Measurement of the near-threshold J$/ψ$ photoproduction cross section with the CLAS12 experiment
IRFU, CEA, Université Paris-Saclay（IRFU, 法国原子能和替代能源委员会，巴黎萨克雷大学）；Thomas Jefferson National Accelerator Facility（托马斯·杰斐逊国家加速器设施）；University of New Hampshire（新罕布什尔大学）；Old Dominion University（老道明大学）；University of Glasgow（格拉斯哥大学）；University of York（约克大学）；Christopher Newport University（克里斯托弗纽波特大学）；Université Paris-Saclay, CNRS/IN2P3, IJCLab（巴黎萨克雷大学，法国国家科学研究中心/法国国家粒子物理研究所，IJCLab）；Argonne National Laboratory（阿贡国家实验室）；INFN, Sezione di Ferrara（意大利国家核物理研究院，费拉拉分部）；INFN, Sezione di Genova（意大利国家核物理研究院，热那亚分部）
P. Chatagnon, V. Kubarovsky, R. Paremuzyan, S. Stepanyan, M. Tenorio, R. Tyson, A. G. Acar, P. Achenbach, J. S. Alvarado, M. J. Amaryan, W. R. Armstrong, H. Ava… 展开作者
P. Chatagnon, V. Kubarovsky, R. Paremuzyan, S. Stepanyan, M. Tenorio, R. Tyson, A. G. Acar, P. Achenbach, J. S. Alvarado, M. J. Amaryan, W. R. Armstrong, H. Avakian, N. A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, F. Benmokhtar, A. Bianconi, A. S. Biselli, S. Boiarinov, M. Bondi, F. Bossù, K. -Th. Brinkmann, W. J. Briscoe, S. Bueltmann, V. D. Burkert, T. Cao, D. S. Carman, A. Celentano, H. Chinchay, G. Ciullo, P. L. Cole, A. D'Angelo, N. Dashyan, M. Defurne, R. De Vita, A. Deur, S. Diehl, C. Dilks, C. Djalali, M. Dugger, R. Dupré, H. Egiyan, M. Ehrhart, A. El Alaoui, L. El Fassi, L. Elouadrhiri, M. Farooq, S. Fegan, R. F. Ferguson, I. P. Fernando, E. Ferrand, A. Filippi, C. Fogler, K. Gates, G. P. Gilfoyle, D. I. Glazier, R. W. Gothe, Y. Gotra, B. Gualtieri, K. Hafidi, H. Hakobyan, F. Hauenstein, T. B. Hayward, D. Heddle, M. Hoballah, M. Holtrop, C. E. Hyde, Y. Ilieva, D. G. Ireland, E. L. Isupov, H. S. Jo, K. Joo, T. Kageya, M. Kerr, A. Kim, H. T. Klest, V. Klimenko, I. Korover, A. Kripko, S. E. Kuhn, L. Lanza, S. Lee, P. Lenisa, X. Li, D. Marchand, D. Martiryan, V. Mascagna, B. McKinnon, A. Mehta, R. G. Milner, M. Mirazita, V. I. Mokeev, E. F. Molina Cardenas, C. Munoz Camacho, P. Nadel-Turonski, K. Neupane, D. Nguyen, S. Niccolai, G. Niculescu, M. Osipenko, M. Ouillon, P. Pandey, M. Paolone, L. L. Pappalardo, E. Pasyuk, C. Paudel, S. J. Paul, N. Pilleux, L. Polizzi, J. Poudel, J. W. Price, Y. Prok, A. Radic, J. Richards, M. Ripani, J. Ritman, P. Rossi, A. A. Rusova, C. Salgado, S. Schadmand, A. Schmidt, M. B. C. Scott, Y. G. Sharabian, E. V. Shirokov, S. Shrestha, E. Sidoretti, N. Sparveris, I. I. Strakovsky, S. Strauch, F. Touchte Codjo, M. Ungaro, D. W. Upton, P. S. H. Vaishnavi, S. Vallarino, C. Velasquez, L. Venturelli, H. Voskanyan, A. Vossen, E. Voutier, Y. Wang, D. P. Watts, U. Weerasinghe, X. Wei, M. H. Wood, L. Xu, Z. Xu, Z. W. Zhao, V. Ziegler, M. Zurek
