Nuclear Theory·nucl-th

Tuesday·October 25, 2022

9 papers—2 primary·7 cross-listed

03
Accessing gluon polarization with high- $P_{T}$ hadrons in SIDIS
R. M. Whitehill🇺🇸 · Yiyu Zhou🇨🇳 · N. Sato🇺🇸 · W. Melnitchouk🇺🇸
A recent global QCD analysis of jet production and other polarized scattering data has found the presence of negative solutions for the gluon helicity distribution in the proton, $Δ g$ , along with the traditional $Δ g > 0$ solutions. We consider polarized semi-inclusive deep-inelastic scattering for hadrons produced with large transverse momentum as a means of constraining the dependence of $Δ g$ on the parton momentum fraction, $x$ . Focusing on the double longitudinal spin asymmetry, we identify the kinematics relevant for future experiments at Jefferson Lab and the Electron-Ion Collider which are particularly sensitive to the polarized gluon channel and could discriminate between the different $Δ g$ behaviors.
↳ hep-phhep-exnucl-thPRD(2023)·11 citations
04
Hunting for an EMC-like effect for antiquarks
Massimiliano Alvioli🇮🇹 · Mark Strikman🇺🇸
We argue that the Drell-Yan process in the $x_{A} \geq 0.15$ kinematics recently studied at FNAL by the E906/SeaQuest experiment may allow to observe an analogous of the EMC effect for antiquarks. The effects of Fermi motion and energy loss are considered. The preliminary E906/SeaQuest data are inconsistent with the growth of the $σ_{A} / A σ_{N}$ ratio expected in the Fermi motion scenario at $x_{A} \geq 0.25$ . The pattern of the $x_{A}$ dependence of the ratio seems also inconsistent with a scenario in which the dominant nuclear effect is a suppression of the cross section due to the energy loss experienced by a quark of the projectile proton involved in the Drell-Yan process. All together the data suggest the possibility of a modification of the antiquark parton distributions in nuclei, with a pattern similar to the one observed in the EMC effect. We argue that optimal kinematics to look for an antiquark EMC-like effect would be to measure the $σ_{A}^{D Y} / A σ_{N}^{D Y}$ ratios for $x_{A}$ = 0.2-0.4 and $x_{p}$ $\approx$ constant.
↳ hep-phhep-exnucl-exnucl-thPLB(2023)·1 citation
05
Independence of current components, polarization vectors, and reference frames in the light-front quark model analysis of meson decay constants
Ahmad Jafar Arifi🇰🇷 · Ho-Meoyng Choi🇰🇷 · Chueng-Ryong Ji🇺🇸 · Yongseok Oh🇰🇷
The issue of resulting in the same physical observables with different current components, in particular from the minus current, has been challenging in the light-front quark model (LFQM) even for the computation of the two-point functions such as meson decay constants. At the level of one-body current matrix element computation, we show the uniqueness of pseudoscalar and vector meson decay constants using all available components including the minus component of the current in the LFQM consistent with the Bakamjian-Thomas construction. Regardless of the current components, the polarization vectors, and the reference frames, the meson decay constants are uniquely determined in the non-interacting constituent quark and antiquark basis while the interactions of the constituents are added to the meson mass operator in the LFQM.
↳ hep-phnucl-thPRD(2023)·21 citations
06
Further understanding the nature of $a_{0} (1710)$ in the $D_{s}^{+} \to π^{0} K^{+} K_{S}^{0}$ decay
Xin Zhu🇨🇳 · Hao-Nan Wang🇨🇳 · De-Min Li🇨🇳 · En Wang🇨🇳 · Li-Sheng Geng🇨🇳 · Ju-Jun Xie🇨🇳
Based on our previous work about the role of $a_{0} (1710)$ in the $D_{s}^{+} \to π^{+} K_{S}^{0} K_{S}^{0}$ decay [Phy. Rev. D 105, 116010 (2022)], we perform a further theoretical study of $a_{0} (1710)^{+}$ in the process $D_{s}^{+} \to π^{0} a_{0} (1710)^{+} \to π^{0} K^{+} K_{S}^{0}$ . In addition to $a_{0} (1710)$ , the contributions of $K^{*}$ and $a_{0} (980)$ are also taken into account. Firstly, we consider the contributions from the tree diagrams of $K^{*+} \to K^{+} π^{0}$ and $K ˉ^{* 0} \to π^{0} K ˉ^{0}$ . Secondly, we describe the final state interaction of $K K ˉ$ in the chiral unitary approach to study the contribution of $a_{0} (980)$ , while the $a_{0} (1710)$ state is dynamically generated from the $K^{*} K ˉ^{*}$ interaction, and then decays into $K^{+} K ˉ^{0}$ . Since the final $K^{+} K_{S}^{0}$ state is in pure isospin $I = 1$ , the $D_{s}^{+} \to π^{0} K^{+} K_{s}^{0}$ decay is an ideal process to study the $a_{0} (1710)^{+}$ and $a_{0} (980)^{+}$ resonances. Based on our theoretical calculations, it is found that the recent experimental measurements on the $K^{+} K_{S}^{0}$ , $π^{0} K^{+}$ , and $π^{0} K_{S}^{0}$ invariant mass distributions can be well reproduced, which supports the molecular $K^{*} K ˉ^{*}$ nature of the scalar $a_{0} (1710)$ resonance.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·32 citations
