Tue·Jul 8, 2025Tuesday·July 8, 2025

1. 01*

   Low-mass vector-meson production at forward rapidity in $p$$+$$p$ and Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$~GeV

   PHENIX Collaboration: N.J. Abdulameer · U. Acharya · A. Adare · C. Aidala · N.N. Ajitanand · Y. Akiba · M. Alfred · D. Anderson · V. Andrieux · S. Antsupov · N. Apadula · H. Asano and 344 other authors

   The PHENIX experiment at the Relativistic Heavy Ion Collider has measured low-mass vector-meson ($\omega +\rho$ and $\varphi$) production through the dimuon decay channel at forward rapidity $(1.2<|\text{mbox}y|<2.2)$ in $p$$+$$p$ and Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$~GeV. The low-mass vector-meson yield and nuclear-modification factor were measured as a function of the average number of participating nucleons, $⟨N_{\mathrm{part}}⟩$, and the transverse momentum $p_T$. These results were compared with those obtained via the kaon decay channel in a similar $p_T$ range at midrapidity. The nuclear-modification factors in both rapidity regions are consistent within the uncertainties. A comparison of the $\omega +\rho$ and $J/\psi$ mesons reveals that the light and heavy flavors are consistently suppressed across both $p_T$ and $⟨N_{\mathrm{part}}⟩$. In contrast, the $\varphi$ meson displays a nuclear-modification factor consistent with unity, suggesting strangeness enhancement in the medium formed.

   nucl-exPRC(2025)·3 citations
2. 02*

   Recent studies on heavy-flavor femtoscopy in heavy-ion collisions by STAR

   Priyanka Roy Chowdhury🇵🇱

   At the initial stage of nuclear-nuclear collisions, heavy quarks are generated in hard partonic scatterings. This allows them to participate in the entire evolution of the heavy-ion collisions. During hadronization, different type of hadrons are produced including D mesons and light-flavoured hadrons, like pion ($\pi$), kaon ($K$), proton ($p$) etc. We can observe different interactions between these hadrons based on the size of collision systems. Such as, hadron re-scattering, suppression of charm quarks and collective effects are weak or missing in $p+p$ system in comparison to $Au+Au$ or $Pb+Pb$ collision system. Femtoscopy is one of the most significant and unique tools for examining the final state interaction behaviors between correlated pair of particles at low momentum in a pair rest frame. It is also possible to explore the size and geometry of emission source through the measurements of femtoscopic correlation functions. Here we report the studies of correlations between neutral charmed meson ($D^0$ / $\overline{D^0}$) and identified charged hadrons (${\pi }^{\pm }$, $K^{\pm }$, $p^{\pm }$) in Au+Au collisions at STAR experiment using femtoscopy technique. This is the first measurement of heavy-flavor femtoscopy in heavy-ion collisions at 200 GeV. STAR results can provide valuable insights into the interactions between $D^0/\overline{D^0}$-${\pi }^{\pm }$, $D^0/\overline{D^0}$-$K^{\pm }$ and $D^0/\overline{D^0}$-$p^{\pm }$ pairs during the hadronic phase. $D^0(\overline{D^0})$ mesons are reconstructed via the $K^{\mp }-{\pi }^{\pm }$ decay channel using topological criteria enabled by the HFT (Heavy Flavor Tracker) detector with excellent track pointing resolution. These proceedings show a comparison study between STAR results and theory predictions using NLO-HMChPT (Next-to-Leading Order-Heavy Meson Chiral Perturbation Theory) scheme and associated physics implications.

   nucl-exhep-ex0 citations
3. 03*

   Electronic Bridge processes in ${}^{229}$Th-doped LiCAF and LiSAF

   Tobias Kirschbaum · Martin Pimon🇦🇹 · Andreas Grüneis · Thorsten Schumm🇦🇹 · Adriana Pálffy🇩🇪

   Electronic bridge mechanisms driving the ${}^{229}$Th nuclear clock transition in the vacuum-ultraviolet-transparent crystals ${}^{229}$Th:LiCAF (LiCaAlF${}_6$) and ${}^{229}$Th:LiSAF (LiSrAlF${}_6$) are investigated theoretically. Due to doping-induced symmetry breaking within the host crystal, electronic defect states emerge around the thorium nucleus and can facilitate nuclear (de)excitation via laser-assisted electronic bridge mechanisms. We investigate spontaneous and laser-assisted electronic bridge schemes for different charge compensation mechanisms. While the calculated spontaneous electronic bridge rates are very small, laser-assisted electronic bridge schemes for nuclear (de)excitation turn out to be significantly more efficient than both spontaneous nuclear decay and direct laser excitation, offering promising prospects for the future clock operation.

   ↳ physics.atom-phcond-mat.mtrl-scinucl-exPRA(2026)·1 citation
4. 04*

   Extraction of ground-state nuclear deformations from ultra-relativistic heavy-ion collisions: Nuclear structure physics context

   J. Dobaczewski🇬🇧 · A. Gade🇺🇸 · K. Godbey🇺🇸 · R.V.F. Janssens🇺🇸 · W. Nazarewicz🇺🇸

   The collective-flow-assisted nuclear shape-imaging method in ultra-relativistic heavy-ion collisions has recently been used to characterize nuclear collective states. In this paper, we assess the foundations of the shape-imaging technique employed in these studies. We argue that some current UHIC nuclear imaging techniques neglect fundamental aspects of spontaneous symmetry-breaking and symmetry-restoration in colliding ions and incorrectly infer one-body multipole moments from studies of nucleonic correlations. Therefore, the impact of this approach on nuclear structure research has been overstated. Conversely, efforts to incorporate existing knowledge on nuclear shapes into analysis pipelines can be beneficial for benchmarking tools and calibrating models used to extract information from ultra-relativistic heavy-ion experiments.

   ↳ nucl-thhep-exhep-phnucl-exPRResearch(2025)·20 citations
5. 05*

   Laser spectroscopy and CP-violation sensitivity of actinium monofluoride

   M. Athanasakis-Kaklamanakis🇨🇭 · M. Au🇨🇭 · A. Kyuberis🇳🇱 · C. Zülch🇩🇪 · K. Gaul🇩🇪 · H. Wibowo🇬🇧 · L. Skripnikov · L. Lalanne🇧🇪 · J. R. Reilly🇬🇧 · A. Koszorús🇧🇪 · S. Bara🇧🇪 · J. Ballof🇩🇪 and 30 other authors

   The apparent invariance of the strong nuclear force under combined charge conjugation and parity (CP) remains an open question in modern physics. Precision experiments with heavy atoms and molecules can provide stringent constraints on CP violation via searches for effects due to permanent electric dipole moments and other CP-odd properties in leptons, hadrons, and nuclei. Radioactive molecules have been proposed as highly sensitive probes for such searches, but experiments with most such molecules have so far been beyond technical reach. Here we report the first production and spectroscopic study of a gas-phase actinium molecule, ${}^{227}$AcF. We observe the predicted strongest electronic transition from the ground state, which is necessary for efficient readout in searches of symmetry-violating interactions. Furthermore, we perform electronic- and nuclear-structure calculations for ${}^{227}$AcF to determine its sensitivity to various CP-violating parameters, and find that a realistic, near-term experiment with a precision of 1 mHz would improve current constraints on the CP-violating parameter hyperspace by three orders of magnitude. Our results thus highlight the potential of ${}^{227}$AcF for exceptionally sensitive searches of CP violation.

   ↳ physics.atom-phnucl-exnucl-thNature(2025)·12 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.