We present measurements of the total and differential cross sections for near-threshold J/$ψ$ photoproduction obtained with the CLAS12 detector at the Thomas Jefferson National Accelerator Facility. The results are based on data collected during the Fall 2018 and Spring 2019 running periods, using electron beams with energies of 10.6 and 10.2 GeV, respectively, scattered off a liquid-hydrogen target. Near-threshold J$/ψ$ photoproduction offers a unique sensitivity to the strong interaction in the non-perturbative regime of Quantum Chromodynamics (QCD). The energy dependence of the cross section constrains the underlying J$/ψ$ production mechanisms, including multi-gluon exchange and potential baryonic excitations. Additionally, the $t$-dependence of the differential cross section can be related to the transverse spatial distribution of gluons in the proton, providing critical input for theoretical descriptions of the gluonic structure of the proton. An interpretation of the results in terms of the gluon content of the proton is presented, providing new experimental constraints on QCD-inspired models of the proton structure and the role of gluonic degrees of freedom in hadronic mass generation.
Measurement of Beauty Photoproduction near Threshold using Di-electron Events with the H1 Detector at HERA
在电子对撞机HERA上，用H1探测器测量了光生产物中ep -> e b \bar{b} X的截面。衰变通道b \bar{b} -> ee X'通过识别b夸克的半电子衰变来选择。总产生截面是在光子虚量Q^2 <= 1 GeV^2、非弹性0.05 <= y <= 0.65和b夸克赝快度的运动学范围内测量的|eta（b）|,|eta（\bar{b}）|<= 2。微分产生截面是美夸克<P_T（b）>的平均横动量的函数。结果进行了比较，下一个领导阶QCD预测。
Near-threshold heavy quarkonium photoproduction in a light-front spectator model
Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；School of Nuclear Science and Technology, University of Chinese Academy of Sciences（中国科学院大学核科学与技术学院）；CAS Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所高精度核谱学重点实验室）；Department of Physics, Indian Institute of Technology Kanpur（坎普尔印度理工学院物理系）；University of Science and Technology of China（中国科学技术大学）
Tests of QCD Factorisation in the Diffractive Production of Dijets in Deep-Inelastic Scattering and Photoproduction at HERA
测量了衍射光生过程（Q^2<0.01 GeV^2）和深度非弹性散射过程（DIS，4<Q^2<80 GeV^2）中的微分双射截面。事件拓扑由ep-> e X Y给出，其中系统X，包含至少两个喷流，与领先的低质量质子残留物系统Y分开一个大的快度间隙。的dijet截面进行了比较与NLO QCD预测的基础上衍射部分子密度先前获得的QCD分析包容衍射DIS截面的H1。在DIS中，dijet数据被很好地描述，支持QCD因式分解的有效性。在高分数部分子动量的衍射DIS dijet数据是更敏感的衍射胶子密度比包容性衍射DIS的测量。在photoproduction，预测dijet截面必须乘以一个因子约0.5的直接和解决光子相互作用来描述的测量。光生过程中测量的dijet截面与NLO预测的比值比DIS中的相同比值小0.5 ± 0.1倍。这种抑制是HERA首次清楚地观察到QCD硬散射因子化破缺。测量值也比较了两个软颜色的中和模型SCI和GAL。SCI模型描述了DIS中的衍射双射流生产，但没有描述光生产。GAL模型在两个运动学区域都失败。
Evaluating the ratio of the exclusive vector meson photoproduction to inclusive hadron/jet production cross section in ultraperipheral heavy ion collisions
Universidade Federal de Santa Catarina（圣卡塔琳娜联邦大学）；Federal University of Rio Grande do Sul (UFRGS)（南里奥格兰德联邦大学）
