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Item type:Publication, Measurement of the inclusive isolated-photon production cross section in pp and Pb–Pb collisions at √ˢɴɴ=5.02 TeV(Springer Nature, 2025)The ALICE Collaboration at the CERN LHC has measured the inclusive production cross section of isolated photons at midrapidity as a function of the photon transverse momentum ( Pʸᴛ ), in Pb–Pb collisions in different centrality intervals, and in pp collisions, at centre-of-momentum energy per nucleon pair of √ˢɴɴ = 5.02 TeV. The photon transverse momentum range is between 10–14 and 40–140 GeV/c , depending on the collision system and on the Pb–Pb centrality class. The result extends to lower Pʸᴛ than previously published results by the ATLAS and CMS experiments at the same collision energy. The covered pseudorapidity range is |ηʸ| < 0.67 . The isolation selection is based on a charged particle isolation momentum threshold Pⁱˢᵒ′ᶜʰᴛ = 1.5 GeV/c within a cone of radii R = 0.2 and 0.4. The nuclear modification factor is calculated and found to be consistent with unity in all centrality classes, and also consistent with the HG-PYTHIA model, which describes the event selection and geometry biases that affect the centrality determination in peripheral Pb–Pb collisions. The measurement is compared to next-to-leading order perturbative QCD calculations and to the measurements of isolated photons and Z⁰ bosons from the CMS experiment, which are all found to be in agreement.3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Measurement of the inclusive isolated-photon production cross section in pp collisions at √s = 13 TeV(Springer Nature, 2025)The production cross section of inclusive isolated photons has been measured by the ALICE experiment at the CERN LHC in pp collisions at centre-of-momentum energy of √s = 13 TeV collected during the LHC Run 2 data-taking period. The measurement is performed by combining the measurements of the electromagnetic calorimeter EMCal and the central tracking detectors ITS and TPC, covering a pseudorapidity range of |ηʸ| < 0.67 and a transverse momentum range of 7 < Pʸᴛ < 200 GeV/c. The result extends to lower Pʸᴛ and Xʸᴛ = 2pʸᴛ\√s ranges, the lowest Xʸᴛ of any isolated photon measurements to date, extending significantly those measured by the ATLAS and CMS experiments towards lower pʸᴛ at the same collision energy with a small overlap between the measurements. The measurement is compared with next-to-leading order perturbative QCD calculations and the results from the ATLAS and CMS experiments as well as with measurements at other collision energies. The measurement and theory prediction are in agreement with each other within the experimental and theoretical uncertainties.8 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Measurement of the production cross section of prompt Ξc0 baryons in p–Pb collisions at √ˢɴɴ =5.02 TeV(Springer Nature, 2025)The transverse momentum (Pᴛ) differential production cross section of the promptly produced charm-strange baryon ⁰c (and its charge conjugate ⁰c) is measuredat midrapidity via its hadronic decay into π⁺⁻ in p-Pb collisions at a centre-of-mass energy per nucleon-nucleon collision √ˢɴɴ = 5.02 TeV with the ALICE detector at the LHC. The ⁰c nuclear modification factor ( RpPb), calculated from the cross sections in pp and p-Pb collisions, is presented and compared with the RpPb of Λ⁺c baryons. The ratios between the Pᴛ-differential production cross section of ⁰c baryons and those of D⁰ mesons and Λ⁺c baryons are also reported and compared with results at forward and backward rapidity from the LHCb Collaboration. The measurements of the production cross section of prompt ⁰c baryons are compared with a model based on perturbative QCD calculations of charm-quark production cross sections, which includes only cold nuclear matter effects in p-Pb collisions, and under- estimates the measurement by a factor of about 50. This discrepancy is reduced when the data is compared with a model that includes string formation beyond leading-colour approximation or in which hadronisation is implemented via quark coalescence. The Pᴛ-integrated cross section of prompt ⁰c -baryon production at midrapidity extrapolated down to Pᴛ = 0 is also reported. These measurements offer insights and constraints for theoretical calculations of the hadronisation process. Additionally, they provide inputs for the calculation of the charm production cross section in p-Pb collisions at midrapidity.