Related papers: Transversity and single spin asymmetries
The role of transverse momentum of quarks in semi-inclusive leptoproduction will be discussed. It involves generalized distribution and fragmentation functions which depend on both the longitudinal lightcone momentum fraction of the quarks…
We study the single transverse spin asymmetry of prompt photon production in high energy proton-proton scattering. We include the contributions from both the direct and fragmentation photons. While the asymmetry for direct photon production…
The study of $\Lambda$ polarization in Semi-Inclusive Deep Inelastic Scattering (SIDIS) with a transversely polarized target has often been suggested as a privileged way to access transversity, as the initial quark polarization can be…
Within the Basis Light-Front Quantization framework, we systematically investigate the subleading twist (twist-3) transverse-momentum-dependent parton distribution functions (TMDs) of the proton beyond the Wandzura-Wilczek (WW)…
Measuring single spin asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) on a transversely polarized target gives a handle to investigate the transversity distribution and transverse momentum dependent distribution functions.…
A general formalism to evaluate time-reversal odd transverse momentum dependent parton distributions (T-odd TMDS) is reviewed and applied to the calculation of the leading-twist quantities, i.e., the Sivers and the Boer-Mulders functions.…
Single-spin asymmetries for pions and charged kaons are measured in semi-inclusive deep-inelastic scattering of positrons and electrons off a transversely nuclear-polarized hydrogen target. The dependence of the cross section on the…
At the leading twist, the transversity distribution function, $h^{q}_{1}(x)$, where $x$ is the longitudinal momentum fraction of the proton carried by quark $q$, encodes the transverse spin structure of the nucleon. Extraction of it is…
As a possible source of the single transverse spin asymmetry, we study the contribution from purely gluonic correlation represented by the twist-3 ``three-gluon correlation" functions in the transversely polarized nucleon. We first define a…
We show that the transverse momentum dependent transversity function is proportional to the longitudinal polarization of a quark in a transversely polarized proton. This result suggests an alternative, convenient method for determining…
Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN, which started taking data in 2002, scattering 160 GeV/c muon beam on a polarized $^6$LiD target. The analysis of the data taken with…
A phenomenological description of single transverse spin asymmetries for the inclusive production of hadrons in proton-proton and lepton-proton processes is discussed within pQCD and a straightforward generalization of the factorization…
Transverse single spin asymmetries in pp --> pion X processes, while on a quite firm ground experimentally, are still a much debated phenomenological issue. We consider them in a transverse momentum dependent factorization scheme. After…
COMPASS is a fixed-target high energy physics experiment at the SPS at CERN \cite{Abbon:2007pq}. One of the important objectives of the experiment is the exploration of the transverse spin structure of the nucleon via spin dependent…
We discuss possible origins of transverse spin asymmetries in hadron-hadron collisions and propose an explanation in terms of a chiral-odd T-odd distribution function with intrinsic transverse momentum dependence, which would signal a…
A selection is presented of recent results from the COMPASS Collaboration on transverse spin and transverse momentum effects in semi-inclusive deeply inelastic scattering (SIDIS) of 160 GeV/c muons off proton and deuteron targets.
The large single spin asymmetries observed at high momentum fractions x_F and transverse momenta k_T in p^\uparrow p -> \pi(x_F,k_T)+X as well as in pp -> \Lambda^\uparrow(x_F,k_T)+X suggest that soft helicity flip processes are coherent…
The study of the spin structure of the nucleon and of the effects rising from the quarks transverse momentum are part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. The azimuthal asymmetries which appear in…
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 study parity-even and parity-odd polarization observables for the process $p \, p \to l^{\pm} \, X$, where the lepton comes from the decay of a $W$-boson. By using the collinear twist-3 factorization approach, we consider the case when…