Strange Star or Neutron StarEoS & Current Observation

Reporter: Long Jiang

Nanjing University 2013 05 27

Outline

• Introduction Why SQS Structure difference between NS and SQS • Equation of State MIT bag model Density dependent model by Dey • Models discussion and my present work Candidates of SQS My recent work

Introduction

• SQM stable than nuclei ~10^15 g/cm^3

Structure description

Equation of State: p=?

R. R. Silbar, S. Reddy, 2004, Am. J. Phys. 72,892

EoS -1: MIT bag Model

• Consider quark-gluon coupling:

• Massless-quark without Q-G coupling:

Chapline &Nauenberg 1977, Phys.Rev.D16,450

EoS-2: Density dependent: Dey

Part 1. Density dependent quark mass:

M. Dey et al. Phys.Lett.B438, 123(1998)

Part 2.Interquark potential:

Pair creation & infrared divergence -- Screening length:

J. L. Richardson, Phys.Lett.B 82(1979)272

Screening length

• Simplify with:

V. Baluni Phys. Rev. D17(1978) 2092

Conditions

• Charge neutrality:

• β-equilibrium

Chemical potential

Parameters

T. Gangopadhyay et al.arXiv:1303.1956

Present Observation

D. Leahy et al. ApJ 672, 1119(2008) S. Guillot et al. arXiv: 1302.0023

Data-Model consistence analysis

a

b

c

天文数据处理方法 P133

Example of model-Fitting

Some results as examples

Input r - + m - +

M28 10.6 1.58 0.45 1.17 0.34 0.31

NGC6304 9.4 1.45 1.45 1.12 0.31 0.31

4U1820-30 9.1 0.4 0.4 1.58 0.06 0.06

Output M28 NGC6304 4U1820-30

Dey2013 14304/9998 11581/10000 514/10000

BBB1 29093/9998 27376/10000 2002/10000

Thank you !!