Thermodynamics of charmed hadrons across chiral crossover from lattice QCD
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Sharma, Sipaz (ORCID:0000000169162233)β
Engineering topics
Petreczky, Peter
Publications and source records attributed to Petreczky, Peter.
QCD Predictions for Meson Electromagnetic Form Factors at High Momenta: Testing Factorization in Exclusive Processes
We report the first lattice QCD computation of pion and kaon electromagnetic form factors, πΉ πβ‘ (π 2 ), at large momentum transfer up to 10 and 28 GeV 2 , respectively. Utilizing physical masses and two fine lattices, we achieve good agreement with JLab experimental results at π 2 β² 4 GeV 2 . For π 2 β³ 4 GeV 2 , our results provide ab initio QCD benchmarks for the forthcoming experiments at JLab 12 GeV and future electron-ion colliders. We also test the QCD collinear factorization framework utilizing our high-π 2 form factors at next-to-next-to-leading order in perturbation theory, which relates the form factors to the leading Fock-state meson distribution amplitudes. Comparisons with independent lattice QCD calculations using the same framework demonstrate, within estimated uncertainties, the universality of these nonperturbative quantities.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Lattice QCD calculation of the pion generalized parton distribution
We present the results of a Lattice QCD computation of pion generalized parton distribution (GPD), employing perturbative matching up to next-to-next-to-leading order (NNLO). The computations are based on an ensemble of Nf=2+1 highly improved staggered quarks (HISQ) with a pion mass of 300 MeV and a lattice spacing of 0.04 fm. Centered on the zero-skewness limit, we utilize a recently proposed Lorentz-invariant definition of GPD, which is derived from Lorentz-invariant amplitudes. We analyze and compare these amplitudes in both Breit and non-Breit kinematic frames at comparable momentum transfers, validating their frame-independent nature. To obtain light-cone GPD, we integrate hybrid scheme renormalization with the large momentum effective theory (LaMET). Moreover, we determine the first three iso-vector generalized form factors (GFFs) of the pion using the ratio scheme renormalization and leading-twist factorization, achieving NNLO accuracy.
Ding, Heng-Tongβ
Non-relativistic QCD Study of Excited Bottomonia at Finite Temperatures on a Fine Lattice
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73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Lattice QCD calculation of the pion distribution amplitude with domain wall fermions at physical pion mass
We present a direct lattice QCD calculation of the x-dependence of the pion distribution amplitude (DA), which is performed using the quasi-DA in large momentum effective theory on a domain-wall fermion ensemble at physical quark masses and spacing a β 0.084 fm. The bare quais-DA matrix elements are renormalized in the hybrid scheme and matched to $\overline{MS}$ with a subtraction of the leading renormalon in the Wilson-line mass. For the first time, we include threshold resummation in the perturbative matching onto the light-cone DA, which resums the large logarithms in the soft gluon limit at next-to-next-to-leading log. The resummed results show controlled scale-variation uncertainty within the range of momentum fraction x Ο΅ [0.25, 0.75] at the largest pion momentum P z β 1.85 GeV. In addition, we apply the same analysis to quasi-DAs from a highly-improved-staggered-quark ensemble at physical pion mass and a = 0.076 fm. By comparison we find with 2Ο confidence level that the DA obtained from chiral fermions is flatter and lower near x = 0.5.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Analysis of static Wilson line correlators from lattice QCD at finite temperature with T -matrix approach
The thermodynamic T-matrix approach is used to study Wilson line correlators (WLCs) for a static quark-antiquark pair in the quark-gluon plasma (QGP). Selfconsistent results that incorporate constraints from the QGP equation of state can approximately reproduce WLCs computed in 2+1-flavor lattice-QCD (lQCD), provided the input potential exhibits less screening than in previous studies. Utilizing the updated potential to calculate pertinent heavylight T-matrices we evaluate thermal relaxation rates of heavy quarks in the QGP. We find a more pronounced temperature dependence for low-momentum quarks than in our previous results (with larger screening), which turns into a weaker temperature dependence of the (temperature-scaled) spatial diffusion coefficient, in fair agreement with the most recent lQCD data.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
QCD material parameters at zero and non-zero chemical potential from the lattice
Using an eighth-order Taylor expansion in baryon-chemical potential, we recently obtained the (2+1) flavor QCD equation of state (EoS) at non zero conserved charge chemical potentials from the lattice. We focused on strangeness-neutral, isospin-symmetric QCD matter, which closely resembles the situation encountered in heavy-ion collision experiments. Using this EoS, we present here results on various QCD material parameters; in particular we compute the specific heat, speed of sound, and compressibility along appropriate lines of constant physics.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Chiral condensate and the equation of state at nonzero baryon density from the hadron resonance gas model with a repulsive mean field
