scholarly journals Low-mass dielectrons in pp, p–Pb and Pb–Pb collisions measured by the ALICE Experiment

2018 ◽  
Vol 171 ◽  
pp. 18011 ◽  
Author(s):  
Ivan Vorobyev
Keyword(s):  
Invariant Mass Distribution ◽  
Black Body ◽  
Heavy Ion ◽  
Black Body Radiation ◽  
Relativistic Heavy Ion Collisions ◽  
Vector Mesons ◽  
Alice Experiment ◽  
Final State ◽  
Correlated Electron ◽  
Ion Collisions

Dielectrons produced in ultra-relativistic heavy-ion collisions at the LHC provide a unique probe of the system evolution as they are unperturbed by final-state interactions. The dielectron continuum is extremely rich in physics sources: on top of ordinary Dalitz and resonance decays of pseudoscalar and vector mesons, thermal black-body radiation is of particular interest as it carries information about the temperature of the hot and dense system created in such collisions. The dielectron invariant-mass distribution is furthermore sensitive to medium modifications of the spectral function of short-lived vector mesons that are linked to the potential restoration of chiral symmetry at high temperatures. Correlated electron pairs from semi-leptonic charm and beauty decays provide complementary information about the heavy-quark energy loss.

scholarly journals Recent results from the ALICE Experiment at LHC

2018 ◽  
Vol 191 ◽  
pp. 01004
Author(s):  
Catalin Ristea
Keyword(s):  
System Size ◽  
Heavy Ion ◽  
Dense Medium ◽  
Production Flow ◽  
Alice Experiment ◽  
Final State ◽  
Proton Proton ◽  
Ion Collisions ◽  
Flow Phenomena ◽  
Nuclear Modification Factors

ALICE (A Large Ion Collider Experiment) at the LHC performed high statistics measurements in Pb-Pb collisions at the top LHC energy, complemented with large recent reference datasets in elementary proton-proton collisions at the same energy. Elementary pp collisions are serving as baseline for testing QCD properties and allow the study of the changes induced by the hot and dense medium produced in heavy ion collisions. Key observables like nuclear modification factors, jet production, flow phenomena and spectra for identified particles, related to the different stages of collision evolution, are presented and compared with the most recent results from p-Pb and Xe-Xe collisions, thus allowing to probe both initial cold nuclear matter and final state effects, combined with the system size dependence of the measurements.

scholarly journals Local spin alignment of vector mesons in relativistic heavy-ion collisions

2021 ◽  
Vol 817 ◽  
pp. 136325
Author(s):  
Xiao-Liang Xia ◽  
Hui Li ◽  
Xu-Guang Huang ◽  
Huan Zhong Huang
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Vector Mesons ◽  
Spin Alignment ◽  
Local Spin ◽  
Ion Collisions

scholarly journals Production of light nuclei at colliders – coalescence vs. thermal model

2020 ◽  
Vol 229 (22-23) ◽  
pp. 3559-3583
Author(s):  
Stanisław Mrówczyński
Keyword(s):  
Correlation Function ◽  
Thermal Model ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Light Nuclei ◽  
Relativistic Heavy Ion Collisions ◽  
Final State ◽  
Coalescence Model ◽  
Ion Collisions ◽  
Final State Interactions

AbstractThe production of light nuclei in relativistic heavy-ion collisions is well described by both the thermal model, where light nuclei are in equilibrium with hadrons of all species present in a fireball, and by the coalescence model, where light nuclei are formed due to final-state interactions after the fireball decays. We present and critically discuss the two models and further on we consider two proposals to falsify one of the models. The first proposal is to measure a yield of exotic nuclide 4Li and compare it to that of 4He. The ratio of yields of the nuclides is quite different in the thermal and coalescence models. The second proposal is to measure a hadron-deuteron correlation function which carries information whether a deuteron is emitted from a fireball together with all other hadrons, as assumed in the thermal model, or a deuteron is formed only after nucleons are emitted, as in the coalescence model. The p − 3He correlation function is of interest in context of both proposals: it is needed to obtain the yield of 4Li which decays into p and 3He, but the correlation function can also tell us about an origin of 3He.

