Tue·Feb 11, 2025Tuesday·February 11, 2025

1. 01*

   Jet and jet substructure: ALICE results

   Haidar Mas'ud Alfanda🇨🇳

   Jets and their substructure in pp collisions offer a unique opportunity to probe various aspects of quantum chromodynamics (QCD), ranging from perturbative QCD (pQCD) tests to studies of non-perturbative phenomena such as hadronization. They also probe the transition between perturbative and non-perturbative regimes. In heavy-ion collisions, jets serve as a novel tool to investigate the microscopic properties of the deconfined quark-gluon plasma (QGP). Recently, significant progress has been made in developing jet substructure observables to explore these properties. The ALICE experiment is particularly well-suited for jet measurements due to its high-precision tracking system, which is especially beneficial for detecting low transverse momentum jets. This contribution will highlight recent ALICE measurements of inclusive and semi-inclusive jets, along with various jet substructure observables in pp, p-Pb, and Pb-Pb collisions. The comparisons between data and predictions from Monte Carlo (MC) models as well as analytical calculations will be discussed.

   nucl-exhep-exActa Phys.Polon.Supp.(2025)·0 citations
2. 02*

   Refined topology of the N = 20 island of inversion with high precision mass measurements of ${}^{31-33}$Na and ${}^{31-35}$Mg

   E. M. Lykiardopoulou🇨🇦 · C. Walls🇨🇦 · J. Bergmann🇩🇪 · M. Brodeur🇺🇸 · C. Brown🇬🇧 · J. Cardona🇨🇦 · A. Czihaly🇨🇦 · T. Dickel🇩🇪 · T. Duguet🇫🇷 · J.-P. Ebran🇫🇷 · M. Frosini🇫🇷 · Z. Hockenbery🇨🇦 and 21 other authors

   Mass measurements of ${}^{31-33}$Na and ${}^{31-35}$Mg using the TITAN MR-TOF-MS at TRIUMF's ISAC facility are presented, with the uncertainty of the ${}^{33}$Na mass reduced by over two orders of magnitude. The excellent performance of the MR-TOF-MS has also allowed the discovery of a millisecond isomer in ${}^{32}$Na. The precision obtained shows that the binding energy of the normally closed N = 20 neutron shell reaches a minimum for ${}^{32}$Mg but increases significantly for ${}^{31}$Na, hinting at the possibility of enhanced shell strength toward the unbound ${}^{28}$O. We compare the results with new ab initio predictions that raise intriguing questions of nuclear structure beyond the dripline.

   nucl-exPRL(2025)·6 citations
3. 03*

   Spin alignment of quarkonia in vortical quark-gluon plasma

   Yuhao Liang🇨🇳 · Shu Lin🇨🇳

   The spin alignment of $J/\psi$ with respect to event plane in relativistic heavy ion collisions exhibits a significant signal. We propose a possible mechanism for spin alignment through spin dependent dissociation of quarkonia in a vortical quark-gluon plasma. The spin dependent dissociation is realized through inelastic scattering between constituents of quarkonium and those of quark-gluon plasma polarized by the vorticity. The spin dependent dissociation rate is found to depend on the directions of vorticity, quantization axis, and quark momentum. We implement our results in a dissociation dominated evolution model for quarkonia in the Bjorken flow, finding the spin $0$ state is slightly suppressed compared to the average of the other two, which is consistent with the sign found in experiments. We also find absence of logarithmic enhancement in binding energy in the vortical correction to dissociation rate, which is understood from the requirement that a spin dependent dissociation can only come from quark coupling to a pair of chromomagnetic and chromoelectric field.

   ↳ hep-phnucl-exnucl-thCPC(2025)·7 citations
4. 04*

   Delta isobar resonance effects studied by summed isospin spin strengths and nuclear matrix elements for double and single beta decays

   Hiroyasu Ejiri🇯🇵

   Nuclear matrix elements (NMEs) for double and single beta decays are crucial for studying neutrino properties beyond and within the standard model. The NMEs consist mainly of the spin isospin components. The delta isobar resonance, which is strongly excited by the qualk spin isospin excitation, is shown to quench the spin isospin NMEs by a coefficient around 0.7. Impact of the delta resonance on neutrino studies in nuclei is discused.

