A Holographic Model of Heavy-light Mesons

TL;DR

This paper develops a holographic AdS/QCD model for heavy-light mesons, capturing heavy quark symmetry, chiral symmetry breaking, and reproducing physical spectra and decay constants, providing insights into non-perturbative QCD effects.

Contribution

It introduces a novel holographic model that incorporates heavy quark symmetry and chiral symmetry breaking for heavy-light mesons, extending AdS/QCD methods.

Findings

Mass spectra of B and D mesons fit well with experimental data.

Decay constants are accurately reproduced by the model.

Couplings to pions are successfully calculated.

Abstract

We construct a holographic model of heavy-light mesons by extending the AdS/QCD to incorporate the behavior of the heavy quark limit. In that limit, the QCD dynamics is governed by the light quark and the heavy quark simply plays the role of a static color source. The heavy quark spin symmetry can be treated as a global symmetry in the AdS bulk. As a consequence, the heavy-light mesons are mapped to "fermions" in the AdS theory. The light flavor chiral symmetry is naturally built in by this construction, and its breaking produces the splitting of the parity-doubled heavy-light meson states. The scaling dependences of physical quantities on the heavy quark mass in the heavy quark effective theory are reproduced. The mass spectra and decay constants of the B and D mesons can be well fit by suitable choices of model parameters. The couplings between the heavy-light mesons and the pions are also calculated. The holographic model may capture the essence of the long distance effects of QCD and can serve as a useful tool for studying the non-perturbative hadronic matrix elements involving heavy-light mesons.