Related papers: A mechanism for the T-odd pion fragmentation funct…
We study the single-spin asymmetries of pions produced in semi-inclusive deep-inelastic scattering on the longitudinally polarized nucleon targets. We particularly consider the effects of the twist-3 transverse-momentum dependent…
We consider the leading and sub-leading twist $T$-odd and even contributions to the $\cos 2\phi$ azimuthal asymmetry in unpolarized dilepton production in Drell-Yan Scattering and semi-inclusive deep inelastic scattering of pions.
We introduce twist-two quark interference fragmentation functions in helicity density matrix formalism and study their physical implications. We show how the nucleon's transversity distribution can be probed through the final state…
The HERMES experiment has measured for the first time single target-spin asymmetries in semi-inclusive two-pion production using a transversely polarized hydrogen target. These asymmetries are related to the product of two unknowns, the…
We study the contribution of the twist-3 fragmentation function to the single transverse-spin asymmetry in SIDIS within the framework of the collinear factorization. Using the Ward-Takahashi identity in QCD, we establish the collinear…
We study the beam spin asymmetry $A_{LU}^{\sin\phi_h}$ in semi-inclusive $\pi^0$ electroproduction contributed by the T-odd twist-3 distribution function $g^\perp(x,k_T^2)$. We calculate this transverse momentum dependent distribution…
We present some estimates of T-odd fragmentation and distribution functions, $H_1^\perp$ and $f_{1T}^{\perp}$, evaluated on the basis of a fit on experimental data in p$^\uparrow$p. Assuming the T-odd fragmentation function to be…
We present examples for the calculation of the distribution and fragmentation functions using the representation in terms of non-local matrix elements of quark field operators. As specific examples, we use a simple spectator model to…
The azimuthal single target-spin asymmetries for pi^{+} production in semi-inclusive deep inelastic scattering of leptons off longitudinally polarized protons are evaluated using two main approaches available in the literature. It is shown…
We investigate the $sin \phi$ azimuthal asymmetry in the semi-inclusive deep-inelastic lepton scattering off longitudinally polarized nucleon target arising from the time reversal odd structures. The order 1/Q contributions of the leading…
The representation of quark distribution and fragmentation functions in terms of non-local operators is combined with a simple spectator model. This allows us to estimate these functions for the nucleon and the pion ensuring correct…
We extract the pion fragmentation functions and their uncertainties from a judicious choice of e+e- and semi-inclusive DIS data. These are used to study the error propagation in the extraction of polarized parton densities from…
The single-spin asymmetry of unpolarized leptons scattering deep-inelastically off transversely polarized nucleons is studied in a partonic picture within a collinear twist-3 framework. Since this observable is generated by multi-photon…
Fracture functions, originally suggested to describe the production of diffractive and leading hadrons in semi-inclusive DIS, may be also applied at fixed target energies. They may also include interference and final state interaction,…
We study the twist-2 double-spin asymmetries for the 2-jets and large-$p_T$ hadron ($\pi$, $\Lambda$ etc) production in semi-inclusive deep inelastic scattering to $O(\alpha_s)$ in perturbative QCD. After deriving the complete set of the…
We study the single-spin (left-right) asymmetry in single-inclusive pion production in hadronic scattering. This asymmetry is power-suppressed in the transverse momentum of the produced pion and can be analyzed in terms of twist-three…
HERMES has measured azimuthal single-spin asymmetries of charged pions produced in deep-inelastic scattering of positrons on a transversely polarised hydrogen target. The presented azimuthal moments provide access to two yet unknown quark…
We define a number of quark fragmentation functions for spin-0, -1/2 and -1 hadrons, and classify them according to their twist, spin and chirality. As an example of their applications, we use them to analyze semi-inclusive deep-inelastic…
The Collins function belongs to the class of the so-called time-reversal odd fragmentation functions. Being chiral-odd as well, it can serve as an important tool to observe the nucleon's transversity distribution in semi-inclusive DIS. Due…
We discuss our present understanding of the transverse spin structure of the nucleon and of related properties originating from parton transverse motion. Starting from the transversity distribution and the ways to access it, we then address…