07
Perturbative Color Correlations in Double Parton Scattering
B.Blok🇮🇱 · J. Mehl🇮🇱
We study the contribution of color correlations to Double Parton Scattering (DPS). We show that there is a specific class of Feynman diagrams related to so called 1 \textrightarrow{} 2 processes when the contribution of these color correlations is not Sudakov suppressed with the transverse scales. The split scale increases with the transverse scale Q, with color correlations being up to 5-10 percent of singlet ones. The effective absence of Sudakov suppression gives hope that although they are small relative to color singlet correlations, they eventually can be observed.
↳ hep-phhep-exhep-latnucl-thInt.J.Mod.Phys.A(2024)·5 citations
08
Cosmological consequences of first-order general-relativistic viscous fluid dynamics
Fábio S. Bemfica · Marcelo M. Disconzi · Jorge Noronha · Robert J. Scherrer
We investigate the out-of-equilibrium dynamics of viscous fluids in a spatially flat Friedmann-Lemaître-Robertson-Walker cosmology using the most general causal and stable viscous energy-momentum tensor defined at first order in spacetime derivatives. In this new framework a pressureless viscous fluid having density $ρ$ can evolve to an asymptotic future solution in which the Hubble parameter approaches a constant while $ρ \to 0$ , even in the absence of a cosmological constant (i.e., $Λ = 0$ ). Thus, while viscous effects in this model drive an accelerated expansion of the universe, the density of the viscous component itself vanishes, leaving behind only the acceleration. This behavior emerges as a consequence of causality in first-order theories of relativistic fluid dynamics and it is fully consistent with Einstein's equations.
↳ gr-qcastro-ph.COhep-thnucl-thPRD(2023)·14 citations
09
Chiral and trace anomalies in Deeply Virtual Compton Scattering
Shohini Bhattacharya🇺🇸 · Yoshitaka Hatta🇺🇸 · Werner Vogelsang🇺🇸
Inspired by recent work by Tarasov and Venugopalan, we calculate the one-loop quark box diagrams relevant to polarized and unpolarized Deep Inelastic Scattering (DIS) by introducing off-forward momentum $l^{μ}$ as an infrared regulator. In the polarized case, we rederive the pole $1/ l^{2}$ related to the axial (chiral) anomaly. In addition, we obtain the usual logarithmic term and the DIS coefficient function. We interpret the result in terms of the generalized parton distributions (GPDs) $H ~$ and $E ~$ and discuss the possible violation of QCD factorization for the Compton scattering amplitude. Remarkably, we also find poles in the unpolarized case which are remnants of the trace anomaly. We argue that these poles are cancelled by the would-be massless glueball poles in the GPDs $H$ and $E$ as well as in their moments, the nucleon gravitational form factors $A, B$ and $D$ . This mechanism sheds light on the connection between the gravitational form factors and the gluon condensate operator $F^{μν} F_{μν}$ .
↳ hep-phhep-thnucl-thPRD(2023)·35 citations

Affiliations

first authorsco-authorsvia INSPIRE

Accessing gluon polarization with high-PT​ hadrons in SIDIS

Hunting for an EMC-like effect for antiquarks

Independence of current components, polarization vectors, and reference frames in the light-front quark model analysis of meson decay constants

Further understanding the nature of a0​(1710) in the Ds+​→π0K+KS0​ decay

Perturbative Color Correlations in Double Parton Scattering

Cosmological consequences of first-order general-relativistic viscous fluid dynamics

Chiral and trace anomalies in Deeply Virtual Compton Scattering

Affiliations

Accessing gluon polarization with high- $P_{T}$ hadrons in SIDIS

Further understanding the nature of $a_{0} (1710)$ in the $D_{s}^{+} \to π^{0} K^{+} K_{S}^{0}$ decay