Re-fit to J/y >yp pbar including FSI MINUIT Likelihood fit to plot 1o02 1 4PN EVE DATA. MPPB-1.876544 a 19-APR一2 Fe38/器8 ED M.1S Include fsi curve from Likelihood= 60. 4 60.4for60-4d C.L.=31.9% A. Sirbirtsev et al rrors Minos ( Phys. Rev. D71:054010,2005) 88 in the fit(=O) 士68.41 士6.6624E-03 348707E-05士92650E-02-0.000 150 M=1830.6±67Mev r<153Me@90%C.L. 5 t=1 In good agreement with X(1835) M-2m
Re-fit to J/p pbar including FSI Include FSI curve from A.Sirbirtsev et al. ( Phys.Rev.D71:054010, 2005 ) in the fit (I=0) M = 1830.6 6.7 MeV G < 153 MeV @90%C.L. M pp 2mp In good agreement with X(1835)
A Possible ppar Bound State x(1835 could be the same structure as ppar mass threshold enhancement It could be a ppar bound state since it dominantly decays to ppar when its mass is above ppar mass threshold Its spin-parity should be 0-t: this would be an important test. Other interpretations are not excluded. Currently all theoretical interpretations have some difficulties PDG2006 takes it as a possible ppar bound state. t Next talk for more detail discussions
A Possible ppbar Bound State § X(1835) could be the same structure as ppbar mass threshold enhancement. § It could be a ppbar bound state since it dominantly decays to ppbar when its mass is above ppbar mass threshold. § Its spin-parity should be 0-+: this would be an important test. * Other interpretations are not excluded. Currently all theoretical interpretations have some difficulties. PDG2006 takes it as a possible ppbar bound state. Next talk for more detail discussions
Observation of pA mass threshold enhancement in Jy→>pKA
Observation of mass threshold enhancement in p J / pK
Observation of an anomalous enhancement near the threshold of pA mass spectrum at BES lI 200}BES‖ J/v→pKA W州 100 3-body phase space 25 .533.544.5 a(Gev) P ka (Gev) Phys.Rev.Le93,12002(2004) For a s-wave bw fit:M=2075±12±5MeV 厂=90±35±9MeV
Observation of an anomalous enhancement near the threshold of p mass spectrum at BES II BES II J / pK 3-body phase space For a S-wave BW fit: M = 2075 12 5 MeV Γ = 90 35 9 MeV Phys. Rev. Lett. 93, 112002 (2004)
KA mass threshold enhancement
K mass threshold enhancement