Holographic QCD model for $N_f=4$

Abstract

We establish a holographic QCD model for four flavors, where a light scalar field X and a heavy scalar field H are introduced, separately. The H field is responsible for the breaking of SU (N f = 4) to SU (N f = 3). The ground state and its Regge excitation of meson spectra in the light flavor sector and heavy flavor sector as well as the ligh-heavy mesons are well in agreement with the Particle data group (PDG). Due to the additional introduction of the H field in the model, different Regge slopes for light and heavy mesons can be achieved.

Incorporation of heavy-quark mass into soft-wall holographic models

“…As a rule, the constructed holographic models describe the sector of light quark flavors, while the progress in holographic description of heavy flavors looks relatively modest. For instance, the SW description of the experimental spectra of heavy quarkonia was addressed only in a few papers [8][9][10][11][12][13][14][15][16]. Perhaps an underlying reason is that the spectrum of excited light mesons has a clear expected pattern in the first approximation a linear Regge form (see, e.g., discussions in [17][18][19][20][21][22][23][24][25] and references therein).…”

“…For the light flavors, the given trouble is avoided by setting the quark masses to zero. In the aforementioned papers [8][9][10][11][12][13][14][15][16], the masses of heavy quarks were inserted into some SW-like models using various ad hoc phenomenological prescriptions. The purpose of the present work is to motivate a universal prescription for incorporating the quark mass scale into the SW holographic models.…”