Dario Martelli
(King's College London)
24/09/2019, 15:15
Razvan Gurau
(CPHT)
24/09/2019, 16:15
I will present a brief introduction to tensor field theories and their large N limit. I will in particular focus on the renormalization group fixed points and the conformal field theories describing them in a particular model.
Zvi Bern
(UCLA)
25/09/2019, 09:00
Michal P. Heller
(AEI MPG)
25/09/2019, 09:30
Mari Carmen Banuls
(MPQ MPQ)
25/09/2019, 10:00
Alexander Zhiboedov
(CERN)
25/09/2019, 11:00
Christian Steinwachs
(Uni. Freiburg)
25/09/2019, 12:00
Gustavo Medina Vazquez
(University of Sussex)
25/09/2019, 14:00
Particle Phenomenology
Much progress has been made in recent years towards a field-theoretic understanding of quantum gravity within the asymptotic safety conjecture. In this talk, I report progress towards the inclusion of Standard Model matter. We perform an extensive fixed point search in theories involving Ricci scalar and tensor, and Riemann tensor invariants alongside SM matter, up to high polynomial orders in...
Dr
Jan Hajer
(UCLouvain)
25/09/2019, 14:00
Cosmology & Astroparticle Physics
Extensions to the SM featuring a low-scale seesaw can be used to to explain the observation of neutrino oscillations, baryogenesis and dark matter. I present the potential to search for right-handed neutrinos using current experiments. I compare the reach of the main detectors at the LHC when a displaced vertex signature in proton collisions is used. Additionally, I show the potential to...
Dr
Evgeny Skvortsov
(AEI, Potsdam)
25/09/2019, 14:00
String & Mathematical Physics
Three-dimensional bosonization duality is one of the remarkable dualities discovered recently in three-dimensional conformal field theories. At least in the large-N limit the duality is tightly linked to higher spin symmetries and, therefore, to Higher Spin Gravities that are AdS/CFT dual to these CFT's.
We propose a new approach to solve conformal field theories and apply it to the...
Dr
Andreas Braun
(University of Oxford)
25/09/2019, 14:20
String & Mathematical Physics
I will review recent progress in the role of G2 manifolds in various
string dualities. This includes the dualities between heterotic strings,
type IIA and M-Theory, as well as mirror symmetries for type II strings.
Mr
Mathias Becker
(TU Dortmund)
25/09/2019, 14:20
Cosmology & Astroparticle Physics
We investigate a model of neutrino portal dark matter where a right-handed neutrino both generates the observed neutrino masses and mediates between the SM and a dark sector, consisting of a fermion and a boson.
We explore the parametrics and different constraints on the neutrino portal to dark matter. In contrast to earlier work, we focus on regions of the parameter space where DM is...
Mr
Kevin Moch
(TU Dortmund)
25/09/2019, 14:25
Particle Phenomenology
Despite its many successes the Standard Model can at best be viewed
as a low energy approximation to a more fundamental theory of nature.
Supersymmetry provides a theoretically attractive extension of the
Standard Model while the idea of asymptotic safety leads to field theories
which can be regarded as being fundamental.
In this talk I investigate whether and how the minimal...
Mr
Sarif Khan
(Goettingen University)
25/09/2019, 14:35
Cosmology & Astroparticle Physics
In this work, we explain three beyond standard model (BSM) phenomena, namely neutrino masses, the baryon asymmetry
of the Universe and Dark Matter, within a single model and in each explanation the right handed (RH) neutrinos play the
prime role. Indeed by just introducing two RH neutrinos we can generate the neutrino masses by the Type-I seesaw
mechanism. The baryon asymmetry of the...
Dr
Guglielmo Lockhart
(University of Amsterdam)
25/09/2019, 14:40
String & Mathematical Physics
In the pure spinor formulation of the superstring, in addition to the spacetime bosons and fermions the string worldsheet theory includes a ghost sector described by pure spinor fields. I will discuss the existence of a hidden action of an affine E6 Lie algebra on this sector, which arises from enhancement of SO(10) spacetime rotations together with a U(1) ghost symmetry, and whose...
