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Nuclear Theory·nucl-th

Tuesday·August 8, 2017

13 papers—8 primary·5 cross-listed

All13Primary8Cross-lists5
  1. 09

    The s-process nucleosynthesis: impact of the uncertainties in the nuclear physics determined by Monte Carlo variations

    G. Cescutti · N. Nishimura · R. Hirschi · T. Rauscher · J. W. den Hartogh · A. St. J. Murphy

    We investigated the impact of uncertainties in neutron-capture and weak reactions (on heavy elements) on the s-process nucleosynthesis in low-mass stars and massive stars using a Monte-Carlo based approach. We performed extensive nuclear reaction network calculations that include newly evaluated temperature-dependent upper and lower limits for the individual reaction rates. We found beta-decay rate uncertainties affect only a few nuclei near s-process branchings, whereas most of the uncertainty in the final abundances is caused by uncertainties in the neutron capture rates. We suggest a list of uncertain rates as candidates for improved measurement by future experiments.

    ↳ astro-ph.SRnucl-exnucl-thMem.Soc.Ast.It.(2017)·1 citation
  2. 10

    Possible Beyond the Standard Model Physics Motivated by Muonic Puzzles

    Yu-Sheng Liu🇺🇸

    Recent measurements of the proton radius using the Lamb shift in muonic hydrogen are troublingly discrepant with values extracted from hydrogen spectroscopy and electron-proton scattering experiments. This discrepancy, which differs by more than five standard deviations, may be a signal of new physics caused by a violation of lepton universality. Another candidate for a new physics signal is the muon anomalous magnetic moment. The measurement at BNL differs from the standard model prediction by at least three standard deviations. Motivated by these two puzzles, first we use polarized lepton-nucleon elastic scattering to search for a new scalar boson, and furthermore we suggest new measurements of the nucleon form factors. Next, we display a method to analyze the beam dump experiments without using approximation on phase space, and we use it to constrain all possible new spin-0 and spin-1 particles, and a variety of other measurements to study the possibility of the new physics. Finally, assuming a new scalar boson can solve the two puzzles simultaneously, we present a general model-independent analysis and constrain the existence of the new physics.

    ↳ hep-phhep-exnucl-thphysics.atom-ph2 citations
  3. 11

    Neutrino scattering in supernovae and spin correlations of a unitary gas

    Zidu Lin · C. J. Horowitz

    Core collapse supernova simulations can be sensitive to neutrino interactions near the neutrinosphere. This is the surface of last scattering. We model the neutrinosphere region as a warm unitary gas of neutrons. A unitary gas is a low density system of particles with large scattering lengths. We calculate modifications to neutrino scattering cross sections because of the universal spin and density correlations of a unitary gas. These correlations can be studied in laboratory cold atom experiments. We find significant reductions in cross sections, compared to free space interactions, even at relatively low densities. These reductions could reduce the delay time from core bounce to successful explosion in multidimensional supernova simulations.

    ↳ astro-ph.HEcond-mat.quant-gasnucl-thPRC(2017)·12 citations
  4. 12

    On the hydrodynamic attractor of Yang-Mills plasma

    Michał Spaliński🇵🇱

    There is mounting evidence suggesting that relativistic hydrodynamics becomes relevant for the physics of quark-gluon plasma as the result of nonhydrodynamic modes decaying to an attractor apparent even when the system is far from local equilibrium. Here we determine this attractor for Bjorken flow in N=4 supersymmetric Yang-Mills theory using Borel summation of the gradient expansion of the expectation value of the energy momentum tensor. By comparing the result to numerical simulations of the flow based on the AdS/CFT correspondence we show that it provides an accurate and unambiguous approximation of the hydrodynamic attractor in this system. This development has important implications for the formulation of effective theories of hydrodynamics.

    ↳ hep-thhep-phnucl-thPLB(2018)·103 citations
  5. 13

    Importance of initial and final state effects for azimuthal correlations in p+Pb collisions

    Moritz Greif🇩🇪 · Carsten Greiner🇩🇪 · Björn Schenke🇺🇸 · Sören Schlichting🇺🇸 · Zhe Xu🇨🇳

    We investigate the relative importance of initial and final state effects on azimuthal correlations of gluons in low and high multiplicity p+Pb collisions. To achieve this, we couple Yang-Mills dynamics of pre-equilibrium gluon fields (IP-GLASMA) to a perturbative QCD based parton cascade for the final state evolution (BAMPS) on an event-by-event basis. We find that signatures of both the initial state correlations and final state interactions are seen in azimuthal correlation observables, such as , their strength depending on the event multiplicity and transverse momentum. Initial state correlations dominate in low multiplicity events for transverse momenta . While final state interactions are dominant in high multiplicity events, initial state correlations affect for as well as the pT integrated .

    ↳ hep-phnucl-thPRD(2017)·84 citations

Affiliations

first authorsco-authorsvia INSPIRE