We study the QCD equation of state and the chiral condensate using the hadron resonance gas model with repulsive mean-field interactions. We find that the repulsive interactions improve the agreement with the lattice results on the derivatives of the pressure with respect to the baryon chemical potential up to eighth order. From the temperature dependence of the chiral condensate we estimate the crossover temperature as a function of baryon chemical potential, T p c ( ΞΌ B ) . We find that the chiral crossover line starts to deviate significantly from the chemical freeze-out line already for ΞΌ B > 400 MeV . Furthermore, we find that the chiral pseudocritical line can be parametrized as T p c ( ΞΌ B ) / T p c ( 0 ) = 1 β ΞΊ 2 [ ΞΌ B / T p c ( 0 ) ] 2 β ΞΊ 4 [ ΞΌ B / T p c ( 0 ) ] 4 with ΞΊ 2 = 0.0150 ( 2 ) and ΞΊ 4 = 3.1 ( 6 ) Γ 10 β 5 , which are in agreement with lattice QCD results for small values of ΞΌ B . For the first time we find a tiny but nonzero value of ΞΊ 4 in our study. Published by the American Physical Society 2024
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
T -matrix analysis of static Wilson line correlators from lattice QCD at finite temperature
Here, we utilize a previously constructed thermodynamic T -matrix approach to the quark-gluon plasma (QGP) to derive constaints on its input by using results on Wilson line correlators (WLCs) of a static quark-antiquark pair from 2 + 1-flavor lattice-QCD (lQCD) computations with realistic pion mass. The self-consistent T -matrix results, which include previous constraints from the lQCD equation of state in the light-parton sector, can describe the lQCD data for WLCs fairly well once refinements of its driving kernel are applied. In particular, the input potential requires less screening than what has been inferred from previous T-matrix analyses. Pertinent predictions for the spectral and transport properties of the QGP are discussed, including the spatial diffusion coefficient for heavy quarks; the latter turns out to have a rather weak temperature dependence, in approximate agreement with recent unquenched lQCD results.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Unscreened forces in the quark-gluon plasma?
We study the correlator of temporal Wilson lines at nonzero temperature in 2+1 flavor lattice QCD with the aim to define the heavy quark-antiquark potential at nonzero temperature. For temperatures 153 MeV β€ π β€ 352 MeV the spectral representation of this correlator is consistent with a broadened peak in the spectral function, position, or width of which then defines the real or imaginary parts of the heavy quark-antiquark potential at nonzero temperature, respectively. We find that the potentialβs real part is not screened contrary to the widely held expectations. We comment on how this fact may modify the picture of quarkonium melting in the quark-gluon plasma.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Transversity PDFs of the proton from lattice QCD with physical quark masses
We present a lattice QCD calculation of the transversity isovector- and isoscalar-quark parton distribution functions (PDFs) of the proton utilizing a perturbative matching at next-to-leading-order (NLO) accuracy. Additionally, we determine the isovector and isoscalar tensor charges for the proton. In both calculations, the disconnected contributions to the isoscalar matrix elements have been ignored. The calculations are performed using a single ensemble of N f = 2 + 1 highly improved staggered quarks simulated with physical-mass quarks and a lattice spacing of a = 0.076 fm . The Wilson-clover action, with physical quark masses and smeared gauge links obtained from one iteration of hypercubic smearing, is used in the valence sector. Using the NLO operator product expansion, we extract the lowest four to six Mellin moments and the PDFs via a neural network from the matrix elements in the pseudo-PDF approach. In addition, we calculate the PDFs in the quasi-PDF approach with hybrid-scheme renormalization and the recently developed leading-renormalon resummation technique, at NLO with the resummation of leading small- x logarithms. Published by the American Physical Society 2024
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
SIMULATeQCD: A simple multi-GPU lattice code for QCD calculations
The rise of exascale supercomputers has fueled competition among GPU vendors, driving lattice QCD developers to write code that supports multiple APIs. Moreover, new developments in algorithms and physics research require frequent updates to existing software. These challenges have to be balanced against constantly changing personnel. At the same time, there is a wide range of applications for HISQ fermions in QCD studies. This situation encourages the development of software featuring a HISQ action that is flexible, high-performing, open source, easy to use, and easy to adapt. In this technical paper, we explain the design strategy, provide implementation details, list available algorithms and modules, and show key performance indicators for SIMULATeQCD, a simple multi-GPU lattice code for large-scale QCD calculations, mainly developed and used by the HotQCD collaboration. The code is publicly available on GitHub.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ
Quark Mass Dependence of Heavy Quark Diffusion Coefficient from Lattice QCD
We present the first study of the quark mass dependence of the heavy quark momentum and spatial diffusion coefficients using lattice QCD with light dynamical quarks corresponding to a pion mass of 320 MeV. We find that, for the temperature range 195 MeV < π < 293 MeV, the spatial diffusion coefficients of the charm and bottom quarks are smaller than those obtained in phenomenological models that describe the π π spectra and elliptic flow of open heavy flavor hadrons.
73 NUCLEAR PHYSICS AND RADIATION PHYSICSβ