Improved holographic Yang–Mills at finite temperature: Comparison with data

Abstract

The semi-phenomenological improved holographic model for QCD is confronted with data of the pure glue, large-N c gauge theory. After fitting two phenomenological parameters in the potential, the model can reproduce in detail all thermodynamic functions at finite temperature. It also reproduces in detail all known spin-0 and spin-2 glueball observables at zero temperature and predicts the rest of the 0 ++ and 2 ++ towers. A similar two parameter fit in the CP-odd sector postdicts the correct second 0 +− glueball mass, and predicts the rest of the 0 +− tower. Appendix 30A. Numerical technique 30 A.1 An alternative technique 34References 36

On finite-temperature holographic QCD in the Veneziano limit

“…The starting point of our finite temperature analysis is the T = 0 holographic model introduced in [26], based on previous theoretical ideas in [30][31][32][33][34][35][36][37][38][39][40]. Moving to finite T implies studying black hole solutions of the action in [26].…”

“…The other scalar, the "tachyon" τ , is dual to the quark mass operatorqq. The potentials and interactions were modeled along successful bottomup models for YM, namely Improved Holographic QCD (IHQCD) [30][31][32][33][34][35][36] and the idea that string theory tachyon condensation describes chiral symmetry breaking [37][38][39][62][63][64][65].…”

“…The pure glue potential V g has been determined from previous studies [33][34][35]. The tachyon potential V f (λ, τ ) must satisfy some basic properties determined by the dual theory or by general properties of tachyons in string theory: (a) To provide the proper dimension for the dual operator near the boundary (b) To exponentially vanish for τ → ∞.…”

“…The notion of regularity is tricky even in the case of IHQCD (pure glue), as there is a naked singularity in the far IR. For the dilaton this has been settled in [30][31][32][33][34][35]. For the tachyon the notion of regularity is different and has been studied in detail in [38,39].…”

“…Black hole solutions for such potentials were discussed in generality in [33][34][35]. After fixing all invariances, they are characterised by a single IR constant, λ h , the value of the dilaton at the horizon.…”