Nuclear Theory·nucl-th

Tuesday·November 27, 2018

18 papers—11 primary·7 cross-listed

12
[Submitted on 23 Nov 2018] (cross-list from hep-ph)
Quarkonium inside Quark-Gluon Plasma: Diffusion, Dissociation, Recombination and Energy Loss
Xiaojun Yao🇺🇸 · Berndt Müller🇺🇸
We consider the quarkonium diffusion, dissociation and recombination inside quark-gluon plasma. We compute scattering amplitudes in potential nonrelativistic QCD for relevant processes. These processes include the gluon absorption/emission at the order $g r$ , inelastic scattering at the order $g^{2} r$ and elastic scattering with medium constituents at the order $g^{2} r^{2}$ . We show these amplitudes satisfy the Ward identity. We also consider one-loop corrections. The dipole interaction between the color singlet and octet is not running at the one-loop level. Interference between the tree-level gluon absorption/emission and its thermal loop corrections cancels the collinear divergence in the $t$ -channel inelastic scattering. The inelastic scattering has no soft divergence because of the finite binding energy of quarkonium. We write out the diffusion, dissociation and recombination terms explicitly for a Boltzmann transport equation and define the dissociation and recombination rates. Furthermore, we calculate the diffusion coefficient of quarkonium. We find our result of diffusion coefficient differs from a previous calculation by two to three orders of magnitude. We explain this and can reproduce the previous result in a certain limit. Finally we discuss two mechanisms of quarkonium energy loss inside quark-gluon plasma.
Comments:
28 pages, 4 figures; added some explanations; added journal information
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.09644 [pdf]
PRD(2019)·81 citations
13
[Submitted on 24 Nov 2018] (cross-list from hep-ph)
New Insights on Low Energy $π N$ Scattering Amplitudes: Comprehensive Analyses at $O (p^{3})$ Level
Yu-Fei Wang🇨🇳 · De-Liang Yao🇨🇳 · Han-Qing Zheng🇨🇳
A production representation of partial-wave $S$ matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the $O (p^{3})$ results obtained in covariant baryon chiral perturbation theory within the extended-on-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in $S_{11}$ and $P_{11}$ channels, as conjectured in our previous paper~\citep{Wang:2017agd}, are firmly established. Specifically, the pole mass of the $S_{11}$ hidden resonance is determined to be $(895 \pm 81) - (164 \pm 23) i$ MeV, whereas, the virtual pole in the $P_{11}$ channel locates at $(966 \pm 18)$ MeV. It is found that analyses at the $O (p^{3})$ level improves significantly the fit quality, comparing with the previous $O (p^{2})$ one. Quantitative studies with cautious physical discussions are also conducted for the other $S$ - and $P$ -wave channels.
Comments:
38 pages. Published in Chinese Physics C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.09748 [pdf]
CPC(2019)·18 citations
14
[Submitted on 24 Nov 2018] (cross-list from hep-ph)
Comparing a few distributions of transverse momenta in high energy collisions
Qi Wang🇨🇳 · Pei-Pin Yang🇨🇳 · Fu-Hu Liu🇨🇳
Transverse momentum spectra of particles produced in high energy collisions are very important due to their relations to the excitation degree of interacting system. To describe the transverse momentum spectra, one can use more than one probability density functions of transverse momenta, which are simply called the functions or distributions of transverse momenta in some cases. In this paper, a few distributions of transverse momenta in high energy collisions are compared with each other in terms of plots to show some quantitative differences. Meanwhile, in the framework of Tsallis statistics, the distributions of momentum components, transverse momenta, rapidities, and pasudorapidities are obtained according to the analytical and Monte Carlo methods. These analyses are useful to understand carefully different distributions in high energy collisions.
Comments:
11 pages, 7 figures. Results in Physics, Accepted
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1811.09883 [pdf]
Results Phys.(2019)·6 citations
15
[Submitted on 25 Nov 2018] (cross-list from astro-ph.HE)
Surface tension of hot and dense quark matter under strong magnetic fields
G. Lugones🇧🇷 · A. G. Grunfeld🇦🇷
We study the surface tension of hot, highly magnetized three flavor quark matter droplets, focusing specifically on the thermodynamic conditions prevailing in neutron stars, hot lepton rich protoneutron stars and neutron star mergers. We explore the role of temperature, baryon number density, trapped neutrinos, droplet size and magnetic fields within the multiple reflection expansion formalism (MRE), assuming that astrophysical quark matter can be described as a mixture of free Fermi gases composed by quarks $u$ , $d$ , $s$ , electrons and neutrinos, in chemical equilibrium under weak interactions. We find that the total surface tension is rather unaffected by the size of the drop, but is quite sensitive to the effect of baryon number density, temperature, trapped neutrinos and magnetic fields (specially above $e B \sim 5 \times 1 0^{- 3} GeV^{2}$ ). Surface tensions parallel and transverse to the magnetic field span values up to $\sim$ 25 MeV/fm $^{2}$ . For $T ≲ 100$ MeV the surface tension is a decreasing function of temperature but above 100 MeV it increases monotonically with $T$ . Finally, we discuss some astrophysical consequences of our results.
