Nuclear Theory·nucl-th

Thursday·January 26, 2023

6 papers—2 primary·4 cross-listed

03
Precision Control in Lattice Calculation of $x$ -dependent Pion Distribution Amplitude
Jack Holligan🇺🇸 · Xiangdong Ji🇺🇸 · Huey-Wen Lin🇺🇸 · Yushan Su🇺🇸 · Rui Zhang🇺🇸
We present a new Bjorken $x$ -dependence analysis of a previous lattice quantum chromodynamics data for the pion distribution amplitude from MILC configurations with three lattice spacing $a = 0.06, 0.09, 0.12$ ~fm. A leading renormalon resummation in renormalization as well as the perturbative matching kernel in the framework of large momentum expansion generates the power accuracy of the matching to the light-cone amplitude. Meanwhile, a small momentum log resummation is implemented for both the quark momentum $x P_{z}$ and the antiquark momentum $(1 - x) P_{z}$ inside a meson of boost momentum $P_{z}$ up to 1.72 GeV along the $z$ direction, allowing us to have more accurate determination of the $x$ -dependence in the middle range. Finally, we use the complementarity between the short-distance factorization and the large momentum expansion to constrain the endpoint regions $x \sim 0, 1$ , thus obtaining the full-range $x$ -dependence of the amplitude.
↳ hep-lathep-phnucl-thNPB(2023)·48 citations
04
Deep learning predicted elliptic flow of identified particles in heavy-ion collisions at the RHIC and LHC energies
Neelkamal Mallick🇮🇳 · Suraj Prasad🇮🇳 · Aditya Nath Mishra🇮🇳 · Raghunath Sahoo🇮🇳 · Gergely Gábor Barnaföldi🇭🇺
Recent developments on a deep learning feed-forward network for estimating elliptic flow ( $v_{2}$ ) coefficients in heavy-ion collisions have shown us the prediction power of this technique. The success of the model is mainly the estimation of $v_{2}$ from final state particle kinematic information and learning the centrality and the transverse momentum ( $p_{T}$ ) dependence of $v_{2}$ . The deep learning model is trained with Pb-Pb collisions at $s_{NN} = 5.02$ TeV minimum bias events simulated with a multiphase transport model (AMPT). We extend this work to estimate $v_{2}$ for light-flavor identified particles such as $π^{\pm}$ , $K^{\pm}$ , and $p + p ˉ$ in heavy-ion collisions at RHIC and LHC energies. The number of constituent quark (NCQ) scaling is also shown. The evolution of $p_{T}$ -crossing point of $v_{2} (p_{T})$ , depicting a change in meson-baryon elliptic flow at intermediate- $p_{T}$ , is studied for various collision systems and energies. The model is further evaluated by training it for different $p_{T}$ regions. These results are compared with the available experimental data wherever possible.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·23 citations
05
Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux
Fabian Brauneis · Areg Ghazaryan · Hans-Werner Hammer · Artem G. Volosniev
The model of a ring threaded by the Aharonov-Bohm flux underlies our understanding of a coupling between gauge potentials and matter. The typical formulation of the model is based upon a single particle picture, and should be extended when interactions with other particles become relevant. Here, we illustrate such an extension for a particle in an Aharonov-Bohm ring subject to interactions with a weakly interacting Bose gas. We show that the ground state of the system can be described using the Bose polaron concept -- a particle dressed by interactions with a bosonic environment. We connect the energy spectrum to the effective mass of the polaron, and demonstrate how to change currents in the system by tuning boson-particle interactions. Our results suggest the Aharonov-Bohm ring as a platform for studying coherence and few- to many-body crossover of quasi-particles that arise from an impurity immersed in a medium.
↳ cond-mat.quant-gascond-mat.mes-hallnucl-thCommun.Phys.(2023)·5 citations
06
Causality violation and the speed of sound of hot and dense quark matter in the Nambu--Jona-Lasinio model
Arthur E. B. Pasqualotto🇧🇷 · Ricardo L. S. Farias🇧🇷 · William R. Tavares🇧🇷 · Sidney S. Avancini🇧🇷 · Gastão Krein🇧🇷
The Nambu--Jona-Lasinio model is widely used to study strong-interaction phenomena in vacuum and quark matter. Since the model is nonrenormalizable, one needs to work within a specific regularization scheme to obtain finite results. Here we show that a commonly used cutoff regularization scheme leads to unphysical results, such as superluminal speed of sound and wrong high-temperature behavior of the specific heat and other thermodynamical quantities. Such a troublesome feature of the cutoff regularization invalidates the model for temperature and baryon density values relevant to the phenomenology of heavy-ion collisions and compact stars. We show that the source of the problems stems from cutting off momentum modes in finite integrals depending on thermal distribution functions in the grand canonical potential. The problems go away when taking into account the full momentum range of those integrals. Explicit examples are worked out in the SU(2)-flavor version of the model.
↳ hep-phhep-lathep-thnucl-thPRD(2023)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE

Precision Control in Lattice Calculation of x-dependent Pion Distribution Amplitude

Deep learning predicted elliptic flow of identified particles in heavy-ion collisions at the RHIC and LHC energies

Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux

Causality violation and the speed of sound of hot and dense quark matter in the Nambu--Jona-Lasinio model

Affiliations

Precision Control in Lattice Calculation of $x$ -dependent Pion Distribution Amplitude