De-Confinement in small systems: Clustering of color sources in high multiplicityp̄pcollisions at √s= 1.8 TeV

L J Gutay

doi:10.1051/epjconf/201612006005

Abstract

It is shown that de-confinement can be achieved in high multiplicity non jet pp collisions at √s = 1.8 TeV Fermi National Accelerator Laboratory(FNAL- E735) experiment. In this paper we have analyzed the transverse momentum spectrum in the framework of the clustering of color sources. This frame-work naturally predicts the reduction in the charged particle multiplicity with respect to the value expected from the number of independent strings. Results are presented for both thermodynamic and transport properties. The initial temperature and energy density are obtained from the data via the color reduction factor F (ξ ) and the associated string density parameter ξ . The results for he trace anomaly Δ and shear viscosity to entropy density ratio(η /s ) are presented. These results confirm our earlier observation that the de-confined state of matter was created in high multiplicity events in pp collisions at √s = 1.8 TeV.

Highlights

The observation of high total multiplicity, high transverse energy, non-jet, isotropic events led Van Hove [1] and Bjorken [2] to conclude that high energy density events are produced in high energy pp collisions [3]
These events have a far greater cross section than the jet production. In these events the transverse energy is proportional to the number of low transverse momentum particles
The QGP according to CSPM is born in local thermal equilibrium because the temperature is determined at the string level

Summary

Introduction

The observation of high total multiplicity, high transverse energy, non-jet, isotropic events led Van Hove [1] and Bjorken [2] to conclude that high energy density events are produced in high energy pp collisions [3]. These events have a far greater cross section than the jet production. In these events the transverse energy is proportional to the number of low transverse momentum particles. CSPM has been successfully applied to heavy ion data for thermodynamics and transport coefficients [5,6,7,8,9]

Color Strings and Percolation

E735 Experiment

Color Suppression Factor and Temperature

Energy Density

Trace anomaly Δ

Summary