Heavy-ion results from the LHC

A summary of the experimental results from Pb-Pb collisions at the LHC is given.Comment: 8 pages. Prepared for the proceedings of XXXI Physics in Collision, Vancouver, BC Canada, August 28 - September 1, 201

ALICE Overview

A general overview of the results obtained by the ALICE experiment from the analysis of the \PbPb data sample collected at the end of 2010 during the first heavy-ion run at the LHC is presented.Comment: 8 pages, proceedings of Strangeness in Quark Matter 2011 conferenc

Open heavy flavour reconstruction in the ALICE central barrel

The ALICE experiment will be able to detect open charm and beauty hadrons in proton-proton and heavy ion collisions in the new energy regime of the CERN Large Hadron Collider (LHC). Heavy flavours are a powerful tool to investigate the medium created in high energy nucleus--nucleus interactions because they are produced in the hard scatterings occurring at early times and, thanks to their long lifetime on the collision timescale, they probe all the stages of the system evolution. The detectors of the ALICE central barrel ($-0.9 < \eta < 0.9$) will allow to track charged particles down to low transverse momentum ($\approx$ 100 MeV/$c$) and will provide hadron and electron identification as well as an accurate measurement of the positions of primary and secondary vertices. It will therefore be possible to measure the production of open heavy flavours in the central rapidity region down to low transverse momentum, exploiting the semi-electronic and the hadronic decay channels. Here we present a general overview of the ALICE perspectives for heavy flavour physics and some examples from the open charm and beauty analyses which have been developed and tested on detailed simulations of the experimental apparatus.Comment: ICHEP0

Results from the commissioning of the ALICE Inner Tracking System with cosmics

The Inner Tracking System (ITS) is the detector of the ALICE central barrel located closest to the beam axis and it is therefore a key detector for tracking and vertexing performance. Here, the main results from the ITS commissioning with atmospheric muons in 2008 are presented, focusing in particular on the detector operation and calibration and on the methods developed for the alignment of the ITS detectors using reconstructed tracks.Comment: 4 pages, 1 figure with 3 panels (=3 separate eps files) To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

Open Heavy Flavor in QCD Matter and in Nuclear Collisions

We review the experimental and theoretical status of open heavy-flavor (HF)production in high-energy nuclear collisions at RHIC and LHC. We first overviewthe theoretical concepts and pertinent calculations of HF transport in QCDmatter, including perturbative and non-perturbative approaches in thequark-gluon plasma, effective models in hadronic matter, as well asimplementations of heavy-quark (HQ) hadronization. This is followed by a briefdiscussion of bulk evolution models for heavy-ion collisions and initialconditions for the HQ distributions which are needed to calculate HF spectra incomparison to observables. We then turn to a discussion of experimental datathat have been collected to date at RHIC and LHC, specifically for the nuclearsuppression factor and elliptic flow of semileptonic HF decays, D mesons,non-prompt $J/\psi$ from B-meson decays, and b-jets. Model comparisons to HFdata are conducted with regards to extracting the magnitude, temperature andmomentum-dependence of HF transport coefficients from experiment

Charmed hadron production in high-energy nuclear collisions

We present a new model for the description of heavy-flavor hadronization in high-energy nuclear (and possibly hadronic) collisions, where the process takes place not in the vacuum, but in the presence of other color charges. We explore its effect on the charmed hadron yields and kinematic distributions once the latter is applied at the end of transport calculations used to simulate the propagation of heavy quarks in the deconfined fireball produced in nuclear collisions. The model is based on the formation of color-singlet clusters through the recombination of charm quarks with light antiquarks or diquarks from the same fluid cell. This local mechanism of color neutralization leads to a strong space-momentum correlation, which provides a substantial enhancement of charmed baryon production -- with respect to expectations based on $e^+e^-$ collisions -- and of the collective flow of all charmed hadrons. We also discuss the similarities between our model and recently developed mechanisms implemented in QCD event generators to simulate medium corrections to hadronization in the presence of other nearby color charges.Comment: 6 pages, proceedings of ICHEP-2022. arXiv admin note: substantial text overlap with arXiv:2209.0423

Heavy-flavor transport and hadronization in pp collisions

Recent experimental results on the Lambda_c/D^0 ratio in proton-proton collisions have revealed a significant enhancement compared to expectations based on universal fragmentation fractions/functions across different colliding systems, from e+e- to pp. This unexpected enhancement has sparked speculation about the potential effects of a deconfined medium impacting hadronization, previously considered exclusive to heavy-ion collisions. In this study, we propose a novel approach that assumes the formation of a small, deconfined, and expanding fireball even in pp collisions, where charm quarks can undergo rescattering and hadronization. We make use of the same in-medium hadronization mechanism developed for heavy-ion collisions, which involves local color-neutralization through recombination of charm quarks with nearby opposite color charges from the background fireball. Our model incorporates the presence of diquark excitations in the hot medium, which promotes the formation of charmed baryons. Moreover, the recombination process, involving closely aligned partons from the same fluid cell, effectively transfers the collective flow of the system to the final charmed hadrons. We show that this framework can qualitatively reproduce the observed experimental findings in heavy-flavor particle-yield ratios, $p_T$-spectra and elliptic-flow coefficients. Our results provide new, complementary supporting evidence that the collective phenomena observed in small systems naturally have the same origin as those observed in heavy-ion collision

X-ray tomography of large wooden artworks: The case study of "Doppio corpo" by Pietro Piffetti

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