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Multiplicity-dependent jet modification from di-hadron correlations in pp collisions at TeV
No full textGSI-2026-0020
First observation of strange baryon enhancement with effective energy in pp collisions at the LHC
No full textThe production of (multi-)strange hadrons is measured at midrapidity in proton-proton collisions at = 13 TeV as a function of the local charged-particle multiplicity in the pseudorapidity interval < 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 , , and 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
Measurement of meson production in pp and p-Pb collisions at TeV
No full textWe present the measurement of the p-differential production cross section of ω mesons in pp and p-Pb collisions at = 5.02 TeV at midrapidity by ALICE. In addition, the first measurement of the nuclear modification factor R for ω mesons at LHC energies is presented, complementing the existing measurements of lighter neutral mesons such as the π and η. Within the measured p range, the R of ω mesons is compatible with no cold nuclear matter effects within the uncertainties, consistent with previous measurements at lower energies. The ω/π ratio is presented for both collision systems, showing no collision system dependence within the uncertainties. The comparison to previously published ω/π ratios at lower and higher collision energies in pp collisions suggests a decreasing trend of the ratio above p = 4 GeV/c with increasing collision energy. The data in both collision systems are compared to predictions from PYTHIA 8, EPOS LHC, and DPMJET event generators, revealing significant shortcomings in these models’ ability to describe the production of ω mesons
Detectors and electronics for the CBM experiment at FAIR
No full textThe Compressed Baryonic Matter (CBM) experiment is a next-generation heavy-ion experiment under development at the future FAIR facility in Darmstadt, Germany. It is designed to explore the QCD phase diagram at high net-baryon densities with unprecedented precision. Operating in fixed-target mode with a continuous beam of up to 11 AGeV for heavy ions and 26 GeV for protons, CBM will investigate rare probes such as multi-strange hyperons, hypernuclei, and dileptons, aiming to identify signatures of a first-order phase transition and the QCD critical point.To achieve these goals, CBM employs a free-streaming, self-triggered readout architecture and a suite of radiation-hard, low-mass detectors capable of operating at interaction rates up to 10 MHz. The experimental set-up consists of several detector subsystems optimised for precise vertexing, tracking, particle identification, and event reconstruction. These subsystems have undergone extensive prototyping and validation campaigns, with many components already tested and integrated into existing experiments such as STAR/RHIC, HADES/SIS18, and E16/J-PARC. These efforts culminated in the realisation of the mCBM test set-up at the SIS18 accelerator, where key systems were successfully commissioned under realistic beam conditions.This contribution provides a concise overview of the current status of detector development, series production, and validation efforts through both simulations and measurement
Deep-Learning-Based Optimization of the Signal/Background Ratio for Particles in the CBM Experiment at FAIR
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Influence of electromagnetic fields on the generation of the directed and elliptic flows of heavy quarks in relativistic heavy-ion collisions
No full textWe study the impact of self-generated electromagnetic fields (EMF) on the momentum evolution of charm quarks in the partonic and hadronic medium created in heavy-ion collisions at energies available at the Relativistic Heavy Ion Collier (RHIC), using the parton-hadron-string dynamics (PHSD) off-shell transport approach. In the quark-gluon plasma (QGP) phase, the charm quark interacts with the off-shell partons, whose mass and widths are given by the dynamical quasiparticle model (DQPM), which can reproduce the lattice QCD thermodynamics. The background electromagnetic fields are computed dynamically within the PHSD considering both the spectators and participants protons as well as newly produced charged hadrons, quarks, and antiquarks, which reflects naturally the electric conductivity sigma el of the medium. We study the directed and elliptic flow of D mesons in the presence of electromagnetic fields. We find that electromagnetically induced v1 splitting in the D meson through D0 and D0 mesons is consistent with the experimental data. Furthermore, we notice that the v1 splitting in the heavy quark as a function of pT is more prominent as a probe of the produced electromagnetic fields. However, we find only a small impact of electromagnetic fields on the heavy quark elliptic flow v2