the DAΦNE Beam-Test Facility, at Laboratori Nazionali di Frascati of INFN, will be used. A fine-grained, high-resolution calorimeter will measure the momentum of the photon in events with no other activity in the detector, thus allowing to measure the A’ mass as the missing mass in the final state. In about one year of data taking, a sensitivity on the interaction strength (ε^2 parameter) down to 10^{−6} is achievable in the mass region M_{A’}<23.7 MeV. The experiment is currently under construction and it is planned to take data in 2018. The status of PADME and its physics potential will be reviewed.

Speaker: Dr Viviana Scherini (INFN Lecce)

Slides 4)_scherini_patras17_e.pdf

74 Axion dark matter detection by laser spectroscopy of ultracold paramagnetic crystals

Dark matter axions may induce transitions between Zeeman states in an atomic paramagnetic system as proposed by Sikivie. The Axioma R&D experiment is looking for a possible approach to look at axion-driven atomic transitions to be detected by resonance- enhanced multi-photon ionization spectroscopy or through up conversion mechanism. Two main lines are under evaluation : 1) Rare Earth Up-Conversion scheme in a crystal. A detector is made by a rare earth doped crystals. A ground state electron of the rare earth is promoted into a Zeeman excited level by the axion. A tunable laser can subsequently transport the electron to an higher state from where a fluorescence signal can be produced and detected with high efficiency. 2) Solid Matrix Spectroscopy and Electron Evaporation Guest Alcaline Atoms are embedded in a Neon, Methane or Para Hydrogen solid matrix. Valence electron level are splitted into Zeeman state of which only the lower one is populated. By axion interaction also the upper level can be populated: by using a properly tuned laser these electrons are brought to the Vacuum level of the Solid Matrix Conduction Band. These free electrons can then be extracted into vacuum and afterward detected by using an high efficiency micro channel plate. Some preliminary results for both schemes will be presented. ( For the AXIOMA collaboration)

Speaker: Prof. giovanni carugno (Padova University &amp; INFN)

Slides 5)_Patras18May2017.pdf

75 Towards a medium-scale axion helioscope: the physics case and a proposal in Troitsk

I discuss the physics case for a medium-scale axion helioscope with sensitivities in the axion-photon coupling a few times better than CAST. Search for an axion-like particle with these couplings is motivated by several persistent astrophysical anomalies. Then I report on the project of such a helioscope to be constructed in INR, Troitsk, Russia. On behalf of pre-collaboration, I discuss early conceptual design, existing infrastructure, projected sensitivity and timeline of this experiment.

Speaker: Prof. Sergey Troitsky (INR, Moscow)

Slides ST-Patras2017.pdf

Coffee break

Session 14

Convener: Prof. Jonghee Yoo (KAIST/IBS)

76 A background-free search for the neutrinoless double beta decay with GERDA

Speaker: Laura Baudis

Slides baudis_gerda_may17.key baudis_gerda_may17.pdf

77 String core effect on the axion dark matter abundance

The axion is a hypothetical particle arising from the spontaneous breaking of a global Peccei-Quinn (PQ) symmetry, which has been introduced to solve the strong CP problem of quantum chromodynamics. Due to the weakness of the coupling with ordinary matters, it is also regarded as a good candidate of dark matter of the universe. However, the estimation of the axion dark matter abundance is not so straightforward if the PQ symmetry is restored and broken after inflation, since in this case we have to analyze the production from the decay of hybrid networks of topological defects called the string-wall systems. In this talk, I will focus on some recent developments of the theoretical estimation of the axion dark matter abundance in the post-inflationary PQ symmetry breaking scenario. In particular, I will highlight a problem of the string core effect, which was overlooked in previous studies and may have a potentially large impact on the estimate of the relic axion dark matter abundance.

Speaker: Ken'ichi Saikawa (DESY)

Slides 2)PATRAS2017_saikawa.pdf

78 Search for axion dark matter with ultracold neutrons

Axion-like particles (ALPs) are good candidates for cold dark matter. They would form a galactic-scale classical field, which on local scales undergoes coherent oscillations. Through their coupling to gluons these particles would induce oscillating electric dipole moments (EDMs) in nucleons and atoms [1,2]. We analyse data of two neutron EDM experiments: ILL, Grenoble, France (1998-2002) and PSI, Villigen, Switzerland (2015-16), explicitly looking for an oscillating neutron EDM signal [3,4]. Our analysis is the first direct laboratory search for the ALP-gluon coupling, with improved sensitivity over indirect bounds from BBN and supernovae observations. Our search also covers the cosmologically interesting range of dark matter particle masses 1e-24 eV < m < 1e-20 eV, which can resolve several long-standing “small-scale crises” of the cold DM model [5]. [1] P. W. Graham, S. Rajendran, Phys. Rev. D 84, 055013 (2011). [2] Y. V. Stadnik, V. V. Flambaum, Phys. Rev. D 89, 043522 (2014). [3] N. Ayres, PhD thesis, University of Sussex, in preparation. [4] M. Rawlik, PhD thesis, ETH Zürich, in preparation. [5] D. J. E. Marsh, Phys. Rept. 643, 1 (2016).

