Measurement of the virtual-photon asymmetry A
              2 and the spin-structure function g
              2 of the proton

Airapetian, A.; Акопов, Н.; Akopov, Z.; Aschenauer, E. C.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetisyan, E.; Belostotski, S.; Bianchi, N.; Blok, H.P.; Borissov, A.; Bowles, J.; Bryzgalov, V.; Burns, J.; Capiluppi, M.; Capitani, G. P.; Cisbani, E.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Deconinck, W.; Лео, Р. Де; Nardo, L. De; Sanctis, E. De; Diefenthaler, M.; Nezza, P. Di; Düren, M.; Ehrenfried, M.; Elbakian, G.; Ellinghaus, F.; Fantoni, A.; Felawka, L.; Frullani, S.; Gabbert, D.; Gapienko, G.; Гапиенко, В. А.; Garibaldi, F.; Gavrilov, G.; Gharibyan, V.; Giordano, F.; Gliske, S.; Golembiovskaya, M.; Hadjidakis, C.; Hartig, M.; Hasch, D.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hristova, I.; Imazu, Y.; Ivanilov, A.; Jackson, H. E.; Jo, H. S.; Joosten, S.; Kaiser, R.; Karyan, G.; Keri, T.; Kinney, E.; Kisselev, A.; Коротков, В. А.; Kozlov, V.; Kravchenko, P.; Krivokhijine, V. G.; Lagamba, L.; Lapikás, L.; Lehmann, I.; Lenisa, P.; Ruiz, A.; Lorenzon, W.; Ma, Bo-Qiang; Mahon, D.; Makins, N.; Manaenkov, S. I.; Manfré, L.; Mao, Y.; Mariański, B.; Ossa, A. Martínez de la; Marukyan, H.; Miller, C. A.; Miyachi, Y.; Movsisyan, A.; Muccifora, V.; Murray, M.; Mussgiller, A.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W.-D.; Pappalardo, L. L.; Pérez-Benito, R.; Petrosyan, A.; Reimer, P. E.; Reolon, A. R.; Riedl, C.; Rith, Klaus; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanftl, F.; Schäfer, Andreas; Schnell, G.; Schüler, K. P.; Seitz, B.; Shibata, T. A.; Shutov, V.; Stancari, M.; Statera, M.; Steffens, E.; Steijger, J. J. M.; Stewart, J.; Stinzing, F.; Taroian, S.; Terkulov, A.; Truty, R.; Trzciński, A.; Tytgat, M.; Vandenbroucke, A.; Haarlem, Y. Van; Hulse, C. Van; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Wang, S.; Yaschenko, S.; Ye, Z.; Yen, S.; Zagrebelnyy, V.; Zeiler, D.; Zihlmann, B.; Żuprański, P.

doi:10.1140/epjc/s10052-012-1921-5

Cited by 40 publications

(40 citation statements)

References 35 publications

(41 reference statements)

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“…The last correction required calculating the polarization dependent inelastic radiative tail of the Bornlevel polarization-dependent cross sections, which form the measured asymmetry. However, numerical studies [19,22] with various models indicate the size of this radiative tail is small for most kinematics, reaching a few [23], E155 (filled up triangle) [24] , E155x (filled down triangle) [25], HERMES (up triangle) [26], and RSS (down triangle) [27] experiments for the virtual Compton scattering asymmetries A p 1 (top) and A p 2 (bottom). The lower band shows systematic uncertainty.…”

Section: (4)mentioning

confidence: 99%

Revealing Color Forces with Transverse Polarized Electron Scattering

Armstrong¹,

Kang²,

Liyanage³

et al. 2019

Phys. Rev. Lett.

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The Spin Asymmetries of the Nucleon Experiment (SANE) measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 GeV and 5.9 GeV. A large-acceptance open-configuration detector package identified scattered electrons at 40 • and covered a wide range in Bjorken x (0.3 < x < 0.8). Proportional to an average color Lorentz force, the twist-3 matrix element,d p 2 , was extracted from the measured asymmetries at Q 2 values ranging from 2.0 to 6.0 GeV 2 . The data display the opposite sign compared to most quark models, including the lattice QCD result, and an apparently unexpected scale dependence. Furthermore when combined with the neutron data in the same Q 2 range the results suggest a flavor independent average color Lorentz force.Today, it is accepted that Quantum Chromodynamics (QCD), the gauge theory of strong interactions, plays a central role in our understanding of nucleon structure at the heart of most visible matter in the universe. QCD successfully describes many observables in high energy scattering processes where the coupling among the con-fined constituents of hadrons (quarks and gluons) is weak and perturbative (pQCD) calculations are possible, taking advantage of factorization theorems and evolution equations similar to quantum electrodynamics (QED). At the same time, QCD offers a clear path to unravel the non-perturbative structure of hadrons using lattice QCD, arXiv:1805.08835v4 [nucl-ex]

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Section: (4)mentioning

confidence: 99%

Revealing Color Forces with Transverse Polarized Electron Scattering

Armstrong¹,

Kang²,

Liyanage³

et al. 2019

Phys. Rev. Lett.

