Nuclear Theory·nucl-th

Wednesday·September 21, 2016

7 papers—5 primary·2 cross-listed

01
Competitive effects of nuclear deformation and density dependence of $Λ N$ interaction
M. Isaka🇯🇵 · Y. Yamamoto🇯🇵 · T h.A. Rijken🇯🇵
Competitive effects of nuclear deformation and density dependence of $Λ N$ -interaction in $Λ$ binding energies $B_{Λ}$ of hypernuclei are studied systematically on the basis of the baryon-baryon interaction model ESC including many-body effects. By using the $Λ N$ G-matrix interaction derived from ESC, we perform microscopic calculations of $B_{Λ}$ in $Λ$ hypernuclei within the framework of the antisymmetrized molecular dynamics under the averaged-density approximation. The calculated values of $B_{Λ}$ reproduce experimental data within a few hundred keV in the wide mass regions from 9 to 51. It is found that competitive effects of nuclear deformation and density dependence of $Λ N$ -interaction work decisively for fine tuning of $B_{Λ}$ values.
nucl-thPRC(2016)·17 citations
02
Heavy flavor $R_{AA}$ and $v_{n}$ in event-by-event viscous relativistic hydrodynamics
Caio A. G. Prado🇧🇷 · Jacquelyn Noronha-Hostler🇺🇸 · Mauro R. Cosentino🇧🇷 · Marcelo G. Munhoz🇧🇷 · Jorge Noronha🇧🇷 · Alexandre A. P. Suaide🇧🇷
Recently it has been shown that a realistic description of the medium via event-by-event viscous hydrodynamics plays an important role in the long-standing $R_{AA}$ vs. $v_{2}$ puzzle at high $p_{T}$ . In this proceedings we begin to extend this approach to the heavy flavor sector by investigating the effects of full event-by-event fluctuating hydrodynamic backgrounds on the nuclear suppression factor and $v_{2} {2}$ of heavy flavor mesons and non-photonic electrons at intermediate to high $p_{T}$ . We also show results for $v_{3} {2}$ of $B^{0}$ and D $^{0}$ for PbPb collisions at $s = 2.76$ TeV.
nucl-thhep-phnucl-exJ.Phys.Conf.Ser.(2017)·7 citations
03
Quark and Gluon Production from a Boost-invariantly Expanding Color Electric Field
Hidetoshi Taya🇯🇵
Particle production from an expanding classical color electromagnetic field is extensively studied, motivated by the early stage dynamics of ultra-relativistic heavy ion collisions. We develop a formalism at one-loop order to compute the particle spectra by canonically quantizing quark, gluon and ghost fluctuations under the presence of such an expanding classical color background field; the canonical quantization is done in the $τ$ - $η$ coordinates in order to take into account manifestly the expanding geometry. As a demonstration, we model the expanding classical color background field by a boost-invariantly expanding homogeneous color electric field with lifetime $T$ , for which we obtain analytically the quark and gluon production spectra by solving the equations of motion of QCD non-perturbatively with respect to the color electric field. In this paper we study (i) finite lifetime effect which is found to modify significantly the particle spectra from those expected from the Schwinger formula; (ii) the difference between the quark and gluon production; and (iii) the quark mass dependence of the production spectra. Implications of these results to ultra-relativistic heavy ion collisions are also discussed.
nucl-thhep-phPRD(2017)·13 citations
04
Collisional broadening of angular correlations in a multiphase transport model
Terrence Edmonds🇨🇳 · Qingfeng Li🇨🇳 · Fuqiang Wang🇨🇳
Systematic comparisons of jetlike correlation data to radiative and collisional energy loss model calculations are essential to extract transport properties of the quark-gluon medium created in relativistic heavy ion collisions. This paper presents a transport study of collisional broadening of jetlike correlations, by following parton-parton collision history in a multiphase transport (AMPT) model. The correlation shape is studied as a function of the number of parton-parton collisions suffered by a high transverse momentum probe parton ( $N_{coll}$ ) and the azimuth of the probe relative to the reaction plane ( $ϕ_{fin.}^{probe}$ ). Correlation is found to broaden with increasing $N_{coll}$ and $ϕ_{fin.}^{probe}$ from in- to out-of-plane direction. This study provides a transport model reference for future jet-medium interaction studies.
nucl-thnucl-exNPA(2017)·4 citations
05
Non-boost-invariant dissipative hydrodynamics
Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱 · Michael Strickland🇺🇸 · Leonardo Tinti🇵🇱
