Wed·Jun 28, 2017Wednesday·June 28, 2017

1. 01*

   Color Screening and Regeneration of Bottomonia in High-Energy Heavy-Ion Collisions

   Xiaojian Du🇺🇸 · Min He🇨🇳 · Ralf Rapp🇺🇸

   The production of ground-state and excited bottomonia in ultrarelativistic heavy-ion collisions is investigated within a kinetic-rate equation approach including regeneration. We augment our previous calculations by an improved treatment of medium effects, with temperature-dependent binding energies and pertinent reaction rates, $B$-meson resonance states in the equilibrium limit near the hadronization temperature, and a lattice-QCD based equation of state for the bulk medium. In addition to the centrality dependence of the bottomonium yields we compute their transverse-momentum ($p_T$) spectra and elliptic flow with momentum-dependent reaction rates and a regeneration component based on $b$-quark spectra from a nonperturbative transport model of heavy-quark diffusion. The latter has noticeable consequences for the shape of the bottomonium $p_T$ spectra. We quantify how uncertainties in the various modeling components affect the predictions for observables. Based on this we argue that the ${\rm Y}(1S)$ suppression is a promising observable for mapping out the in-medium properties of the QCD force, while ${\rm Y}(2S)$ production can help to quantify the role of regeneration from partially thermalized $b$ quarks.

   ↳ hep-phnucl-exnucl-thPRC(2017)·198 citations
2. 02*

   Precision Theoretical Analysis of Neutron Radiative Beta Decay to Order "O(\alpha^2/\pi^2)"

   A. N. Ivanov🇦🇹 · R. Höllwieser🇦🇹 · N. I. Troitskaya🇦🇹 · M. Wellenzohn🇦🇹 · Ya. A. Berdnikov🇷🇺

   In the Standard Model (SM) we calculate the decay rate of the neutron radiative beta decay to order "O(\alpha^2/\pi^2 ~ 10^{-5})", where "\alpha$"is the fine--structure constant, and radiative corrections to order "O(\alpha/\pi ~ 10^{-3})". The obtained results together with the recent analysis of the neutron radiative beta decay to next-to-leading order in the large proton-mass expansion, performed by Ivanov et al. Phys. Rev. D95, 033007 (2017), describe recent experimental data by the RDK II Collaboration (Bales et al., Phys. Rev. Lett. 116, 242501 (2016)) within 1.5 standard deviations. We argue a substantial influence of strong low-energy interactions of hadrons coupled to photons on the properties of the amplitude of the neutron radiative beta decay under gauge transformations of real and virtual photons.

   ↳ hep-phastro-ph.COhep-exnucl-ex+1PRD(2017)·13 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.