Infrared dynamics of a large N QCD model, the massless string sector and mesonic spectra

Abstract

A consistency check for any UV complete model for large N QCD should be, among other things, the existence of a well-defined vector and scalar mesonic spectra. In this paper, we use our UV complete model in type IIB string theory to study the IR dynamics and use this to predict the mesonic spectra in the dual type IIA side. The advantage of this approach is two-fold: not only will this justify the consistency of the supergravity approach, but it will also give us a way to compare the IR spectra and the model with the ones proposed earlier by Sakai and Sugimoto. Interestingly, the spectra coming from the massless stringy sector are independent of the UV physics, although the massive string sector may pose certain subtleties regarding the UV contributions as well as the mappings to actual QCD. Additionally, we find that a component of the string landscape enters the picture: there are points in the landscape where the spectra can be improved somewhat over the existing results in the literature. These points in the landscape in-turn also determine certain background supergravity components and fix various pathologies that eventually lead to a consistent low energy description of the theory.

Delocalized SYZ mirrors and confronting top–down SU(3)-structure holographic meson masses at finite g and $$N_c$$ N c with P(article) D(ata) G(roup) values

“…This paper fills in this gap. Using the delocalized type IIA SYZ mirror (with SU (3) structure) of the holographic type IIB dual of large-N thermal QCD of [1] as constructed in [2] at finite coupling and number of colors (N c = Number of D5(D5)branes wrapping a vanishing two-cycle in the top-down holographic construct of [1] = O(1) in the IR in the MQGP limit of [2] at the end of a Seiberg duality cascade), we obtain analytical (not just numerical) expressions for the vector and scalar meson spectra and compare our results with previous calculations of [3], [4], and obtain a closer match with the Particle Data Group (PDG) results [5]. Through explicit computations, we verify that the vector and scalar meson spectra obtained by the gravity dual with a black hole for all temperatures (small and large) are nearly isospectral with the spectra obtained by a thermal gravity dual valid for only low temperatures; the isospectrality is much closer for vector mesons than scalar mesons.…”

“…the holographic Sakai-Sugimoto model [3] does not address the UV) with fundamental quarks is the one given in [1] involving N D3-branes, M D5/(D5) branes wrapping a vanishing two-cycle and N f D7(D7) flavor-branes in a warped resolved conifold at finite temperature in the brane picture (and M D5-branes and D7(D7)-branes with a black-hole and fluxes in a resolved warped deformed conifold gravitational dual). In [4], the authors (some also part of [1]) obtained the vector and scalar mesonic spectra by taking a single T-dual of the holographic type IIB background of [1]. Comparison of the (pseudo-)vector mesons with PDG results, provided a reasonable agreement.…”

Velocity-induced heavy quarkonium dissociation using the gauge-gravity correspondence

“…The UV contribution to the the heavy quark potential for the heavy quark bound states are dominant compared to IR part because since their mass is larger than QCD scalei so the relative velocity is very small and becomes weakly coupled (v ∼ α s , α s is the strong interaction coupling). The comparison of Sakai-Sugimoto model with the one that we use here has recently been done in [51].…”

M-theory exotic scalar glueball decays to mesons at finite coupling

“…We calculated up to (N)LO in N, masses of 0 ++ , 0 −− , 0 −+ , 1 ++ and 2 ++ glueballs, and found very good agreement with some of the lattice results on the same. In [7] we continued by evaluating the spectra of (pseudo-)vector and (pseudo-)scalar mesons and compared our results with [8], [9] and [10]. In this paper, we look at two-, three-and four-body ('exotic' scalar) glueball decays into ρ and π mesons, and show that our results permit obtaining an exact match with PDG data including any improvements upon the same expected to be obtained in the future.…”