Enhanced production of strange baryons in high-energy nuclear collisions from a multiphase transport model

Abstract

We introduce additional coalescence factors for the production of strange baryons in a multiphase transport (AMPT) model in order to describe the enhanced production of multistrange hadrons observed in Pb + Pb collisions at √ s NN = 2.76 TeV at the Large Hadron Collider (LHC) and Au + Au collisions at √ s NN = 200 GeV at Relativistic Heavy-Ion Collider (RHIC). This extended AMPT model is found to also give a reasonable description of the multiplicity dependence of the strangeness enhancement observed in high multiplicity events in pp collisions at √ s = 7 TeV and p-Pb collisions at √ s NN = 5.02 TeV. We find that the coalescence factors depend on the system size but not much on whether the system is produced from A + A or p + A collisions.The extended AMPT model thus provides a convenient way to model the mechanism underlying the observed strangeness enhancement in collisions of both small and large systems at RHIC and LHC energies.

Apparent strangeness enhancement from multiplicity selection in high energy proton-proton collisions

“…The strangeness data together with other measurements in high-multiplicity pp collisions, in particular the ridge [9,10], resemble collective properties as found in heavy-ion collisions and provoke speculation about the formation of a QGP in these collisions [1,11]. Indeed, models incorporating final-state interactions originally developed for heavy-ion collisions, are also able to describe the pp data [12][13][14][15]. Refined models based on the "core/corona" approach, where the core of the collisions is assumed to "hydrodynamize", while the corona is treated as a superposition of independent nucleon-nucleon collision, achieve a good description of data across all systems with a rather universal approach [16,17].…”

Production of light antinuclei in $pp$ collisions by dynamical coalescence and their fluxes in cosmic rays near earth

“…The key parameters in the Lund string fragmentation for generating the initial conditions for the AMPT model are set to a L = 0.5 and b L = 0.9 GeV −2 , respectively. To describe proton and antiproton production in low-multiplicity collisions, the parameter r BM , which controls the baryon-tomeson yield ratio, is set to 0.55 at LHC energies [33,34]. This parameter is tuned to 0.75 in this study to describe the low energy data [20].…”

Further developments of a multi-phase transport model for relativistic nuclear collisions

“…It has also been shown to qualitatively describe the near-side anticorrelation feature of baryon-baryon azimuthal correlations observed in small systems at the LHC [33,113]. In addition, it can be easily extended to include individual r BM factors specific to given hadron species, e.g., to describe the enhanced multi-strange baryon productions in nuclear collisions [123]. The string melting AMPT model with the new quark coalescence thus provides a better overall description of the bulk matter in high-energy nuclear collisions.…”