Hyperon/meson ratios in rare high-multiplicity $pp$ collisions at energies available at the Large Hadron Collider, and potential signatures for mini-quark-gluon plasma formation

Abstract

We use the framework of the HIJING/BB v2.0 model to simulate high-multiplicity (HM) $p+p$ collision events at the Large Hadron Collider (LHC) to study observables sensitive to possible collective phenomena, such as strong longitudinal color fields (SLCF) modeled by an enhanced string tension ($\hat{I}º$). We focus on the hyperon/meson yield ratios at center-of-mass (c.m.) energy $\sqrt{s}$ = 7 TeV, in the transverse momentum region, $1<p_T<4$ GeV/{\it c}. For minimum bias events these ratios are well described assuming an energy dependence $\hat{I}º=\hat{I}º(s)=\hat{I}{º}_0(s/s_0{)}^{0.04}GeV/fm$ ($\hat{I}{º}_0$= 1 GeV/fm), giving a value $\hat{I}º=2$ GeV/fm at $\sqrt{s}$ = 7 TeV. We compare minimum bias (MB) events to simulated HM events assuming that $\hat{I}º(MB)=2$ GeV/fm could grow to an extreme value of $\hat{I}º(HM)=5$ GeV/fm that saturates the strangeness suppression factor. With this assumption the model predicts a very strong enhancement of (multi)strange baryon/meson ratios in HM events. If observed, such an enhancement could be also interpreted as a possible signature for formation in HM $p+p$ collision events of a deconfined but out of local thermal equilibrium {\em mini quark-gluon plasma} (mQGP).

version2, text modifications,new figures and references added; 22 pages, 8 figures. Accepted for publication, Phys. Rev. C