Related papers: Azimuthal asymmetries from unpolarized data at COM…
COMPASS is a fixed-target experiment on the SPS M2 beamline at CERN. Its LiD target can be polarised both longitudinally and transversally with respect to the longitudinally polarised 160 GeV/c muon beam. Approximately 20% of the beam-time…
The single-spin asymmetry of unpolarized leptons scattering deep-inelastically off transversely polarized nucleons is discussed. This observable is generated by a two-photon exchange between lepton and nucleon. In a partonic description of…
We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction, where two hadrons are produced in opposite hemispheres along the z-axis in the center-of-mass…
Within the LO QCD parton model of SIDIS with unintegrated quark distribution and fragmentation functions we study the transverse momentum and azimuthal dependencies of the double spin asymmetries $A_{LT}$ and $A_{LL}$. For later we include…
We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered…
After reviewing the most important COMPASS results on transverse spin effects in SIDIS, I will present the recent work we have done on weighted Sivers asymmetries and "transversity induced" $\Lambda$ polarisation. Using the high statistics…
HERMES has measured azimuthal single-spin asymmetries of pions and charged kaons produced in deep-inelastic scattering of electrons and positrons off a transversely polarized hydrogen target. These asymmetries provide information about the…
Azimuthal asymmetries in semi-inclusive production of positive (h^+) and negative hadrons (h^-) have been measured by scattering 160 GeV muons off longitudinally polarised deuterons at CERN. The asymmetries were decomposed in several terms…
Transverse spin and transverse momentum distribution functions of the constituents of the nucleon are a crucial input for a complete description of the nucleon. COMPASS measured such for longitudinally and transversely polarized deuterons…
We consider the single-spin azimuthal asymmetries recently measured at the HERMES experiment for charged pions produced in semi-inclusive deep inelastic scattering of leptons off longitudinally polarized protons. Guided by the experimental…
Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\psi$ about…
Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of…
The inclusive A_1,p and hadron double-spin asymmetries A_p^pi+, A_p^pi-, A_p^K+, A_p^K- measured at COMPASS (CERN SPS) in deep-inelastic scattering of a polarized muon beam off a polarized NH_3 solid target are presented. The results have…
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…
In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a…
We analyze the longitudinal-transverse double-spin asymmetry in lepton-nucleon collisions where a single hadron is detected in the final state, i.e., $\vec{\ell}\,N^\uparrow \rightarrow h\,X$. This is a subleading-twist observable in…
The production of vector mesons in SIDIS is a particularly interesting channel to study the polarized fragmentation and related phenomena. Preliminary COMPASS results for the first measurement of inclusive $\rho^0$ Collins and Sivers…
The azimuthal dependence of hadrons produced in lepton scattering off a polarized hadron probes the quark transverse-spin distributions. In the calculation of the asymmetries, transverse momenta of quarks in the distribution and…
The Collins and Sivers asymmetries for charged hadrons produced in deeply inelastic scattering on transversely polarised protons have been extracted from the data collected in 2007 with the CERN SPS muon beam tuned at 160 GeV/c. At large…
The differential cross section for production of charged hadrons with high transverse momenta in scattering of 160\,GeV/$c$ muons off nucleons at low photon virtualities has been measured at the COMPASS experiment at CERN. The results,…