Fri·Nov 1, 2024Friday·November 1, 2024

1. 01*

   First $D^0+{\overline{D}}^0$ measurement in heavy-ion collisions at SPS energies with NA61/SHINE

   Anastasia Merzlaya · the NA61/SHINE Collaboration

   The measurement of open charm meson production provides a tool for the investigation of the properties of the hot and dense matter created in nucleus-nucleus collisions at relativistic energies. In particular, charm mesons are of vivid interest in the context of the study of the nature of the phase-transition between confined hadronic matter and the quark-gluon plasma. Recently, the experimental setup of the NA61/SHINE experiment was upgraded with the high spatial resolution Vertex Detector which enables the reconstruction of secondary vertices from open charm meson decays. In this presentation the first $D^0$ meson yields at the SPS energy regime will be shown. The analysis used the most central 20\% of Xe+La collisions at 150A GeV/c from the data set collected in 2017. This allowed the estimation of the corrected yields (dN/dy) for $D^0+{\overline{D}}^0$ via its ${\pi }^{+/-}+K^{-/+}$ decay channel at mid-rapidity in the center-of-mass system. The results will be compared and discussed in the context of several model calculations including statistical and dynamical approaches

   nucl-exhep-exEPJ Web Conf.(2025)·9 citations
2. 02*

   One-proton emission of ${}^{102}$Sb and its sensitivity to proton-neutron interaction

   Tomohiro Oishi🇯🇵 · Masaaki Kimura🇯🇵 · Lorenzo Fortunato🇮🇹

   One-proton emission from the ${}^{102}$Sb nucleus is discussed, assuming an inert ${}^{100}$Sn core and the valence proton and neutron. There are experimentally measured bound states in the ${}^{100}$Sn-neutron system, whereas no particle-bound ${}^{100}$Sn-proton state has been observed. With time-dependent three-body calculations, the $1^{+}$ ground state of ${}^{102}$Sb is suggested as a possible proton emitter. This conclusion is reached by assuming a weakening effect on the proton-neutron ($pn$) interaction with respect to a bare deuteron. An analogous phenomenon is necessary to reproduce the empirical binding energies of ${}^{42}$Sc and ${}^{18}$F. Continuous shift from the unbound to bound regions by changing the $pn$-interaction strength is demonstrated. The lower limit of lifetime is evaluated as $\tau \gtrsim 4.4\times 10^{-18}$ seconds in the no-$pn$-interaction limit. However, the actual lifetime is expected as longer with a finite $pn$ interaction. Observation of a resonant state in ${}^{102}$Sb and its decay would provide a benchmark of the $pn$-pairing correlation.

   ↳ nucl-thnucl-exPRC(2025)·0 citations
3. 03*

   A two-body femtoscopy approach to the proton-deuteron correlation function

   Juan M. Torres-Rincon🇪🇸 · Angels Ramos🇪🇸 · Joel Rufí🇪🇸

   The proton-deuteron correlation function measured by the ALICE collaboration in high multiplicity p+p collisions shows a momentum dependence which is in contradiction with the predictions of the Lednický-Lyuboshitz formalism of the two-body interaction. This result motivated a more sophisticated three-body description in terms of a composite deuteron. Encouraged by the good description of other deuteron observables in the context of heavy-ion collisions, we revisit this correlation function under the two-body approximation without relying on the Lednický-Lyuboshitz approximation, but using the solution of the Schrödinger equation by incorporating both strong and Coulomb interactions. The two-body description provides a reasonable agreement to ALICE data for natural values of the source size. Interpreting the previously assumed attractive character of the $(L,S)=(0,3/2)$ channel of the $pd$ interaction into a more-likely repulsion, the results agree better not only with the ALICE measurements but also with recent STAR data in Au+Au collisions.

   ↳ nucl-thhep-phnucl-exPRC(2025)·18 citations
4. 04*

   Azimuthal asymmetries in lepton and heavy-quark pair production in UPCs

   Daniël Boer🇳🇱 · Luca Maxia🇳🇱 · Cristian Pisano🇮🇹

   Azimuthal modulations in lepton and heavy-quark pair production in ultraperipheral collisions (UPCs) of highly charged ions are investigated. The modulations in the azimuthal angles of the sum and difference of the transverse momenta of the pair of particles in the final state, as well as of the transverse impact parameter, arise from the collisions of unpolarized and polarized photons. A full description of the cross section in terms of Generalized Transverse Momentum Dependent parton distributions (GTMDs) for photons is given including a careful consideration of the Fourier transform to impact parameter space. In particular, this leads to a feed-in mechanism among harmonics of different orders, which in principle generates harmonics of all (even) orders. Wherever comparable, our analytical results for the azimuthal modulations agree with those presented in other papers on this topic. Compared to these other works, we separate effects that arise from the anisotropies of the GTMDs from those that do not and retain terms proportional to the mass of the produced particles, as they are relevant for muon, charm and bottom quark production. We show that the normalized differential cross section changes considerably with the produced particle mass, which should be discernible in UPCs at RHIC and LHC. For the numerical results we adopt several models for the photon GTMD correlator, and find that all of them are in fairly good agreement with each other and with UPC data from STAR. We also present results for various azimuthal modulations for RHIC kinematics, where we compare $e^{+}{e}^{-}$ production with the production of heavier particles, and for LHC kinematics, focusing on ${\mu }^{+}{\mu }^{-}$ production. These results exhibit interesting mass-dependent features in the asymmetries that may help study the anisotropies arising from the underlying photon GTMD description.

   ↳ hep-phhep-exnucl-exJHEP(2025)·1 citation
5. 05*

   The Systematics and Operational Studies (SOS) Apparatus as a testbed for nEDM@SNS experiment

   V. Cianciolo🇺🇸 · R. Golub🇺🇸 · B. W. Filippone🇺🇸 · P. R. Huffman🇺🇸 · K. Leung🇺🇸 · E. Korobkina🇺🇸 · C. Swank🇺🇸

   The nEDM experiment at the SNS (nEDM@SNS) is the first measurement of the neutron EDM to directly measure the precession frequency of the neutron spin due to magnetic and electric fields. Previous measurements have inferred the precession frequency by measuring the residual polarization of neutrons after a long period of free precession. This difference provides independent information on potential unknown systematic uncertainties compared to previous and on-going measurements. It is precisely because nEDM@SNS is using a number of novel techniques, that it is essential to perform detailed studies of these techniques in order to optimize the statistical sensitivity and minimize the systematic uncertainty. The Systematic and Operational Studies Apparatus (SOSA) was one of the main efforts of nEDM@SNS collaboration, concentrated on development of a cryogenic test-bed for learning precise manipulation of spins and studing systematic effects of the proposed new technique. The test bed does not need an electric field but designed to have full NMR capability to the same level as nEDM@SNS.

   ↳ physics.ins-detnucl-ex2 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.