Photoproduction of meson pairs: First measurement of the polarization observable I^s
E. Gutz, V. Sokhoyan, H. van Pee, A. V. Anisovich, J. C. S. Bacelar, B. Bantes, O. Bartholomy, D. Bayadilov, R. Beck, Yu. Beloglazov, R. Castelijns, V. Crede, H… 展开作者
E. Gutz, V. Sokhoyan, H. van Pee, A. V. Anisovich, J. C. S. Bacelar, B. Bantes, O. Bartholomy, D. Bayadilov, R. Beck, Yu. Beloglazov, R. Castelijns, V. Crede, H. Dutz, D. Elsner, R. Ewald, F. Frommberger, M. Fuchs, Ch. Funke, R. Gregor, A. Gridnev, W. Hillert, Ph. Hoffmeister, I. Horn, I. Jaegle, J. Junkersfeld, H. Kalinowsky, S. Kammer, V. Kleber, Frank Klein, Friedrich Klein, E. Klempt, M. Kotulla, B. Krusche, M. Lang, H. Loehner, I. Lopatin, S. Lugert, D. Menze, T. Mertens, J. G. Messchendorp, V. Metag, M. Nanova, V. Nikonov, D. Novinski, R. Novotny, M. Ostrick, L. Pant, M. Pfeiffer, D. Piontek, W. Roberts, A. Roy, A. Sarantsev, S. Schadmand, Ch. Schmidt, H. Schmieden, B. Schoch, S. Shende, A. Suele, V. Sumachev, T. Szczepanek, A. Thiel, U. Thoma, D. Trnka, R. Varma, D. Walther, Ch. Weinheimer, Ch. Wendel
备注：
11 pages, 6 figures, v2 to appear in Phys. Lett. B
首次测量了线偏振光子产生的多介子末态共面运动学所特有的偏振可观测I^s。对于入射光子能量在970 MeV和1650 MeV之间以及光束不对称性I^c，给出了反应g p -> p π 0 eta的结果。这种极大的不对称性表明了I^s对反应动力学的高度敏感性。使用Bonn-Gatchina分波分析的拟合表明，新的偏振观测值携带有贡献的分波的重要信息。
英文摘要：
The polarization observable I^s, a feature exclusive to the acoplanar kinematics of multi-meson final states produced via linearly polarized photons, has been measured for the first time. Results for the reaction g p -> p pi0 eta are presented for incoming photon energies between 970 MeV and 1650 MeV along with the beam asymmetry I^c. The comparably large asymmetries demonstrate a high sensitivity of I^s to the dynamics of the reaction. Fits using Bonn-Gatchina partial wave analysis demonstrate that the new polarization observables carry significant information on the contributing partial waves.
Nuclear effects in photoproduction of heavy quarks and vector mesons in ultraperipheral PbPb and pPb collisions at the LHC
通过比较$c\bar{c}$和b-b（bar）在PbPb和pPb碰撞中的光生截面，可以得到对核遮蔽效应的敏感性.光生矢量介子对底层胶子的分布更为敏感。本文研究了在sqrt（s_NN）=5 TeV和sqrt（s_NN）=2.76 $ TeV, respectively. The potentials of using these processes for constraining nuclear gluon shadowing are explored. It is found that photoproduction of $ J/J条件下，在大型强子对撞机上进行的超周边pPb和PbPb碰撞中，重夸克光生和矢量介子光生的截面及其与快度的关系。特别是PbPb碰撞中的$ and $对胶子遮蔽表现出很好的敏感性。
Inclusive heavy meson photoproduction in $pPb$ and $PbPb$ collisions
Federal University of Pelotas（佩洛塔斯联邦大学）；The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences (PAN)（波兰科学院亨利克·涅沃德尼茨基核物理研究所）
Incoherent $ρ$ meson photoproduction in ultraperipheral nuclear collisions at the LHC
利用Gribov-Glauber模型的光子-核散射和广义矢量介子模型的光子强子结构，对大型强子对撞机中Pb-Pb超周边碰撞（UPC）中的非相干光生$ρ$截面进行了预测.我们发现，非弹性核阴影的影响是显着的，并导致额外的25%的抑制的非相干截面。将我们的预测与STARlight Monte Carlo框架的预测进行比较，我们观察到非常显著的差异。
