In this talk, I will start by generally introducing the non-perturbative formulation of QCD on a Euclidean lattice. Then, I will present a state-of-the-art computation of unpolarized, helicity and transversity parton distribution functions (PDFs) calculated using the so-called quasi-PDF approach introduced by Xiangdong Ji in 2013 and intensively developed thereafter. We employed lattice QCD...
In this talk I will first review the current status of higher-order perturbative calculations in pure QCD of the evolution/resummation of transverse-momentum-dependent functions (TMDs). Then, after introducing the proper definition of TMDs in QCDxQED, I will present new results for the QED corrections to their evolution.
We investigated to what extent jets - instead of hadrons - can be used to study Transverse Momentum Distributions. I will show that suitably defined jets behave exactly like single hadrons, the two being interchangeable in factorization theorems and obeying the same double-scale evolution. Such jets are excellent probes in processes like semi-inclusive deeply inelastic scattering, with the...
The parton distributions obtained in lepton proton scattering experiments correspond to the Fourier transform of the quark-quark correlation function where the quark field operators are separated by a light cone distance known as Ioffe time. The Ioffe time behavior of the correlator can be determined unambiguously both in the short distance regime, through matrix elements of local operators...
We present the Parton Branching (PB) method for the evolution of both collinear and transverse momentum dependent (TMD) parton distribution functions (PDFs). This method enables one to take into account explicitly the kinematics at each branching in the parton cascade and to study in detail the dynamics of QCD evolution, including different ordering scenarios (pt, virtuality, angular...
Unintegrated (or transverse momentum dependent, TMD) parton distributions in a proton are important in high energy physics. Using the latest LHC data on the hadron production in pp collisions, we determine the parameters of the initial TMD gluon density, derived in the framework of quark-gluon string model at the low scale $\mu_0 \sim 1 - 2$ GeV and refine its large-x behaviour using data on...
In the talk I will review the current status of nonperturbative estimates of nucleon's TMD structure functions using Lattice QCD.
Parton Reggeization Approach (PRA) is a generalized scheme of kT-factorization which uses the formalism of Reggeized gluons and quarks to define gauge-invariant hard-scattering matrix elements with off-shell partons in the initial state (See Ref. [1] for more detailed discussion). The calculations in PRA are performed in the framework of Lipatov's gauge invariant effective theory for...
We resum the leading logarithms at subleading power of the Drell-Yan process employing soft-collinear effective theory in position space. Expansion of the resummed result leads to the prediction of the leading logarithms at fixed loop order. The corresponding results are given at N3LO and N4LO.
We present solutions of the BFKL equation with higher order corrections such as the kinematical constraint and DGLAP terms of the splitting fucntion. We use the results to evaluate relative contribution of each of the corrections. The study is a first step towards fitting the experimental proton structure function data.
At the LHC energies, top quarks are mostly produced in pairs (top-antitop), and also with a reasonable rate in the boosted regime: top jets with pt>400GeV. Increasing the pt of the top candidates, the back to back configuration is enriched, and in this region soft gluon re-summation effects play an important role and its studies are crucial in order to understand the imbalance between the...
