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The observed amount of lithium for low metallicity population II stars (known as the Spite plateau) is a factor of $\sim 3-5$ lower than the predictions of the standard cosmology. Since the observations are limited to the local Universe…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-06 Maxim Pospelov , Niayesh Afshordi

Supernovae of type IIP are marked by the long plateau seen in their optical light curves. The plateau is believed to be the result of a recombination wave that propagates through the outflowing massive hydrogen envelope. Here, we…

High Energy Astrophysical Phenomena · Physics 2014-04-28 Tomer Goldfriend , Ehud Nakar , Re'em Sari

Resonance spectral lines such as H I Ly {\alpha}, Mg II h&k, and Ca II H&K that form in the solar chromosphere are influenced by the effects of 3D radiative transfer as well as partial redistribution (PRD). So far no one has modeled these…

Solar and Stellar Astrophysics · Physics 2016-12-28 Andrii V. Sukhorukov , Jorrit Leenaarts

The radiation background above the ionization edge of HeII varies strongly during and after helium reionization, because the attenuation length of such photons is relatively short (<40 Mpc) and because the ionizing sources (quasars) are…

Astrophysics · Physics 2009-10-02 Steven Furlanetto

We develop and apply a new framework for reconstructing the ionization history during the epoch of recombination with combinations of cosmic microwave background (CMB), baryon acoustic oscillation (BAO) and supernova data. We find a wide…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-15 Gabriel P. Lynch , Lloyd Knox , Jens Chluba

In the first paper of this series, we discussed analytically, in an approximate way, the mixing processes which occur in slowly rotating stars when the feed-back effects due to the diffusion-induced $\mu$-gradients are introduced in the…

Astrophysics · Physics 2009-11-07 Sylvie Theado , Sylvie Vauclair

The secondary-to-primary ratios are unique tools to investigate cosmic ray propagation mechanisms. In this work, we use the latest data of deuteron-to-helium~4 ratio and helium~3-to-helium~4 ratio measured by PAMELA combined with other…

High Energy Astrophysical Phenomena · Physics 2018-12-31 Juan Wu , Chen Huan

The 21-cm hyperfine line of neutral hydrogen is a useful tool to probe the conditions of the Universe during the Dark Ages, Cosmic Dawn, and the Epoch of Reionisation. In most of the current calculations, the 21-cm line signals at given…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-23 Jennifer Y. H. Chan , Qin Han , Kinwah Wu , Jason D. McEwen

The recent EDGES measurements of the global 21-cm signal from the cosmic dawn suggest that the kinetic temperature of the inter-galactic medium (IGM) might be significantly lower compared to its expected value. The colder IGM directly…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-02 Kanan K. Datta , Aritra Kundu , Ankit Paul , Ankita Bera

We update our previous work of a Langevin-with-interaction model for charmonium in heavy-ion collisions, by considering the effect due to recombination. We determine the contribution to J/psi yields from charm-anticharm pairs whose…

Nuclear Theory · Physics 2014-11-20 Clint Young , Edward Shuryak

A key assumption of the standard cosmological model is that the temperature of the cosmic microwave background (CMB) radiation scales with cosmological redshift $z$ as $T_{\rm CMB}(z) \propto (1+z)$ at all times after recombination at…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-10 J. Colin Hill , Boris Bolliet

We estimate the nuclear polarizability correction to atomic transition frequencies in various helium isotopes. This effect is non-negligible for high precision tests of quantum electrodynamics or accurate determination of the nuclear charge…

Nuclear Theory · Physics 2015-06-26 K. Pachucki , A. M. Moro

We study the effects of periodic matter in kaon regeneration, motivated by the possibility of parametric resonance in neutrino oscillations. The large imaginary parts of the forward kaon-nucleon scattering amplitudes and the decay width…

High Energy Physics - Phenomenology · Physics 2008-11-26 Evgeny Akhmedov , Augusto Barroso , Petteri Keränen

We have used semi-numerical simulations of reionization to study the behaviour of the power spectrum of the EoR 21-cm signal in redshift space. We have considered two models of reionization, one which has homogeneous recombination (HR) and…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-05 Suman Majumdar , Somnath Bharadwaj , T. Roy Choudhury

We consider the effect of optical depth of the 2 ^{3}S level on the nebular recombination spectrum of He I for a spherically symmetric nebula with no systematic velocity gradients. These calculations, using many improvements in atomic data,…

Astrophysics · Physics 2009-11-07 Robert A. Benjamin , Evan D. Skillman , Derck P. Smits

The coupled-channel model [Phys. Rev. A {\bf 59}, 363 (1999)] that yields converged low-energy phase shifts, and exact binding and resonance features in Ps-H [Phys. Rev. A {\bf 59}, 2058 (1999)] is applied to study Ps-He$^+$ scattering.…

Atomic Physics · Physics 2007-05-23 P K Biswas , H. M. Gupta

We examine in detail the changes in the production of primordial helium resulting from nonthermal neutrino momentum distributions produced by resonant transformation of electron-type neutrinos to steriles. These transformations, anti-nu_e…

Astrophysics · Physics 2007-05-23 Kevork Abazajian , Xiangdong Shi , George M. Fuller

We review the distortions of spectra of relic neutrinos due to the interactions with electrons, positrons, and neutrinos in the early universe. We solve integro-differential kinetic equations for the neutrino density matrix, including…

High Energy Physics - Phenomenology · Physics 2022-12-05 Kensuke Akita , Masahide Yamaguchi

We present the results of numerical simulations and experimental studies about the effects of resonant and random excitations on proton losses, emittances, and beam distributions in the Large Hadron Collider (LHC). In addition to shedding…

Accelerator Physics · Physics 2019-09-30 Miriam Fitterer , Giulio Stancari , Alexander Valishev , Stefano Redaelli , Daniel Valuch

We present observations and models of the behaviour of the HI and HeI lines between 1.6 and 2.2um in a small sample of compact HII regions. As in our previous papers on planetary nebulae, we find that the `pure' 1.7007um 4^3D-3^3P and…

Astrophysics · Physics 2009-11-07 S. L. Lumsden , P. J. Puxley , M. G. Hoare , T. J. T. Moore , N. A. Ridge