arXiv subjects

J. Letessier

Publications and source records attributed to J. Letessier.

15 recordsLinked to original sources

arXiv2014

SHARE with CHARM

SHARE with CHARM program (SHAREv3) implements the statistical hadronization model description of particle production in relativistic heavy-ion collisions. Given a set of statistical parameters, SHAREv3 program evaluates yields and therefore also ratios, and furthermore, statistical particle abundance fluctuations. The physical bulk properties of the particle source is evaluated based on all hadrons produced, including the fitted yields. The bulk properties can be prescribed as a fit input complementing and/or replacing the statistical parameters. The modifications and improvements in the SHARE suite of programs are oriented towards recent and forthcoming LHC hadron production results including charm hadrons. This SHAREv3 release incorporates all features seen previously in SHAREv1.x and v2.x and, beyond, we include a complete treatment of charm hadrons and their decays, which further cascade and feed lighter hadron yields. This article is a complete and self-contained manual explaining and introducing both the conventional and the extended capabilities of SHARE with CHARM. We complement the particle list derived from the Particle Data Group tabulation composed of up, down, strange $u,d,s$ quarks (including resonances) with hadrons containing charm $c,\bar c$ quarks. We provide a table of the charm hadron decays including partial widths. The branching ratios of each charm hadron decays add to unity, which is achieved by including some charm hadron decay channels based on theoretical consideration in the absence of direct experimental information. A very successful interpretation of all available LHC results has been already obtained using this program.

hep-ph↗

arXiv2013

Charm decay as a source of multistrange hadrons

We describe a newly formulated approach to account for charm production and decay in Statistical Hadronization approach. Considering Pb--Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV at LHC we show that charm hadron decays can be a significant contributor to the multistrange hadron abundance. We discuss the magnitude of expected effects as a function of charm yield.

hep-ph↗

arXiv2009

Resonances Do Not Equilibrate

We discuss, in qualitative and quantitative fashion, the yields of hadron resonances. We show that these yields, in general, are not in chemical equilibrium. We evaluate the non-equilibrium abundances in a dynamic model implementing the $1+2\leftrightarrow 3$ resonance formation reactions. Due to the strength of these reactions, we show the $Σ(1385)$ enhancement, and the $Λ(1520)$ suppression explicitly.

nucl-th↗

arXiv2007

Thermal Dileptons at LHC

We predict dilepton invariant-mass spectra for central 5.5 ATeV Pb-Pb collisions at LHC. Hadronic emission in the low-mass region is calculated using in-medium spectral functions of light vector mesons within hadronic many-body theory. In the intermediate-mass region thermal radiation from the Quark-Gluon Plasma, evaluated perturbatively with hard-thermal loop corrections, takes over. An important source over the entire mass range are decays of correlated open-charm hadrons, rendering the nuclear modification of charm and bottom spectra a critical ingredient.

hep-ph↗

arXiv2007

SHAREv2: fluctuations and a comprehensive treatment of decay feed-down

This the user's manual for SHARE version 2. SHARE (Statistical Hadronization with Resonances) is a collection of programs designed for the statistical analysis of particle production in relativistic heavy-ion collisions. While the structure of the program remains similar to v1.X, v2 provides several new features such as evaluation of statistical fluctuations of particle yields, and a greater versatility, in particular regarding decay feed-down and input/output structure. This article describes all the new features, with emphasis on statistical fluctuations.

nucl-th↗

arXiv2005

Hadronization of Expanding QGP

We discuss how the dynamics of an exploding hot fireball of quark--gluon matter impacts the actual phase transition conditions between the deconfined and confined state of matter. We survey the chemical conditions prevailing at hadronization.

