Pseudoscalar glueballs in the Klebanov-Strassler theory

Abstract

In this paper we describe a pseudoscalar subsector of the Klebanov-Strassler model. This subsector completes the holographic reconstruction of the spectrum of the lowest-lying glueball states, which are singlet under the global symmetry group SU(2) × SU(2). We derive the linearized supergravity equations for the pseudoscalar fluctuations and analyze their spectrum. The system of equations is shown to be compatible with six eigenmodes, as expected from supersymmetry. Our numerical analysis allows to reliably extract four of the corresponding towers. Their values match well the eigenvalues of the 0++ scalar states known from an earlier work. Assuming the masses of 0++ as a reference, we compare the lightest states of the holographic spectrum with lattice calculations in the quenched QCD at Nc = 3 and Nc = ∞.

Spectrum of large N glueballs: holography vs lattice

“…Notwithstanding supersymmetry, the mentioned properties of the Klebanov-Strassler theory make it the most suitable candidate for the holographic study of the glueball sector of JHEP11(2022)164 shown, as well as the references to the works, from which the values are extracted. For the scalar sector, the assignment was made based on the analysis of [72,80]. These masses are compared with the masses recently obtained for the SU(∞) bosonic Yang-Mills on the lattice [28] (right table).…”

“…The spectrum of singlet fluctuations of the Klebanov-Strassler background was studied in a series of papers including [63][64][65][66][67][68][69][70][71][72]. (See also [73][74][75][76][77][78][79] for the studies of non-singlet states or deformations of the Klebanov-Strassler theory.)…”

“…(See also [73][74][75][76][77][78][79] for the studies of non-singlet states or deformations of the Klebanov-Strassler theory.) The structure of the spectrum in the supergravity limit was explained in [70][71][72]: it contains two massless scalar supermultiplets and thirteen massive supermultiples including one graviton, two gravitino, four vector and six scalar supermultiplets. The latter are massive N = 1 supermultiplets labeled by the highest spin component, except for the scalar multiplet, which is conventionally labeled by its lowest spin component.…”

“…In table 4 we measure all masses in the units of the mass of the ground state of the graviton multiplet, the 2 ++ glueball. This state is particularly easy to analyze on the supergravity side, since the 2 ++ fluctuation above the background decouples from In the 0 ++ /0 −+ sector the results of [66] are shown in full color, while that of [72] are faded. States that do not have pairs correspond to hybrid glueballs with no analog in the bosonic theory, except for the heaviest 0 ++ that has not been approached on the lattice.…”

“…The scalar multiplet containing the gluino bilinear λλ state is expected to be the lightest in the spectrum of the supersymmetric Yang-Mills. Apart from tr λλ and the scalars due to tr F µµ F µν and tr F µν F µν operators, the holographic model includes other 0 ++ and 0 −+ gluon-gluino states associated with the composite operators of dimension ∆ = 3, 4, 5, 6, 7, 8 (see [61,62,71,72] for the classification).…”