对于0.75 GeV < E(γ) < 3 GeV，质子上η介子的光生过程。

Photoproduction of eta mesons off protons for 0.75 GeV<E(gamma)<3 GeV.

作者信息

Credé V, Bartholomy O, Anisovich A V, Anton G, Bantes R, Beloglazov Yu, Bogendörfer R, Castelijns R, Ehmanns A, Ernst J, Fabry I, Flemming H, Fösel A, Freiesleben H, Fuchs M, Funke Ch, Gothe R, Gridnev A, Gutz E, Höffgen S K, Horn I, Hössl J, Joosten R, Junkersfeld J, Kalinowsky H, Klein F, Klempt E, Koch H, Konrad M, Kopf B, Krusche B, Langheinrich J, Löhner H, Lopatin I, Lotz J, Matthäy H, Menze D, Messchendorp J, Morales C, Novinski D, Ostrick M, van Pee H, Radkov A, Reinnarth J, Sarantsev A V, Schadmand S, Schmidt Ch, Schmieden H, Schoch B, Suft G, Sumachev V, Szczepanek T, Thoma U, Walther D, Weinheimer Ch

机构信息

Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Nussallee 14-16, D-53115 Bonn, Germany.

出版信息

Phys Rev Lett. 2005 Jan 14;94(1):012004. doi: 10.1103/PhysRevLett.94.012004.

DOI:10.1103/PhysRevLett.94.012004

PMID:15698071

Abstract

Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.

摘要

已测量了反应p(γ,η)p在750 MeV至3 GeV能量范围内的总截面和微分截面。低能数据主要由S11波主导，该波在2 GeV以下的能量区域有两个极点。在它们衰变为pη的过程中观察到11个核子共振。在中等能量下，我们发现了一个新的共振态N(2070)D15，其质量和宽度分别为(M,Γ)=(2068±22, 295±40) MeV。在γ能量高于1.5 GeV时，向前方向出现一个强烈的峰，这表明在t通道中矢量介子的交换。