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30/11/2022, 09:55
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Ilia Musco30/11/2022, 10:10
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Gabriele Franciolini30/11/2022, 11:20
Primordial Black Holes (PBHs) might comprise a significant fraction of dark matter in the Universe and can give rise to observable signatures in current and future gravitational wave (GW) experiments. Focusing on the formation PBHs in the mass range probed by the LIGO/Virgo/Kagra detectors, I will first discuss the main features of a population of PBH mergers, highlighting the smoking-gun...
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Virgile Dandoy30/11/2022, 12:00
In this work, we consider the formation of primordial black holes from large curvature perturbations at scales unconstrained by CMB observations. In addition to black holes, those curvature perturbations would induce gravitational waves able to explain the possible signal observed in the last NANOGrav 12.5-years data set and the second IPTA data release. We use here a log-normal profile for...
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Nicolas Esser30/11/2022, 12:15
We propose a way to constrain the primordial black hole (PBH) abundance in the range of PBH masses around 10^20g based on their capture by Sun-like stars in dwarf galaxies, with subsequent star destruction. We calculate numerically the probability of a PBH capture by a star at the time of its formation in an environment typical of dwarf galaxies. Requiring that no more than a fraction of stars...
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30/11/2022, 12:30
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Pasquale Serpico (LAPTh - CNRS & Univ. Savoie (FR))30/11/2022, 14:00
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Francesco Ziparo30/11/2022, 14:40
Recent measurements of the cosmic X-ray and radio backgrounds (CXB and CRB) unveil an excess of radiation with respect to what is expected from known sources, suggesting the presence of an elusive population of still undiscovered emitters. We investigate the hypothesis that the CXB and CRB excesses are due to primordial black holes (PBHs) which may constitute an arbitrary fraction of dark...
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Miguel Cuadrat-Grzybowski30/11/2022, 14:55
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Chris Kouvaris30/11/2022, 15:10
I will entertain the possibility that part of dark matter is in the form of primordial black holes formed in a matter dominated phase of the Universe. I will also address the possibility that strongly interacting dark matter might form its own compact objects.
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Dr Raghuveer Garani Ramesh (INFN, Florence)30/11/2022, 16:20
A promising probe to unmask particle dark matter is to observe its effect on neutron stars,
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the prospects of which depend critically on whether captured dark matter thermalizes in a timely
manner with the stellar core via repeated scattering with the Fermi-degenerate medium. In this
talk I will estimate the timescales for thermalization for multiple scenarios. These include: (a) spin-0
and... -
30/11/2022, 17:00
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Martti Raidal (National Institute of Chemical Physics and Biophysics (EE))01/12/2022, 09:40
I present a scale-invariant Higgs-dilaton model of dynamical symmetry breaking and dark matter which, in the multi-phase criticality regime, generates a huge hierarchy between the electroweak and new physics scales in a technically natural way. The hierarchy follows from tiny scalar couplings required by the multi-phase criticality. I discuss dark matter freeze-out and freeze-in processes as...
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Marco HUFNAGEL01/12/2022, 10:20
We propose a novel mechanism to generate sterile neutrinos νs in the early Universe, by converting ordinary neutrinos να in scattering processes νs να → νs νs. After initial production by oscillations, this leads to an exponential growth in the νs abundance. We show that such a production regime naturally occurs for self-interacting νs, and that this opens up significant new parameter space...
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Rupert Coy (ULB)01/12/2022, 10:45
Thermal dark matter (DM) covers a well-motivated class of candidates. In this talk, I will firstly consider DM in a hidden sector with temperature T', and find the allowed, model-independent parameter space in terms of the DM mass and the ratio T'/T. Then I will look specifically at the T'/T >> 1 case, taking dark QED as a representative example, and show how large entropy production allows...
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Kalliopi Petraki01/12/2022, 11:40
If dark matter couples to force mediators that are much lighter than itself, then bound states appear in the spectrum of the theory. The formation and decay of metastable dark matter bound states in the early universe can deplete the dark matter abundance, thereby changing the predicted parameters and the interpretation of experimental constraints. I will discuss how metastable bound states...
