Nuclear Theory·nucl-th

Tuesday·June 4, 2019

15 papers—10 primary·5 cross-listed

11
Improved Gauss law model and in-medium heavy quarkonium at finite density and velocity
David Lafferty🇩🇪 · Alexander Rothkopf🇳🇴
We explore the in-medium properties of heavy-quarkonium states at finite baryo-chemical potential and finite transverse momentum based on a modern complex-valued potential model. Our starting point is a novel, rigorous derivation of the generalized Gauss law for in-medium quarkonium, combining the non-perturbative physics of the vacuum bound state with a weak coupling description of the medium degrees of freedom. Its relation to previous models in the literature is discussed. We show that our approach is able to reproduce the complex lattice QCD heavy quark potential even in the non-perturbative regime, using a single temperature dependent parameter, the Debye mass $m_{D}$ . After vetting the Gauss-law potential with state-of-the-art lattice QCD data, we extend it to the regime of finite baryon density and finite velocity, currently inaccessible to first principles simulations. In-medium spectral functions computed from the Gauss-law potential are subsequently used to estimate the $ψ^{'} / J / ψ$ ratio in heavy-ion collisions at different beam energies and transverse momenta. We find qualitative agreement with the predictions from the statistical model of hadronization for the $s_{N N}$ dependence and a mild dependence on the transverse momentum.
↳ hep-phhep-latnucl-thPRD(2020)·82 citations
12
Discussions on the Line-shape of $X (4660)$ Resonance
Qin-Fang Cao🇨🇳 · Hong-Rong Qi🇨🇳 · Yu-Fei Wang🇨🇳 · Han-Qing Zheng🇨🇳
A careful reanalysis is made on $e^{+} e^{-} \to X (4660) \to (Λ_{c} Λ ˉ_{c}) / (ψ^{'} π π)$ processes, aiming at resolving the apparent conflicts between Belle and BESIII data above $Λ_{c} Λ ˉ_{c}$ threshold. We use a model containing a Breit-Wigner resonance and $Λ_{c} Λ ˉ_{c}$ four-point contact interactions, with which the enhancement right above the $Λ_{c} Λ ˉ_{c}$ threshold is well explained by a virtual pole generated by $Λ_{c} Λ ˉ_{c}$ attractive final state interaction, located at $M_{V} = 4.566 \pm 0.007$ GeV. Meanwhile, $X (4660)$ remains to be a typical Breit-Wigner resonance, and is hence of confinement nature. Our analysis strongly suggests the existence of the virtual pole with statistical significance of $4.2$ standard deviation ( $σ$ ). Nevertheless, the conclusion crucially depends on the line-shape of cross sections which are of limited statistics, hence we urge new experimental analyses from Belle II, BESIII, and LHCb to settle the issue.
↳ hep-phnucl-thPRD(2019)·32 citations
13
Flavor hierarchy of jet quenching in relativistic heavy-ion collisions
Wen-Jing Xing🇨🇳 · Shanshan Cao🇺🇸 · Guang-You Qin🇨🇳 · Hongxi Xing🇨🇳
Relativistic heavy-ion experiments have observed similar quenching effects for (prompt) $D$ mesons compared to charged hadrons for transverse momenta larger than 6-8~GeV, which remains a mystery since heavy quarks typically lose less energies in quark-gluon plasma than light quarks and gluons. Recent measurements of the nuclear modification factors of $B$ mesons and $B$ -decayed $D$ mesons by the CMS Collaboration provide a unique opportunity to study the flavor hierarchy of jet quenching. Using a linear Boltzmann transport model combined with hydrodynamics simulation, we study the energy loss and nuclear modification for heavy and light flavor jets in high-energy nuclear collisions. By consistently taking into account both quark and gluon contributions to light and heavy flavor hadron productions within a next-to-leading order perturbative QCD framework, we obtain, for the first time, a satisfactory description of the experimental data on the nuclear modification factors for charged hadrons, $D$ mesons, $B$ mesons and $B$ -decayed $D$ mesons simultaneously over a wide range of transverse momenta (8-300~GeV). This presents a solid solution to the flavor puzzle of jet quenching and constitutes a significant step towards the precision study of jet-medium interaction. Our study predicts that at transverse momenta larger than 30-40~GeV, $B$ mesons also exhibit similar suppression effects to charged hadrons and $D$ mesons, which may be tested by future measurements.
↳ hep-phnucl-exnucl-thPLB(2020)·62 citations
14
Kibble-Zurek Scaling in a Holographic p-wave Superconductor
Yanyan Bu🇨🇳 · Mitsutoshi Fujita🇨🇳 · Shu Lin🇨🇳
We study the Kibble-Zurek mechanism in a 2d holographic p-wave superconductor model with a homogeneous source quench on the critical point. We derive, on general grounds, the scaling of the Kibble-Zurek time, which marks breaking-down of adiabaticity. It is expressed in terms of four critical exponents, including three static and one dynamical exponents. Via explicit calculations within a holographic model, we confirm the scaling of the Kibble-Zurek time and obtain the scaling functions in the quench process. We find the results are formally similar to a homogeneous quench in a higher dimensional holographic s-wave superconductor. The similarity is due to the special type of quench we take. We expect differences in the quench dynamics if the condition of homogeneous source and dominance of critical mode are relaxed.
↳ hep-thcond-mat.supr-connucl-thPRD(2020)·6 citations
15
Using bottomonium production as a tomographic probe of the quark-gluon plasma
Michael Strickland🇺🇸
The suppression of bottomonia in ultrarelativistic heavy-ion collisions is a smoking gun for the production of a strongly interacting final state in ultrarelativistic heavy-ion collisions. Furthermore, these final state interactions are consistent with the production of a hot hydrodynamically expanding quark-gluon plasma with initial temperatures on the order of 600-700 MeV at LHC collision energies. Models which incorporate plasma screening and bound-state breakup based on high-temperature quantum chromodynamics are in good agreement with the centrality, transverse-momentum, and rapidity dependence of the suppression seen in the highest energy LHC Pb-Pb collisions. The models of heavy-quark bound state breakup/formation are coupled to the soft dynamics of the quark-gluon plasma using 3+1d relativistic anisotropic hydrodynamics. At later times, excited state feed-down is taken into account using independently constrained excited state feed down fractions. Comparisons with LHC experimental data are consistent with primordial suppression of all bottomonium states, with states having the lowest binding energies being the ones which suffer the most suppression. In this proceedings contribution, I will review recent work to (a) include the effects of regeneration on bottomonium production and (b) to assess the effects of a rapidly changing in-medium potential on bottomonium production in the quark-gluon plasma.
↳ hep-phnucl-thPoS(2020)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Improved Gauss law model and in-medium heavy quarkonium at finite density and velocity

Discussions on the Line-shape of X(4660) Resonance

Flavor hierarchy of jet quenching in relativistic heavy-ion collisions

Kibble-Zurek Scaling in a Holographic p-wave Superconductor

Using bottomonium production as a tomographic probe of the quark-gluon plasma

Affiliations

Discussions on the Line-shape of $X (4660)$ Resonance