scholarly journals Strange hadron production in pp, pPb, and PbPb collisions at LHC energies

2018 ◽  
Vol 171 ◽  
pp. 13008
Author(s):  
Hong Ni
Keyword(s):  
Particle Production ◽  
Dynamical Evolution ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Strange Particle ◽  
Relativistic Heavy Ion Collisions ◽  
High Multiplicity ◽  
Collective Effects ◽  
Additional Information ◽  
Particle Ratios

Identified particle spectra provide an important tool for understanding the particle production mechanism and the dynamical evolution of the medium created in relativistic heavy ion collisions. Studies involving strange and multi-strange hadrons, such as K0S, Λ, and Ξ−, carry additional information since there is no net strangeness content in the initial colliding system. Strangeness enhancement in AA collisions with respect to pp and pA collisions has long been considered as one of the signatures for quark-gluon plasma (QGP) formation. Recent observations of collective effects in high-multiplicity pp and pA collisions raise the question of whether QGP can also be formed in the smaller systems. Systematic studies of strange particle abundance, particle ratios, and nuclear modification factors can shed light on this issue. The CMS experiment has excellent strange-particle reconstruction capabilities over a broad kinematic range, and dedicated high-multiplicity triggers in pp and pPb collisions. The spectra of K0S, Λ, and Ξ− hadrons have been measured in various multiplicity and rapidity regions as a function of pT in pp, pPb, and PbPb collisions for several collision energies. The spectral shapes and particle ratios are compared in the different collision systems for events that have the same multiplicity and interpreted in the context of hydrodynamics models.

scholarly journals Strangeness Production in pp, p–Pb and Pb–Pb Collisions at the LHC Energies Measured with ALICE

2018 ◽  
Vol 46 ◽  
pp. 1860017
Author(s):  
D. Colella
Keyword(s):  
Particle Production ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Strange Particle ◽  
Weak Decay ◽  
Relativistic Heavy Ion Collisions ◽  
Strangeness Production ◽  
Heavy Ion Physics ◽  
Ion Collisions ◽  
Increasing Trend

The main goal of heavy-ion physics is to study the properties of the deconfined state of matter known as the Quark-Gluon Plasma (QGP) created in ultra-relativistic heavy-ion collisions. A systematic study of strangeness production is of fundamental importance for determining the thermal properties of the system created in such collisions. In the central barrel of the ALICE detector, K[Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] can be identified reconstructing their weak decay topology. It will be shown that the relative production (to pions) of strange particles follows a continuous increasing trend from low multiplicity pp to peripheral Pb–Pb collisions, above which a saturation is visible for central Pb–Pb collisions. This increasing trend is similar for pp and p–Pb collisions. Moreover, comparison of strange particle production in pp collisions at two different energies ([Formula: see text] = 7 TeV and 13 TeV) will be used to demonstrate that the observed trend in multiplicity is also energy independent.

ISENTROPIC QUARK HADRON PHASE BOUNDARY AND STRANGENESS ENHANCEMENT

2000 ◽  
Vol 15 (22) ◽  
pp. 3563-3575
Author(s):  
B. K. PATRA ◽  
C. P. SINGH ◽  
F. C. KHANNA
Keyword(s):  
Phase Boundary ◽  
Chemical Potential ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Strange Particle ◽  
Phase Boundaries ◽  
Two Phase ◽  
Hadron Phase ◽  
Particle Ratios ◽  
Strangeness Enhancement

We develop a phenomenological equation of state for the quark–gluon plasma containing nf flavors when the entropy per baryon ratio remains continuous across the phase boundary and thus derive a generalized expression for the temperature and baryon chemical potential dependent bag constant. The phase boundaries are obtained for an isentropic quark–hadron phase transition after using Gibbs' criteria and the transition to an ideal QGP from the solution of the condition B(μ,T)=0. The variation of critical temperature Tc with nf and the temperature variation of the quantity (ε-4P)/T4 which measures the interaction present in QGP are obtained and compared with the results from lattice calculations. Finally we obtain the strange particle ratios on the two phase boundaries which will be useful in identifying deconfined and/or ideal QGP formation in the heavy-ion experiments.

scholarly journals Hawking-Unruh Hadronization and Strangeness Production in High Energy Collisions

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Paolo Castorina ◽  
Helmut Satz
Keyword(s):  
Quark Mass ◽  
Particle Production ◽  
Mass Effect ◽  
Heavy Ion ◽  
Strange Particle ◽  
High Energy ◽  
Relativistic Heavy Ion Collisions ◽  
Thermalization Time ◽  
Strange Particle Production ◽  
High Energy Collisions