Sandeepan Gupta
(Durham)
25/09/2019, 14:50
Cosmology & Astroparticle Physics
We present a unified relaxion solution to the five major
outstanding issues in particle physics: the hierarchy problem, dark
matter, matter-antimatter asymmetry, neutrino masses and the strong CP
problem. The only additional field content in our construction with
respect to standard relaxion models is an up-type vector-like fermion
pair and three right-handed neutrinos charged under the...
Mr
Tom Steudtner
(U Sussex)
25/09/2019, 14:50
Particle Phenomenology
I will discuss asymptotically safe extensions of the Standard Model with new matter fields at the TeV scale. The BSM sector contains singlet scalars and vector-like fermions in representations which permit Yukawa interactions with the Standard Model leptons and a Higgs portal coupling. UV safety is explored up to the Planck regime in dependence of the BSM couplings. Moreover, phenomenological...
Dr
Markus Dierigl
(Utrecht University)
25/09/2019, 15:00
String & Mathematical Physics
In this talk we will investigate the Swampland Distance Conjecture in type IIB string theory compactified on K3 x T2. As conjectured one indeed finds a tower of exponentially light states using the Hodge-Deligne splitting of the middle homology in the degeneration limit. This tower, however, consists of quarter-BPS states, which can potentially decay into a pair of half-BPS states at walls of...
Mr
Philipp Klose
(Université Catholique de Louvain)
25/09/2019, 15:10
Cosmology & Astroparticle Physics
For leptogenesis with heavy sterile neutrinos above the Casus-Ibarra bound, asymmetries produced by relativistic sterile neutrinos at early times can be relevant in the case of weak washout or if the asymmetry is partly protected from washout by being transferred to partially equilibrated spectator fields. We thus study the relevance of relativistic effects for leptogenesis in a minimal seesaw...
Gregor Kasieczka
25/09/2019, 15:15
Valentina De Romeri
(IFIC (CSIC-Univ. Valencia))
25/09/2019, 15:20
Cosmology & Astroparticle Physics
Assuming light vector mediators, we discuss the effects of CP violation on the coherent elastic neutrino-nucleus scattering (CEvNS) process in the COHERENT sodium-iodine, liquid argon and germanium detectors. We show that in some regions of the parameter space, the presence of a dip in the event rate spectrum can be used to constraint CP violating effects. In other regions, we find that CP...
Dr
Thorsten Schimannek
(University of Vienna)
25/09/2019, 15:20
String & Mathematical Physics
We discuss the relation between certain auto-equivalences of the category of B-branes on elliptic Calabi-Yau threefolds and modular properties of the corresponding topological string partition function.
This suggests a geometric explanation and generalization of recent conjectures on the appearance of lattice Jacobi forms.
In particular, we will shed light on the special case where the...
Ms
Anja Brenner
(Technische Universität München)
25/09/2019, 15:40
Cosmology & Astroparticle Physics
Dark matter particles from the galactic halo can be captured by the sun and can then annihilate into Standard Model particles which makes the sun a source of GeV neutrinos. One goal of the IceCube Neutrino Observatory (IceCube) is to detect these neutrinos. In this work, we present the constraints on the DM-nucleon interactions which we obtain from 3-year IceCube observations of the Sun.
Mr
Takahiro Yoshida
(Niigata University)
25/09/2019, 15:40
Particle Phenomenology
We discuss the model with the modular $A_4$ invariance. It has been shown that this model can explain neutrino masses and mixing angles observed by oscillation experiments. We investigate the leptogenesis in this model. It is found that the leptogenesis by decay of right-handed neutrinos works well. Especially, we show that the Dirac and Majorana CP-phases in the PMNS matrix and right-handed...
Ms
Urmi Ninad
(Doctoral student)
25/09/2019, 15:40
String & Mathematical Physics
We analyse certain 2d supersymmetric gauge theories (GLSMs) with a boundary which in the IR flow to SCFTs that are relevant for string compactifications with D-branes. Certain non-abelian GLSMs exhibit Seiberg-like dualities which relate seemingly different UV gauge theories with the same IR physics. We extend the analysis of such dualities to theories with boundaries and propose the action of...
Mr
Henrique Rubira
(DESY)
25/09/2019, 15:50
Cosmology & Astroparticle Physics
We study the power spectrum of dark matter density fluctuations in the framework of the Effective Field Theory of Large Scale Structures (EFTofLSS) up to three loop orders. In principle, several counter-terms may be needed to handle the short-distance sensitivity in perturbation theory. However, we show that a small number of extra coefficients are sufficient to match numerical simulations...
