### Conveners

#### Parallel Session: Cosmology & Astroparticle Physics

- Kai Schmidt-Hoberg ()

#### Parallel Session: Cosmology & Astroparticle Physics

- Mathias Garny ()

#### Parallel Session: Cosmology & Astroparticle Physics

- Thomas Konstandin ()

#### Parallel Session: Cosmology & Astroparticle Physics

- Alexander Westphal ()

Dr
Alexander Merle
(Max-Planck-Institut für Physik)

9/28/16, 2:00 PM

Cosmology & Astroparticle Physics

In the absence of a clear WIMP signal, we should think about alternative candidates for Dark Matter. A very well motivated example is a (up to now hypothetical) sterile neutrino with a mass of a few keV. In this talk, I will give an overview over the topic of keV sterile neutrino Dark Matter, with a particular focus on Dark Matter production in the early Universe and on phenomenological...

Dr
Sebatien Clesse
(RWTH Aachen University)

9/28/16, 2:15 PM

Cosmology & Astroparticle Physics

The recent detection by Advanced LIGO of gravitational waves (GW) from the merging of a binary black hole system sets new limits on the merging rates of massive primordial black holes (PBH) that could be identified to the dark matter in the Universe. If PBH are regrouped in clusters with a similar density to the one observed in ultra-faint dwarf galaxies, merging rates are comparable to...

Dr
Stefano Stefano Camera
(Jodrell Bank Centre for Astrophysics, The University of Manchester)

9/28/16, 2:30 PM

Cosmology & Astroparticle Physics

A tremendous experimental effort is underway with the goal of delivering the first non- gravitational detection of dark matter (DM). Indeed, despite its huge abundance, very little is known about the true nature of DM, and the community is eager for new and innovative ideas able to finally pin down its properties. In this talk, I shall review how cross-correlations of astrophysical and...

Dr
Camilo Alfredo Garcia Cely
(ULB)

9/28/16, 2:45 PM

Cosmology & Astroparticle Physics

The observation of line-like signals of high-energy gamma rays is considered a discovery channel of dark matter.
Nevertheless, calculating the rate and the spectral shape associated to these processes is highly non-trivial and depends on the details of the underlying dark matter model.
I will argue that, in spite of this situation, there are a number of model-independent statements that...

Dr
Andrzej Hryczuk
(University of Oslo)

9/28/16, 3:00 PM

Cosmology & Astroparticle Physics

In recent years there has been an increasing interest in computations of the dark matter thermal relic density beyond the leading order in perturbation theory. In this talk we point out that the standard calculation, based on solving the Boltzmann equations, at NLO suffers from a temperature-dependent IR divergence. In an example model we show how both soft and collinear temperature-dependent...

Andreas Rappelt
(Technische Universität München)

9/28/16, 3:15 PM

Cosmology & Astroparticle Physics

In this work, we develop a method to compare results from various direct detection experiments without making assumptions on the velocity distribution of the dark matter particles in the Solar System. Furthermore, we consider the particular case when one of the experiments reports a positive signal, and we apply our method to investigate the compatibility of the DAMA claim with the null...

Dr
Christian Gross
(Helsinki University)

9/28/16, 3:30 PM

Cosmology & Astroparticle Physics

Simple single component WIMP Dark Matter (DM) models are under pressure from direct detection (DD). This is related to the relation between annihilation- and DD cross-section in such models. By contrast, multicomponent WIMP DM models leave open a large part of the parameter space and allow for a very rich phenomenology. We study these issues using the example of a UV complete framework...

Mr
Juraj Klarić
(Technical University Munich)

9/28/16, 4:15 PM

Cosmology & Astroparticle Physics

The extension of the Standard Model by heavy right-handed neutrinos can simultaneously explain the observed neutrino masses via the seesaw mechanism and the baryon asymmetry of the Universe via leptogenesis. If the mass of the heavy neutrinos is below the electroweak scale, they may be found at LHCb, BELLE II, the proposed SHiP experiment or a future high-energy collider. In this mass range,...

Dr
Viviana Niro
(IFT UAM/CSIS and UAM)

9/28/16, 4:30 PM

Cosmology & Astroparticle Physics

In this talk, I'll show how updated information from gamma-rays experiments constrain the spectrum of the galactic sources previously detected by the Milagro collaboration.
I'll show the number of through-going muons expected from these sources at the IceCube detector and I'll discuss the statistical significance of each source as a function of the detector running time.
Moreover, I'll...

Dr
Iason Baldes
(DESY)

9/28/16, 4:45 PM

Cosmology & Astroparticle Physics

If the Standard Model Yukawa couplings varied in the early universe and started with order one values before electroweak symmetry breaking, the CP violation associated with the CKM matrix could be the origin of the matter-antimatter asymmetry. The large effective Yukawa couplings which lead to the enhanced CP violation can also help in achieving a strong first-order electroweak phase...

Mr
Rasmus Rasmussen
(DESY)

9/28/16, 5:00 PM

Cosmology & Astroparticle Physics

It has been shown that heavy neutral leptons (HNLs) can explain many phenomena seen in Nature such as the neutrino oscillation data, dark matter and the baryon asymmetry. Therefore, alot of theoretical and experimental effort has been put into this subject. I will discuss the parameter space reach of future experiments searching for HNLs at the GeV scale in terms of neutrino mass models with...

