Related papers: QCD evolution of naive-time-reversal-odd fragmenta…
The transversity distribution can be measured at leading-twist in single-particle inclusive DIS, where it appears in connection with chiral-odd fragmentation functions. Among these functions, we focus on the time-reversal odd ones. They…
We present the third-order contributions to the quark-gluon and gluon-quark timelike splitting functions for the evolution of fragmentation functions in perturbative QCD. These quantities have been derived by studying physical evolution…
The Collins fragmentation function is extracted from HERMES data on azimuthal single spin asymmetries in semi-inclusive deeply inelastic scattering, and BELLE data on azimuthal asymmetries in electron positron annihilations. A Gaussian…
We present an update of a previous global analysis of the experimental data on azimuthal asymmetries in semi-inclusive deep inelastic scattering (SIDIS), from the HERMES and COMPASS Collaborations, and in e+ e- -> h1 h2 X processes, from…
We derive the complete set of evolutions of chirality-odd twist-3 fragmentation functions at one-loop level. There are totally nine real twist-3 fragmentation functions, among which seven are independent. The renormalization-scale…
We extend the Collins-Soper-Sterman (CSS) formalism to apply it to the spin-dependence governed by the Sivers function. We use it to give a correct numerical QCD evolution of existing fixed-scale fits of the Sivers function. With the aid of…
The thesis is devoted to the study of the fragmentation process of polarized quarks, and in particular of the Collins effect used for the extraction of the quark transversity distribution. The aim is to include the spin degree of freedom in…
The Collins-Soper kernel relates transverse momentum-dependent parton distribution functions (TMDPDFs) at different energy scales. For small parton transverse momentum $q_T\sim \Lambda_\text{QCD}$, this kernel is non-perturbative and can…
We study Collins azimuthal asymmetries for pion-in-jet production in polarized lepton-proton collisions, extending previous analyses of polarized $pp$ scattering to a complementary and theoretically simpler process. We keep adopting a…
We study the QCD evolution for the twist-three quark-gluon correlation functions associated with the transverse momentum odd quark distributions. Different from that for the leading twist quark distributions, these evolution equations…
The QCD evolution of the unpolarized Transverse Momentum Dependent (TMD) distribution functions and of the Sivers functions have been discussed in recent papers. Following such results we reconsider previous extractions of the Sivers…
We define twist-two and twist-three quark fragmentation functions in Quantum Chromodynamics (QCD) and study their physical implications. Using this formalism we show how the nucleon's transversity distribution can be measured in single pion…
The recent data on the transverse single spin asymmetry $A_{UT}^{\sin(\phi_h+\phi_S)}$ from HERMES and COMPASS Collaborations are analysed within LO parton model with unintegrated parton distribution and fragmentation functions. A fit of…
The transverse polarization of $\Lambda$ hyperons within unpolarized jets originates from the transverse-momentum-dependent (TMD) fragmentation function $D_{1T}^\perp (z, p_T, \mu^2)$. In the vacuum environment, the QCD evolution of this…
The $Q^2$ evolution of polarised parton fragmentation functions is discussed using Altarelli-Parisi evolution equations. The first moments of both polarised quark and gluon fragmentation functions are shown to behave in a similar fashion at…
We construct the evolution equations for the twist-3 chiral-odd spin independent fracture functions in QCD. The Gribov-Lipatov reciprocity relation is fulfilled at the one-loop level for the quasi-partonic two-particle cut vertices only. It…
In the framework of large-momentum effective theory at one-loop matching accuracy, we perform a lattice calculation of the Collins-Soper kernel which governs the rapidity evolution of transverse-momentum-dependent (TMD) distributions. We…
The theoretical aspects of two leading twist transversity single spin asymmetries, one arising from the Collins effect and one from the interference fragmentation functions, are reviewed. Issues of factorization, evolution and Sudakov…
We analyze the transverse momentum dependent distribution and fragmentation functions in space-like and time-like hard processes involving at least two hadrons, in particular 1-particle inclusive leptoproduction, the Drell-Yan process and…
We will give an outline of the computation of the QCD corrections to the spin structure function g_1(x,Q^2) and the spin fragmentation function g_1^H(x,Q^2) which are measured in deep inelastic electron-proton scattering and in…