Dr
Carlos Tamarit
(Technische Universität München)
25/09/2019, 16:30
Cosmology & Astroparticle Physics
High-scale axion models are sensitive to CMB isocurvature bounds, which are thought to rule out scenarios with an axion decay constant fA above 10^14 GeV. This would be incompatible with grand unification scenarios featuring an axion with fA related to the unification scale, which could otherwise be primary targets for future experiments like CASPER and ABRACADABRA. In view of the above, we...
Dr
Marcus Sperling
(Yau Mathematical Sciences Center, Tsinghua University)
25/09/2019, 16:30
Cosmology & Astroparticle Physics
The physics of M5 branes placed near an M9 plane on an A-type ALE singularity exhibits a variety of phenomena that introduce additional massless degrees of freedom. There are tensionless strings whenever two M5 branes coincide or whenever an M5 brane approaches the M9 plane. These systems do not admit a low-energy Lagrangian description so new techniques are desirable to shed light on the...
Dr
Martin Vollmann
(TUM)
25/09/2019, 16:45
Cosmology & Astroparticle Physics
A particularly promising prediction of several wimp DM models is the quasi-monochromatic emission of gamma rays due to their pair-annihilation in e.g. the innermost part of the Milky Way. High energy gamma-ray fluxes due to such annihilation processes are naively suppressed by the inverse-squared dependence on the heavy DM mass and by the fact that the cross section is loop-suppressed....
Dr
Antonio Pittelli
(Uppsala University)
25/09/2019, 16:50
Cosmology & Astroparticle Physics
We consider 4d N=1 gauge theories with R-symmetry on a hemisphere times a torus. We apply localization techniques to evaluate the exact partition function through a cohomological reformulation of the supersymmetry transformations. Our results represent the natural elliptic lifts of the lower dimensional analogs as well as a field theoretic derivation of the conjectured 4d holomorphic blocks,...
Dr
Xuan Chen
(University of Zurich)
25/09/2019, 17:00
Particle Phenomenology
Fiducial differential cross sections are reliable observables at the LHC. Precision measurements are providing unprecedented data which reveals the detailed structure of the Standard Model. From the theory point of view, event generators could simulate the underlying scattering processes and apply the same experimental selection criterions to reduce systematical errors when comparing with...
Kai Urban
(TUM)
25/09/2019, 17:05
Cosmology & Astroparticle Physics
For heavy electroweak dark matter, the resummation of large quantum corrections due to long-range potentials (the "Sommerfeld effect") is crucial in determining the precise annihilation cross-section. In this talk, I will consider the one-loop correction to the potential which provides the leading non-relativistic correction to the Sommerfeld effect in the case of wino or wino-like dark matter...
Mr
Romain Ruzziconi
(ULB and International Solvay Institutes)
25/09/2019, 17:10
Cosmology & Astroparticle Physics
In this talk, I will discuss the solution space of general relativity in Bondi gauge, with non-vanishing cosmological constant. Using the dictionary between Bondi and Fefferman-Graham gauges, the analogues of the Bondi news, Bondi mass and Bondi angular momentum aspects at the boundary of generic asymptotically locally dS4 spacetimes will be identified. Then, I will introduce the Λ-BMS4 group...
Mr
Tobias Binder
(Kavli IPMU)
25/09/2019, 17:20
Cosmology & Astroparticle Physics
The thermal decoupling description of multi-TeV scale dark matter (and co-annihilating partners) is reconsidered. In several works it has been pointed out that the inclusion of quantum mechanical effects in the computation of the thermal relic abundance is in certain cases required in order to make a precise determination of the upper bound on the DM mass. One of these quantum mechanical...
Domenico Bonocore
(Universität Münster)
25/09/2019, 17:30
Particle Phenomenology
Recently, several groups have investigated the possibility to extend the traditional soft gluon factorization and resummation framework at subleading power. In particular, for processes with colourless final state particles, resummation has been achieved at the leading-log accuracy. In this talk, after introducing the general set up, I focus on a particular ingredient for such factorization...