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“…The inclusive DIS data sets considered in this analysis include polarization asymmetries of the proton, deuteron and 3 He measured at CERN in the EMC [1], SMC [30,31] and COMPASS [32,33] experiments, at SLAC with the E130 [34], E142 [35], E143 [36], E154 [37], E155 [38][39][40] and E155x [41] experiments, by the HERMES Collaboration [42][43][44] at DESY, as well as more recent experiments in Hall A [45,46] and Hall B [47,48] at Jefferson Lab.…”

Section: B Datamentioning

confidence: 99%

“…The HERMES p and d data are given in terms of the A ∥ asymmetry [42], while the earlier neutron data (extracted from 3 He) are given in terms of A 1 [43]. The more recent transverse polarization analysis [44] measured the A 2 asymmetry of the proton. For most of the SLAC experiments on p and d targets, both A ∥ and A ⊥ were measured; for 3 He targets, the earlier E142 experiment [35] presented results for A 1 and A 2 , while the later E154 experiment [37] provided A ∥ and A ⊥ .…”

Section: B Datamentioning

confidence: 99%

Impact of hadronic and nuclear corrections on global analysis of spin-dependent parton distributions

2014

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We present the first results of a new global next-to-leading order analysis of spin-dependent parton distribution functions from the most recent world data on inclusive polarized deep-inelastic scattering, focusing in particular on the large-x and low-Q 2 regions. By directly fitting polarization asymmetries we eliminate biases introduced by using polarized structure function data extracted under nonuniform assumptions for the unpolarized structure functions. For analysis of the large-x data we implement nuclear smearing corrections for deuterium and 3 He nuclei, and systematically include target mass and higher twist corrections to the g 1 and g 2 structure functions at low Q 2 . We also explore the effects of Q 2 and W 2 cuts in the data sets, and the potential impact of future data on the behavior of the spin-dependent parton distributions at intermediate and large x.

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“…Data support (3.9) to a good accuracy [23][24][25]61], although especially at smaller x more stringent tests are not yet possible. Overall it has been estimated that the WW approximation for g 2 (x) and g a T (x) works with an accuracy of about 40 % or better [62].…”

Section: Tests Of Ww Approximation In Dis Experimentsmentioning

confidence: 95%

“…(3.9), for proton (P) and neutron (N) targets, and data from the SLAC E144 and E155 experiments at Q 2 = 7.1 GeV 2 [23,24]. Right panel: HERMES data for Q 2 > 1 GeV 2 with Q 2 = 2.4 GeV 2 [25]. The estimate of the theoretical uncertainty is described in the text.…”

Section: Tests Of Ww Approximation In Dis Experimentsmentioning

confidence: 99%

Semi-inclusive deep inelastic scattering in Wandzura-Wilczek-type approximation

et al. 2019

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We present the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed O(1/Q 2 ) terms in the Wandzura-Wilczek-type approximation, which consists in systematically assuming thatqgq-terms are much smaller thanqq-correlators. We compute all twist-2 and twist-3 structure functions and the corresponding asymmetries, and discuss the applicability of the Wandzura-Wilczek-type approximations on the basis of available data. We make predictions that can be tested by data from COMPASS, HERMES, Jefferson Lab, and the future Electron-Ion Collider. The results of this paper can be readily used for phenomenology and for event generators, and will help to improve the description of semi-inclusive deep-inelastic processes in terms of transverse momentum dependent parton distribution functions and fragmentation functions beyond the leading twist.

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Measurement of the virtual-photon asymmetry A 2 and the spin-structure function g 2 of the proton

Cited by 40 publications

References 35 publications

Revealing Color Forces with Transverse Polarized Electron Scattering

Revealing Color Forces with Transverse Polarized Electron Scattering

Impact of hadronic and nuclear corrections on global analysis of spin-dependent parton distributions

Semi-inclusive deep inelastic scattering in Wandzura-Wilczek-type approximation

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