scholarly journals Single-spin asymmetries for small-angle pion production in high-energy hadron collisions

1999 ◽  
Vol 11 (4) ◽  
pp. 703 ◽  
Author(s):  
A. Ahmedov ◽  
I.V. Akushevich ◽  
E.A. Kuraev ◽  
P.G. Ratcliffe
1999 ◽  
Vol 11 (4) ◽  
pp. 703-708 ◽  
Author(s):  
A. Ahmedov ◽  
I.V. Akushevich ◽  
E.A. Kuraev ◽  
P.G. Ratcliffe

2000 ◽  
Vol 15 (07) ◽  
pp. 927-982 ◽  
Author(s):  
ZUO-TANG LIANG ◽  
C. BOROS

It has been realized for quite a long time that single-spin experiments, in which one of the colliding objects is transversely polarized, can be helpful in studying the properties of strong interaction in general and in testing quantum chromodynamics (QCD) in particular. Striking effects have been observed in the past few years which deviate drastically from the expectation of the perturbative QCD parton model. These effects have received much attention. New experiments of the similar type are underway and/or planned. Different theoretical attempts have been made to understand these effects. In this review, the special role played by singly polarized high-energy hadron–hadron collisions in high energy spin physics is emphasized. Characteristics of the available data for inclusive hadron productions are briefly summarized. Different theoretical approaches for such processes are reviewed with special attention to a nonperturbative model which explicitly takes the orbital motion of the valence quarks and hadronic surface effects into account. The connection between such asymmetries and hyperon polarization in unpolarized reactions is discussed. An example of the possible application of such experimental results in other processes is given.


2003 ◽  
Vol 18 (16) ◽  
pp. 2871-2892 ◽  
Author(s):  
Stanley J. Brodsky

The advent of back-scattered laser beams for e±e-colliders will allow detailed studies of a large array of high energy γγ and γe collision processes with polarized beams. These include tests of electroweak theory in photon-photon annihilation such as γγ → W+W-, γγ → Higgs bosons, and higher-order loop processes, such as γγ → γγ, Zγ, H0Z0and ZZ. Methods for measuring the anomalous magnetic and quadrupole moments of the W and Z gauge bosons to high precision in polarized electron-photon and photon-photon collisions are discussed. Since each photon can be resolved into a W+W-pair, high energy photon-photon collisions can also provide a remarkably background-free laboratory for studying WW collisions and annihilation. I also review high energy γγ and eγ tests of quantum chromodynamics, including the production of two gluon jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Exclusive hadron production processes in photon-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes which are also important for the analysis of exclusive semi-leptonic and two-body hadronic B-decays.


1995 ◽  
Vol 348 (3-4) ◽  
pp. 577-581 ◽  
Author(s):  
A.V. Efremov ◽  
V.M. Korotkiyan ◽  
O.V. Teryaev

2016 ◽  
Vol 40 ◽  
pp. 1660045 ◽  
Author(s):  
Zhun Lu ◽  
Wenjuan Mao

The single-spin asymmetry [Formula: see text] of charged and neutral pion production in semi-inclusive deep-inelastic scattering on longitudinally polarized nucleon targets is studied. We particularly consider the effects of the twist-3 transverse-momentum dependent distribution functions [Formula: see text] and [Formula: see text], which are calculated in two different spectator-diquark models. We estimate the asymmetry for [Formula: see text], [Formula: see text] and [Formula: see text] produced off the proton target at HERMES and compare the results with the HERMES measurements. We also predict the same asymmetric moment for different pions at the kinematics of CLAS 5.5 GeV on a proton target, as well as at COMPASS on a deuteron target for comparison.


2016 ◽  
Vol 40 ◽  
pp. 1660030
Author(s):  
Wenjuan Mao ◽  
Zhun Lu ◽  
Bo-Qiang Ma

We estimate the single-spin asymmetries with [Formula: see text] and [Formula: see text] angular dependencies for electroproduction of pions in transversely polarized semi-inclusive DIS process. We consider the effect of the twist-3 transverse momentum dependent distributions which convoluted with twist-2 fragmentation functions. We calculate these distributions in a spectator-diquark model, and predict the corresponding single-spin asymmetries at the kinematics of HERMES, JLab and COMPASS. We find that the numerical estimates show that the asymmetries are sizable, and the T-odd twist-3 TMDs play an important role in these asymmetries.


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