Nuclear Theory·nucl-th

Tuesday·October 15, 2024

16 papers—8 primary·8 cross-listed

09
Consistent chiral limit in on-shell renormalized quark-meson model with ChPT scaling
Vivek Kumar Tiwari🇮🇳
Chiral perturbation theory (ChPT) predicted scaling of the pion,~kaon decay constants $f_{π}, f_{K}$ and $M_{η}^{2} = m_{η}^{2} + m_{η^{'}}^{2}$ has been used in the renormalized $2 + 1$ flavor quark-meson (RQM) model,~to find a consistent path to chiral limit as the $π and K$ meson masses approach zero.~The left side of the Columbia plot is generated free from any ambiguity or heuiristic adjustment in the model parameter fixing away from the physical point. The on-shell renormalization of parameters and consistent treatment of the divergent quark one-loop vacuum fluctuations in the RQM model,~make the axial $U_{A} (1)$ anomaly significantly stronger and the light (strange) explicit chiral symmetry breaking strength becomes weaker by a small (relatively large) amount.~The first order chiral transition region in the $m_{π} - m_{K}$ and $μ - m_{K}$ planes of Columbia plot,~increases due to the above novel features of the RQM model.~Comparing the softening effect of quark one-loop vacuum fluctuation on the chiral transition,~it looks overestimated in a recent functional renormalization group study.
↳ hep-phnucl-thPRD(2025)·5 citations
10
Rotation induced color confinement
Guojun Huang🇨🇳 · Shile Chen🇨🇳 · Yin Jiang🇨🇳 · Jiaxing Zhao🇩🇪 · Pengfei Zhuang🇨🇳
The rotation effect on the QCD properties is an open question. We study the dynamic gluon mass in a dense QCD matter, the rotation is introduced by taking a covariant transformation between the flat and curved spaces. The law of causality which restricts the rotation strength of the system is carefully considered in the calculation. we find that the rotation effect is not monotonous. Overall, it behaves like an anti-screening effect, reflecting in the decreasing gluon mass, but the strength changes with the rotation. For a QCD matter with low baryon density, the screening effect in the flat space can be completely canceled by the rotation, and gluons are confined in a strongly rotating matter. When the rotation is extremely high, the matter approaches to a weakly interacting gas.
↳ hep-phnucl-thPLB(2025)·0 citations
11
Measurement of Quadrupole Deformation using E $2$ and M $1 +$ E $2$ Transitions in Heavy Isotopes in the Mass Range of $150 < A < 250$
Prajwal MohanMurthy · Lixin Qin · Jeff A. Winger
The measurement of a permanent electric dipole moment (EDM) in atoms is crucial for understanding the origins of CP-violation. However, accurate interpretation of the EDM in systems involving deformed isotopes requires the characterization of their deformation. While nuclear deformation is indicated in various structure models, there is substantial mutual disagreement between the theoretical models or between theoretical models and experimental values. Nuclear E $2$ transitions allow access to quantify quadrupole deformation, but these transitions are often mixed with M $1$ transitions. Both E $2$ and M $1$ transitions are well characterized by Weisskopf estimates, which rely on a single-particle approximation, but deviate due to collective nuclear deformations. Previously, Weisskopf estimates were only available for the mass range $A < 150$ , and in this work we have extended the Weisskopf estimates of both E $2$ and M $1$ transition lifetimes to the mass range of $150 \leq A \leq 250$ . We comprehensively studied the deviation of E $2$ and M $1 +$ E $2$ transition lifetimes from the newly established Weisskopf estimates in $91$ candidate isotopes, by comparing the transition lifetimes of the candidate isotopes to their nearest even-even counterparts, whose E $2$ transition strengths are very well understood. Estimates of collective nuclear quadrupole deformation in $67$ of these isotopes were thus obtained, either from E $2$ or M $1 +$ E $2$ transition lifetimes. In $32$ cases they were obtained from both types of transitions independently, and are mutually consistent, as well as following the trends established in theory. We thereby identify the isotopes $^{223, 225}$ Fr, $^{221, 223}$ Ra, $^{223, 225, 227}$ Ac and $^{229}$ Pa, where EDM measurements are foreseen and information on nuclear deformation is needed, for which no measurement of nuclear quadrupole deformation has been made.
↳ nucl-exnucl-thPoS(2025)·0 citations
12
Chiral symmetry breaking, chiral partners, and the $K_{1}$ and $K^{*}$ in medium
Su Houng Lee🇰🇷
We clarify the concept of chiral partners. For a vector meson, the isospin-zero and hypercharge-zero state in the flavor octet mixes with the flavor singlet state. Since the flavor singlet vector meson does not have a chiral partner, the mixed $ω$ and $ϕ$ mesons will not have chiral partners. This means that even when chiral symmetry is restored, these mesons will not become degenerate with their corresponding parity partners. On the other hand, the $K_{1}$ and $K^{*}$ mesons are chiral partners, and both have widths smaller than 100 MeV. Therefore, we emphasize that studying these mesons in environments where chiral symmetry is restored is particularly important for understanding the effect of chiral symmetry restoration on chiral partners and their masses.
↳ hep-phnucl-exnucl-thJ.Subatomic Part.Cosmol.(2024)·2 citations
13
Strong decay widths of S- and P-wave singly-, doubly- and triply-heavy charm and bottom baryons