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Johannes Herms (Max-Planck-Institut für Kernphysik)01/12/2022, 12:20
Sub-GeV thermal relic dark matter typically requires the existence of a light mediator particle. We introduce the light two-Higgs-doublet portal, illustrated by a minimal UV-complete model for sub-GeV DM with kinematically forbidden annihilations into leptons. All new physics states in this scenario lie at or below the electroweak scale, affecting Higgs physics, the muon anomalous magnetic...
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01/12/2022, 12:35
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Xiaoyong Chu01/12/2022, 14:00
A dark sector with its internal structure can generate the observed dark matter abundance and baryon asymmetry and thus addresses the coincidence between the two. This talk focuses on the framework in which non-vanishing chemical potentials may grow in such a dark sector, leading to a rich phenomenology. I will discuss the models and the relevant phenomenological predictions, including dark...
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Yannis Georis01/12/2022, 14:40
In this talk, we describe how one can map the range of active-sterile neutrino mixing angles in which leptogenesis is possible in the type I seesaw model with three heavy neutrinos with Majorana masses between 50 MeV and 70 TeV, covering the entire experimentally accessible mass range. Our study includes both, the asymmetry generation during freeze-in (ARS mechanism) and freeze-out (resonant...
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Juan Antonio AGUILAR SANCHEZ01/12/2022, 14:55
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Dr Gabrijela Zaharijas (University of Nova Gorica)01/12/2022, 16:05
We live in a golden age for astro-particle physics, with a significant number of experiments actively monitoring high-energy Universe. Many of these probes provide excellent tests of particle physics models of dark matter particles. In particular, experiments such as Fermi -LAT, AMS-02, Ice Cube, ... are significantly cutting into the parameter space of one of the most popular candidates, the...
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Bryan Zaldivar01/12/2022, 16:45
In this talk I plan to review Dark Matter studies which benefit from modern statistical algorithms and tools. I will start by motivating the use of such tools in nowadays physics, while stressing their most important "warnings", typically overlooked by our community. The discussion will then focus on some astrophysical DM studies, also including direct detection and collider searches.
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Androniki Dimitriou01/12/2022, 17:25
High-resolution cosmological N-body simulations are excellent tools for modelling the formation and clustering of dark matter haloes. These simulations suggest complex physical theories of halo formation governed by a set of effective physical parameters. Our goal is to extract these parameters and their uncertainties in a Bayesian context. In this talk, I will explain how we make a step...
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01/12/2022, 17:40
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Nuria Rius (Valencia University)02/12/2022, 10:00
I will discuss recent work about the possibility of Dark Matter interacting only gravitationally in extra dimensional scenarios.
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Maxim Laletin02/12/2022, 10:40
We study a novel dark matter (DM) production mechanism based on the freeze-in through the inverse of semi-annihilation process. A peculiar feature of this scenario is that the production rate is suppressed by a small initial abundance of DM and consequently creating the observed abundance requires much larger coupling values than for the usual freeze-in. We provide a concrete example model...
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Prof. Malcolm Fairbairn (Physics, King's College London)02/12/2022, 11:25
We consider axion stars which may explode at early times, changing the ionisation history of the Universe. We will explain the concept, the calculation and the constraints on parameter space.
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Alexander C Jenkins (University College London)02/12/2022, 12:05
Next-generation gravitational-wave (GW) observatories will provide exquisite measurements of the merger rate of high-redshift binary black holes (BBHs), detecting many thousands of these systems every year. The abundance of these binaries is a direct tracer of the early stages of star formation, and therefore of cosmic structure formation. This opens the possibility of using GW observations to...
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Gonzalo Herrera02/12/2022, 12:20
In this talk, I will discuss the attenuation of high energy neutrinos and photons produced in a blazar when they propagate through the dark matter spike around the central black hole and the halo of the host galaxy. In particular, I will discuss new constraints on the dark matter-neutrino and dark matter-photon scattering cross sections obtained from the observation by IceCube of a few...
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02/12/2022, 12:30
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Julien Lesgourgues (TTK, RWTH Aachen University)
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