Mr
Andrea Legramandi
(University of Milano-Bicocca)
25/09/2019, 17:35
Cosmology & Astroparticle Physics
Spinor bilinears have played an important role in classification of supergravity vacuum solutions. In this talk I will present a novel reformulation of supersymmetry conditions for type II theories in terms of spinor bilinears without assuming any factorization of space-time. These bispinors can be used to define brane calibrations, namely differential forms whose integrals measure minimal...
Dr
Stefan Vogl
(Max-Planck-Institut für Kernphysik)
25/09/2019, 17:35
Cosmology & Astroparticle Physics
Chemical equilibrium is a commonly made assumption in the freeze-out calculation of coannihilating dark matter. We explore the possible failure of this assumption and find a new conversion-driven freeze-out mechanism. Considering a representative simplified model inspired by supersymmetry with a neutralino- and sbottom-like particle we find regions in parameter space with very small couplings...
Dr
Giorgio Arcadi
(University of Rome 3)
25/09/2019, 17:55
Cosmology & Astroparticle Physics
We ilustrate an accurate numerical Analysis of the scenario of real scalar dark matter with negligible coupling with the SM states. Assuming that the DM is produced during inflation and can reach at least kinetic Equilibrium due to its self-coupling, we illustrate a fully relativistic analysis of dark matter evolution, thermalization conditions and different freeze– out regimes, including the...
Marius Gerbershagen
(Universität Würzburg)
25/09/2019, 17:55
Cosmology & Astroparticle Physics
Due to the non-factorization of the Hilbert space into tensor products, the definition of entanglement entropy in gauge theories is subtle. It can be defined either by resorting to an algebraic approach or by embedding the state into an enlarged factorizing Hilbert space. The equivalence of these two approaches will be shown for entanglement between spatial degrees of freedom in 2d CFTs with...
Ilaria Brivio
(Univ. Heidelberg)
25/09/2019, 18:00
Particle Phenomenology
I will give a brief introduction to the Standard Model Effective Field
Theory (SMEFT) and discuss how its parameters can be constrained with
global analyses of LHC data, allowing to extract information on physics
beyond the SM with a minimum bias. As a case study, I will present the
preliminary results of a fit to top quark measurements and illustrate
some interesting features of this analysis.
Mr
Marco Hufnagel
(DESY Hamburg)
25/09/2019, 18:10
Cosmology & Astroparticle Physics
Meta-stable dark sector particles decaying into electrons or photons may non-trivially change the Hubble rate, lead to entropy injection into the thermal bath of Standard Model particles and may also photodisintegrate light nuclei formed in the early universe. We study generic constraints from Big Bang Nucleosynthesis on such a setup, with a particular emphasis on MeV-scale particles which are...
Mr
Christian Northe
(Universität Würzburg)
25/09/2019, 18:20
Cosmology & Astroparticle Physics
We construct Kondo-like flows in the D1/D5 system. Within CFT, the
Kondo effect is described via branes which acquire additional dimensions. Starting from the D1/D5 system, we have found the BPS solutions to the DBI system describing Kondo-like RG flows between D1- and D3-brane solutions. Using a class of half BPS solutions we find corresponding backreacted supergravity interface solutions...
Cem Eroncel
25/09/2019, 18:25
Rafael Aoude
(Mainz)
25/09/2019, 18:30
Particle Phenomenology
The one-loop matching between the Standard Model Effective Field Theory (SMEFT) and FCNC operators of the Weak Effective Theory enables the incorporation of high-precision flavour data in Electroweak global fits of SMEFT at high energies. We explore the flavour bounds on the linear combination of the SMEFT Wilson coefficients given by the one-loop matching with a Minimal Flavour Violation assumption.
Mr
Hugo Camargo
(Max Planck Institute for Gravitational Physics)
25/09/2019, 18:40
String & Mathematical Physics
We apply the recently developed notion of complexity for field theory to a quantum quench through a critical point in 1+1 dimensions. We begin with a toy model consisting of a quantum harmonic oscillator, and show that complexity exhibits universal scalings in both the slow and fast quench regimes. We then generalize our results to a one-dimensional harmonic chain, and show that preservation...
Frank Saueressig
(Nijmegen U.)
