Determination of the proton spin structure functions for 
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 using CLAS

Fersch, R.; Guler, N.; Bosted, P.; Deur, A.; Griffioen, K. A.; Keith, C.; Kuhn, S. E.; Minehart, R.; Prok, Y.; Adhikari, K. P.; Adhikari, S.; Akbar, Z.; Amaryan, M. J.; Pereira, S. Anefalos; Asryan, G.; Avakian, H.; Ball, J.; Balossino, I.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, Volker; Cao, F.; Carman, D. S.; Careccia, S. L.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Credé, V.; D’Angelo, A.; Dashyan, N.; Vita, R. De; Sanctis, E. De; Djalali, C.; Dodge, G. E.; Dupré, R.; Egiyan, H.; Alaoui, A. El; Fassi, L. El; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Garçon, M.; Gavalian, G.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Golovatch, E.; Gothe, R. W.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, David; Joo, K.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lagerquist, V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Camacho, C. Muñoz; Murdoch, G.; Nadel-Turoński, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pierce, J.; Pisano, S.; Pogorelko, O.; Price, J. W.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Riser, D.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, Carlos A.; Schumacher, R. A.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stanković, Ivana; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.

doi:10.1103/physrevc.96.065208

Cited by 43 publications

(55 citation statements)

References 124 publications

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“…[33], the effective polarizability fm ep µp rZ [34,39] 1.055 (13) 1.055 (13) rR [34,39] -0.1411 (14) -0.1203 (8) rZ + rR [34,39] 0.914 (13) 0.935 (13) r (πN, KN, ηN ) -0.027 -0.027 r pol [34,39] -0.051 (13) -0.052 (13) r p 2γ from eH 1S HFS [33,39] 0.861 (6) 0.880 (8) r p 2γ [34,39] 0.863 (20) 0.883 (19) radii in electronic and muonic hydrogen based on structure functions of Refs. [64][65][66] are close to each other. Likewise the GDH sum rule [67,68], the saturation pattern of the contributions from different channels from the neutron is similar to the proton case with slightly different decomposition.…”

mentioning

confidence: 71%

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Two-photon exchange on the neutron and the hyperfine splitting

Tomalak

2019

Phys. Rev. D

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We calculate the contribution from the two-photon exchange on the neutron to the hyperfine splitting of S energy levels. We update the value of the neutron Zemach radius and estimate total recoil and polarizability corrections. The resulting two-photon exchange in electronic atoms exceeds by an order of magnitude the leading Zemach term and has different sign both in electronic and muonic hydrogen.Modern spectroscopical measurements in light muonic atoms support the physics community with precise values of the Rydberg constant and nuclei electromagnetic radii [1][2][3]. The unexpected discrepancy between muonic and electronic values of the charge radius in hydrogen and deuterium [4-9] calls for revisiting the higher-order corrections with an emphasis on the uncertain hadronic and nuclei contributions. In particular, to analyze measurements of the hyperfine splitting in light muonic nuclei and to extract the precise value of the Zemach radius, the higher-order radiative corrections have to be taken into account [10,11]. In recent decades, the O α 5 contribution from the graph with two exchanged photons (TPE) on a proton and nucleus (see Fig. 1) to the Lamb shift and hyperfine splitting was scrutinized by numerous authors . Besides the scattering on a proton, the TPE effect in light atoms contains contributions from nuclei excitations as well as from the scattering on a neutron. The contribution from the two-photon exchange on the neutron to the Lamb shift was recently investigated in Ref. [39,40]. For the hyperfine splitting, only the leading Zemach correction was evaluated in Refs. [41,42] from parametrizations of the neutron form factors. FIG. 1: Two-photon exchange graph. The contribution of the crossed graph is included into the lower blob.In this work, we reproduce the result of Refs. [41,42] exploiting the modern form factor parametrizations which satisfy the consistency criterium of Ref. [34] for such a calculation. We account for the two-photon exchange effects beyond the Zemach term by means of the forward Compton scattering amplitudes [35]. We estimate the polarizability contribution from the MAID partial-wave solution and illustrate how good such an estimate can be on the example of the TPE on the pro-ton.We determine the hyperfine-splitting correction from the forward scattering amplitude at threshold. It is convenient to express the resulting hyperfine splitting and individual contributions in terms of the effective radii. The resulting nucleon radius r N 2γ is given as a sum of three terms:where r Z , r R and r pol stand for the Zemach, recoil and polarizability radii, respectively (the terminology is taken from the hydrogen TPE). These radii are expressed as the photon energy ν γ and virtuality Q 2 integrals over the neutron electric G E and magnetic G M form factors and polarized spin structure functions g 1 , g 2 [27,29,35,43,44]:

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mentioning

confidence: 71%

“…To test such evaluation and estimate the polarizability correction, we compare the results from the structure functions measurements [64][65][66] to the MAID-based evaluation of HFS on the proton in Table 2. We notice that the effect of KN and ηN channels is much smaller than the leading πN contribution as in case of the neutron.…”

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confidence: 99%

Two-photon exchange on the neutron and the hyperfine splitting

Tomalak

2019

Phys. Rev. D

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“…44 (right panel) between proton spin polarizabilities in RCS and VCS respectively. Left: the brown band is the sum rule constraint based on the empirical information for I 1 (0) from JLab/CLAS (115,116), and for r 2 2 from (117). Right: the brown band is the sum rule constraint based on the phenomenological MAID2007 (45) information for δ LT (0).…”

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confidence: 99%

Dispersion Theory in Electromagnetic Interactions

Pasquini

Vanderhaeghen

2018

Annu. Rev. Nucl. Part. Sci.

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We review various applications of dispersion relations (DRs) to the electromagnetic structure of hadrons. We discuss the way DRs allow one to extract information on hadron structure constants by connecting information from complementary scattering processes. We consider the real and virtual Compton scattering processes off the proton, and summarize recent advances in the DR analysis of experimental data to extract the proton polarizabilities, in comparison with alternative studies based on chiral effective field theories. We discuss a multipole analysis of real Compton scattering data, along with a DR fit of the energy-dependent dynamical polarizabilities. Furthermore, we review new sum rules for the double-virtual Compton scattering process off the proton, which allow for model independent relations between polarizabilities in real and virtual Compton scattering, and moments of nucleon structure functions. The information on the double-virtual Compton scattering is used to predict and constrain the polarizability corrections to muonic hydrogen spectroscopy.

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“…To convert the fit results in Eqs. (9)(10)(11) into a prediction for the asymmetry A p 1 as a function of x, it is important to note that s Q 2 /x at large centre-of-mass energy [4], COMPASS [5], GDH [8], HERMES [7], and SLAC E-143 [6] experiments with Q 2 < 0.5GeV 2 .…”

Section: Fitting the High Energy Spin Asymmetrymentioning

confidence: 99%

“…Here we investigate this behaviour using the new high statistics measurements from CLAS at Jefferson Laboratory [4] and COMPASS at CERN [5] of the spin asymmetry for polarised photon-proton collisions at low photon virtuality Q 2 < 0.5 GeV 2 and centre-of-mass energy √ s ≥ 2.5 GeV, together with earlier measurements from the E-143 experiment at SLAC [6], HERMES at DESY [7] and the GDH Collaboration in Bonn [8].…”

Section: Introductionmentioning

confidence: 99%

Updating spin-dependent Regge intercepts

2018

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We use new high statistics data from CLAS and COMPASS on the nucleon's spin structure function at low Bjorken x and low virtuality, Q 2 < 0.5 GeV 2 , together with earlier measurements from the SLAC E-143, HERMES and GDH experiments to estimate the effective intercept(s) for spin dependent Regge theory. We find αa 1 = 0.31 ± 0.04 for the intercept describing the high-energy behaviour of spin dependent photoabsorption together with a new estimate for the high-energy part of the Gerasimov-Drell-Hearn sum-rule, −15 ± 2µb from photon-proton centre-of-mass energy greater than 2.5 GeV. Our value of αa 1 suggests QCD physics beyond a simple straight-line a1 trajectory.

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Determination of the proton spin structure functions for 0.05<Q2<5GeV2 using CLAS

Cited by 43 publications

References 124 publications

Two-photon exchange on the neutron and the hyperfine splitting

Two-photon exchange on the neutron and the hyperfine splitting

Dispersion Theory in Electromagnetic Interactions

Updating spin-dependent Regge intercepts

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