   ↳ nucl-thnucl-ex1 citation
5. 05*

   Insights into the ${\gamma }^{(\ast )}+\mathbf{N}(940){\frac{1}{2}}^{+}\to \mathbf{\Delta }(1700){\frac{3}{2}}^{-}$ transition

   L. Albino🇪🇸 · G. Paredes-Torres🇲🇽 · K. Raya🇪🇸 · A. Bashir🇲🇽 · J. Segovia🇪🇸

   We report novel theoretical results for the ${\gamma }^{(\ast )}+N(940){\frac{1}{2}}^{+}\to \Delta (1700){\frac{3}{2}}^{-}$ transition, utilizing a symmetry-preserving treatment of a vector$\otimes$vector contact interaction (SCI) within the Dyson-Schwinger equations (DSEs) formalism. In this approach, both nucleon, $N(940){\frac{1}{2}}^{+}$, and $\Delta (1232)$'s parity partner, $\Delta (1700){\frac{3}{2}}^{-}$, are treated as quark-diquark composites, with their internal structures governed accordingly by a tractable truncation of the Poincaré-covariant Faddeev equation. Nonpointlike quark+quark (diquark) correlations within baryons, which are deeply tied to the processes driving hadron mass generation, are inherently dynamic in the sense that they continually break apart and recombine guided by the Faddeev kernel. For the nucleon, isoscalar-scalar and isovector-axial-vector diquarks dominate, while the $\Delta (1700){\frac{3}{2}}^{-}$ state only includes contributions from isovector-axial-vector diquarks because the SCI-interaction excludes isovector-vector diquarks. Once the Faddeev wave function of the baryons involved in the electromagnetic transition is normalized taking into account that its elastic electric form factor must be one at the on-shell photon point, we compute the transition form factors that describe the ${\gamma }^{(\ast )}+N(940){\frac{1}{2}}^{+}\to \Delta (1700){\frac{3}{2}}^{-}$ reaction and, using algebraic relations, derive the corresponding helicity amplitudes. When comparing with experiment, our findings highlight a strong sensitivity of these observables to the internal structure of baryons, offering valuable insights. Although the SCI-framework has obvious limitations, its algebraic simplicity provides analytical predictions that serve as useful benchmarks for guiding more refined studies within QCD-based DSEs frameworks.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2025)·5 citations
6. 06*

   Impact of Tracking Resolutions on $\varphi$-Meson Spin Alignment Measurement

   C.W. Robertson🇺🇸 · Yicheng Feng🇺🇸 · Fuqiang Wang🇺🇸

   Measurements of global spin alignment of vector mesons in relativistic heavy-ion collisions can provide unique insights into spin-orbit interactions and vector meson dynamics in the Quark-Gluon Plasma (QGP) produced in those collisions. The global spin alignment is measured by the $00^{\mathrm{th}}$ coefficient of the spin density matrix, ${\rho }_{00}$, via the polar angle (${\theta }^{\ast }$) of the decay-daughter momentum in the parent rest frame with respect to the direction of the orbital angular momentum of the collision. Such measurements are affected by the angular and momentum resolutions of the reconstructed tracks in the experiment. Such effects are nontrivial because of kinematic complications caused by the boost to the parent rest frame, and could be important given that the global spin alignment signal is weak. In this paper, we investigate the effects of experimental tracking resolutions on measurements of the $\varphi$(1020) meson ${\rho }_{00}$. We study these effects for two methods of ${\rho }_{00}$ measurements, the conventional method analyzing the $\varphi$-meson yield versus ${\cos }^2{\theta }^{\ast }$ and the invariant mass ($m_{\mathrm{inv}}$) method utilizing $⟨{\cos }^2{\theta }^{\ast }⟩$ versus $m_{\mathrm{inv}}$. Using typical resolution values from experiments, we find that the effect of track resolution on ${\rho }_{00}$ is small, well within typical measurement uncertainties.

   ↳ physics.data-annucl-exPRC(2025)·2 citations
7. 07*

   QED nuclear medium effects at EIC energies

   Shohini Bhattacharya🇺🇸 · Oleksandr Tomalak🇺🇸 · Ivan Vitev🇺🇸

   We present the first calculation of quantum electrodynamics (QED) nuclear medium effects under the experimental conditions of future Electron-Ion Collider (EIC) experiments. Our work offers numerical estimates, particularly in the context of inclusive deep inelastic scattering on a ${}_{82}^{208}\mathrm{Pb}$ nucleus. While prior studies have predominantly focused on elastic scattering, our investigation extends to the more complex scenarios of inelastic processes within a nuclear medium. Our findings suggest that the cross-section corrections due to QED nuclear medium effects could be substantial, reaching or exceeding the level of experimental precision. This work further compares the effects of single re-scattering events with those of multiple re-scatterings, as particles travel the nuclear volume. We estimate the dominant source of the uncertainties associated with our formalism by varying the scale of the atomic physics where the screening of the electric field of the nucleus happens. This calculation not only contributes to the understanding of QED nuclear medium effects, but also offers a path to a more precise extraction of the process-independent non-perturbative structure of nuclei.

   ↳ nucl-thhep-exhep-phnucl-exPRD(2025)·2 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.