Compact strange stars with a medium dependence in gluons at finite temperature

¹ Dept. of Physics, Presidency College, 86/1, College Street, Kolkata 700073, India e-mail: mnj2003@vsnl.net; kamal1@vsnl.com
² Inter University Centre for Astronomy and Astrophysics (IUCAA), Post Bag # 4, Ganeshkhind, Pune 411007, India e-mail: sray@iucaa.ernet.in

Received: 30 June 2005
Accepted: 19 December 2005

Abstract

Aims.The possible existence of strange stars in the universe will help in the understanding of various properties of quantum chromodynamics, like asymptotic freedom and chiral symmetry restoration, which is otherwise very difficult to prove in laboratory experiments.

Methods.Strange star properties were calculated using large color approximation with built-in chiral symmetry restoration. A relativistic Hartree Fock calculation was performed using the Richardson potential as an interquark interaction. This potential has the asymptotic freedom and a confinement-deconfinement mechanism built into it and the present calculation employs an application of this potential with modified two scale parameters Λ and , to find a new set of equations of state for strange quark matter. The linear confinement string tension from lattice calculations is 350 MeV and the Coulomb -like part has the parameter 100 MeV from deep inelastic scattering experiments. We also consider the effect of temperature, on gluon mass in a simple way, in addition to the usual density dependence,

Results.We obtained a set of new equation of states for strange quark matter and also found that the transition temperature from hadronic matter to strange matter is at 80 MeV, close to the 100 MeV estimated in literature.

Conclusions.Formation of strange stars may be the only signal for formation of quark-gluon plasma with asymptotic freedom and chiral symmetry restoration and this may be observable through many processes – such as for example through delayed γ ray afterglow.