Mr
Miguel Campos
(Max-Planck-Institut für Kernphysik)

9/28/16, 5:15 PM

Cosmology & Astroparticle Physics

We determine constraints on sterile neutrino warm dark matter through direct detection experiments, taking XENON100, XENON1T and DARWIN as example. While not competitive with astrophysical constraints from X-ray data, the constraints are the first direct laboratory bounds on sterile neutrino warm dark matter, and will be in some parts of parameter space the strongest limits on keV-scale neutrinos.

Dr
Julia Harz
(ILP / LPTHE Paris)

9/28/16, 5:30 PM

Cosmology & Astroparticle Physics

Interactions that manifest themselves as lepton number violating processes at low energies in combination with sphaleron transitions typically erase any pre-existing baryon asymmetry of the Universe. We demonstrate in a model independent approach that the observation of neutrinoless double beta decay would impose a stringent constraint on mechanisms of high-scale baryogenesis, including...

Guillermo Ballesteros
(IPhT CEA - Saclay)

9/29/16, 2:00 PM

Cosmology & Astroparticle Physics

I will describe a minimal extension of the Standard Model of particle physics that accounts for inflation, dark matter, baryogenesis,
the smallness of neutrino masses and solves the strong CP problem, with a new physics scale around ~10^11 GeV.

Wolfgang Gregor Hollik
(DESY)

9/29/16, 2:15 PM

Cosmology & Astroparticle Physics

The discovery of the Higgs boson puts a severe constraint on the available parameter space in any SUSY model. In the MSSM, a 125 GeV Higgs together with relatively light stops needs a very large stop mixing, therefore large trilinear terms in the scalar potential. Those are known to destabilize the electroweak ground state and induce a true vacuum in association with squark vevs. Previous...

Dr
Kyohei Mukaida
(Kavli IPMU)

9/29/16, 2:30 PM

Cosmology & Astroparticle Physics

We revisit the compatibility between chaotic inflation, which provides a natural solution to the initial condition problem, and the metastable electroweak vacuum, which is suggested by the results of the LHC and the current mass measurements of top quark and Higgs boson. It is known that chaotic inflation poses a threat to the stability of the electroweak vacuum because it easily generates...

Maria Archidiacono
(RWTH Aachen University)

9/29/16, 2:45 PM

Cosmology & Astroparticle Physics

Within the next few years cosmological structure formation will be probed in greater detail than ever before by new and very large surveys, most notably EUCLID and LSST.
While this opens great possibilities for probing for example dark energy and the mass of neutrinos, it also puts very stringent requirements on theoretical calculations of cosmological observables, such as the matter power...

Dr
Cora Uhlemann
(Utrecht University)

9/29/16, 3:00 PM

Cosmology & Astroparticle Physics

We investigate the formation of a dark matter halo using an idea that is rooted in the correspondence between phase space distributions in classical and quantum mechanics. The dynamics of cold dark matter is governed by the Vlasov (or collisionless Boltzmann) equation whose nonlinearity is induced by gravity according to the Poisson equation. Determining the evolution of density and velocity...

Mr
Marco Zatta
(University of Helsinki)

9/29/16, 3:15 PM

Cosmology & Astroparticle Physics

Current Higgs boson and top quark data favour metastability of our vacuum which raises questions as to why the Universe has chosen an energetically disfavoured state and remained there during the primordial dynamics. In this talk I will point out that allowing a simple Higgs-inflaton coupling can explain why the Higgs ended up in the electroweak vacuum after inflation. I will show that this...

Dr
Javier Rubio
(ITP Heidelberg)

9/29/16, 4:05 PM

Cosmology & Astroparticle Physics

I will describe how the geometrical properties of the target manifold affect the inflationary predictions of two-field scalar-tensor theories invariant under dilatations. The results presented extend the predictions of the Higgs-dilaton model to a full class of theories defined by an underlying principle. In particular, I will show that when the field-derivative space in the Einstein frame is...

Dr
Nico Wintergerst
(Stockholm University)

9/29/16, 4:20 PM

Cosmology & Astroparticle Physics

Black holes possess a wide range of rather peculiar properties, many of them in connection with their ability to process, store and release information. I explore the possibility that the physical origin of these properties is quantum criticality. To this end, I will demonstrate that simple Bose condensates exhibit a plethora of black hole like properties. This includes trapping, baldness,...

Mr
Alexander Gussmann
(Arnold-Sommerfeld-Center, LMU Munich)

9/29/16, 4:35 PM

Cosmology & Astroparticle Physics

Standard folk-theorem arguments claim that global charges, such as baryon number, cannot be conserved by semiclassical black holes. We argue that the existence of black holes with classical skyrmion hair invalidates these standard arguments. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole
is seemingly-unable to return the baryon number ...

Ken'ichi Saikawa
(DESY)

9/29/16, 4:50 PM

Cosmology & Astroparticle Physics

Minimal chaotic models of D-term inflation predicts too large primordial tensor perturbations. Although it can be made consistent with observations utilizing higher order terms in the Kaehler potential, expansion is not controlled in the absence of symmetries. We comprehensively study the conditions of Kaehler potential for D-term plateau-type potentials and discuss its symmetry. They include...