Speaker: Mr M. Rawlik (ETH Zürich, Institute for Particle Physics, CH-8093 Zürich, Switzerland, On behalf of the nEDM collaboration at PSI)

Slides Michał_Rawlik_-_Search_for_axion_dark_matter_with_ultracold_neutrons.pdf

79 Status of the COSINE-100 experiment

Presently a number of experiments are operating to search for the WIMP, a dark matter candidate. Among these experiments, DAMA/LIBRA claims to observe an annually modulated WIMP signal, while other experiments, using different technologies and target materials, exclude the DAMA/LIBRA signal region in the parameter space. The COSINE experiment aims at exploring these contradicting results by using NaI(Tl), the same target material as DAMA/LIBRA. The first phase detector with 106 kg of NaI(Tl), COSINE-100, was installed at the Yangyang underground laboratory in Korea. It consists of several shield structures, including a liquid scintillator veto system. The experiment has started physics data taking in late September 2016 and has been operating stably since then. The details and the current status of the COSINE-100 experiment will be presented.

Speaker: Kyungwon Kim (Institute for Basic Science (CUP))

Slides status_of_the_cosine100_experiment.pdf

80 aKWISP: investigating short-distance interactions at sub-micron scales

The sub-micron range in the field of short distance interactions has yet to be opened to experimental investigation, and may well hold the key to understanding al least part of the dark matter puzzle. The aKWISP (advanced-KWISP) project introduces the novel Double Membrane Interaction Monitor (DMIM), a combined source-sensing device where interaction distances can be as short as 100 nm or even 10 nm, much below the ≈10-30 micron distance which is the lower limit encountered by current experimental efforts. aKWISP builds on the technology and the results obtained with the KWISP opto-mechanical force sensor now searching at CAST for the direct coupling to matter of solar chameleons. It will reach the ultimate quantum-limited sensitivity by exploiting an array of technologies, including operation at sub-Kelvin temperatures. Recent suggestions point at short-distance interactions studies as intriguing possibilities for the detection of axions and of new physical phenomena.

Speaker: Prof. Giovanni Cantatore (University and INFN Trieste - CERN)

Slides GC_aKWISP_Patras2017.pdf

81 Single Photon Detection for ALPS

The Axion-like particle search (ALPS) experiment at DESY plans to use a heterodyne detection scheme to detect the regenerated light field. The scheme takes advantage of the coherence between the original laser field and the regenerated laser field and is currently being developed at the University of Floria. I will discuss the current status of the experiments in Florida and how we plan to implement it in ALPS.

Speaker: Prof. Guido Mueller (University of Florida)

Slides GuidoMueller_TH_6pm.pdf

82 WIMP/axion astronomy in dark matter experiments

Terrestrial dark matter detection experiments are crucially dependent on an understanding of the phase space structure of the local Milky Way halo. As such, the uncertainties in the astrophysical ingredients to predictions for dark matter signals feed directly into all experimental results. The bright side however is that our experiments are in a unique position to study this same astrophysical dependence, and in fact represent the only way to probe the local Milky Way halo on sub-milliparsec scales. I will talk about how to do this in the context of two particular novel search strategies: directional detectors in the case of WIMPs, and microwave cavity haloscopes in the case of axions.

Speaker: Mr Ciaran O'Hare (University of Nottingham)

Slides OHare_axionswimps.pdf

Conference dinner

Friday 19 May

Session 15

Convener: Andreas Ringwald (DESY)

83 Dark Matter absorption in condensed matter

Speaker: Tien-Tien Yu

Slides PATRAS_absorption_May2017_(1).pdf

84 CERN woeking group "physic beyond colliders"

Speaker: Claude Vallee

Slides Vallee_PBC.pdf

85 US Cosmic Visions

Speaker: Prof. Gray Rybka (University of Washington)

Slides rybka_patras_visions_overview.pdf

86 MADMAX: MAgnetised Disk-and-Mirror Axion eXperiment

The Axion is a hypothetical low-mass boson predicted by the Peccei-Quinn mechanism solving the strong CP problem. It is naturally also a cold dark matter candidate, thus, simultaneously solving two major problems of nature. All existing experimental efforts to detect QCD axions focus on a range of axion masses below 20 ueV. The mass range above ~40ueV, preferred by models in which the Peccei-Quinn symmetry was restored after inflation, could not to be explored so far. The MADMAX project is designed to be sensitive for axions with masses 40ueV – 400 ueV. The experimental design is based on the idea of enhanced axion photon conversion in a system with several layers with alternating dielectric constants. The experimental idea and the proposed design of the MADMAX experiment will be discussed. First results from measurements with a prototype dielectric haloscope will be discussed. The prospects for reaching sensitivity enough to cover the parameter space predicted for QCD dark matter axions with mass in the range 40-400 ueV will be presented.

