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A single-spin asymmetry in the distribution of exclusively produced pi^+ mesons azimuthally around the virtual photon direction relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of…

High Energy Physics - Experiment · Physics 2008-11-26 HERMES Collaboration , A. Airapetian

Recent measurements from Jefferson Lab show significant beam single spin asymmetries in deep inelastic scattering. The asymmetry is due to interference of longitudinal and transverse photoabsorption amplitudes which have different phases…

High Energy Physics - Phenomenology · Physics 2007-05-23 Andrei Afanasev , C. E. Carlson

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…

High Energy Physics - Experiment · Physics 2010-05-28 HERMES Collaboration , A. Airapetian

Due to the lack of free neutron targets, studies of the structure of the neutron are typically made by scattering electrons from either $^2$H or $^3$He targets. In order to extract useful neutron information from a $^3$He target, one must…

The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive $\pi^0$ production in a wide kinematic region with the photon virtualities $Q^2$ up to 8 GeV$^2$ and the Bjorken scaling variable $x_B$…

Nuclear Experiment · Physics 2023-07-18 A. Kim , S. Diehl , K. Joo , V. Kubarovsky , P. Achenbach , Z. Akbar , J. S. Alvarado , Whitney R. Armstrong , H. Atac , H. Avakian , C. Ayerbe Gayoso , L. Barion , M. Battaglieri , I. Bedlinskiy , B. Benkel , A. Bianconi , A. S. Biselli , M. Bondi , F. Bossù , S. Boiarinov , K. T. Brinkmann , W. J. Briscoe , W. K. Brooks , S. Bueltmann , V. D. Burkert , R. Capobianco , D. S. Carman , J. C. Carvajal , A. Celentano , G. Charles , P. Chatagnon , V. Chesnokov , T. Chetry , G. Ciullo , B. Clary , G. Clash , P. L. Cole , M. Contalbrigo , G. Costantini , V. Crede , A. D'Angelo , N. Dashyan , R. DeVita , M. Defurne , A. Deur , C. Dilks , C. Djalali , R. Dupre , H. Egiyan , M. Ehrhart , A. ElAlaoui , L. ElFassi , S. Fegan , A. Filippi , C. Fogler , G. Gavalian , G. P. Gilfoyle , G. Gosta , F. X. Girod , D. I. Glazier , A. A. Golubenko , R. W. Gothe , L. Guo , K. Hafidi , H. Hakobyan , M. Hattawy , F. Hauenstein , T. B. Hayward , D. Heddle , A. Hobart , M. Holtrop , Yu-Chun Hung , Y. Ilieva , D. G. Ireland , E. Isupov , H. S. Jo , R. Johnston , S. Joosten , M. Khachatryan , A. Khanal , W. Kim , V. Klimenko , A. Kripko , S. E. Kuhn , L. Lanza , M. Leali , M. L. Kabir , S. Lee , P. Lenisa , X. Li , I . J . D. MacGregor , D. Marchand , V. Mascagna , B. McKinnon , D. Matamoros , S. Migliorati , T. Mineeva , M. Mirazita , V. Mokeev , P. Moran , C. MunozCamacho , P. Naidoo , K. Neupane , D. Nguyen , S. Niccolai , G. Niculescu , M. Osipenko , M. Ouillon , P. Pandey , M. Paolone , L. L. Pappalardo , R. Paremuzyan , E. Pasyuk , S. J. Paul , W. Phelps , N. Pilleux , M. Pokhrel , J. Poudel , J. W. Price , Y. Prok , A. Radic , N. Ramasubramanian , Trevor Reed , J. Richards , M. Ripani , J. Ritman , P. Rossi , F. Sabatié , C. Salgado , S. Schadmand , A. Schmidt , Y. G. Sharabian , E. V. Shirokov , U. Shrestha , D. Sokhan , N. Sparveris , M. Spreafico , S. Stepanyan , I. I. Strakovsky , S. Strauch , J. Tan , N. Trotta , R. Tyson , M. Ungaro , S. Vallarino , L. Venturelli , H. Voskanyan , E. Voutier , D. P. Watts , X. Wei , R. Wishart , M. H. Wood , M. Yurov , N. Zachariou , J. Zhang , V. Ziegler , M. Zurek

The beam spin asymmetry (BSA) in the exclusive reaction ep->ep pi0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer(CLAS). The xB, Q2, t and phi dependences of the pi0 BSA are presented in the…

High Energy Physics - Experiment · Physics 2010-04-06 CLAS Collaboration , R. De Masi

Modifying the numerical codes, dispersion corrections to the beam-normal spin asymmetry which arise from low-lying transient nuclear excitations up to 30 MeV, are estimated for collision energies between 50 MeV and 1 GeV. A nonperturbative…

Nuclear Theory · Physics 2025-12-09 D. H. Jakubassa-Amundsen

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive $\pi^+$ electroproduction reaction $\gamma^* p \to n \pi^+$. The results were obtained from scattering of 6 GeV longitudinally polarized…

