x(1860 has large BR to ppar We bes)measured: BR(J/→(860)BR(X(1860)→>P)~7×103 From Crystal Ball result, we etimate BR(J/→Y(1860)<2×10 So we would have BR(X(1860)→PD)>4 ( This would be the largest BR to ppbar among all known mesons Considering that decaying into ppbar is only from the tail of X(1860) and the phase space is very small, such a BR indicates X(1860 has large coupling to ppar
X(1860) has large BR to ppbar § We (BES) measured: § From Crystal Ball result, we etimate: § So we would have: (This would be the largest BR to ppbar among all known mesons) 5 ( / (1860)) ( (1860) ) ~ 7 10 BR J X BR X pp 3 ( / (1860)) 2 10 BR J X BR(X (1860) pp) 4% Considering that decaying into ppbar is only from the tail of X(1860) and the phase space is very small, such a BR indicates X(1860) has large coupling to ppbar !
Summary of the properties of the strong ppbar mass threshold enhancement X(1860) So far, it is only observed in Jhy radiative decays: It has production properties similar to n' meson It could have strong coupling to gluons as n'meson. It could have the largest decay bR to ppar among all PDG particles It has strong coupling to ppar
Summary of the properties of the strong ppbar mass threshold enhancement X(1860) § So far, it is only observed in J/ radiative decays: • It has production properties similar to ’ meson. • It could have strong coupling to gluons as ’ meson. § It could have the largest decay BR to ppbar among all PDG particles: • It has strong coupling to ppbar
New Observation of X(1835)in J1y→yx:rmn PRL95,262001(2005)
New Observation of X(1835) in J PRL 95, 262001 (2005)
Observation of X(1835)in 7y→yx+xn Statistical significance 7.7 o J/y→y+xn 140 E120 O寸0-z山> 141.61.822.22.42.62.83 m(tr n)(GeV/c) The ITn' mass spectrum for n' decaying into n→ππ m and n→γp
Observation of X(1835) in The +- mass spectrum for decaying into +- and Statistical Significance 7.7 J J
Mass spectrum fitting 120 The Ttnn’ mass spectrum y077 forn’ decaying into > n-ππ m and n→yp Q0-zu>山 60 N,=264±54 obs m=1833.7±6.1±2.7Me BESII Preliminary F=67.7±20.3±77Mep 13 1.5 1.9 23 25 m(t'in)(EvIC B(Jy→Y)B(X→xm)=(22±04±04)×10
Mass spectrum fitting Nobs 264 54 m 1833.7 6.1 2.7MeV G 67.7 20.3 7.7MeV 4 ( ) ( ) (2.2 0.4 0.4) 10 B J X B X 7.7 The +- mass spectrum for decaying into +- and BESII Preliminary