Nuclear Theory·nucl-th

Thursday·May 26, 2022

14 papers—7 primary·7 cross-listed

08
[Submitted on 24 May 2022] (cross-list from hep-ph)
One-loop matching for gluon lattice TMDs
Stella T. Schindler🇺🇸 · Iain W. Stewart🇺🇸 · Yong Zhao🇺🇸
Transverse-momentum-dependent parton distributions (TMDs) can be calculated from first principles by computing a related set of Euclidean lattice observables and connecting them via a factorization formula. This work focuses on the leading-power factorization formula connecting the lattice quasi-TMD and continuum Collins TMD for gluons. We calculate the one-loop gluon matching coefficient, which is known to be independent of spin and exhibits no mixing with quarks. We demonstrate that this coefficient satisfies Casimir scaling with respect to the quark matching coefficient at one-loop order. Our result facilitates reliable lattice QCD calculations of gluon TMDs.
Comments:
11 pages, 2 figures, v2: updates to match journal
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2205.12369 [pdf]
JHEP(2022)·24 citations
09
[Submitted on 24 May 2022] (cross-list from hep-ph)
Designing Observables for Quantum Interference in Jets at Subleading Color
Andrew J. Larkoski🇺🇸
The large- $N_{c}$ or topologically planar limit of gauge theories can be considered as a classical limit because all gauge bosons are distinguishable particles and therefore cannot exhibit interference. Quantum effects due to the flow of color therefore arise starting at subleading in $1/ N_{c}$ . We introduce kinematic observables explicitly sensitive to effects at subleading color formed from the ratio of interfering to squared color-ordered amplitudes. Such observables are in general not infrared and collinear safe, so we introduce angular observables defined from appropriate multi-point energy correlators motivated by the form of color-ordered amplitudes. We demonstrate that color interference effects are manifest as sinusoidal oscillation in the simplest system, a collinear jet with three particles, and show the limitations of predicting this observable in all-purpose, leading-color parton shower Monte Carlos.
Comments:
19 pages, 5 figures; v2: updated comparison to parton shower simulation; v3: title change and other minor changes, SciPost version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2205.12375 [pdf]
SciPost Phys.(2023)·4 citations
10
[Submitted on 25 May 2022] (cross-list from hep-ph)
New aspect of chiral and axial breaking in QCD
Chuan-Xin Cui🇨🇳 · Mamiya Kawaguchi🇨🇳 · Jin-Yang Li🇨🇳 · Shinya Matsuzaki🇨🇳 · Akio Tomiya🇯🇵
Violation of the $U (1)$ axial symmetry in QCD is stricter than the chiral $S U (2)$ breaking, simply because of the presence of the quantum axial anomaly. If the QCD gauge coupling is sent to zero, the strength of the $U (1)$ axial breaking coincides with that of the chiral $S U (2)$ breaking, which we shall in short call an axial-chiral coincidence. This coincidence is trivial since QCD then becomes a non-interacting theory. Actually, there exists another limit in the QCD parameter space, where an axial-chiral coincidence occurs even with nonzero QCD gauge coupling, that can be dubbed a nontrivial coincidence: it is the case with the massive light quarks $(m_{l} \neq = 0)$ and the massless strange quark ( $m_{s} = 0$ ), due to the flavor-singlet nature of the topological susceptibility. This coincidence is robust and tied to the anomalous chiral Ward-Takahashi identity, which is operative even at hot QCD. This implies that the chiral $S U (2)$ symmetry is restored simultaneously with the $U (1)$ axial symmetry at high temperatures. This simultaneous restoration is independent of $m_{l} (\neq = 0)$ , hence is irrespective to the order of the chiral phase transition. In this paper, we discuss how the real-life QCD can be evolved from the nontrivial chiral-axial coincidence limit, by working on a Nambu-Jona-Lasinio model with the $U (1)$ axial anomaly contribution properly incorporated. It is shown that at high temperatures the large differences between the restorations of the chiral $S U (2)$ symmetry and the $U (1)$ axial symmetry for two light quarks and a sufficiently large current mass for the strange quark is induced by a significant interference of the topological susceptibility. Thus the deviation from the nontrivial coincidence, which is monitored by the strange quark mass controlling the topological susceptibility, provides a new way of understanding the chiral $S U (2)$ and $U (1)$ axial breaking in QCD.
Comments:
23 pages, 11 figures, some references added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2205.12479 [pdf]
Particles(2024)·10 citations
11
[Submitted on 25 May 2022] (cross-list from hep-lat)
Centre Vortex Structure of QCD-Vacuum Fields and Confinement
Derek Leinweber🇦🇺 · James Biddle🇦🇺 · Waseem Kamleh (University of Adelaide)🇦🇺
The non-trivial ground-state vacuum fields of QCD form the foundation of matter. Using modern visualisation techniques, this presentation examines the microscopic structure of these fields. Of particular interest are the centre vortices identified within the ground-state fields of lattice QCD. Our current focus is on understanding the manner in which dynamical fermions in the QCD vacuum alter the centre-vortex structure. The impact of dynamical fermions is significant and provides new insights into the role of centre vortices in underpinning both confinement and dynamical chiral symmetry breaking in QCD.