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arXiv2004

Strange Pentaquark Hadrons in Statistical Hadronization

We study, within the statistical hadronization model, the influence of narrow strangeness carrying baryon resonances (pentaquarks) on the understanding of particle production in relativistic heavy ion collisions. There is a great variation of expected yields as function of heavy ion collision energy due to rapidly evolving chemical conditions at particle chemical freeze-out. At relatively low collision energies, these new states lead to improvement of statistical hadronization fits.

hep-ph↗

arXiv2003

Strangeness and Quark Gluon Plasma

A brief summary of strangeness mile stones is followed by a chemical non-equilibrium statistical hadronization analysis of strangeness results at SPS and RHIC. Strange particle production in AA interactions at \sqrt{s_{NN}}\ge 8.6 GeV can be understood consistently as originating from the deconfined quark--gluon plasma in a sudden hadronization process. Onset of QGP formation as function of energy is placed in the beam energy interval 10--30A GeV/c. Strangeness anomalies at LHC are described.

hep-ph↗

arXiv2003

QCD Equations of State and the QGP Liquid Model

Recent advances in the study of equations of state of thermal lattice Quantum Chromodynamics obtained at non-zero baryon density allow validation of the quark-gluon plasma (QGP) liquid model equations of state (EoS). We study here the properties of the QGP-EoS near to the phase transformation boundary at finite baryon density and show a close agreement with the lattice results.

hep-ph↗

arXiv2002

Testing limits of statistical hadronization

Much of the energy of the nuclei colliding at RHIC or SPS is converted into final state hadronic particles. About a quarter of this energy is in baryons and antibaryons. There are nearly 10 strange quark pairs per central rapidity participant. Do we really understand the hadronic particle yields? Do we need to introduce post-Fermi-model ideas such as chemical non-equilibrium in order to understand how a deconfined state hadronizes?

nucl-th↗

arXiv2000

QGP fireball explosion

We identify the major physics milestones in the development of strange hadrons as an observable for both the formation of quark-gluon plasma, and of the ensuing explosive disintegration of deconfined matter fireball formed in relativistic heavy ion collisions at 160--20A GeV. We describe the physical properties of QGP phase and show agreement with the expectations based on an analysis of hadron abundances. We than also demonstrate that the m_t shape of hadron spectra is in qualitative agreement with the sudden breakup of a supercooled QGP fireball.

nucl-th↗

arXiv1998

QCD-bag mass spectrum and phase transitions

We obtain the hadronic mass spectrum in the `bag of bags' statistical bootstrap model (BBSBM), implementing the colorless state condition, aside of baryon and strangeness conservation, using group projection method. We study the partition function, investigate the properties of dense hadronic matter, and determine the conditions under which the system undergoes a phase transition to a deconfined quark-gluon plasma. We show that a phase transition cannot occur in the N=1 (Abelian) limit of our model, and is first order for QCD-like case N=3.

hep-ph↗

arXiv1997

Evidence for a high entropy phase in nuclear collisions

We determine the entropy per baryon content of the central reaction region in terms of the charged particle multiplicity. We study the consistency of our findings with recent data on strange anti-baryon production at 200 GeV A in S -> A collisions (A=200) assuming formation of a central fireball. Hadron gas models which do not invoke strong medium modifications of hadron masses do not provide enough entropy and are inconsistent with the combined experimental results. In contrast the quark-gluon plasma hypothesis explains them naturally.

hep-ph↗

arXiv1997

Thermal Flavor Production and Signatures of Deconfinement

Using renormalization group methods we evaluate the thermal strangeness and charm chemical equilibrium relaxation times in the deconfined quark-gluon plasma. We present a reaction model and evaluate the total production rate of strangeness in fixed target Pb-Pb collisions at 10--300 A GeV. We discuss the relevance of our results to the diagnosis and understanding of the properties of the deconfined state.

hep-ph↗

arXiv1992

Strangeness Conservation in Hot Nuclear Fireballs

A constraint between thermal fireball parameters arises from the requirement that the balance of strangeness in a fireball is (nearly) zero. We study the impact of this constraint on (multi-)strange (anti-)baryon multiplicities and compare the hadron gas and quark-gluon plasma predictions. We explore the relation between the entropy content and particle multiplicities and show that the data are compatible with the quark-gluon plasma hypothesis, but appear to be inconsistent with the picture of an equilibrated hadron gas fireball. We consider the implications of the results on the dynamics of evolution and decay of the particle source.

hep-ph↗