Related papers: Single Spin Asymmetries in the BRAHMS Experiment
Within a generalized parton model approach, with inclusion of spin and intrinsic transverse momentum effects, we show how the latest, highly precise, midrapidity data on the transverse single spin asymmetry measured in $pp\to\pi^0\, X$ by…
We discuss the quark transversity distribution function and a possible way to access it through the measurement of single spin azimuthal asymmetry in semi-inclusive single pion electroproduction on a transversely polarized target.
We present the measurement of Single Beam-Spin Azimuthal Asymmetries in pion electroproduction off hydrogen in semi-inclusive deep inelastic scattering (SIDIS). The measurement was made using the HERMES spectrometer with an internal gas…
A single-spin asymmetry in the azimuthal distribution of neutral pions relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of positrons off longitudinally polarized protons. The…
We study a possible origin of single spin asymmetries in the large $p_T$ inclusive production of hadrons in the scattering of unpolarized protons or leptons on transversely polarized nucleons. Such asymmetry is related to the single-spin…
We report some results in large pseudo rapidity pi^0-production in polarized proton collisions at 200 GeV center of mass energy. The single spin asymmetry for positive Feynman x (x_F) is consistent with zero up to ~0.35, then increases with…
The transversity parton distribution remains a poorly known cornerstone in the nucleon spin structure. While the Collins effect in spin asymmetries in Semi-Inclusive DIS (SIDIS) is one crucial tool to address the transversity function, the…
The much debated issue of the transverse single spin asymmetry A_N observed in the inclusive large P_T production of a single hadron in pp interactions, p(transv. polarized) p --> pion X, is considered in a TMD factorization scheme. A…
In the year 2005 run PHENIX has accumulated 3.8 pb$^{-1}$ integrated luminosity in longitudinally polarized $p+p$ collisions at $\sqrt{s}=200$ GeV. Double helicity asymmetries of neutral pions lead to restrictions of the gluon polarization…
The sPHENIX experiment is a next-generation collider detector at the Relativistic Heavy Ion Collider (RHIC) designed for rare jet and heavy-flavor probes of Au + Au, $p$ + Au, and polarized $p+p$ collisions. The experiment includes a large…
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…
We report the transverse single-spin asymmetries of $J/\psi$ production at forward and backward rapidity, $1.2<|y|<2.2$, as a function of $J/\psi$ transverse momentum ($p_T$) and Feynman-$x$ ($x_F$). The data analyzed were recorded by the…
Measurements of transverse-single-spin asymmetries ($A_{N}$) in $p$$+$$p$ collisions at $\sqrt{s}=$62.4 and 200 GeV with the PHENIX detector at RHIC are presented. At midrapidity, $A_{N}$ is measured for neutral pion and eta mesons…
Recently HERMES has observed an azimuthal asymmetry in electro-production of neutral pions in semi-inclusive deep-inelastic scattering of unpolarized positrons off longitudinally polarized protons. This asymmetry (like those observed in the…
In this talk it is reported on an analysis of hard exclusive pion electroproduction within the handbag approach. Particular emphasis is laid on single-spin asymmetries. It is argued that a recent HERMES measurement of asymmetries measured…
We report the first evidence for a non-zero beam-spin azimuthal asymmetry in the electroproduction of positive pions in the deep-inelastic region. Data have been obtained using a polarized electron beam of 4.3 GeV with the CLAS detector at…
Transverse single-spin asymmetries (SSA) are expected to be small in perturbative QCD because of the chiral nature of the theory. Experiment shows large transverse SSA for particle produced in special kinematics. This contribution reviews…
We discuss the single-spin asymmetry in semi-inclusive DIS, $e p^\uparrow \to e \pi X$, based on the twist-3 mechanism in the collinear factorization relevant for the pion production with the large transverse-momentum. This updates our…
We report the first measurements of transverse single-spin asymmetries for inclusive jet and jet + $\pi^{\pm}$ production at midrapidity from transversely polarized proton-proton collisions at $\sqrt{s} = 500$ GeV. The data were collected…
The STAR collaboration has previously reported a large transverse single spin asymmetry, A_N, for forward pi0 meson production. The cross-section in this region was measured up to Feynman-x (xF) of 0.55, and found to be consistent with…