26/09/2019, 09:00
Thomas Thiemann
(IQG Erlangen-Nürnberg)
26/09/2019, 09:30
Beatriz Elizaga de Navascues
(FAU)
26/09/2019, 10:00
Henrik Johansson
(Uppsala)
26/09/2019, 11:00
Andrew Strominger
(Harvard)
26/09/2019, 11:45
Laura Lopez Honorez
(Université Libre de Bruxelles)
26/09/2019, 14:00
Particle Phenomenology
In my talk I will discuss the dependence of the dark matter production mechanism in the early universe on its coupling to the Standard Model and mediator. For illustration, I will focus on the case of compressed mass spectrum dark matter scenario and show that we can continuously go from freeze-in to freeze-out with an intermediate stage of conversion driven freeze-out. In the latter case,...
Dr
Teresa Bautista
(Max Planck Institute for Gravitational Physics)
26/09/2019, 14:00
String & Mathematical Physics
The Euclidean path integral of quantum gravity requires a proper definition because the kinetic term for the conformal factor of the metric comes with an additional minus sign. We propose a definition of two-dimensional quantum gravity with a cosmological constant based on the conformal bootstrap results of timelike Liouville theory coupled to matter. For the spectrum, we prove a no-ghost...
Dr
Jinsu Kim
(Georg-August University Goettingen)
26/09/2019, 14:00
Cosmology & Astroparticle Physics
Inflationary models based on particle physics naturally involve multiple fields in addition to the inflaton field. Consequently these multiple fields may contribute to inflaton correlation functions via loop corrections. We study the quantum corrections to the inflaton two-point correlation functions due to massive scalar and fermion fields, employing the Schwinger-Keldysh formalism. We shall...
Jorinde Van de Vis
(NIKHEF Amsterdam)
26/09/2019, 14:15
Cosmology & Astroparticle Physics
We study particle production after multifield inflation with
nonminimal couplings to gravity. A comparison between a linearized
treatment and lattice simulations allows us to determine when nonlinear
effects, such as rescattering and backreaction, become important. We
track the equation of state on the lattice and show that it relaxes to
1/3. We also show that the spectra of the produced...
Marc Schiffer
(Heidelberg University)
26/09/2019, 14:20
String & Mathematical Physics
After a short introduction to asymptotically safe quantum gravity, I explore the question why our universe is four dimensional from an asymptotically safe vantage point.
I present indications that asymptotically safe quantum fluctuations of gravity could only solve the $U(1)$ Landau-pole problem in the Standard Model in four dimensions. This could single out the observed dimensionality of the...
Yohei Ema
(DESY)
26/09/2019, 14:30
Cosmology & Astroparticle Physics
We point out that a light scalaron dynamically emerges if scalar fields have a sizable non-minimal coupling to the Ricci scalar as in the Higgs inflation model. We support this claim in two ways. One is based on the renormalization group equation; the non-minimal coupling inevitably induces a Ricci scalar quadratic term due to the renormalization group running. The other is based on scattering...
Elias Bernreuther
(RWTH-Aachen)
26/09/2019, 14:30
Particle Phenomenology
I will discuss the cosmology and LHC phenomenology of a consistent strongly interacting dark sector coupled to Standard Model particles through a generic vector mediator. I will lay out the requirements for the model to be cosmologically viable, consider the dominant freeze-out processes and discuss bounds from direct detection. At the LHC the model predicts dark showers, which can give rise...
Dr
Edoardo Vescovi
(Imperial College London)
26/09/2019, 14:40
String & Mathematical Physics
In this talk, based on [1906.07733] with Y. Jiang and S. Komatsu, we derive the first non-perturbative result for the structure constants of two determinant operators and a non-BPS single-trace operator of finite length in planar $\mathcal{N}=4$ SYM. First, we introduce a new method based on large-N collective fields, which efficiently computes correlators of such non-single-trace operators in...
Gilles Buldgen
(UC Louvain)
26/09/2019, 14:45
Cosmology & Astroparticle Physics
“Warm Inflation” is an alternative to the standard inflationary paradigm in cosmology. It is characterized by a quasi-equilibrium between the dissipation due to particle production and the dilution due to the Hubble expansion, which keeps a thermal bath of radiation at a constant high temperature during inflation. We derive a quantum kinetic equation of motion for a slowly-rolling scalar field...