Emmanuel Ortiz-Pacheco · Roelof Bijker
We present a study of two-body decay widths of heavy baryons into another heavy baryon and a light pseudoscalar meson in the framework of the non-relativistic quark model in combination with the elementary emission model for the strong couplings. The present study includes the decays of 1S- and 1P-wave baryons with one, two or three heavy quarks, either charm (c) or bottom (b). The relative partial widths are given by the appropriate flavor SU(3) isoscalar factors. The flavor, spin and orbital contributions are discussed explicitly as well as selection rules for forbidden decays. The total widths are compared with the available experimental data as well as with other theoretical studies. The calculated widths of singly-heavy baryons are found to be in reasonable agreement with the observed widths. The decay widths of doubly-heavy baryons are suppressed with respect to those of the singly-heavy baryons by the ratios of the quark masses appearing in the orbital contributions.
↳ hep-phhep-exnucl-th9 citations
14
General theory of constructing potential with bound states in the continuum
Mao Kurino · Kazuo Takayanagi
We present a general theory of potentials that support bound states at positive energies (bound states in the continuum). On the theoretical side, we prove that, for systems described by nonlocal potentials of the form $V (r, r^{'})$ , bound states at positive energies are as common as those at negative energies. At the same time, we show that a local potential of the form $V (r)$ rarely supports a positive energy bound state. On the practical side, we show how to construct a (naturally nonlocal) potential which supports an arbitrary normalizable state at an arbitrary positive energy. We demonstrate our theory with numerical examples both in momentum and coordinate spaces with emphasis on the important role played by nonlocal potentials. Finally, we discuss how to observe bound states at positive energies, and where to search for nonlocal potentials which may support them.
↳ quant-phnucl-thPTEP(2024)·0 citations
15
Pentaquarks $P_{c}$ in a dynamical coupled-channel approach of $γ p \to J / ψ p$ reaction
Xu Zhang🇨🇳
We construct a dynamical coupled-channel approach to photon-induced $J / ψ$ production to search for the trace of the pentaquarks $P_{c}$ . In this approach, the considered open-charm intermediate states are $Λ_{c} D ˉ^{(*)}$ and $Σ_{c} D ˉ^{(*)}$ . Scattering amplitude involving $Λ_{c} D ˉ^{(*)}$ , $Σ_{c} D ˉ^{(*)}$ and $J / ψ p$ interactions is calculated from solving a set of coupled-channel integral equations. The coupled-channel interaction potentials are generated from one-boson-exchange. The pentaquarks $P_{c}$ are dynamically generated from the coupled-channel interactions. Moreover, the background contributions to the $P_{c}$ signals are assumed to be the Pomeron exchange and $σ$ exchange. The predicted total and differential cross sections of $J / ψ$ photoproduction are within the range of the data from the GlueX and $J / ψ$ - $007$ experiments. It is found that the $σ$ exchange plays a crucial role for determining the very near threshold cross section. The total cross section gets enhanced due to the open-charm state rescattering in the $P_{c} (4312)$ , $P_{c} (4440)$ and $P_{c} (4457)$ production regions, and is of order 1 nb.
↳ hep-phhep-exnucl-thEPJC(2025)·10 citations
16
Correlations and fluctuations in a magnetized PNJL model with and without inverse magnetic catalysis effect
Shijun Mao🇨🇳
The correlation $χ_{11}^{B Q}$ and quadratic fluctuations $χ_{2}^{B}, χ_{2}^{Q}, χ_{2}^{T}$ of baryon number $B$ , electric charge $Q$ and temperature $T$ are investigated in a two-flavor Polyakov loop extended Nambu-Jona-Lasinio (PNJL) model at finite temperature and magnetic field. The inverse magnetic catalysis (IMC) effect is introduced through the magnetic field dependent parameters $G (e B)$ or $T_{0} (e B)$ , and we make comparison of the results in the cases with and without IMC effect. With nonvanishing magnetic field, the correlation $χ_{11}^{B Q}$ and fluctuations $χ_{2}^{B}, χ_{2}^{Q}, χ_{2}^{T}$ increase with temperature, and then show the peak around the pseudocritical temperatures of chiral restoration and deconfinement phase transitions in the cases with and without the IMC effect. The correlation and fluctuations along the phase transition line under external magnetic field are characterized by the scaled correlation $χ^_{11}^{B Q} = \frac{χ _{11}^{B Q} ( e B , T _{p c}^{c} ( e B ))}{χ _{11}^{B Q} ( e B = 0 , T _{p c}^{c} ( e B = 0 ))}$ and scaled fluctuations $χ^_{2}^{B (Q, T)} = \frac{χ _{2}^{B (Q, T)} ( e B , T _{p c}^{c} ( e B ))}{χ _{2}^{B (Q, T)} ( e B = 0 , T _{p c}^{c} ( e B = 0 ))}$ at the pseudocritical temperature $T_{p c}^{c}$ of chiral restoration phase transition. $χ^_{11}^{B Q}, χ^_{2}^{B}$ , and $χ^_{2}^{Q}$ increase with magnetic fields, and the inclusion of IMC effect leads to some enhancement in their values. However, $χ^_{2}^{T}$ is altered by the IMC effect. Without IMC effect, $χ^_{2}^{T}$ slightly increases and then decreases with magnetic fields. Taking into account of the IMC effect by $G (e B)$ , $χ^_{2}^{T}$ monotonically increases with magnetic fields, and by $T_{0} (e B)$ , it is a nonmonotonic function of magnetic field.
↳ hep-phhep-latnucl-thCPC(2025)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE