Wed·Feb 26, 2025Wednesday·February 26, 2025

1. 01*

   Measurement of isolated prompt photon production in pp and p-Pb collisions at the LHC

   ALICE Collaboration

   This paper presents the measurement of the isolated prompt photon inclusive production cross section in pp and p-Pb collisions by the ALICE Collaboration at the LHC. The measurement is performed in p-Pb collisions at centre-of-mass energies per nucleon pair of $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV and $8.16$ TeV, as well as in pp collisions at $\sqrt{s}=5.02$ TeV and $8$ TeV. The cross section is obtained at midrapidity $(|y|<0.7)$ using a charged-track based isolation momentum $p_{\mathrm{T}}^{\mathrm{iso},\mathrm{ch}}<1.5$ GeV/$c$ in a cone with radius $R=0.4$. The data for both collision systems are well reproduced by perturbative QCD (pQCD) calculations at next-to-leading order (NLO) using recent parton distribution functions for free (PDF) and bound (nPDF) nucleons. Furthermore, the nuclear modification factor $R_{\text{pA}}$ for both collision energies is consistent with unity for $p_{\mathrm{T}}>20$ GeV/$c$. However, deviations from unity ($R_{\mathrm{pA}}<1$) of up to 20% are observed for $p_{\mathrm{T}}<20$ GeV/$c$ with limited significance, indicating the possible presence of nuclear effects in the initial state of the collision. The suppression increases with decreasing \pt with a significance of $2.3\sigma$ for a non-zero slope and yields $R_{\mathrm{pA}}<1$ with a significance of $1.8\sigma$ at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV for $p_{\mathrm{T}}<20$ GeV/$c$. In addition, a significance of $1.1\sigma$ is observed for $R_{\mathrm{pA}}<1$ at the lower collision energy $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV for $p_{\mathrm{T}}<14$ GeV/$c$. The magnitude and shape of the suppression are consistent with pQCD predictions at NLO using nPDFs that incorporate nuclear shadowing effects in the Pb nucleus.

   nucl-exhep-exEPJC(2025)·11 citations
2. 02*

   Charged-particle multiplicity distributions over a wide pseudorapidity range in p-Pb collisions at ${\sqrt{\mathbf{s}}}_{\mathrm{NN}}=5.02$ TeV

   ALICE Collaboration

   This paper presents the primary charged-particle multiplicity distributions in proton-lead collisions at a centre-of-mass energy per nucleon-nucleon collision of $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. The distributions are reported for non-single diffractive collisions in different pseudorapidity ranges. The measurements are performed using the combined information from the Silicon Pixel Detector and the Forward Multiplicity Detector of ALICE. The multiplicity distributions are parametrised with a double negative binomial distribution function which provides satisfactory descriptions of the distributions for all the studied pseudorapidity intervals. The data are compared to models and analysed quantitatively, evaluating the first four moments (mean, standard deviation, skewness, and kurtosis). The shape evolution of the measured multiplicity distributions is studied in terms of KNO variables and it is found that none of the considered models reproduces the measurements. This paper also reports on the average charged-particle multiplicity, normalised by the average number of participating nucleon pairs, as a function of the collision energy. The multiplicity results are then compared to measurements made in proton-proton and nucleus-nucleus collisions across a wide range of collision energies.

   nucl-exhep-exEPJC(2025)·7 citations
3. 03*

   Observation of the $\Omega$(2012) baryon at the LHC

   ALICE Collaboration

   A signal consistent with the $\Omega$(2012) baryon has been observed with a significance of $15\sigma$ in pp collisions at $\sqrt{s}=13$ TeV at the LHC. In this paper, the analysis technique is described and measurements of the mass and width of the $\Omega$(2012) are reported, along with the first measurement of its transverse-momentum spectrum and yield. This paper corroborates the observation by Belle of this excited $\Omega$ state and the observation that the $\Omega$(2012) has a rather narrow width for a strongly decaying resonance. The yield measurement is combined with a statistical thermal model calculation of strange baryon yield ratios to obtain estimates of the $\Omega {(2012)}^{-}\to \Xi \overline{\mathrm{K}}$ branching ratios. These results will improve our understanding of the internal structure and mass spectrum of excited baryon states and serve as a baseline for searches regarding modifications of these properties in high-temperature media.

   ↳ hep-exnucl-exPRD(2025)·11 citations
4. 04*

   Microscopic investigation of $E2$ matrix elements in atomic nuclei

   S.P. Rouoof · Nazira Nazir · S. Jehangir🇮🇳 · G.H. Bhat🇮🇳 · J.A. Sheikh🇮🇳 · N. Rather · S. Frauendorf

   A systematic analysis of $E2$ matrix elements of ${}^{72}$Ge, ${}^{76}$Ge, ${}^{168}$Er, ${}^{186}$Os, ${}^{188}$Os, ${}^{190}$Os, ${}^{192}$Os and ${}^{194}$Pt nuclides is performed using the beyond mean-field approach of triaxial projected shell model (TPSM). For these nuclei, large sets of $E2$ matrix elements have been deduced from the multi-step Coulomb excitation experiments, and it is shown that TPSM approach provides a reasonable description of the measured transitions. We have evaluated 1496 $E2$ matrix elements up to spin, $I=10$ for the eight nuclei studied, and tabulate them for future experimental and theoretical comparisons. Further, shape invariant analysis has been performed with the calculated $E2$ transitions using the Kumar-Cline sum rules. It is inferred from the analysis that the resulting shape, after configuration mixing of the quasiparticle states, transforms from $\gamma$-rigid to that of $\gamma$-soft for some nuclei, in conformity with the experimental data.

   ↳ nucl-thnucl-exPRC(2025)·3 citations
5. 05*

   Probing $\Lambda$ potential at high and low densities via \(^3_{\Lambda}\)H production in C+C reactions

   Gao-Chan Yong🇨🇳 · J. L. Rodríguez-Sánchez🇪🇸 · Yapeng Zhang🇨🇳

   The production of Lambda hyperons and light hypernuclei in heavy-ion collisions provides critical insights into the nuclear equation of state (EoS) and hyperon interactions in dense matter, addressing the longstanding ``hyperon puzzle'' in neutron star physics. Using the INCL+ABLA and AMPT-HC models, we systematically investigate C+C collisions at beam energies of 1.1 and 1.9 GeV/nucleon to explore the sensitivity of hyperon and hypernuclei yields to the EoS and hyperon potential. Our results reveal that Lambda hyperon production is predominantly influenced by the nuclear EoS, while light hypernuclei formation (e.g., \(^3_{\Lambda}\)H) exhibits stronger sensitivity to the hyperon potential at high/low densities with the incident beam energies of 1.1/1.9 GeV. The study provides a framework for future experiments at facilities like HIAF and FAIR/GSI to resolve the hyperon puzzle, thus advancing our understanding of quantum chromodynamics in high-density regimes.

   ↳ nucl-thnucl-exPRC(2025)·3 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.