Nuclear Theory·nucl-th

Tuesday·June 16, 2020

17 papers—10 primary·7 cross-listed

11
[Submitted on 12 Jun 2020] (cross-list from hep-ph)
Power expansion for heavy quarkonium production at next-to-leading order in $e^{+} e^{-}$ annihilation
Kyle Lee🇺🇸 · George Sterman🇺🇸
We study heavy quarkonium production associated with gluons in $e^{+} e^{-}$ annihilation as an illustration of the perturbative QCD (pQCD) factorization approach, which incorporates the first nonleading power in the energy of the produced heavy quark pair. We show how the renormalization of the four-quark operators that define the heavy quark pair fragmentation functions using dimensional regularization induces "evanescent" operators that are absent in four dimensions. We derive closed forms for short-distance coefficients for quark pair production to next-to-leading order ( $α_{s}^{2}$ ) in the relevant color singlet and octet channels. Using non-relativistic QCD (NRQCD) to calculate the heavy quark pair fragmentation functions up to $v^{4}$ in the velocity expansion, we derive analytical results for the differential energy fraction distribution of the heavy quarkonium. Calculations for $^{3} S_{1}^{[1]}$ and $^{1} S_{0}^{[8]}$ channels agree with analogous NRQCD analytical results available in the literature, while several color-octet calculations of energy fraction distributions are new. We show that the remaining corrections due to the heavy quark mass fall off rapidly in the energy of the produced state. To explore the importance of evolution at energies much larger than the mass of the heavy quark, we solve the renormalization group equation perturbatively to two-loop order for the $^{3} S_{1}^{[1]}$ case.
Comments:
44 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2006.07375 [pdf]
JHEP(2020)·5 citations
12
[Submitted on 14 Jun 2020] (cross-list from hep-ph)
Anomalous scattering and transport in chiral matter
Kirill Tuchin🇺🇸
Chiral anomaly modifies the scattering processes in chiral systems which can be computed using the Maxwell-Chern-Simons theory that couples electrodynamics to the pseudoscalar field $θ$ describing the topological charge induced be external sources. Assuming slow variation of the topological charge density, the fermion scattering cross section is computed in the Born approximation and is found to have a resonance at the scattering angles proportional to the chiral conductivity. As a result, the transport coefficients are suppressed at high temperatures. The anisotropy of the cross section arises due to the spatial variation of the topological charge; its effect on the electrical conductivity is discussed.
Comments:
14 pages, v2: improved presentation, the role of the chiral instability discussed, typos fixed
Subjects:
High Energy Physics — Phenomenology (hep-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Nuclear Theory (nucl-th)
arXiv:
2006.07950 [pdf]
PLB(2020)·7 citations
13
[Submitted on 14 Jun 2020] (cross-list from hep-th)
A new consistent Neutron Star Equation of State from a Generalized Skyrme model
Christoph Adam🇪🇸 · Alberto García Martín-Caro🇪🇸 · Miguel Huidobro García🇪🇸 · Ricardo Vázquez🇪🇸 · Andrzej Wereszczynski🇵🇱
We propose a new equation of state for nuclear matter based on a generalized Skyrme model which is consistent with all current constraints on the observed properties of neutron stars. This generalized model depends only on two free parameters related to the ranges of pressure values at which different submodels are dominant, and which can be adjusted so that mass-radius and deformability constraints from astrophysical and gravitational wave measurements can be met. Our results support the Skyrme model and its generalizations as good candidates for a low energy effective field-theoretic description of nuclear matter even at extreme conditions such as those inside neutron stars.
Comments:
8 pages, 3 figures. Minor typos fixed. Version accepted for publication in Phys. Lett. B
Subjects:
High Energy Physics — Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2006.07983 [pdf]
PLB(2020)·34 citations
14
[Submitted on 14 Jun 2020] (cross-list from hep-ph)
Chiral anomaly and the pion properties in the light-front quark model
Ho-Meoyng Choi (Kyungpook National University)🇰🇷 · Chueng-Ryong Ji (North Carolina State University)🇺🇸
