Related papers: An Eta Primer: Solving the U(1) Problem with AdS/Q…
Using the $[SU(3)_{\mathrm{L}} \times SU(3)_{\mathrm{R}}]_{\mathrm{global}% }\times [SU(3)_V]_{\mathrm{local}}$ chiral Lagrangian with hidden local symmetry, we evaluate the cross sections for the absorption of eta meson ($% \eta$) by pion…
This MSc dissertation is based on the papers arXiv:2502.12694 and arXiv:2408.14813. The AdS/CFT correspondence provides a powerful framework for modeling strongly coupled gauge theories and, as a consequence, investigating non-perturbative…
The naturalness problem of PQ symmetry motivates study of the heavy QCD axion, with masses $m_a >$ 1 MeV generated at scales above the QCD scale, and low values of the PQ symmetry breaking scale, $f_a$. We compute the abundance of such…
We consider the light-front holographic QCD with the light-front wave functions for mesons, modified for massive quarks. We evaluate the wave functions, distribution amplitudes, and form factors for $\pi$, $\rho$, $K$, and $J/\psi$ mesons…
The production of eta and eta-prime mesons in elementary nucleon-nucleon collisions has been investigated at the synchrotrons CELSIUS, COSY and SATURNE. The magnitude and energy dependence of the total cross section as well as the…
Probing the $\bar ss$ content of the $\eta$ and $\eta'$ mesons and considering mixing between these states as well as gluonic contributions, the form factors responsible for semileptonic $D_s \to (\eta, \eta') l \nu$ transitions are…
In high energy heavy ion collisions a hot and dense medium is formed, where the U_A(1) or chiral symmetry may temporarily be restored. As a consequence, the mass of the eta'(958) mesons may be reduced to its quark model value, and the…
The widths for pionic decays of lowest two excited doublets (0^+,1^+) and (1^+,2^+) of heavy mesons are studied with QCD sum rules in the leading order of heavy quark effective theory. The ambiguity due to presence of two distinct 1^+…
We give a further study on chiral phase diagram in the improved soft-wall AdS/QCD model with $2+1$ flavors. The equations of motion for the octet pseudoscalar, vector and axial-vector mesons are derived to compute the octet meson spectra…
In this paper, we present results on strong two-body decay widths of light $q\bar q$ mesons calculated in a covariant quark model. The model is based on the Bethe-Salpeter equation in its instantaneous approximation and has already been…
The mass of the axion and its decay rate are known to depend only on the scale of Peccei-Quinn symmetry breaking, which is constrained by astrophysics and cosmology to be between $10^9$ and $10^{12}$ GeV. We propose a new mechanism such…
We present results for screening masses of light and strange mesons in 2+1 flavour QCD using improved (p4fat3) staggered fermions on 6x24^3 lattices. We have studied the screening masses of scalar, pseudo-scalar, vector and axial-vector…
A QCD based calculation of the photon spectrum in semi-inclusive $\eta_Q$ decays is performed. The method applied is an effective theory based on a 1/m_Q expansion of QCD.
We present results for the mass of the eta-prime meson in the continuum limit for two-flavor lattice QCD, calculated on the CP-PACS computer, using a renormalization-group improved gauge action, and Sheikholeslami and Wohlert's fermion…
We consider the reaction g+d -> pi+d in a wide energy range around and above the eta-meson photoproduction threshold at backward CM angles of the outgoing pion. Our theoretical analysis is essentially motivated by the recent measurements of…
This study utilizes theoretical tools including the double copy relation and AdS/CFT correspondence. Applying analogies, we establish a system to discuss the associations and equivalence relations among QCD, QED, and various (mixed) gauge…
We argue that lattice calculations of the $\eta'$ mass in QCD with $N_c=2$ colors performed at non-zero baryon chemical potential can be used to study the mechanism responsible for the mass of the $\eta'$. QCD with two colors is an ideal…
We study the photon-to-meson transition form factors (TFFs) F_{M \gamma}(Q^2) for gamma gamma^* \to M using light-front holographic methods. The Chern-Simons action, which is a natural form in 5-dimensional anti-de Sitter (AdS) space, leads…
The calculations of masses and decay constants of the radial excitations of light pseudoscalar and scalar mesons within QCD sum rules method are briefly reviewed. The predictions are based on the $1/N_c$-supported model spectra, which…
Light quark masses are important fundamental parameters of the Standard Model. The decays psi'-->J/psi pi^0 (eta) were widely used in determining the light quark mass ratio m_u/m_d. However, there is a large discrepancy between the…