The thermal multihadron production observed in different high energy collisions poses many basic problems: why do even elementary,e+e-and hadron-hadron, collisions show thermal behaviour? Why is there in such interactions a suppression of strange particle production? Why does the strangeness suppression almost disappear in relativistic heavy ion collisions? Why in these collisions is the thermalization time less than≃0.5 fm/c? We show that the recently proposed mechanism of thermal hadron production through Hawking-Unruh radiation can naturally answer the previous questions. Indeed, the interpretation of quark (q)-antiquark (q̅) pairs production, by the sequential string breaking, as tunneling through the event horizon of colour confinement leads to thermal behavior with a universal temperature,T≃170 Mev, related to the quark acceleration,a, byT=a/2π. The resulting temperature depends on the quark mass and then on the content of the produced hadrons, causing a deviation from full equilibrium and hence a suppression of strange particle production in elementary collisions. In nucleus-nucleus collisions, where the quark density is much bigger, one has to introduce an average temperature (acceleration) which dilutes the quark mass effect and the strangeness suppression almost disappears.

scholarly journals Particle Production and Collectivity in High Multiplicity pp and pPb at the LHC

2018 ◽  
Vol 171 ◽  
pp. 19007
Author(s):  
George S. F. Stephans
Keyword(s):  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Multiplicity ◽  
Small Systems ◽  
Ion Collisions ◽  
Cms Detector

Recent unexpected evidence for collectivity in high multiplicity pp and pPb collisions at LHC energies has challenged the notion that such small systems do not exhibit any of the properties that have been used to study the quark gluon plasma in heavy ion collisions. An overview of recent results concerning particle production and collectivity in such collisions using the CMS detector at the LHC is presented.

scholarly journals ALICE Highlights

Proceedings ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 6 ◽  
Author(s):  
Francesco Collaboration
Keyword(s):  
Heavy Ion Collisions ◽  
Particle Production ◽  
Heavy Ion ◽  
High Multiplicity ◽  
Collective Effects ◽  
Ion Collisions ◽  
Strongly Interacting ◽  
Selection Of

Deconfined strongly interacting QCD matter is produced in the laboratory at the highest energy densities in heavy-ion collisions at the LHC. A selection of recent results from ALICE is presented, spanning observables from the soft sector (bulk particle production and correlations), the hard probes (charmed hadrons and jets) and signatures of possible collective effects in pp and p–Pb collisions with high multiplicity. Finally, the perspectives after the detectors upgrades, taking place in the period 2019–2020, are presented.

MEASUREMENTS OF MULTI-STRANGE (ANTI-)BARYON PRODUCTION IN Cu+Cu COLLISIONS WITH THE STAR EXPERIMENT AT RHIC

2007 ◽  
Vol 16 (07n08) ◽  
pp. 2091-2096
Author(s):  
◽  
M. G. MUNHOZ ◽  
J. TAKAHASHI
Keyword(s):  
Particle Production ◽  
System Size ◽  
Heavy Ion ◽  
Strange Particle ◽  
Relativistic Heavy Ion Collisions ◽  
High Transverse Momentum ◽  
Baryon Production ◽  
200 Gev ◽  
Star Experiment ◽  
Momentum Region

Strange particle production has always been an important probe to study various aspects of the high density, strong interacting matter created in ultra-relativistic heavy-ion collisions. Yields and spectra of strange hadrons have been measured by the STAR experiment for center of mass energies of 62.4 GeV, 130 GeV and 200 GeV per nucleon pair for Au + Au , p + p and d + Au collisions. We have now measured Cu + Cu collisions at 62.4 GeV and 200 GeV, complementing the study of the system size dependence initiated with the centrality dependence study of Au + Au data. We will present preliminary results on Ξ, Ω and their anti-particles produced in Cu + Cu collisions. Yields and ratios are compared to results from Au + Au collisions normalized by the equivalent number of participants. The nuclear modification factor of the measured particles from Cu + Cu data also shows the same suppression effects in the high transverse momentum region and a baryon/meson difference in the intermediate momentum region.

scholarly journals Particle Production in Ultrarelativistic Heavy-Ion Collisions: A Statistical-Thermal Model Review

2013 ◽  
Vol 2013 ◽  
pp. 1-27 ◽  
Author(s):  
S. K. Tiwari ◽  
C. P. Singh
Keyword(s):  
Thermal Model ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Transverse Mass ◽  
Current Status ◽  
Thermal Models ◽  
Ion Collisions ◽  
Ultrarelativistic Heavy Ion Collisions

The current status of various thermal and statistical descriptions of particle production in the ultrarelativistic heavy-ion collisions experiments is presented in detail. We discuss the formulation of various types of thermal models of a hot and dense hadron gas (HG) and the methods incorporated in the implementing of the interactions between hadrons. It includes our new excluded-volume model which is thermodynamically consistent. The results of the above models together with the experimental results for various ratios of the produced hadrons are compared. We derive some new universal conditions emerging at the chemical freeze-out of HG fireball showing independence with respect to the energy as well as the structure of the nuclei used in the collision. Further, we calculate various transport properties of HG such as the ratio of shear viscosity-to-entropy using our thermal model and compare with the results of other models. We also show the rapidity as well as transverse mass spectra of various hadrons in the thermal HG model in order to outline the presence of flow in the fluid formed in the collision. The purpose of this review article is to organize and summarize the experimental data obtained in various experiments with heavy-ion collisions and then to examine and analyze them using thermal models so that a firm conclusion regarding the formation of quark-gluon plasma (QGP) can be obtained.

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