Nuclear Theory·nucl-th

Wednesday·October 19, 2022

8 papers—3 primary·5 cross-listed

04
Bjorken sum rule with hyperasymptotic precision
Cesar Ayala🇨🇱 · Antonio Pineda🇪🇸
We obtain an improved determination of the normalization of the leading infrared renormalon of the Bjorken sum rule: $Z_{B} (n_{f} = 3) = - 0.407 \pm 0.119$ . Estimates of higher order terms of the perturbative series are given. We compute the Bjorken sum rule with hyperasymptotic precision by including the leading terminant, associated with the first infrared renormalon. We fit the experimental data to the operator product expansion theoretical prediction with $f^_{3}^{PV}$ as the free parameter. We obtain a good agreement with the experiment with $f^_{3}^{PV} \times 1 0^{3} = 3 2_{- 196}^{+ 187} GeV^{2}$ for $Q^{2} \geq 1$ GeV $^{2}$ .
↳ hep-phnucl-thPRD(2022)·17 citations
05
Beautiful and Charming Energy Correlators
Evan Craft🇺🇸 · Kyle Lee🇺🇸 · Bianka Meçaj🇺🇸 · Ian Moult🇺🇸
Understanding the detailed structure of energy flow within jets, a field known as jet substructure, plays a central role in searches for new physics, and precision studies of QCD. Many applications of jet substructure require an understanding of jets initiated by heavy quarks, whose description has lagged behind remarkable recent progress for massless jets. In this Letter, we initiate a study of correlation functions of energy flow operators on beauty and charm jets to illuminate the effects of the intrinsic mass of the elementary particles of QCD. We present a factorization theorem incorporating the mass of heavy quarks, and show that the heavy quark jet functions for energy correlators have a simple structure in perturbation theory. Our results achieve the very first full next-to-leading-logarithmic calculation of the heavy quark jet substructure observable at the LHC. Using this framework, we study the behavior of the correlators, and show that they exhibit a clear transition from a massless scaling regime, at precisely the scale of the heavy quark mass. This manifests the long-sought-after dead-cone effect and illustrates fundamental effects from the intrinsic mass of beauty and charm quarks in a perturbative regime, before they are confined inside hadrons. Our theoretical framework for studying energy correlators using heavy jets has many exciting applications for improving the description of mass effects in next generation parton shower event generators, probing the QGP, and studying heavy flavor fragmentation functions.
↳ hep-phhep-exnucl-exnucl-thPRD(2026)·100 citations
06
Effective model for pure Yang-Mills theory on $T^{2} \times R^{2}$ with Polyakov loops
Daiki Suenaga🇯🇵 · Masakiyo Kitazawa🇯🇵
We investigate the phase diagram and thermodynamics of $S U (N)$ pure Yang-Mills theory on a manifold $T^{2} \times R^{2}$ with an effective model that includes two Polyakov loops along two compactified directions. We find that a rich phase structure can appear owing to the spontaneous breaking of two center symmetries for $N = 2$ and $3$ . Thermodynamic quantities are obtained in the model and compared with recent lattice results. It is shown that two Polyakov loops play significant roles in thermodynamics on $T^{2} \times R^{2}$ .
↳ hep-phhep-lathep-thnucl-thPRD(2023)·5 citations
07
Towards the finite-volume spectrum of the Roper resonance
Daniel Severt🇩🇪
The finite-volume energy levels corresponding to the Roper resonance based on a two-flavor chiral effective Lagrangian at leading one-loop order are investigated. It is shown that the Roper mass can be extracted from these levels for not too large lattice volumes. Further, to include three-body $N π π$ dynamics, a non-relativistic effective field theory for the Roper resonance within a covariant particle-dimer picture is introduced. This particle-dimer approach is a suitable framework to investigate three-particle scattering relevant for the Roper channel. The appearing dimer fields are analyzed, the energy levels of the Roper resonance in a finite volume are calculated and compared to the results from the chiral effective Lagrangian.
↳ hep-lathep-phnucl-thPoS(2023)·4 citations
08
Gluon Parton Distribution of the Nucleon from 2+1+1-Flavor Lattice QCD in the Physical-Continuum Limit
Zhouyou Fan🇺🇸 · William Good🇺🇸 · Huey-Wen Lin🇺🇸
We present the first physical-continuum limit $x$ -dependent nucleon gluon distribution from lattice QCD using the pseudo-PDF approach, on lattice ensembles with $2 + 1 + 1$ flavors of highly improved staggered quarks (HISQ), generated by MILC Collaboration. We use clover fermions for the valence action on three lattice spacings $a \approx 0.9$ , 0.12 and 0.15~fm and three pion masses $M_{π} \approx 220$ , 310 and 690~MeV, with nucleon two-point measurements numbering up to $O (1 0^{6})$ and nucleon boost momenta up to 3~GeV. We study the lattice-spacing and pion-mass dependence of the reduced pseudo-ITD matrix elements obtained from the lattice calculation, then extrapolate them to the continuum-physical limit before extracting $xg (x) / ⟨ x ⟩_{g}$ . We use the gluon momentum fraction $⟨ x ⟩_{g}$ calculated from the same ensembles to determine the nucleon gluon unpolarized PDF $xg (x)$ for the first time entirely through lattice-QCD simulation. We compare our results with previous single-ensemble lattice calculations, as well as selected global fits.
↳ hep-lathep-phnucl-thPRD(2023)·35 citations

Affiliations

first authorsco-authorsvia INSPIRE

Bjorken sum rule with hyperasymptotic precision

Beautiful and Charming Energy Correlators

Effective model for pure Yang-Mills theory on T2×R2 with Polyakov loops

Towards the finite-volume spectrum of the Roper resonance

Gluon Parton Distribution of the Nucleon from 2+1+1-Flavor Lattice QCD in the Physical-Continuum Limit

Affiliations

Effective model for pure Yang-Mills theory on $T^{2} \times R^{2}$ with Polyakov loops