On Theta Dependence of Glueballs from AdS/CFT

TL;DR

This paper investigates how the theta parameter influences the glueball spectrum in a strongly coupled large N gauge theory using AdS/CFT, revealing mixing patterns and CP-odd effects that persist at large N.

Contribution

It explicitly diagonalizes gravity equations in AdS/CFT to analyze glueball mixing and CP-odd effects related to the theta dependence in large N gauge theories.

Findings

Scalar and pseudoscalar glueballs mix without suppression.

CP-odd effects persist at large N.

Mass eigenvalues remain unchanged with or without theta in the large N limit.

Abstract

We study the theta dependence of the glueball spectrum in a strongly coupled cousin of large N gluodynamics defined via the AdS/CFT correspondence. By explicitly diagonalizing the 10d gravity equations in the presence of the RR 3-form and 1-form fluxes we found a mixing pattern for the lowest-spin lightest glueballs. The mixing between the scalar and pseudoscalar states is not suppressed, suggesting that the CP-odd effects persist in the large N theory. As a consequence, the lightest mass eigenstate ceases to be a parity eigenstate. We found the former as a linear combination of a scalar and pseudoscalar glueballs. On the other hand, the mass eigenvalues in a theory with and without the theta term remain equal in the large N limit.