Some Aspects of Strange Matter in Astrophysics

TL;DR

This paper explores the properties, origins, and astrophysical implications of strange quark matter, proposing models for strangelets, deriving the Chandrasekhar limit for strange stars, and linking quark nuggets to dark matter and cosmic observations.

Contribution

It introduces a new model for strangelet propagation, derives the Chandrasekhar limit for strange quark stars, and suggests quark nuggets as dark matter candidates explaining MACHO observations.

Findings

Correlation of strangelet models with cosmic ray events

Derived Chandrasekhar limit depending on fundamental constants

Proposed quark nuggets as dark matter explaining gravitational lensing

Abstract

The present work is connected with the investigation of the origin and properties of compact astrophysical objects endowed with strangeness, with the objective of finding out their relevance in the formation and evolution of the universe. In the first part of the thesis, Chap.~1-3, we discuss a model, proposed by us, to describe the propagation of small lumps of Strange Quark Matter (SQM) or strangelets, through the Terrestrial atmosphere. The theoretical results were found to be well correlated with exotic cosmic ray events characterized by very low charge to mass ratio. In the next part, we have investigated the other end of the mass spectrum of SQM. In Chap 5, we have developed an analytical expression for the Chandrasekhar Limit of Strange Quark Stars. The limit is found to depend on the fundamental constants (including the bag constant). In the last chapter we have endeavored to show that the quark nuggets, surviving the quark-hadron phase transition in the millisecond era of the early Universe can provide the required closure density and can merge to form compact quark matter objects, whose maximum mass would be governed by the formulation laid out in the preceding chapter. We have also found that these Cold Dark Matter objects can explain the recent astronomical observations of MACHOS by gravitational micro-lensing techniques in the Large Magellanic clouds in the Halo of our Galaxy.