Christian Doering
(MPIK)
26/09/2019, 15:00
Azadeh Maleknejad
(MPA Garching)
26/09/2019, 15:00
Cosmology & Astroparticle Physics
Primordial SU(2) gauge fields coupled to axions can contribute
to the physics of inflation. Their rich phenomenology and unique
observational features, e.g., chiral primordial gravitational waves,
turned this class of models to a hot topic of study since their
discovery in 2011. In this talk, I will briefly review the models in
this class, which so far have been studied in the literature....
Dr
Florian Loebbert
(Humboldt University Berlin)
26/09/2019, 15:00
String & Mathematical Physics
We report on progress in exploring the constraining power of the conformal Yangian symmetry that was recently found to be a feature of fishnet Feynman integrals. In particular, we explicitly investigate the four-point box and the six-point double-box integrals.
Mr
Stefan Sandner
(IFIC / CSIC)
26/09/2019, 15:20
Cosmology & Astroparticle Physics
I will talk about early Universe inflation driven by an axion-like particle interacting with (non-) Abelian gauge fields. In the case of a non-Abelian gauge group, this can lead to the formation of a stable, homogeneous and isotropic gauge field background. However this only happens significantly after the relevant CMB scales left the horizon. This makes the model practically indistinguishable...
Dr
Raul Pereira
(Trinity College Dublin)
26/09/2019, 15:20
String & Mathematical Physics
In this talk I consider five-point functions of N=4 SYM, which at strong coupling become AdS amplitudes in type IIB supergravity. I will show how to exploit symmetries and self-consistency conditions to bootstrap these amplitudes, which are naturally written in Mellin space. Finally, I will highlight the new data obtained and comment on generalizations of this work.
Dr
Wolfgang Gregor Hollik
(KIT)
26/09/2019, 15:30
Particle Phenomenology
We are studying the effects of light New Physics that can materialise in deviations from the Coulomb potential on the length scale of molecules. Precision molecular spectroscopy thus sets complementary constraints on parameters that are not accessible in other type of experiments. We compare an estimate of the theoretical uncertainties to the available experimental precision in order to...
Kyohei Mukaida
(DESY)
26/09/2019, 16:00
Cosmology & Astroparticle Physics
The coupling of an axion-like particle driving inflation to the Standard Model particle content through a Chern-Simons term generically sources a dual production of massless helical gauge fields and chiral fermions. We demonstrate that the interplay of these two components results in a highly predictive baryogenesis model, which requires no further ingredients beyond the Standard Model. If the...
Mr
Alfredo Guevara
(Perimeter)
26/09/2019, 16:10
String & Mathematical Physics
Motivated by the advent of LIGO and Virgo measurements, it has been observed that scattering amplitudes can be used to derive perturbative observables appearing in the collision of two black holes. In this talk we will cover recent progress in obtaining such quantities for the phenomenologically relevant setup of spinning black holes, focusing on radiation and the spin multipole expansion....
Dr
Andrey Saveliev
(Immanuel Kant Baltic Federal University)
26/09/2019, 16:15
Cosmology & Astroparticle Physics
The origin of the first magnetic fields in the Universe is a standing problem in cosmology. Intergalactic Magnetic Fields (IGMFs) may be an untapped window to the primeval Universe, providing further constrains on magnetogenesis. We demonstrate the feasibility of using gamma rays from electromagnetic cascades originating from TeV blazars and Ultra-High-Energy Cosmic Rays...
Mr
Henning Bahl
(DESY Hamburg)
26/09/2019, 16:30
Particle Phenomenology
We review recent progress in the calculation of the MSSM Higgs boson masses for low $M_A$ and $\tan\beta$ using the THDM as low-energy EFT. As an application of this calculation, we present two new Higgs benchmark scenarios valid in the region of low $\tan\beta$. While all SUSY masses are chosen relatively heavy in the first scenario, the second scenario features light neutralinos and...
Dr
Fazlollah Hajkarim
(Goethe University Frankfurt)
26/09/2019, 16:30
Cosmology & Astroparticle Physics
Using the quantum chromodynamics (QCD) equation of state (EoS) from lattice calculations we investigate effects from QCD on primordial gravitational waves (PGWs) produced during the inflationary era. We also consider different cases for vanishing and nonvanishing lepton asymmetry where the latter one is constrained by cosmic microwave background experiments.
Also, we investigate scenarios...
