Sivers and cos⁡2ϕ\cos 2\phi Asymmetries in Semi-inclusive Deep Inelastic Scattering in Light-front Holographic Model

The spin asymmetries in SIDIS associated with $T$-odd TMDs are presented in a light-front quark-diquark model of a proton. To incorporate the effects of the final state interaction, the light front wave functions are modified to have a phase factor which is essential to have Sivers or Boer-Mulders functions. The Sivers and Boer-Mulder asymmetries are compared with HERMES and COMPASS data.Comment: 24 pages, 09 figure

Relating transverse structure of various parton distributions

We present the results of T-even TMDs in a light front quark-diquark model of nucleons with the wave functions constructed from the soft-wall AdS/QCD prediction. The relations amongst TMDs are discussed. The $p_\perp$ dependence of the TMDs are compared with the $t$-dependence of the GPDs. AdS/QCD wave function provides an explanation behind the approximate $x$ and $p_\perp$ factorization observed in lattice TMD calculations.Comment: 11 pages, 8 figures, modified extensively, added new results and discusssion

Quark generalized TMDs at skewness and Wigner Distribution in boost invariant longitudinal space

The boost-invariant longitudinal space, defined by the parameter $\sigma=\frac{1}{2}b^-P^+$ can be studied from the Fourier transformation of distributions over the conjugate variable skewness $\xi$. We investigate quark Wigner distributions in the $\sigma$ space in dressed quark model and found diffraction patterns that are analogous to the single slit experiment of light in optics. The width of the central maxima varies with energy transfer to the system and essentially $\xi$ behaves like a slit-width. Qualitatively similar diffraction pattern is reported recently in other models. In this model, we compute all the leading twist GTMDs with non-zero skewness for quarks which provides Wigner distributions under Fourier transformation

Gluon Wigner Distributions in boost invariant longitudinal space

We present the gluon Wigner distributions in the boost invariant longitudinal space. The boost-invariant longitudinal space is defined as $\sigma=\frac{1}{2}b^-\Delta^+$ and is conjugate to the skewness variable $\xi$. We use the dressed quark model, where a high-energetic quark is dressed by a gluon. This two-particle system has the advantage of addressing both the gluon and the quark sectors. The different contributions in Wigner distributions coming from different polarizations of gluon and the dressed quark system are investigated

Angularity in Higgs boson decays via H→gg\boldsymbol{H\to gg} at NNLL′^{'} accuracy

We present improved predictions of a class of event-shape distributions called angularity for a contribution from an effective operator $H\to gg$ in Higgs hadronic decay that suffers from large perturbative uncertainties. In the frame of Soft-Collinear Effective Theory, logarithmic terms of the distribution are resummed at NNLL$^{'}$ accuracy, for which 2-loop constant of gluon-jet function for angularity is independently determined by a fit to fixed-order distribution at NLO corresponding to ${\mathcal{O}}(\alpha_s^2)$ relative to the born rate. Our determination shows reasonable agreement with value in a thesis recently released. In the fit, we use an asymptotic form with a fractional power conjectured from recoil corrections at one-loop order and it improves the accuracy of determination in positive values of angularity parameter $a$. The resummed distribution is matched to the NLO fixed-order results to make our predictions valid at all angularity values. We also discuss the first moment and subtracted moment of angularity as a function of $a$ that allow to extract information on leading and subleading nonperturbative corrections associated with gluons.Comment: 33 pages, 12 figure

Gluon distributions in the proton in a light-front spectator model

We formulate a light-front spectator model for the proton incorporating the gluonic degree of freedom. In this model, at high energy scattering of the proton, the active parton is a gluon and the rest is viewed as a spin-$\frac{1}{2}$ spectator with an effective mass. The light front wave functions of the proton are constructed using a soft wall AdS/QCD prediction and parameterized by fitting the unpolarized gluon distribution function to the NNPDF3.0nlo data set. We investigate the helicity distribution of gluon in this model. We find that our prediction for the gluon helicity asymmetry agrees well with existing experimental data and satisfies the perturbative QCD constraints at small and large longitudinal momentum regions. We also present the transverse momentum dependent distributions (TMDs) for gluon in this model. We further show that the model-independent Mulders-Rodrigues inequalities are obeyed by the TMDs computed in our model.Comment: 14 pages, 7 figure