Avakian H, Hayward T B, Kotzinian A, Armstrong W R, Atac H, Ayerbe Gayoso C, Baashen L, Baltzell N A, Barion L, Bashkanov M, Battaglieri M, Bedlinskiy I, Benkel B, Benmokhtar F, Bianconi A, Biondo L, Biselli A S, Bondi M, Boiarinov S, Bossù F, Brinkman K T, Briscoe W J, Brooks W K, Bueltmann S, Bulumulla D, Burkert V D, Capobianco R, Carman D S, Carvajal J C, Celentano A, Chatagnon P, Chesnokov V, Chetry T, Ciullo G, Cole P L, Contalbrigo M, Costantini G, D'Angelo A, Dashyan N, De Vita R, Defurne M, Deur A, Diehl S, Dilks C, Djalali C, Dupre R, Egiyan H, El Alaoui A, El Fassi L, Elouadrhiri L, Fegan S, Filippi A, Forest T, Gates K, Gavalian G, Ghandilyan Y, Glazier D I, Golubenko A A, Gosta G, Gothe R W, Gotra Y, Griffioen K A, Guidal M, Hakobyan H, Hattawy M, Hauenstein F, Heddle D, Hobart A, Holtrop M, Hyde C E, Ilieva Y, Ireland D G, Isupov E L, Jo H S, Johnston R, Joo K, Kabir M L, Keller D, Khachatryan M, Khanal A, Kim A, Kim W, Klimenko V, Kripko A, Kubarovsky V, Kuhn S E, Lagerquist V, Lanza L, Leali M, Lee S, Lenisa P, Li X, MacGregor I J D, Marchand D, Mascagna V, McKinnon B, Migliorati S, Mineeva T, Mirazita M, Mokeev V, Montgomery R A, Munoz Camacho C, Nadel-Turonski P, Naidoo P, Neupane K, Nguyen D, Niccolai S, Nicol M, Niculescu G, Osipenko M, Pandey P, Paolone M, Pappalardo L L, Paremuzyan R, Pasyuk E, Paul S J, Phelps W, Pilleux N, Pogorelko O, Pokhrel M, Poudel J, Price J W, Prok Y, Raue B A, Reed T, Richards J, Ripani M, Ritman J, Rossi P, Sabatié F, Salgado C, Schmidt A, Sharabian Y G, Shirokov E V, Shrestha U, Simmerling P, Sokhan D, Sparveris N, Stepanyan S, Strakovsky I I, Strauch S, Tan J A, Trotta N, Tyson R, Ungaro M, Vallarino S, Venturelli L, Voskanyan H, Vossen A, Voutier E, Watts D P, Wei X, Wishart R, Wood M H, Zachariou N, Zhao Z W, Zurek M
Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA.
University of Connecticut, Storrs, Connecticut 06269, USA.
Phys Rev Lett. 2023 Jan 13;130(2):022501. doi: 10.1103/PhysRevLett.130.022501.
We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e^{'}pπ^{+}X events, where Δϕ is the difference of the azimuthal angles of the proton and pion in the virtual photon and target nucleon center-of-mass frame, indicate that correlations between the spin and transverse momenta of hadrons produced in the target- and current-fragmentation regions may be significant. The measured beam-spin asymmetries provide a first access in dihadron production to a previously unexplored leading-twist spin- and transverse-momentum-dependent fracture function. The fracture functions describe the hadronization of the target remnant after the hard scattering of a virtual photon off a quark in the target particle and provide a new avenue for studying nucleonic structure and hadronization.
我们报告了在深度非弹性散射过程中背对背双强子电产生中深度非弹性散射自旋相关方位不对称性的首次测量结果。在这个反应中，在虚光子 - 靶核子质心参考系中，两个强子沿着z轴在相反的半球产生，第一个强子在电流碎裂区域产生，第二个在靶碎裂区域产生。数据是使用杰斐逊实验室的CLAS12光谱仪，用能量为10.2 GeV和10.6 GeV的纵向极化电子束入射到未极化的液态氢靶上获取的。在ep→e'pπ⁺X事件中观察到非零的sinΔϕ调制，其中Δϕ是在虚光子和靶核子质心参考系中质子和π介子方位角的差值，这表明在靶碎裂和电流碎裂区域产生的强子的自旋和横向动量之间的相关性可能很显著。测量到的束流自旋不对称性为双强子产生中以前未探索的领先扭转自旋和横向动量相关的碎裂函数提供了首次访问途径。碎裂函数描述了虚光子与靶粒子中的夸克发生硬散射后靶残余物的强子化过程，并为研究核子结构和强子化提供了一条新途径。
