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11.
Two-integral distribution functions in axisymmetric galaxies: Implications for dark matter searches
Piero Ullio, Mihael Petač, 2019, izvirni znanstveni članek

Opis: We address the problem of reconstructing the phase-space distribution function for an extended collisionless system, with known density profile and in equilibrium within an axisymmetric gravitational potential. Assuming that it depends on only two integrals of motion, namely the energy and the component of the angular momentum along the axis of symmetry Lz , there is a one-to-one correspondence between the density profile and the component of the distribution function that is even in Lz, as well as between the weighted azimuthal velocity profile and the odd component. This inversion procedure was originally proposed by Lynden-Bell and later refined in its numerical implementation by Hunter and Qian; after overcoming a technical difficulty, we apply it here for the first time in presence of a strongly flattened component, as a novel approach of extracting the phase-space distribution function for dark matter particles in the halo of spiral galaxies. We compare results obtained for realistic axisymmetric models to those in the spherical symmetric limit as assumed in previous analyses, showing the rather severe shortcomings in the latter. We then apply the scheme to the Milky Way and discuss the implications for the direct dark matter searches. In particular, we reinterpret the null results of the Xenon1T experiment for spin-(in)dependent interactions and make predictions for the annual modulation of the signal for a set of axisymmetric models, including a self-consistently defined corotating halo.
Najdeno v: ključnih besedah
Povzetek najdenega: ...dark matter, astrophysics of galaxies, high energy physics, phenomenology...
Ključne besede: dark matter, astrophysics of galaxies, high energy physics, phenomenology
Objavljeno: 01.10.2021; Ogledov: 727; Prenosov: 0
.pdf Polno besedilo (1,22 MB)

12.
Testing the predictions of axisymmetric distribution functions of galactic dark matter with hydrodynamical simulations
Emmanuel Nezri, Julien Lavalle, Arturo Núñez-Castiñeyra, Mihael Petač, 2021, izvirni znanstveni članek

Opis: Signal predictions for galactic dark matter (DM) searches often rely on assumptions regarding the DM phase-space distribution function (DF) in halos. This applies to both particle (e.g. p-wave suppressed or Sommerfeld-enhanced annihilation, scattering off atoms, etc.) and macroscopic DM candidates (e.g. microlensing of primordial black holes). As experiments and observations improve in precision, better assessing theoretical uncertainties becomes pressing in the prospect of deriving reliable constraints on DM candidates or trustworthy hints for detection. Most reliable predictions of DFs in halos are based on solving the steady-state collisionless Boltzmann equation (e.g. Eddington-like inversions, action-angle methods, etc.) consistently with observational constraints. One can do so starting from maximal symmetries and a minimal set of degrees of freedom, and then increasing complexity. Key issues are then whether adding complexity, which is computationally costy, improves predictions, and if so where to stop. Clues can be obtained by making predictions for zoomed-in hydrodynamical cosmological simulations in which one can access the true (coarse-grained) phase-space information. Here, we test an axisymmetric extension of the Eddington inversion to predict the full DM DF from its density profile and the total gravitational potential of the system. This permits to go beyond spherical symmetry, and is a priori well suited for spiral galaxies. We show that axisymmetry does not necessarily improve over spherical symmetry because the (observationally unconstrained) angular momentum of the DM halo is not generically aligned with the baryonic one. Theoretical errors are similar to those of the Eddington inversion though, at the 10-20% level for velocity-dependent predictions related to particle DM searches in spiral galaxies. We extensively describe the approach and comment on the results.
Najdeno v: ključnih besedah
Povzetek najdenega: ...theory, cosmology, nongalactic astrophysics, astrophysics of galaxies, high energy physics...
Ključne besede: galaxy dynamics, dark matter experiments, dark matter simulations, dark matter theory, cosmology, nongalactic astrophysics, astrophysics of galaxies, high energy physics
Objavljeno: 01.10.2021; Ogledov: 743; Prenosov: 31
URL Polno besedilo (0,00 KB)
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13.
Equilibrium axisymmetric halo model for the Milky Way and its implications for direct and indirect dark matter searches
Mihael Petač, 2020, izvirni znanstveni članek

