Nuclear Theory·nucl-th

Friday·August 22, 2025

9 papers—6 primary·3 cross-listed

07
Helicity amplitudes of $N (1520)$ and $N (1535)$ including pentaquark components
Kai Xu🇹🇭 · Attaphon Kaewsnod🇹🇭 · Zheng Zhao🇹🇭 · Ayut Limphirat🇹🇭 · Yupeng Yan🇹🇭
We investigate the helicity amplitudes of the $N (1520)$ and $N (1535)$ resonances in the electromagnetic transition process $γ^{*} p \to N^{*}$ , where the $N (1520)$ and $N (1535)$ are assumed to include both the $L = 1$ three-quark and $L = 0$ spatial symmetric $q^{4} q ˉ$ pentaquark components. The helicity transition amplitudes $A_{1/2}$ , $A_{3/2}$ (for spin 3/2 states) and $S_{1/2}$ are computed within the constituent quark model. The inclusion of the $q^{4} q ˉ$ pentaquark components via the $γ^{*} \to q q ˉ$ diagram significantly improves the theoretical description of the helicity amplitudes for both $N (1520)$ and $N (1535)$ , yielding a closer agreement with experimental data compared to the pure three-quark picture. The work reveals that the $N (1520)$ and $N (1535)$ resonances may contain a considerable pentaquark components.
↳ hep-phhep-thnucl-thPRD(2025)·0 citations
08
Dilepton Spectra and Even Flow Harmonics in a Magnetized QGP: An Ideal Hydrodynamic Study
Ankit Kumar Panda🇮🇳 · Aritra Das🇺🇸 · Ashutosh Dash🇩🇪 · Aritra Bandyopadhyay🇷🇴 · Chowdhury Aminul Islam🇸🇮
We present the first comprehensive study of dilepton production from a hot, magnetized quark-gluon plasma in heavy-ion collisions (HIC), incorporating realistic, time-dependent, and spatially inhomogeneous magnetic field profiles within an analytically solvable Gubser flow background. This framework provides a significant improvement over previous static calculations with homogeneous fields and moves toward the long-term goal of full $3 + 1$ D magnetohydrodynamic simulations. We explore the effects of impact parameter, electrical conductivity, and invariant mass on the dilepton spectra and anisotropic even flow coefficients. It is found that transverse momentum spectra increase with impact parameter, dominated by annihilation processes, while decay contributions remain sub-leading. Strikingly, the elliptic flow $v_{2}$ from decay channels is nonzero even in nearly central collisions, exhibiting a characteristic shape--positive at low $p_{T}$ and negative at high $p_{T}$ --that is largely independent of impact parameter and conductivity. In contrast, $v_{2}$ from annihilation processes is smaller in magnitude but dominates the total flow in magnitude due to its larger yield. Higher harmonics, such as $v_{4}$ , are an order of magnitude smaller as compared to $v_{2}$ along with distinctive zero-crossing patterns. Conductivity enhances both spectra and flow but leaves no unambiguous signature for its extraction. Varying the invariant mass reveals the strongest enhancements at low mass, with harmonic coefficients suppressed at higher masses. Overall, our results suggest that central and semi-central collisions can carry imprints of the background magnetic field, and that characteristic correlations in even flow harmonics may provide a robust probe of electromagnetic effects in HICs.
↳ hep-phnucl-th3 citations
09
Critical Phenomena in Hadronic and DIS Processes
L.L. Jenkovszky🇺🇦 · C. Merino🇪🇸
We compare the critical phenomena (e.g. phase transitions, crossover) in proton-proton, proton-nucleus scattering and in lepton-proton deep inelastic scattering (DIS) systems.
↳ hep-phnucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Helicity amplitudes of N(1520) and N(1535) including pentaquark components

Dilepton Spectra and Even Flow Harmonics in a Magnetized QGP: An Ideal Hydrodynamic Study

Critical Phenomena in Hadronic and DIS Processes

Affiliations

Helicity amplitudes of $N (1520)$ and $N (1535)$ including pentaquark components