We explore the link between the chiral symmetry of QCD and the numerical results of the light-front quark model, analyzing both the two-point and three-point functions of the pion. Including the axial-vector coupling as well as the pseudoscalar coupling in the light-front quark model, we discuss the implication of the chiral anomaly in describing the pion decay constant, the pion-photon transition form factor and the electromagnetic form factor of the pion. In constraining the model parameters, we find that the chiral anomaly plays a critical role and the analysis of $F_{π γ} (Q^{2})$ in timelike region is important. Our results indicate that the constituent quark picture is effective for the low and high $Q^{2}$ ranges implementing the quark mass evolution effect as $Q^{2}$ grows.
Comments:
13 pages, 7 figures, update abstract, typo corrected, version to appear in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2006.08034 [pdf]
PRD(2020)·10 citations
15
[Submitted on 14 Jun 2020] (cross-list from math-ph)
Proof of the orthogonal--Pin duality
K. Neergård
This article contains the proof of a theorem on orthogonal-Pin duality that was cited without proof in a previous article in this journal.
Subjects:
Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
2006.08047 [pdf]
Bulg.J.Phys.(2023)·3 citations
16
[Submitted on 15 Jun 2020] (cross-list from hep-ph)
Masses of doubly heavy tetraquarks $T_{Q Q^{'}}$ in a relativized quark model
Qi-Fang Lü🇨🇳 · Dian-Yong Chen🇨🇳 · Yu-Bing Dong🇨🇳
In the present work, the mass spectra of doubly heavy tetraquarks $T_{Q Q^{'}}$ are systematically investigated in a relativized quark model. The four-body systems including the Coulomb potential, confining potential, spin-spin interactions, and relativistic corrections are solved within the variational method. Our results suggest that the $I J^{P} = 0 1^{+}$ $bb u ˉ d ˉ$ state is 54 MeV below the relevant $B ˉ B ˉ$ and $B ˉ B ˉ^{*}$ thresholds, which indicates that both strong and electromagnetic decays are forbidden, and thus this state can be a stable one. Its large hidden color component and small root mean square radius demonstrate that it is a compact tetraquark rather than a loosely bound molecule or point-like diquark-antidiquark structure. Our predictions of the doubly heavy tetraquarks may provide valuable information for future experimental searches.
Comments:
13 pages, 7 figures, comments and suggestions are welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2006.08087 [pdf]
PRD(2020)·93 citations
17
[Submitted on 15 Jun 2020] (cross-list from hep-ph)
Bubble dynamics in a strong first-order quark-hadron transition
Shuying Zhou🇨🇳 · Song Shu🇨🇳 · Hong Mao🇨🇳
We investigate the dynamics of a strong first-order quark-hadron transition driven by cubic interaction via homogeneous bubble nucleation in the Friedberg-Lee model. The one-loop effective thermodynamics potential of the model and the critical bubble profiles have been calculated at different temperatures and chemical potentials. By taking the temperature and the chemical potential as the variables, the evolutions of the surface tension, the typical radius of the critical bubble and the shift in the coarse-grained free energy in the presence of a nucleation bubble are obtained and the limit on the reliability of the thin-wall approximation is also addressed accordingly. Our results are compared to those obtained for a weak first-order quark-hadron phase transition, especially the spinodal decomposition is relevant.
Comments:
11 pages,6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2006.08298 [pdf]
CPC(2021)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE

Power expansion for heavy quarkonium production at next-to-leading order in e+e− annihilation

Anomalous scattering and transport in chiral matter

A new consistent Neutron Star Equation of State from a Generalized Skyrme model

Chiral anomaly and the pion properties in the light-front quark model

Proof of the orthogonal--Pin duality

Masses of doubly heavy tetraquarks TQQ′​ in a relativized quark model

Bubble dynamics in a strong first-order quark-hadron transition

Affiliations

Power expansion for heavy quarkonium production at next-to-leading order in $e^{+} e^{-}$ annihilation

Masses of doubly heavy tetraquarks $T_{Q Q^{'}}$ in a relativized quark model