Nuclear Experiment · Physics 2017-03-29 P. E. Bosted , M. J. Amaryan , S. Anefalos Pereira , H. Avakian , R. A. Badui , J. Ball , N. A. Baltzell , M. Battaglieri , V. Batourine , I. Bedlinskiy , A. S. Biselli , W. J. Briscoe , S. Bültmann , V. D. Burkert , D. S. Carman , A. Celentano , S. Chandavar , G. Charles , L. Clark , L. Colaneri , P. L. Cole , M. Contalbrigo , V. Crede , A. D'Angelo , R. De Vita , A. Deur , E. De Sanctis , C. Djalali , R. Dupre , H. Egiyan , A. El Alaoui , L. El Fassi , L. Elouadrhiri , P. Eugenio , E. Fanchini , G. Fedotov , A. Filippi , J. A. Fleming , T. Forest , A. Fradi , N. Gevorgyan , G. P. Gilfoyle , F. X. Girod , C. Gleason , W. Gohn , E. Golovatch , R. W. Gothe , K. A. Griffioen , M. Guidal , H. Hakobyan , M. Hattawy , K. Hicks , M. Holtrop , S. M. Hughes , Y. Ilieva , D. G. Ireland , B. S. Ishkhanov , E. L. Isupov , H. Jiang , H. S. Jo , K. Joo , S. Joosten , G. Khachatryan , M. Khandaker , A. Kim , W. Kim , F. J. Klein , S. Koirala , V. Kubarovsky , S. E. Kuhn , L. Lanza , L. A. Net , P. Lenisa , K. Livingston , I. J. D. MacGregor , M. E. McCracken , B. McKinnon , C. A. Meyer , M. Mirazita , V. I. Mokeev , R. A. Montgomery , E. Munevar , C. Munoz Camacho , G. Murdoch , P. Nadel-Turonski , S. Niccolai , M. Osipenko , A. I. Ostrovidov , K. Park , E. Pasyuk , P. Peng , W. Phelps , S. Pisano , O. Pogorelko , J. W. Price , Y. Prok , D. Protopopescu , B. A. Raue , M. Ripani , G. Rosner , P. Rossi , R. A. Schumacher , Iu. Skorodumina , G. D. Smith , D. Sokhan , N. Sparveris , I. Stankovic , I. I. Strakovsky , S. Strauch , M. Taiuti , B. Torayev , M. Ungaro , H. Voskanyan , E. Voutier , X. Wei , L. B. Weinstein , J. Zhang , I. Zonta

We calculate the target normal single-spin asymmetry caused by two-photon exchange in inclusive electron-nucleon scattering in the resonance region. Our analysis uses the $1/N_c$ expansion of low-energy QCD and combines $N$ and $\Delta$…

High Energy Physics - Phenomenology · Physics 2022-11-23 J. L. Goity , C. Weiss , C. T. Willemyns

The double spin asymmetry in the $\vec{e}\vec{p}\to e' \pi^+ n$ reaction has been measured for the first time in the resonance region for four-momentum transfer $Q^2=0.35-1.5$ GeV$^2$. Data were taken at Jefferson Lab with the CLAS detector…

High Energy Physics - Experiment · Physics 2010-04-06 CLAS Collaboration , R. De Vita

The $Q_{weak}$ Collaboration has completed a challenging measurement of the parity-violating asymmetry in elastic electron-proton ($\vec{e}$p) scattering at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The initial…

Nuclear Experiment · Physics 2015-10-02 Manolis Kargiantoulakis

The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the parity-violating asymmetry in elastic scattering at very low $Q^2$ of a longitudinally polarized electron beam on a proton target. The experiment will measure the…

High Energy Physics - Experiment · Physics 2019-08-14 Gregory S. Mitchell

We report the first measurement of the target single-spin asymmetry, $A_y$, in quasi-elastic scattering from the inclusive reaction $^3$He$^{\uparrow}(e,e^\prime)$ on a $^3$He gas target polarized normal to the lepton scattering plane.…

The analysis of inclusive $\pi$-meson single spin asymmetry measurements was done. It was found that the single spin asymmetry starts to grow up at the same value of the $\pi$-meson energy in the center of mass system for fixed target…

High Energy Physics - Experiment · Physics 2007-05-23 V. V. Mochalov , A. N. Vasiliev

We consider weak measurements (WM) of a spin observable in quantum mechanics beyond the usual asymptotic regime. This is done by obtaining the exact time-dependent wave functions of the measuring apparatus for general non-ideal…

Quantum Physics · Physics 2015-03-19 A. K. Pan , A. Matzkin

We report the most precise measurement to date of a parity-violating asymmetry in elastic electron-proton scattering. The measurement was carried out with a beam energy of 3.03 GeV and a scattering angle <theta_lab>=6 degrees, with the…

Nuclear Experiment · Physics 2012-08-27 The HAPPEX Collaboration

We report on a measurement of the asymmetry in the scattering of transversely polarized electrons off unpolarized protons, A$_\perp$, at two Q$^2$ values of \qsquaredaveragedlow (GeV/c)$^2$ and \qsquaredaveragedhighII (GeV/c)$^2$ and a…

A measurement of the proton spin structure function g1p(x,Q^2) in deep-inelastic scattering is presented. The data were taken with the 27.6 GeV longitudinally polarised positron beam at HERA incident on a longitudinally polarised pure…

High Energy Physics - Experiment · Physics 2009-04-15 A. Airapetian

We present the preliminary results of measurements of single spin asymmetries, $A_L$ for $W^\pm$ boson production in longitudinally polarized p+p collisions at $\sqrt{s}=510$ GeV and measurements of cross section ratios, $\sigma _{W^+} /…

Nuclear Experiment · Physics 2019-08-14 Devika Gunarathne