Comments:
10 pages, 7 figures with 4 3D interactive. XXXIII International (Online) Workshop on High Energy Physics, "Hard Problems of Hadron Physics: Non-Perturbative QCD & Related Quests" November 8-12, 2021. arXiv admin note: substantial text overlap with arXiv:2204.04825
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2205.12518 [pdf]
SciPost Phys.Proc.(2022)·4 citations
12
[Submitted on 25 May 2022] (cross-list from hep-ph)
Faddeev fixed-center approximation to the $D D ˉ K$ system and the hidden charm $K_{c c ˉ} (4180)$ state
Xiang Wei🇨🇳 · Qing-Hua Shen🇨🇳 · Ju-Jun Xie🇨🇳
We perform a theoretical study on the $D D ˉ K$ three body system, using the fixed center approximation to the Faddeev equations, considering the interaction between $D$ and $K$ , $D$ and $D ˉ$ from the chiral unitary approach. We assume the scattering of $K$ meson on a clusterized system $D D ˉ$ , where a scalar meson $X (3720)$ could be formed. Thanks to the strong $D K$ interaction, where the scalar $D_{s 0}^{*} (2317)$ meson is dynamically generated, a resonance structure shows up in the modulus squared of the three body $K$ - $(D D ˉ)_{X (3720)}$ scattering amplitude and supports that a $D D ˉ K$ bound state can be formed. The result is in agreement with previous theoretical studies, which claim a new excited hidden charm $K$ meson, $K_{c c ˉ} (4180)$ with quantum numbers $I (J^{P}) = \frac{1}{2} (0^{-})$ and mass about $4180$ MeV. It is expected that these theoretical results motivate its search in experimental measurements.
Comments:
6 pages, 5 figures. Typos fixed, more discussions added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2205.12526 [pdf]
EPJC(2022)·19 citations
13
[Submitted on 25 May 2022] (cross-list from hep-lat)
Towards the chiral phase transition in the Roberge-Weiss plane
F. Cuteri🇩🇪 · J. Goswami🇯🇵 · F. Karsch🇩🇪 · Anirban Lahiri🇩🇪 · M. Neumann🇩🇪 · O. Philipsen🇩🇪 · Christian Schmidt🇩🇪 · A. Sciarra🇩🇪
We discuss the interplay between chiral and center sector phase transitions that occur in QCD with an imaginary quark chemical potential $μ = i (2 n + 1) π T /3$ . Based on a finite size scaling analysis in (2+1)-flavor QCD using HISQ fermions with a physical strange quark mass and a range of light quark masses, we show that the endpoint of the line of first-order Roberge-Weiss (RW) transitions between center sectors is second order for light quark masses $m_{l} \geq m_{s} /320$ , and that it belongs to the $3$ -d, $Z (2)$ universality class. The operator for the chiral condensate behaves like an energy-like operator in an effective spin model for the RW phase transition. As a consequence, for any non-zero value of the quark mass, the chiral condensate will have an infinite slope at the RW phase transition temperature, $T_{R W}$ . Its fluctuation, the disconnected chiral susceptibility, behaves like the specific heat in $Z (2)$ symmetric models and diverges in the infinite volume limit at the RW phase transition temperature $T_{R W}$ for any non-zero value of the light quark masses. Our analysis suggests the critical temperatures for the RW phase transition and the chiral phase transition coincide in the RW plane. On lattices with temporal extent $N_{τ} = 4$ , we find in the chiral limit $T_{χ} = T_{R W} = 195 (1)$ MeV.
Comments:
17 pages
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2205.12707 [pdf]
PRD(2022)·29 citations
14
[Submitted on 25 May 2022] (cross-list from quant-ph)
Variational thermal quantum simulation of the lattice Schwinger model
Xu-Dan Xie🇨🇳 · Xingyu Guo🇨🇳 · Hongxi Xing🇨🇳 · Zheng-Yuan Xue🇨🇳 · Dan-Bo Zhang🇨🇳 · Shi-Liang Zhu🇨🇳
Confinement of quarks due to the strong interaction and the deconfinement at high temperatures and high densities are a basic paradigm for understanding the nuclear matter. Their simulation, however, is very challenging for classical computers due to the sign problem of solving equilibrium states of finite-temperature quantum chromodynamical systems at finite density. In this paper, we propose a variational approach, using the lattice Schwinger model, to simulate the confinement or deconfinement by investigating the string tension. We adopt an ansatz that the string tension can be evaluated without referring to quantum protocols for measuring the entropy in the free energy. Results of numeral simulation show that the string tension decreases both along the increasing of the temperature and the chemical potential, which can be an analog of the phase diagram of QCD. Our work paves a way for exploiting near-term quantum computers for investigating the phase diagram of finite-temperature and finite density for nuclear matters.
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2205.12767 [pdf]
PRD(2022)·44 citations

Affiliations

first authorsco-authorsvia INSPIRE

One-loop matching for gluon lattice TMDs

Designing Observables for Quantum Interference in Jets at Subleading Color

New aspect of chiral and axial breaking in QCD

Centre Vortex Structure of QCD-Vacuum Fields and Confinement

Faddeev fixed-center approximation to the DDˉK system and the hidden charm Kccˉ​(4180) state

Towards the chiral phase transition in the Roberge-Weiss plane

Variational thermal quantum simulation of the lattice Schwinger model

Affiliations

Faddeev fixed-center approximation to the $D D ˉ K$ system and the hidden charm $K_{c c ˉ} (4180)$ state