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We investigate the leading-twist gluonic distribution functions within the proton by formulating a light-front spectator model. The proton light-front wave functions (LFWFs) are adopted from the soft-wall AdS/QCD predictions, and the model parameters are determined using the gluon unpolarized parton distribution function from the NNPDF3.0nlo dataset. Furthermore, we demonstrated the model calculations for gluon transverse momentum distributions (TMDs) and generalized parton distributions (GPDs). We also predicted the gluon spin and orbital angular momentum (OAM) contributions to the total proton spin., Comment: Contribution to the 31st International Workshop on Deep Inelastic Scattering (DIS2024), 8-12 April 2024, Grenoble, France

Using the variational principle, we systematically investigate the mass spectra and wave functions of both $1S$ and $2S$ state heavy pseudoscalar $(P)$ and vector $(V)$ mesons within the light-front quark model. This approach incorporates a Coulomb plus logarithmic confinement potential to accurately describe the constituent quark and antiquark dynamics. Additionally, spin hyperfine interactions are introduced perturbatively to compute the masses of pseudoscalar and vector mesons. The present analyses of the $1S$ and $2S$ states require the consideration of mixing between them to account for empirical constraints. These constraints include the mass gap $\Delta M_{P} > \Delta M_{V}$, where $\Delta M_{P(V)} = M^{2S}_{P(V)} - M^{1S}_{P(V)}$ and the hierarchy of the decay constants $f_{1S} > f_{2S}$. We find the optimal value of the mixing angle to be $\theta = 18^{\circ}$, significantly enhancing the consistency between our spectroscopic predictions and the experimental data compiled by the Particle Data Group (PDG). Furthermore, based on the predicted mass, the newly observed resonance $B_J(5840)$ could be assigned as a $2^1S_0$ state in the $B$ meson family. The study also reports various pertinent observables, including twist-2 distribution amplitudes, electromagnetic form factors, charge radii, $\xi$ moments, and transition form factors which are found to be consistent with both available lattice simulations and experimental data. In addition, our predicted branching ratios for the channels of $B^+ \rightarrow \tau^+ \nu_{\tau}$ as well as rare decays of $B^0$ and $B_s^0$ appear in accordance with experimental data., Comment: 20 pages, 9 figures

We compute all the leading-twist azimuthal spin asymmetries in the pion-proton induced Drell-Yan process. These spin asymmetries arise from convolutions of the leading-twist transverse-momentum-dependent parton distributions (TMDs) of both the incoming pion and the target proton. We employ the holographic light-front pion wave functions for the pion TMDs, while for the proton TMDs, we utilize a light-front quark-diquark model constructed by the soft-wall AdS/QCD. The gluon rescattering is crucial to predict nonzero time-reversal odd TMDs. We study the utility of a nonperturbative SU$(3)$ gluon rescattering kernel, which extends beyond the typical assumption of perturbative U$(1)$ gluons. Subsequently, we employ Collins-Soper scale evolution at Next-to-Leading Logarithmic precision for the TMDs evolution. Our predictions for the spin asymmetries are consistent with the available experimental data from COMPASS and other phenomenological studies. We also present the cross section for the pion-nucleus induced Drell-Yan process with the obtained pion TMDs supplemented by the TMDs of the target nucleus., Comment: 13 Pages, 7 Figures

Using a recently developed light-front spectator model that incorporates gluon, where the light-front wave functions are modeled from the soft-wall AdS/QCD prediction, we examine the leading twist gluon generalized parton distributions (GPDs) inside the proton. We derive the chirally even and odd distributions by using the overlap representation of the light-front wave functions. In terms of GPDs at non-zero skewness, we investigate the entire three-dimensional representation of gluons. We analyse the gluon impact parameter distributions at $\xi=0$ using the Fourier transform of GPDs. We address the total angular momentum contribution of the gluons by using the Ji's sum rule and also give our predictions for both the canonical and kinetic orbital angular momentum in the light-cone gauge., Comment: 18 pages, 9 figures

We determine the mass spectroscopy and light-front wave functions (LFWFs) of the $\rho$-meson by solving the holographic Schr\"odinger equation of light-front chiral QCD along with the 't Hooft equation of (1+1)-dimensional QCD in the large $N_c$ limit. Subsequently, we utilize the obtained LFWFs in conjunction with the color glass condensate dipole cross-section to calculate the cross sections for the diffractive $\rho$-meson electroproduction. Our spectroscopic results align well with the experimental data. Predictions for the diffractive cross sections demonstrate good consistency with the available experimental data at different energies from H1 and ZEUS collaborations. Additionally, we show that the resulting LFWFs for the $\rho$-meson can effectively describe various properties, including its decay constant, distribution amplitudes, electromagnetic form factors, charge radius, magnetic and quadrupole moments. Comparative analyses are conducted with experimental measurements and the available theoretical predictions., Comment: 18 pages, 9 figures, 5 tables