Nuclear Theory·nucl-th

Tuesday·February 14, 2023

5 papers—1 primary·4 cross-listed

02
Updated analyses of gluon distribution functions for the pion and kaon from the gauge-invariant nonlocal chiral quark model
Parada T. P. Hutauruk🇰🇷 · Seung-il Nam🇰🇷
In this work, we investigate the gluon distribution functions for the pion and kaon, in addition to the improved result of the valence-quark ones, in the gauge-invariant nonlocal chiral-quark model (NL $χ$ QM), in which the momentum dependence of the quark interactions is properly taken into account. We then analyze the gluon distribution functions, generated dynamically through the splitting functions in the DGLAP QCD evolution. By comparing with the recent lattice QCD results and JAM global analyses, it is found that the present numerical results for the gluon parton distribution functions for the pion exhibit a remarkable agreement, followed by the valence up-quark distribution results for the pion by reproducing the reanalyzed experimental data. Our prediction on the gluon distribution functions for the kaon is also consistent with the recent lattice data for the kaon within the errors.
↳ hep-phnucl-thPRD(2024)·9 citations
03
Localization measures of parity adapted U( $D$ )-spin coherent states applied to the phase space analysis of the $D$ -level Lipkin-Meshkov-Glick model
Alberto Mayorgas🇪🇸 · Julio Guerrero🇪🇸 · Manuel Calixto🇪🇸
We study phase-space properties of critical, parity symmetric, $N$ -quDit systems undergoing a quantum phase transition (QPT) in the thermodynamic $N \to \infty$ limit. The $D = 3$ level (qutrit) Lipkin-Meshkov-Glick (LMG) model is eventually examined as a particular example. For this purpose, we consider U $(D)$ -spin coherent states (DSCS), generalizing the standard $D = 2$ atomic coherent states, to define the coherent state representation $Q_{ψ}$ (Husimi function) of a symmetric $N$ -quDit state $∣ ψ >$ in the phase space $C P^{D - 1}$ (complex projective manifold). DSCS are good variational aproximations to the ground state of a $N$ -quDit system, specially in the $N \to \infty$ limit, where the discrete parity symmetry $Z_{2}^{D - 1}$ is spontaneously broken. For finite $N$ , parity can be restored by projecting DSCS onto $2^{D - 1}$ different parity invariant subspaces, which define generalized ``Schrödinger cat states'' reproducing quite faithfully low-lying Hamiltonian eigenstates obtained by numerical diagonalization. Precursors of the QPT are then visualized for finite $N$ by plotting the Husimi function of these parity projected DSCS in phase space, together with their Husimi moments and Wehrl entropy, in the neighborhood of the critical points. These are good localization measures and markers of the QPT.
↳ quant-phmath-phmath.MPnucl-thPRE(2023)·6 citations
04
QCD equation of state at finite chemical potential from unbiased exponential resummation of the lattice QCD Taylor series
Sabarnya Mitra🇮🇳 · Prasad Hegde🇮🇳
Exponential resummation of the QCD finite-density Taylor series has been recently introduced as an alternative way of resumming the finite-density lattice QCD Taylor series. Unfortunately the usual exponential resummation formula suffers from stochastic bias which must be subtracted before identifying genuine higher-order contributions. In this paper, we present a new way of subtracting the stochastic bias at the level of each individual gauge configuration, up to a certain order of either the Taylor series or the cumulant expansion, by modifying the argument of the exponential. Retaining the exponential form of the resummation allows us to also calculate the phase factor of the fermion determinant on each gauge configuration. We present our results for the excess pressure, number density, and the average phase factor and show that the new results contain less stochastic bias and are in better agreement with the QCD Taylor series compared to the previous exponential resummation.
↳ hep-lathep-phnucl-exnucl-thPRD(2023)·7 citations
05
Universality of the Collins-Soper kernel in lattice calculations
Hai-Tao Shu🇩🇪 · Maximilian Schlemmer🇩🇪 · Tobias Sizmann🇩🇪 · Alexey Vladimirov🇪🇸 · Lisa Walter🇩🇪 · Michael Engelhardt🇺🇸 · Andreas Schäfer🇩🇪 · Yi-Bo Yang🇨🇳
The Collins-Soper (CS) kernel is a nonperturbative function that characterizes the rapidity evolution of transverse-momentum-dependent parton distribution functions (TMDPDFs) and wave functions. In this Letter, we calculate the CS kernel for pion and proton targets and for quasi-TMDPDFs of leading and next-to-leading power. The calculations are carried out on the CLS ensemble H101 with dynamical $N_{f} = 2 + 1$ clover-improved Wilson fermions. Our analyses demonstrate the consistency of different lattice extractions of the CS kernel for mesons and baryons, as well as for twist-two and twist-three operators, even though lattice artifacts could be significant. This consistency corroborates the universality of the lattice-determined CS kernel and suggests that a high-precision determination of it is in reach.
↳ hep-lathep-phnucl-thPRD(2023)·47 citations

Affiliations

first authorsco-authorsvia INSPIRE

Updated analyses of gluon distribution functions for the pion and kaon from the gauge-invariant nonlocal chiral quark model

Localization measures of parity adapted U(D)-spin coherent states applied to the phase space analysis of the D-level Lipkin-Meshkov-Glick model

QCD equation of state at finite chemical potential from unbiased exponential resummation of the lattice QCD Taylor series

Universality of the Collins-Soper kernel in lattice calculations

Affiliations

Localization measures of parity adapted U( $D$ )-spin coherent states applied to the phase space analysis of the $D$ -level Lipkin-Meshkov-Glick model