Nuclear Theory·nucl-th

Thursday·July 7, 2016

11 papers—3 primary·8 cross-listed

04
[Submitted on 11 Aug 2014] (cross-list from hep-ex)
Direct photon production in Au+Au collisions at $s_{N N} = 200$ GeV at STAR
Chi Yang🇨🇳
We present the direct photon production for $1 < p_{T} < 10$ GeV/ $c$ derived from continuum in the dielectron invariant mass region $0.1 < M_{ee} < 0.3$ GeV/ $c^{2}$ from one billion $s_{N N} = 200$ GeV Au+Au events taken in year 2010 and 2011. A clear excess in the invariant yield compared to the number of binary collision scaled $p + p$ reference is observed in the \pt~range 1-4 GeV/ $c$ . Model calculations with contributions from thermal radiation and initial hard parton scattering are consistent within uncertainties with the direct photon invariant yield.
Comments:
4 pages, 5 figures, QM2014 proceedings
Subjects:
High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1408.2371 [pdf]
NPA(2014)·7 citations
05
[Submitted on 6 Jul 2016] (cross-list from nucl-ex)
Direct virtual photon production in Au+Au collisions at $s_{N N}$ = 200 GeV
STAR Collaboration
We report the direct virtual photon invariant yields in the transverse momentum ranges $1 < p_{T} < 3$ GeV/ $c$ and $5 < p_{T} < 10$ GeV/ $c$ at mid-rapidity derived from the dielectron invariant mass continuum region $0.10 < M_{ee} < 0.28$ GeV/ $c^{2}$ for 0-80\% minimum-bias Au+Au collisions at $s_{N N} = 200$ GeV. A clear excess in the invariant yield compared to the number-of-binary-collisions ( $N_{bin}$ ) scaled $p + p$ reference is observed in the $p_{T}$ range $1 < p_{T} < 3$ GeV/ $c$ . For $p_{T} > 6$ GeV/ $c$ the production follows $N_{bin}$ scaling. Model calculations with contributions from thermal radiation and initial hard parton scattering are consistent within uncertainties with the direct virtual photon invariant yield.
Comments:
9 pages, 6 figures
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.01447 [pdf]
PLB(2017)·96 citations
06
[Submitted on 6 Jul 2016] (cross-list from astro-ph.HE)
Nuclear neutrino energy spectra in high temperature astrophysical environments
G. Wendell Misch🇨🇳 · George M. Fuller🇺🇸
Astrophysical environments that reach temperatures greater than $\sim$ 100 keV can have significant neutrino energy loss via both plasma processes and nuclear weak interactions. We find that nuclear processes likely produce the highest-energy neutrinos. Among the important weak nuclear interactions are both charged current channels (electron capture/emission and positron capture/emission) and neutral current channels (de-excitation of nuclei via neutrino pair emission). We show that in order to make a realistic prediction of the nuclear neutrino spectrum, one must take nuclear structure into account; in some cases, the most important transitions may involve excited states, possibly in both parent and daughter nuclei. We find that the standard technique of producing a neutrino energy spectrum by using a single transition with a Q-value and matrix element chosen to fit published neutrino production rates and energy losses will not accurately capture important spectral features.
Comments:
11 pages, 17 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1607.01448 [pdf]
PRC(2016)·15 citations
07
[Submitted on 6 Jul 2016] (cross-list from hep-ph)
Axial form factor of the nucleon at large momentum transfers
I.V. Anikin🇩🇪 · V.M. Braun🇩🇪 · N. Offen🇩🇪
Motivated by the emerging possibilities to study threshold pion electroproduction at large momentum transfers at Jefferson Laboratory following the 12 GeV upgrade, we provide a short theory summary and an estimate of the nucleon axial form factor for large virtualities in the $Q^{2} = 1 - 10 GeV^{2}$ range using next-to-leading order light-cone sum rules.
Comments:
A comparison to the new neutrino data analysis and several references added. Final version to appear in Phys.Rev.D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1607.01504 [pdf]
PRD(2016)·27 citations
08
[Submitted on 6 Jul 2016] (cross-list from cond-mat.quant-gas)
Effective Field Theory for Few-Boson Systems
Betzalel Bazak🇫🇷 · Moti Eliyahu🇮🇱 · Ubirajara van Kolck🇫🇷