PARTICLE IDENTIFICATION IN THE DYNAMICAL STRING-PARTON MODEL OF RELATIVISTIC HEAVY-ION COLLISIONS

1999 ◽  
Vol 08 (04) ◽  
pp. 299-309 ◽  
Author(s):  
D. E. MALOV ◽  
A. S. UMAR ◽  
D. J. ERNST ◽  
D. J. DEAN
Keyword(s):  
Heavy Ion Collisions ◽  
Parton Model ◽  
Heavy Ion ◽  
Particle Identification ◽  
Relativistic Heavy Ion Collisions ◽  
Mass Window ◽  
Final State ◽  
Ion Collisions ◽  
Physical Mass ◽  
The Masses

The dynamical string-parton model for relativistic heavy-ion collisions is generalized to include particle identification of the final-state hadrons by phenomenologically quantizing the masses of the classical strings which result from string breaking. General features of the Nambu-Gotō strings are used to motivate a model that identifies a mass window near the physical mass of a meson, and does not allow the string to decay further if its mass falls within the window. Data from e+e- collisions in the region [Formula: see text] to 30 GeV are well reproduced by this model.

scholarly journals Probing the hadronic phase with resonances of different lifetimes in Pb-Pb collisions with ALICE

2018 ◽  
Vol 171 ◽  
pp. 15001
Author(s):  
Neelima Agrawal
Keyword(s):  
Heavy Ion ◽  
High Energy ◽  
Special Focus ◽  
Alice Experiment ◽  
Comprehensive Overview ◽  
Final State ◽  
Hadronic Phase ◽  
Ion Collisions ◽  
Hadronic Resonances

The ALICE experiment has measured the production of a rich set of hadronic resonances, such as ρ(770)0, K*(892)0, ϕ(1020), ∑±(1385), Λ(1520) and Ξ*0 in pp, p-Pb and Pb-Pb collisions at various energies at the LHC. A comprehensive overview and the latest results are presented in this paper. Special focus is given to the role of hadronic resonances for the study of final-state effects in high-energy collisions. In particular, the measurement of resonance production in heavy-ion collisions has the capability to provide insight into the existence of a prolonged hadronic phase after hadronisation. The observation of the suppression of the production of Λ(1520) resonance in central Pb-Pb collisions at [see formula in PDF] =2.76 TeV adds further support to the existence of such a dense hadronic phase, as already evidenced by the ratios K*(892)0/K and ρ(770)0/π.

scholarly journals OPEN CHARM ANALYSIS ON THE FIRST PP COLLISIONS AT $\sqrt{s} = 7~{\rm TeV}$ WITH ALICE

2011 ◽  
Vol 02 ◽  
pp. 25-30 ◽  
Author(s):  
◽  
GIACOMO ORTONA
Keyword(s):  
Production Cross ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Nucleon Nucleon ◽  
Relativistic Heavy Ion Collisions ◽  
Alice Experiment ◽  
Proton Proton ◽  
Ion Collisions ◽  
Density State ◽  
Energy Domain

A Large Ion Collider Experiment (ALICE) is one of the four large experiments at the Large Hadron Collider (LHC), and the one dedicated to ultra relativistic heavy ion collisions, aiming at investigating the properties of the high-density state of QCD matter produced in such events. ALICE started to collect data in proton-proton collisions at the LHC at CERN in November 2009 (with a centre of mass energy [Formula: see text]). Since March 2010 data are being recorded at an energy of [Formula: see text] while from November 7 to December 6 LHC provided Pb-Pb collisions at an energy of [Formula: see text] per nucleon-nucleon pair. In Pb-Pb collisions heavy quarks are regarded as sensitive probes of the interaction dynamics between the parton and medium produced in the collisions, and the energies available at LHC will allow to study the production of heavy flavours with high statistics. Proton-proton data will be used to measure the heavy flavours production cross section to compare with perturbative QCD calculations in an unexplored energy domain and they will provide the reference for the study of Pb-Pb collisions. After a description of the ALICE experiment focused on its heavy flavour related performance, the status of the first analysis on charm production, measured by reconstructing the decays of D0, D+, D*+, and Ds into hadronic and semi-leptonic channels will be presented. An outlook of the same measurements for the upcoming Pb-Pb run will also be discussed.

Sign in / Sign up

Export Citation Format

Share Document