The one-dimensional non-boost-invariant evolution of the quark-gluon plasma, presumably produced during the early stages of heavy-ion collisions, is analyzed within the frameworks of viscous and anisotropic hydrodynamics. We neglect transverse dynamics and assume homogeneous conditions in the transverse plane but, differently from Bjorken expansion, we relax longitudinal boost invariance in order to study the rapidity dependence of various hydrodynamical observables. We compare the results obtained using several formulations of second-order viscous hydrodynamics with a recent approach to anisotropic hydrodynamics, which treats the large initial pressure anisotropy in a non-perturbative fashion. The results obtained with second-order viscous hydrodynamics depend on the particular choice of the second-order terms included, which suggests that the latter should be included in the most complete way. The results of anisotropic hydrodynamics and viscous hydrodynamics agree for the central hot part of the system, however, they differ at the edges where the approach of anisotropic hydrodynamics helps to control the undesirable growth of viscous corrections observed in standard frameworks.
nucl-thhep-phPRC(2016)·21 citations
06
Glue spin and helicity in proton from lattice QCD
Yi-Bo Yang🇺🇸 · Raza Sabbir Sufian🇺🇸 · Andrei Alexandru🇺🇸 · Terrence Draper🇺🇸 · Michael J. Glatzmaier🇺🇸 · Keh-Fei Liu🇺🇸 · Yong Zhao🇺🇸
We report the first lattice QCD calculation of the glue spin in the nucleon. The lattice calculation is carried out with valence overlap fermions on 2+1 flavor DWF gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The glue spin $S_{G}$ in the Coulomb gauge in the $MS$ scheme is obtained with the 1-loop perturbative matching. We find the results fairly insensitive to lattice spacing and quark masses. We also find that the proton momentum dependence of $S_{G}$ in the range $0 \leq ∣ p ∣ < 1.5$ GeV is very mild, and we determine it in the large momentum limit to be $S_{G} = 0.251 (47) (16)$ at the physical pion mass in the $MS$ scheme at $μ^{2} = 10$ GeV $^{2}$ . If the matching procedure in large momentum effective theory is neglected, $S_{G}$ is equal to the glue helicity measured in high-energy scattering experiments.
↳ hep-phhep-latnucl-thPRL(2017)·97 citations
07
Multi-particle correlations and KNO scaling in the medium-induced jet evolution
Miguel A. Escobedo🇫🇷 · Edmond Iancu🇫🇷
We study the gluon distribution produced via successive medium-induced branchings by an energetic jet propagating through a weakly-coupled quark-gluon plasma. We show that under suitable approximations the evolution of the jet can be described as a classical stochastic process, which is exactly solvable. For this process, we construct exact analytic solutions for all the n-point correlation functions (the n-body densities in the space of energy). The corresponding results for the one-point and the two-point functions were already known, but those for the higher-point functions are new. These results demonstrate strong correlations associated with the existence of common ancestors in the branching process. By integrating these n-point functions over the gluon energies, we deduce the mean gluon multiplicity $⟨ N ⟩$ as well as the higher moments $⟨ N^{p} ⟩$ with $p \geq 2$ . We find that the multiplicities of the soft gluons are parametrically large and show a remarkable regularity, known as Koba-Nielsen-Olesen (KNO) scaling: the reduced moments $⟨ N^{p} ⟩ / ⟨ N ⟩^{p}$ are pure numbers, independent of any of the physical parameters of the problem. We recognize a special negative binomial distribution which is characterized by large statistical fluctuations. These predictions can be tested in Pb+Pb collisions at the LHC, via event-by-event measurements of the di-jet asymmetry.
↳ hep-phhep-exnucl-thJHEP(2016)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE

Competitive effects of nuclear deformation and density dependence of ΛN interaction

Heavy flavor RAA​ and vn​ in event-by-event viscous relativistic hydrodynamics

Quark and Gluon Production from a Boost-invariantly Expanding Color Electric Field

Collisional broadening of angular correlations in a multiphase transport model

Non-boost-invariant dissipative hydrodynamics

Glue spin and helicity in proton from lattice QCD

Multi-particle correlations and KNO scaling in the medium-induced jet evolution

Affiliations

Competitive effects of nuclear deformation and density dependence of $Λ N$ interaction

Heavy flavor $R_{AA}$ and $v_{n}$ in event-by-event viscous relativistic hydrodynamics