We study universal bosonic few-body systems within the framework of effective field theory at leading order (LO). We calculate binding energies of systems of up to six particles and the atom-dimer scattering length. Convergence to the limit of zero-range two- and three-body interactions is shown, indicating that no additional few-body interactions need to be introduced at LO. Generalizations of the Tjon line are constructed, showing correlations between few-body binding energies and the binding energy of the trimer, for a given dimer energy. As a specific example, we implement our theory for 4He atomic systems, and show that the results are in surprisingly good agreement with those of sophisticated 4He-4He potentials. Potential implications for the convergence of the EFT expansion are discussed.
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
1607.01509 [pdf]
PRA(2016)·47 citations
09
[Submitted on 6 Jul 2016] (cross-list from hep-th)
Charge redistribution from anomalous magnetovorticity coupling
Koichi Hattori🇨🇳 · Yi Yin🇺🇸
We investigate novel transport phenomena in a chiral fluid originated from an interplay between a vorticity and strong magnetic field, which induces a redistribution of vector charges in the system and an axial current along the magnetic field. The corresponding transport coefficients are obtained from an energy-shift argument for the chiral fermions in the lowest Landau level (LLL) due to a spin-vorticity coupling and also from diagrammatic computations on the basis of the linear response theory. Based on consistent results from the both methods, we observe that the transport coefficients are proportional to the anomaly coefficient and are independent of temperature and chemical potential. We therefore speculate that these transport phenomena are connected to quantum anomaly.
Comments:
5 pages, 1 figure. Typos corrected. Published in PRL
Subjects:
High Energy Physics — Theory (hep-th); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.01513 [pdf]
PRL(2016)·49 citations
10
[Submitted on 6 Jul 2016] (cross-list from hep-ph)
Dynamical scheme for hadronization with first-order phase transition
Bohao Feng🇨🇳 · Zhe Xu🇨🇳 · Carsten Greiner🇩🇪
We present a dynamical scheme for hadronization with first-order confinement phase transition. The thermodynamical conditions of phase equilibrium, the fluid velocity profile, and the dissipative effect determine the macroscopic changes of the parton volume and the corresponding hadron volume during the phase transition. The macroscopic volume changes are the basis for building up a dynamical scheme by considering microscopic transition processes from partons to hadrons and backwards. The established scheme is proved by comparing the numerical results with the analytical solutions in the case of a one-dimensional expansion of a dissipative fluid with Bjorken boost invariance. The comparisons show almost perfect agreements, which demonstrate the applicability of the introduced scheme.
Comments:
12 pages, 7 figues; minor corrections, 1 figure added; published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.01644 [pdf]
PRC(2017)·6 citations
11
[Submitted on 6 Jul 2016] (cross-list from hep-ph)
Revealing proton shape fluctuations with incoherent diffraction at high energy
Heikki Mäntysaari🇺🇸 · Björn Schenke🇺🇸
The differential cross section of exclusive diffractive vector meson production in electron proton collisions carries important information on the geometric structure of the proton. More specifically, the coherent cross section as a function of the transferred transverse momentum is sensitive to the size of the proton, while the incoherent, or proton dissociative cross section is sensitive to fluctuations of the gluon distribution in coordinate space. We show that at high energies the experimentally measured coherent and incoherent cross sections for the production of $J /Ψ$ mesons are very well reproduced within the color glass condensate framework when strong geometric fluctuations of the gluon distribution in the proton are included. For $ρ$ meson production we also find reasonable agreement. We study in detail the dependence of our results on various model parameters, including the average proton shape, analyze the effect of saturation scale and color charge fluctuations and constrain the degree of geometric fluctuations.
Comments:
16 pages, 17 figures. v2: new references and clarifications, published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.01711 [pdf]
PRD(2016)·159 citations

Affiliations

first authorsco-authorsvia INSPIRE