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Recent cosmological observations, such as the measurement of the primordial 4He abundance, CMB, and large scale structure, give preference to the existence of extra radiation component, Delta N_nu > 0. The extra radiation may be accounted…

高能物理 - 唯象学 · 物理学 2011-06-27 Kazunori Nakayama , Fuminobu Takahashi , Tsutomu T. Yanagida

Asymmetric Dark Matter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the Dark Matter (DM) abundance. Both asymmetries are usually generated by the same mechanism and…

高能物理 - 唯象学 · 物理学 2015-06-04 Mattias Blennow , Enrique Fernandez-Martinez , Olga Mena , Javier Redondo , Paolo Serra

We construct the New Minimal Standard Model that incorporates the new discoveries of physics beyond the Minimal Standard Model (MSM): Dark Energy, non-baryonic Dark Matter, neutrino masses, as well as baryon asymmetry and cosmic inflation,…

高能物理 - 唯象学 · 物理学 2009-09-29 Hooman Davoudiasl , Ryuichiro Kitano , Tianjun Li , Hitoshi Murayama

Recently, the Planck satellite found a larger and most precise value of the matter energy density, that impacts on the present values of other cosmological parameters such as the Hubble constant, the present cluster abundances and the age…

宇宙学与河外天体物理 · 物理学 2014-02-11 A. Caramete , L. A. Popa

Blazar-Boosted Dark Matter (BBDM) is a novel mechanism whereby dark matter (DM) particles are accelerated to ultrarelativistic energies through interactions with blazar jets. Focusing on a vector portal DM model, we systematically…

高能物理 - 唯象学 · 物理学 2025-09-04 Jin-Wei Wang

The flux of high-energy cosmic-ray electrons plus positrons recently measured by the DArk Matter Particle Explorer (DAMPE) exhibits a tentative peak excess at an energy of around $1.4$ TeV. In this paper, we consider the minimal gauged…

高能物理 - 唯象学 · 物理学 2018-09-03 Nobuchika Okada , Osamu Seto

The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos N_eff. This quantity, in case of no extra degrees of freedom,…

宇宙学与河外天体物理 · 物理学 2015-03-17 G. Mangano , G. Miele , S. Pastor , O. Pisanti , S. Sarikas

We study the complete cosmological evolution of dark matter (DM) density fluctuations for DM particles that decoupled being ultrarelativistic during the radiation dominated era which is the case of keV scale warm DM (WDM). The new framework…

宇宙学与河外天体物理 · 物理学 2015-06-03 H. J. de Vega , N. G. Sanchez

Cosmological constraints are usually derived under the assumption of a $6$ parameters $\Lambda$-CDM theoretical framework or simple one-parameter extensions. In this paper we present, for the first time, cosmological constraints in a…

宇宙学与河外天体物理 · 物理学 2015-12-30 Eleonora Di Valentino , Alessandro Melchiorri , Joseph Silk

After reviewing the main mechanisms by which cosmological measurements constrain the sum of neutrino masses, I give the current reached upper limits, emphasizing the level of model-dependence. A large improvement is to be expected with…

宇宙学与河外天体物理 · 物理学 2015-03-17 Stephane Plaszczynski

Neutrinos are perhaps the most elusive known particles in the universe. We know they have some nonzero mass, but unlike all other particles, the absolute scale remains unknown. In addition, their fundamental nature is uncertain; they can…

核理论 · 物理学 2023-07-31 A. Belley , T. Miyagi , S. R. Stroberg , J. D. Holt

Recent DESI results indicate a strong preference for dynamical dark energy (DE) when baryon acoustic oscillation (BAO) measurements are combined with supernovae (SNe) and cosmic microwave background (CMB) data using the…

宇宙学与河外天体物理 · 物理学 2026-01-26 Shubham Barua , Shantanu Desai

Sterile neutrinos with the mass in the keV range are interesting warm dark matter (WDM) candidates. The restrictions on their parameters (mass and mixing angle) obtained by current X-ray missions (XMM-Newton or Chandra) can only be improved…

天体物理学 · 物理学 2008-11-26 Alexey Boyarsky , Jan Willem den Herder , Andrey Neronov , Oleg Ruchayskiy

Since the B-mode polarization of the cosmic microwave background (CMB) was detected by the BICEP2 experiment and an unexpectedly large tensor-to-scalar ratio, $r=0.20^{+0.07}_{-0.05}$, was found, the base standard cosmology should at least…

宇宙学与河外天体物理 · 物理学 2014-07-22 Jing-Fei Zhang , Yun-He Li , Xin Zhang

The number of effective relativistic neutrino species represents a fundamental probe of the thermal history of the early Universe, and as such of the Standard Model of Particle Physics. Traditional approaches to the neutrino decoupling are…

高能物理 - 唯象学 · 物理学 2019-09-09 Miguel Escudero

Cosmic acceleration is widely believed to require either a source of negative pressure (i.e., dark energy), or a modification of gravity, which necessarily implies new degrees of freedom beyond those of Einstein gravity. In this paper we…

高能物理 - 理论 · 物理学 2017-06-28 Lasha Berezhiani , Justin Khoury , Junpu Wang

Cosmological determinations of the number of relativistic neutrino species, $N^{ }_{\rm eff}$, are becoming increasingly accurate, and further improvements are expected both from CMB and BBN data. Given this context, we update the…

高能物理 - 唯象学 · 物理学 2026-02-16 M. Escudero , G. Jackson , M. Laine , S. Sandner

We propose boosted dark matter (BDM) as a possible explanation for the excess of keV electron recoil events observed by XENON1T. BDM particles have velocities much larger than those typical of virialized dark matter, and, as such,…

高能物理 - 唯象学 · 物理学 2020-10-15 Bartosz Fornal , Pearl Sandick , Jing Shu , Meng Su , Yue Zhao

One of important questions concerning particles which compose the Dark Matter (DM) is their average speed. We consider the model of relativistic weakly interacting massive particles and try to impose an upper bound on their actual and past…

天体物理学 · 物理学 2014-11-18 Julio C. Fabris , Ilya L. Shapiro , Flavia Sobreira

We examine the performance of the six-parameter $\Lambda$CDM model and its extensions in light of recent cosmological observations, with particular focus on neutrino properties inferred from cosmology. Using a broad suite of nine…

宇宙学与河外天体物理 · 物理学 2025-02-12 Helena García Escudero , Kevork N. Abazajian