Polarisation of the omega meson in the pd-->3He+omega reaction at 1360 and 1450 MeV
K. Schonning, Chr. Bargholtz, M. Bashkanov, M. Berlowski, D. Bogoslawsky, H. Calen, H. Clement, L. Demirors, C. Ekstrom, K. Fransson, L. Geren, L. Gustafsson, B… 展开作者
K. Schonning, Chr. Bargholtz, M. Bashkanov, M. Berlowski, D. Bogoslawsky, H. Calen, H. Clement, L. Demirors, C. Ekstrom, K. Fransson, L. Geren, L. Gustafsson, B. Hoistad, G. Ivanov, M. Jacewicz, E. Jiganov, T. Johansson, S. Keleta, O. Khakimova, I. Koch, F. Kren, S. Kullander, A. Kupsc, A. Kuzmin, K. Lindberg, P. Marciniewski, B. Morosov, W. Oelert, C. Pauly, H. Pettersson, Y. Petukhov, A. Povtorejko, R. J. M. Y. Ruber, W. Scobel, R. Shafigullin, B. Shwartz, T. Skorodko, V. Sopov, J. Stepaniak, P. -E. Tegner, P. Thorngren Engblom, V. Tikhomirov, A. Turowiecki, G. J. Wagner, C. Wilkin, M. Wolke, J. Zabierowski, I. Zartova, J. Zlomanczuk
The tensor polarisation of omega mesons produced in the pd-->3He+omega reaction has been studied at two energies near threshold. The 3He nuclei were detected in coincidence with the pi0pi+pi- or pi0gamma decay products of the omega. In contrast to the case of phi meson production, the omega mesons are found to be unpolarised. This brings into question the applicability of the Okubo-Zweig-Iizuka rule when comparing the production of vector mesons in low energy hadronic reactions.
Differential cross sections and spin density matrix elements for the reaction gamma p -> p omega
高统计微分截面和自旋密度矩阵元素的反应γ p -> p Ω已被测量使用CLAS在杰斐逊实验室的质心(CM)的能量从阈值到2.84 GeV。结果报告在112 10兆电子伏宽CM能量箱,每个细分为cos(θ CM)箱的宽度为0.1。这些是迄今为止最精确和最广泛的欧米茄光合作用测量。一些突出的结构在数据中清晰可见。由于早期测量的统计数据有限,其中许多以前没有观察到。
Near-threshold production of omega mesons in the pn -> d omega reaction
用氘团簇-喷流靶首次测量了Q = 28和57 MeV的pn-> d Ω总截面。快氘的动量是在COSY-Juelich的ANKE光谱仪中测量的,而慢“旁观者”质子p(sp)的动量是在靠近目标的硅望远镜中测量的,该质子来自p d -> p(sp)d Ω反应。截面高于p p -> p p Ω的测量值,但似乎低于理论预测值。
We report a measurement of the spin polarisation of the recoiling neutron in deuterium photodisintegration, utilising a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300~--~700~MeV provides the first measurement of recoil neutron polarisation at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarisation in a narrow structure centred around $E_γ\sim$~570~MeV is observed, which is inconsistent with current theoreti…