Speaker: Stefan Knirck

Slides 2017-05-19_madmax_patras.pdf

87 Spectral hardening of cosmic TeV photons in realistic extragalactic magnetic fields

Large-scale extragalactic magnetic fields may induce conversions between very-high-energy photons and axion-like particles (ALPs), thereby shielding the photons from absorption on the extragalactic background light. We consider realistic models of extragalactic magnetic fields obtained from large-scale cosmological simulations. Such simulated magnetic fields would have large enhancement in the filaments of matter. As a result, photon-ALP conversions would produce a significant spectral hardening for cosmic TeV photons respect to the simplified "cell" models previously considered in literature.

Speaker: Dr Daniele Montanino (University of Salento & INFN, Lecce)

Slides Montanino_D.pdf

Coffee break

Session 16

Convener: Giovanni Cantatore (University of Trieste)

88 The Case for Preserving Our Knowledge and Data in Physics Experiments

Data from Particle Physics experiments are collected with significant financial and human effort and are mostly unique. Experiment data are maintained by personal effort of scientists until they are judged no longer worth that effort. The tools and knowledge to interpret the data are lost as the members of the experiment move on to other projects. When later discoveries or new hypotheses for beyond-the-Standard-Model Physics renew interest in this forgotten data, theorists resort to recasting previously published results. Often this requires either extrapolations and assumptions or the need to be overly conservative in the possible interpretations because the original data or input needed to understand the data have been lost. This imposes limits on the scientific reach of our data. This is particularly worrisome as new physics is suspected in an increasing number of possible directions. During this presentation I will describe my two year experience working with the collaboration for Data Preservation for High Energy Physics (cern.ch/dphep). I will show that it is cost-efficient to warehouse data from completed experiments on tape archives of our national and international laboratories. These subject specific data stores also offer the technologies to capture and archive knowledge about the experiment in the form of technical notes, electronic logs, websites, etc. The computer centres of our laboratories also provide the infrastructure to archive our source code and computing environments through virtualization and container technology. In my presentation I will cover tools and technologies at our disposal for scientific data preservation, I will show that it is a cost-effective way of extending the scientific reach of our experiments, and I will relay my experiences and cover best practices in preserving data for the long term.

Speaker: Frank Berghaus (University of Victoria)

Slides digital_preservation.pdf

89 Toward Self-Interaction Constraints With a New Sample of Merging Galaxy Clusters

Merging galaxy clusters can potentially constrain SIDM models in multiple ways, with systematics complementary to those of other astrophysical probes. I will give an overview of Merging Cluster Collaboration activities to drive down the upper limit from merging clusters: new ways of discovering and selecting merging clusters; a weak lensing and spectroscopic survey of a substantial sample of merging clusters; and dynamical modeling to determine the merger phase. I will assess the potential for improved constraints with these techniques and place our work in context with other work in the field.

Speaker: David Wittman (UC Davis)

Slides mergers.pdf

90 Evidence of vacuum birefringence from the polarisation of the optical emission of an Isolated Neutron Star

RX J1856.5-3754 is a radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through its purely thermal surface emission. Owing to its large inferred magnetic field of ∼1013 G, radiation from its surface is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission. A large observed polarisation degree is, however, expected only if quantum-electrodynamics (QED) polarisation effects are present in the magnetised vacuum around the star. In this talk, I will report on the measurement of optical linear polarisation for RX J1856.5-3754 (V∼25.5) with the Very Large Telescope. We measured a polarisation degree P.D.=16.43%±5.26%, large enough to support the presence of vacuum birefringence, as predicted by QED.

Speaker: Prof. roberto mignani (INAF/IASF)

Slides eso1641a.mpg mignani.pptx

91 DARWIN

Speaker: Prof. Marc Schumann (Univertity of Freiburg)

Slides patras_schumann.pdf

92 Searching for the QCD Axion with Gravitational Microlensing

The phase transition responsible for axion dark matter production can create large amplitude isocurvature perturbations which collapse into dense objects known as axion miniclusters. We use microlensing data from the EROS survey, and from recent observations with the Subaru Hyper Suprime Cam to place constraints on the minicluster scenario.

Speaker: Malcolm Fairbairn (King's College London)

Slides patras17fairbairn.pdf

93 Axion Global Fits in GAMBIT

In the past years, the landscape of axion models has extended considerably beyond the original QCD axion. Axion-like particles could play a significant role in astrophysics as well as cosmology and many new experiments and observables have been proposed. The big landscape of axion models and observables generally poses a problem for obtaining coherent statistical inferences. The same holds true for a consistent treatment of the various experimental results and astrophysical observables such as cooling hints. Global fits offer a solution for this dilemma. I will show how the upcoming, publically available software GAMBIT will provide an excellent opportunity for studying and comparing axion models.

Speaker: Mr Sebastian Hoof (Imperial College London)

Slides SH_AxionWIMP17.pdf

Sandwiches