Comments:
8 pages, 6 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.09954 [pdf]
PRC(2019)·38 citations
16
[Submitted on 25 Nov 2018] (cross-list from hep-ph)
Spin-isospin correlated configurations in complex nuclei and neutron skin effect in W $^{\pm}$ production in high-energy proton-lead collisions
Massimiliano Alvioli🇮🇹 · Mark Strikman🇺🇸
We extend our Monte Carlo generator of global configurations in nuclei to include different spatial distributions of protons and neutrons in heavy nuclei taking into account the difference of spatial correlations between two protons, two neutrons and proton-neutron pairs. These configurations are used for building an event generator for proton-heavy nucleus collisions at the LHC for final states with a hard interaction in the channels where cross section for p-p and p-n scattering differ. Soft interactions are taken into account in the color fluctuation extension of the Glauber algorithm taking into account the inherently different transverse geometry of soft and hard p-N collisions. We use the new event generator to test an interesting observation of Physics Letters B745 (2015) 73-78, that the ratio of W $^{+}$ /W $^{-}$ production rates in p-Pb collisions should significantly deviate from the inclusive value for peripheral collisions due to the presence of a neutron skin. We qualitatively confirm expectation of Physics Letters B745 (2015) 73-78, though for a realistic centrality trigger, we find the effect to be a factor of two smaller than the original estimate.
Comments:
27 pages, 11 figures. This version was accepted for publication by Physical Review C, 5 August 2019. Additional files and information at http://sites.psu.edu/color
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1811.10078 [pdf]
PRC(2019)·21 citations
17
[Submitted on 26 Nov 2018] (cross-list from hep-ph)
The $D ˉ^{*} D ˉ^{*} Σ_{c}$ Three-Body System
Manuel Pavon Valderrama🇨🇳
In the molecular picture the hidden-charm, pentaquark-like $P_{c} (4450)$ resonance is a $D ˉ^{*} Σ_{c}$ bound state with quantum numbers $I = \frac{1}{2}$ and $J^{P} = \frac{3}{2}^{-}$ . If this happens to be the case, it will be natural to expect the existence of $D ˉ^{*} D ˉ^{*} Σ_{c}$ three-body bound states. The most probable quantum numbers for a bound $D ˉ^{*} D ˉ^{*} Σ_{c}$ trimer are the isoscalar $J^{P} = \frac{1}{2}^{+}$ , $\frac{5}{2}^{+}$ and the isovector $J^{P} = \frac{3}{2}^{+}$ , $\frac{5}{2}^{+}$ configurations. Calculations within a contact-range theory indicate a trimer binding energy $B_{3} \sim 3 - 5 MeV$ and $14 - 16 MeV$ for the isoscalar $\frac{1}{2}^{+}$ and $\frac{5}{2}^{+}$ states and $B_{3} \sim 1 - 3 MeV$ and $3 - 5 MeV$ for the isovector $\frac{3}{2}^{+}$ and $\frac{5}{2}^{+}$ states, respectively, with $B_{3}$ relative to the $D ˉ^{*} P_{c} (4450)$ threshold. These predictions are affected by a series of error sources that we discuss in detail.
Comments:
8 pages, 1 figure, extended discussion on regulator dependence, corresponds to published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1811.10173 [pdf]
PRD(2019)·5 citations
18
[Submitted on 26 Nov 2018] (cross-list from hep-ph)
Regularization issues for a cold and dense quark matter model in $β -$ equilibrium
Dyana C. Duarte🇧🇷 · Ricardo L.S. Farias🇧🇷 · Rudnei O. Ramos🇧🇷
A regularization scheme that explicitly separates vacuum contributions from medium effects is applied to a Nambu--Jona-Lasinio model with diquark interactions and in $β -$ equilibrium. We perform a comparison of this proposed scheme with the more traditional one, where no separation of vacuum and medium effects is done. Our results point to both qualitative and quantitative important differences between these two methods, in special regarding the phase structure of the model in the cold and dense nuclear matter case.
Comments:
14 pages, 6 figures, replaced with updated version matching the published one
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1811.10598 [pdf]
PRD(2019)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE

Quarkonium inside Quark-Gluon Plasma: Diffusion, Dissociation, Recombination and Energy Loss

New Insights on Low Energy πN Scattering Amplitudes: Comprehensive Analyses at O(p3) Level

Comparing a few distributions of transverse momenta in high energy collisions

Surface tension of hot and dense quark matter under strong magnetic fields

Spin-isospin correlated configurations in complex nuclei and neutron skin effect in W± production in high-energy proton-lead collisions

The Dˉ∗Dˉ∗Σc​ Three-Body System

Regularization issues for a cold and dense quark matter model in β−equilibrium

Affiliations

New Insights on Low Energy $π N$ Scattering Amplitudes: Comprehensive Analyses at $O (p^{3})$ Level

Spin-isospin correlated configurations in complex nuclei and neutron skin effect in W $^{\pm}$ production in high-energy proton-lead collisions

The $D ˉ^{} D ˉ^{} Σ_{c}$ Three-Body System

Regularization issues for a cold and dense quark matter model in $β -$ equilibrium