(1)奇特的θ+“五夸克态” Strange pentaquark Abstract 0t predicted by We predict an exotic Zt baryon(having spin 1/2, isospin 0 and strangeness +1)with a D Diakonov et al. relatively low mass of about 1530 Mev and total width of less than 15 mel It seems that Z. Phys. A359(1997)305 this region of masses has avoided thorough searches in the past nk Z+(1530 uudds N(1710 undid ∑(1890) usad t useS 3 三3/2(2070) ∑-K ∑+K ddss ussd
（1）奇特的q + “五夸克态” Strange pentaquark q + predicted by D.Diakonov et al., Z.Phys.A359 (1997)305 uuddd uudss 3 2 3 1 + uusdd uusss 3 1 3 2 +
First evidence from LEPS A=1.54+0.01M Yn→>KKn T<25 Mev Gaussian significance 4.6o 15 NoA(1520) peak in events without a proton. s9oeo山 10 5 T Nakano et al., Phys. Rev. Lett.91(2003)012002 45151551.6165171.7518 MM.(GeVic2y
First evidence from LEPS g n→K+K-n No (1520) peak in events without a proton. M = 1.540.01 MeV G < 25 MeV Gaussian significance 4.6s T. Nakano et al., Phys.Rev.Lett. 91 (2003) 012002 q +
Evidence for Penta-Quark States DIANA JLab.d ELSA COSY. TOF 00+2e ITEP SVD//HEP hw JLab.p This is a lot of evidence HERMES sar'uy的 Nomad CERNAA49 ZEUS Ht p的 小科
8: PDG2004 established particle Boom of theoretical papers 140 120 eoretical papers Jan2003→Feb2004 100 80 E60 40 20 6令岂9薏♀§§ about 2.5 resubmissions/paper
q + : PDG2004 established particle
Experiements on the 6 similar number of positive and negative results have been reported But most of the recent ones are negative And there are many unpublished negative results from the high energy experiments Positive result Negative result Group Reaction Ma Group Reaction (Mev) LEPS 7C→K+K-X1540±10BES DIANA K+Xe→K"pX1539±2|BaB 6-→T(4S)→pN"X CLAS d-K+Kp(n)1542±5 Belle ete--BB0一p"X SAPHIR d→I+"(m)1540±6 LEP z→pX ITEP UA→K°pX HERA-B A→XpX 1533±5 SPHINX CLAS pC→H"6+X Cu→KpX HERMES Pp→丌+K+K-(n)155±10 perCP etd→FpX 1526±3cDF KpX ZEUS p-e+KpX152±3 FOCUS 7BeO→KpX COSY-TOF PP-Kyp∑+ 1530±5Bell 丌+Si→KpX SVD PA→KpX|1526±5 PHENIX Au+Au→K-nX K Hicks, hep-ex/0504027