Opis: We for the first time provide self-consistent axisymmetric phase-space distribution models for the Milky Way's dark matter (DM) halo which are carefully matched against the latest kinematic measurements through Bayesian analysis. By using broad priors on the individual galactic components, we derive conservative estimates for the astrophysical factors entering the interpretation of direct and indirect DM searches. While the resulting DM density profiles are in good agreement with previous studies, implying ρ⊙≈10-2 M⊙/pc3, the presence of baryonic disc leads to significant differences in the local DM velocity distribution in comparison with the standard halo model. For direct detection, this implies roughly 30% stronger cross section limits at DM masses near detectors maximum sensitivity and up to an order of magnitude weaker limits at the lower end of the mass range. Furthermore, by performing Monte Carlo simulations for the upcoming DARWIN and DarkSide-20k experiments, we demonstrate that upon successful detection of heavy DM with coupling just below the current limits, the carefully constructed axisymmetric models can eliminate bias and reduce uncertainties by more then 50% in the reconstructed DM coupling and mass, but also help in a more reliable determination of the scattering operator. Furthermore, the velocity anisotropies induced by the baryonic disc can lead to significantly larger annual modulation amplitude and sizable differences in the directional distribution of the expected DM-induced events. For indirect searches, we provide the differential J factors and compute several moments of the relative velocity distribution that are needed for predicting the rate of velocity-dependent annihilations. However, we find that accurate predictions are still hindered by large uncertainties regarding the DM distribution near the galactic center.
Najdeno v: ključnih besedah
Povzetek najdenega: ...dark matter, astrophysics, galaxies, high energy physics, experiments, phenomenology...
Ključne besede: dark matter, astrophysics, galaxies, high energy physics, experiments, phenomenology
Objavljeno: 01.10.2021; Ogledov: 683; Prenosov: 20
URL Polno besedilo (0,00 KB)
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14.
Experimental bounds on sterile-active neutrino mixing angles
Mihael Petač, 2015, magistrsko delo

Opis: Despite the success of the Standard Model in the last few decades, we know it is not complete. There is strong motivation for assuming the existence of additional heavy neutral leptons, which can account for active neutrino masses and possibly also have cosmological implications. In this work I consider the Standard Model with two neutral lepton singlets (sterile neutrinos) with degenerated masses in the range 20MeV - 2GeV. The constraints on the active-sterile neutrino mixing angles are evaluated based on recent neutrino oscillations data. Using these constraints the bounds from accelerator experiments are reanalyzed for the case of the considered model. Finally, the results are compared with cosmological constraints coming from Big Bang nucleosynthesis and the nMSM resonant leptogenesis.
Najdeno v: ključnih besedah
Povzetek najdenega: ...Sterile neutrinos, Neutrino mixing, See-saw, High-Energy Physics - Phenomenology, High-Energy Physics - Experiments...
Ključne besede: Sterile neutrinos, Neutrino mixing, See-saw, High-Energy Physics - Phenomenology, High-Energy Physics - Experiments
Objavljeno: 01.10.2021; Ogledov: 655; Prenosov: 21
.pdf Polno besedilo (1,93 MB)

15.
Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Serguei Vorobiov, Samo Stanič, Jon Paul Lundquist, Andrej Filipčič, P. Abreu, Lukas Zehrer, 2022, izvirni znanstveni članek

Najdeno v: ključnih besedah
Povzetek najdenega: ...cosmic ray experiments, ultra high energy, cosmic rays, physics of the early...
Ključne besede: cosmic ray experiments, ultra high energy, cosmic rays, physics of the early universe, Pierre Auger Observatory, Lorentz invariance violation effects
Objavljeno: 18.01.2022; Ogledov: 505; Prenosov: 14
URL Polno besedilo (0,00 KB)
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16.
Probing the fundamental nature of Dark Matter with the Large Synoptic Survey Telescope
Alex Drlica-Wagner, Yao-Yuan Mao, Susmita Adhikari, Robert Armstrong, Arka Banerjee, Nilanjan Banik, Keith Bechtol, Simeon Bird, Christopher Eckner, Gabrijela Zaharijas, 2019, projektna dokumentacija (idejni projekt, izvedbeni projekt)

Najdeno v: ključnih besedah
Povzetek najdenega: ...dark matter, high energy physics, astrophysical observations, cosmological observations, Large...
Ključne besede: dark matter, high energy physics, astrophysical observations, cosmological observations, Large Synoptic Survey Telescope (LSST)
Objavljeno: 03.05.2022; Ogledov: 255; Prenosov: 8
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17.
Dark Matter science in the era of LSST
Keith Bechtol, Alex Drlica-Wagner, Kevork N. Abazajian, Muntazir Abidi, Susmita Adhikari, Yacine Ali-Haïmoud, James Annis, Behzad Ansarinejad, Christopher Eckner, Gabrijela Zaharijas, 2019, projektna dokumentacija (idejni projekt, izvedbeni projekt)

Najdeno v: ključnih besedah
Povzetek najdenega: ...cosmology, nongalactic astrophysics, high energy astrophysical phenomena, high energy physics, experiments...
Ključne besede: cosmology, nongalactic astrophysics, high energy astrophysical phenomena, high energy physics, experiments
Objavljeno: 03.05.2022; Ogledov: 266; Prenosov: 8
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