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Proton emission in ultraperipheral Pb-Pb collisions at √ˢɴɴ =5.02 TeV(American Physical Society, 2025)The first measurements of proton emission accompanied by neutron emission in the electromagnetic dissociation (EMD) of ²⁰⁸Pb nuclei in the ALICE experiment at the Large Hadron Collider are presented. The EMD protons and neutrons emitted at very forward rapidities are detected by the proton and neutron zero degree calorimeters of the ALICE experiment. The emission cross sections of zero, one, two, and three protons accompanied by at least one neutron were measured in ultraperipheral ²⁰⁸Pb - ²⁰⁸Pb collisions at a center-of-mass energy per nucleon pair √ˢɴɴ = 5.02 TeV. The 0p and 3p cross sections are described by the RELDIS model within their measurement uncertainties, while the 1p and 2p cross sections are underestimated by the model by 17–25%. According to this model, these 0p, 1p, 2p, and 3p cross sections are associated, respectively, with the production of various isotopes of Pb, Tl, Hg, and Au in the EMD of ²⁰⁸Pb. The cross sections of the emission of a single proton accompanied by the emission of one, two, or three neutrons in EMD were also measured. The data are significantly overestimated by the RELDIS model, which predicts that the (1p,1n), (1p,2n), and (1p,3n) cross sections are very similar to the cross sections for the production of the thallium isotopes ²⁰⁶'²⁰⁵'²⁰⁴TI.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Studying charm hadronisation into baryons with azimuthal correlations of Λc+ with charged particles in pp collisions at s=13 TeV(Elsevier, 2025)The distribution of angular correlations between prompt charm hadrons and primary charged particles in pp collisions is sensitive to the charm-quark hadronisation process. In this letter, charm-baryon correlations are measured for the first time by studying the azimuthal-angle difference between charged particles and prompt Λ+ c baryons produced in pp collisions at a centre-of-mass energy of √𝑠 = 13 TeV, with the ALICE detector. Λ+ c baryons are reconstructed at midrapidity (|𝑦| < 0.5) in the transverse-momentum interval 3 < 𝑝T < 16 GeV/𝑐, and correlated with charged particles with 𝑝T > 0.3 GeV/𝑐 and pseudorapidity |𝜂| < 0.8. For 3 < 𝑝Λ+ c ,D T < 5 GeV/𝑐, the comparison with published measurements of D-meson and charged-particle correlations in the same collision system hints at a larger number of low-momentum particles associated with Λ+ c -baryon triggers than with D-meson triggers, both in the collinear and opposite directions with respect to the trigger particle. These differences can be quantified by the comparison of the properties of the near- and away-side correlation peaks, and are not reproduced by predictions of various Monte Carlo event generators, generally underpredicting the associated particle yields at 𝑝assoc T < 1 GeV/𝑐. This tension between Λ+ c -baryon and D-meson associated peak yields could suggest a modified fragmentation of the charm quark, or a different hadronisation process, when a charm baryon is produced in the final state2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, First observation of strange baryon enhancement with effective energy in pp collisions at the LHC(Springer Science and Business Media Deutschland GmbH, 2025)The production of (multi-)strange hadrons is measured at midrapidity in protonproton collisions at √s = 13 TeV as a function of the local charged-particle multiplicity in the pseudorapidity interval |η| < 0.5 and of the very-forward energy measured by the ALICE Zero-Degree Calorimeters. The latter provides information on the effective energy, i.e. the energy available for particle production in the collision once subtracted from the centre-of-mass energy. The yields of K⁰ₛ, Λ+Λ̄, and Ξ⁻ + Ξ⁺ per charged-particle increase with the effective energy. In addition, this work exploits a multi-differential approach to decouple the roles of local multiplicity and effective energy in such an enhancement. The results presented in this article provide new insights into the interplay between global properties of the collision, such as the initial available energy in the event, and the locally produced final hadronic state, connected to the charged-particle multiplicity at midrapidity. Notably, a strong increase of strange baryon production with effective energy is observed for fixed charged-particle multiplicity at midrapidity. These results are discussed within the context of existing phenomenological models of hadronisation implemented in different tunes of the PYTHIA 8 event generator.4