Killing twins: strong model-agnostic constraints for twin-star solutions

Killing twins: strong model-agnostic constraints for twin-star solutions

Pacific
Speaker(s) Christian Ecker (Goethe University Frankfurt)
Description

Please contact divya.singh@berkeley.edu, tianqi.zhao@berkeley.edu, or klund@berkeley.edu for zoom links.

Twin stars have long been proposed as a signature of phase transitions in dense QCD matter. In this talk, I will show how model-agnostic EOS inference, constrained by chiral effective field theory, perturbative QCD, and multimessenger observations, strongly disfavors twin-star solutions. The few surviving cases require highly fine-tuned EOS behavior: either a phase transition near saturation density or a high-density rapid crossover with a double-peaked speed of sound. Since neither case exhibits conformalization on the second branch, the standard interpretation of twin stars as a robust signature of deconfinement is effectively ruled out.