Dr
Gustav Mogull
(Uppsala University)
26/09/2019, 16:30
String & Mathematical Physics
Conformal supergravities are an intriguing class of theories; although they contain ghost-like states suggesting non-unitary behavior, they may have exceptionally good behavior in the ultraviolet regime. In this talk I will describe aspects of their tree-level scattering amplitudes, showing how they can be understood from double copy, Lagrangian, and string theory perspectives.
Dr
Mikael Chala
(UGR & IPPP)
26/09/2019, 16:45
Cosmology & Astroparticle Physics
I will discuss the dependence of the parameters describing the gravitational waves produced in a first order phase transition (Tn, alpha, beta/H) on
the global properties
(e.g. height of the barrier) of the scalar that spontaneously tunnels
between two
vacua. Particularizing on the Higgs field, I will show the potential
of gravitational wave observatories to unravel its global...
Mr
Jan Gerken
(Max Planck Institute for Gravitational Physics)
26/09/2019, 16:50
String & Mathematical Physics
When tree-level scattering amplitudes in open string theory are expanded in $\alpha'$, the coefficients are multiple zeta values (MZVs). These are mapped to a subset by the single-valued map from analytic number theory. As was proven recently, the corresponding MZVs in closed string amplitudes are just the single-valued image of the open string MZVs, therefore removing the need to calculate...
Sydney Otten
(NIKHEF)
26/09/2019, 16:55
Mr
Juan S. Cruz
(TUM)
26/09/2019, 17:05
Cosmology & Astroparticle Physics
Following previous work on self-consistent methods geared towards dealing with false vacuum decay in quantum field theory; a $U(1)$-gauge theory with a complex scalar is considered together with a polynomial potential which presents a metastable vacuum at tree level. Fluctuations around an inhomogeneous bounce-type background interpolating between vacua are studied and computed within a 1-PI...
Mr
Francesco Aprile
(Milano Bicocca University)
26/09/2019, 17:10
String & Mathematical Physics
We explore the structure of supergravity on AdS5xS5 at one loop, by constructing multi-channel four-point correlators for Kaluza Klein modes on the five-sphere.
We do so by insisting on the consistency of the OPE of N=4 SYM, and using analytical bootstrap techniques. In particular, the presence of 1/N^4 contributions from protected double trace operators at the unitarity bound is a novel...
Mr
Felix Giese
(DESY/Hamburg U.)
26/09/2019, 17:20
Cosmology & Astroparticle Physics
We discuss vacuum stability in Froggatt-Nielsen (FN) models. One concern in FN models is that for large flavon VEVs the running of the quartic Higgs coupling is enhanced what might lead to a more severe instability compared to the Standard Model (SM). We study this issue using the renormalization-group improved scalar potential. Another issue is that the
mixing between the Higgs and the...
26/09/2019, 17:55
Alessandra Buonanno
(AEI MPG)
27/09/2019, 09:00
Jan Steinhoff
(AEI MPG)
27/09/2019, 09:45
Alejandra Castro
(Amsterdam U.)
27/09/2019, 11:15
Dr
Erik Lentz
(University of Goettingen)
Cosmology & Astroparticle Physics
To what extent do axions as the dark matter form structure distinguishable from cold dark matter? This question has generated much debate in axion cosmology for decades, due largely to uncertainty in modeling the axion's highly-degenerate state. The standard approach thus far has been to treat the degenerate Bose fluid of axions as a classical field, limiting its distinguishable dynamics to...
Yvette Welling
(DESY)
Cosmology & Astroparticle Physics
Recent swampland conjectures highlight again the importance of finding viable scenarios for inflation that are not strictly single-field. In particular, one may wonder whether there are multi-field inflationary scenarios that have a similar phenomenology to single field inflation. We present a family of exact models of inflation - dubbed Orbital Inflation - in which the multi-field effects are...
Dr
Raghuveer Garani
(Universite Libre De Bruxelles)
Cosmology & Astroparticle Physics
Due to their extreme density and low temperature, neutron stars (NS) are efficient probes to unveil interactions between standard model and dark matter (DM) particles. From elastic scatterings on NS material, DM can get gravitationally trapped by the star.
The in-falling DM unavoidably transfers heat to the NS and can increase the temperature of old NS up to $\sim$ 1700 K. Moreover, if DM...
