Speaker
Description
In this contribution we present the main results of the calculations of spectra of meson and glueballs. To this aim the so called graviton soft-wall (GSW) has been used. This holographic semi-classic approximation to non perturbative QCD has been developed for the first time in Ref. [1] to calculate the scalar and tensor component spectra of glueballs. In particular we proposed to consider as dual field of the glueball operator in QCD a graviton propagating in a modified space with respect to the usual AdS5, i.e. the space
involved in the known AdS/QCD approaches. The resulting spectra were described by
linear trajectories has expected from lattice QCD. In particular, the quoted ground state
mass is comparable with that addressed same years later in Ref. [2]. Moreover, with this
model, also the light scalar meson spectrum has been calculated, see Refs. [3, 4], together
with the mixing condition, between scalar and glueball states. The main result is that
above masses of 2 GeV pure glueball state are expected. In addition in Ref. [5] the GSW
model has been applied to heavy scalar, vector, a1 and pseudo-scalar meson spectra. The
results obtained with only two and not flexible parameters are comparable with present
data. Finally, in Ref. [6] a strategy based on the longitudinal light-front dynamics, see
e.g. Ref. [7, 8], has been adopted to implement chiral symmetry breaking into the GSW
model to describe the pion. This approach has been used to calculate (with only two
additional parameters coming from the longitudinal contribution) the pion: spectrum,
form factor, effective form factor [9], distribution amplitude, transitional form factor and
parton distribution function. Also in this case results are in fair agreement with data and
thus highlighting the predicting power of the GSW model.
References
[1] M. Rinaldi and V. Vento, Eur. Phys. J. A 54, 151 (2018)
[2] E. Klempt, K. V. Nikonov, A. V. Sarantsev and I. Denisenko, Phys. Lett. B 830, 137171
(2022)
[3] M. Rinaldi and V. Vento, J. Phys. G 47, no.5, 055104 (2020)
[4] M. Rinaldi and V. Vento, J. Phys. G 47, no.12, 125003 (2020)
[5] M. Rinaldi and V. Vento, Phys. Rev. D 104, no.3, 034016 (2021)
[6] M. Rinaldi, F. A. Ceccopieri and V. Vento, Eur. Phys. J. C 82, no.7, 626 (2022)
[7] G. ’t Hooft, Nucl. Phys. B 75, 461-470 (1974)
[8] G. F. de Teramond and S. J. Brodsky, Phys. Rev. D 104, no.11, 116009 (2021)
[9] M. Rinaldi, Eur. Phys. J. C 80, no.7, 678 (2020)
