arXiv subjects

Jacopo Tarello

Publications and source records attributed to Jacopo Tarello.

3 recordsLinked to original sources

arXiv2025

Collins-Soper Kernel and Reduced Soft Function in Lattice QCD

We evaluate the Collins-Soper kernel and the reduced soft function in lattice QCD, incorporating $\mathcal{O}(\alpha_s)$ matching corrections. The calculation relies on the evaluation of the quasi-transverse momentum-dependent wave function with asymmetric staple-shaped quark bilinear operators and four-point meson form factors. These quantities are computed non-perturbatively using two $N_f=2+1+1$ twisted-mass fermion ensembles with the same lattice spacing of $a=0.093$ fm: the first ensemble has a lattice size of $24^3 \times 48$ and a pion mass of 346 MeV; the second one has a lattice size of $32^3 \times 64$ and a pion mass of 261 MeV. The Collins-Soper kernel and the soft function are needed for the determination of the transverse momentum-dependent parton distribution functions.

hep-lat↗

arXiv2024

Nonperturbative renormalization of asymmetric staple-shaped operators in twisted mass lattice QCD

Staple-shaped Wilson line operators are necessary for the study of transverse momentum-dependent parton distribution functions (TMDPDFs) in lattice QCD and beyond. In this work, we study the renormalization of such operators in the general case of an asymmetric staple. We analyze the mixing pattern of these operators using their symmetry properties, where we find that the possible mixing is restricted within groups of four operators. We then present numerical results using the regularization independent momentum subtraction (RI/MOM) scheme to study the importance of mixing using one operator in particular, the $γ_0$ operator. Based on these results, we consider the short distance ratio (SDR) scheme, which is desirable in the absence of mixing. Finally, we investigate a variant of the RI/MOM scheme, where the renormalization factors are computed at short distances.

hep-lat↗

arXiv2022

Lattice QCD Study of Transverse-Momentum Dependent Soft Function

In this work, we perform a lattice QCD study of the intrinsic, rapidity-independent soft function within the framework of large momentum effective theory. The computation is carried out using a gauge ensemble of $N_f=2+1+1$ clover-improved twisted mass fermion. After applying an appropriate renormalization procedure and the removal of significant higher-twist contamination, we obtain the intrinsic soft function that is comparable to the one-loop perturbative result at large external momentum. The determination of the nonperturbative soft function from first principles is crucial to sharpen our understanding of the processes with small transverse momentum such as the Drell-Yan production and the semi-inclusive deep inelastic scattering. Additionally, we calculate the Collins-Soper evolution kernel using the quasi-transverse-momentum-dependent wave function as input.

hep-lat↗