中国科学院高能物理研究所：New Results from BES（BESII 物理结果，PPT讲稿）

BESII最新物理结果 金山 (for BES Collaboration) 中国科学院高能物理研究所 jins @mail.ihep.ac.cn 高能物理学会第七届学术年会 桂林,2006年10月28日

BESII 最新物理结果 金 山 (for BES Collaboration) 中国科学院高能物理研究所 jins@mail.ihep.ac.cn 高能物理学会第七届学术年会 桂林, 2006年10月28日

Preliminary Remarks 自从上届重庆会议至今,一年多来,BES在国际期 刊上共发表论文30余篇,其中Phys. Rev, Lett文 章6篇。 由于时间限制,仅报告其中部分重要进展(更多更 详细内容将在实验分会报告)。 将主要报告实验结果(只简单提及目前的一些理论 解释),有关详细理论讨论请见下一个报告

Preliminary Remarks § 自从上届重庆会议至今，一年多来，BES在国际期 刊上共发表论文 30 余篇，其中Phys. Rev. Lett. 文 章 6 篇 。 § 由于时间限制，仅报告其中部分重要进展 （更多更 详细内容将在实验分会报告）。 § 将主要报告实验结果（只简单提及目前的一些理论 解释）， 有关详细理论讨论请见下一个报告

报告主要内容 北京谱仪实验发现一系列新粒子或新共振结构 psi衰变的12%规则检验 ps(3770)非 DEbar衰变模式的寻找研究 J/psi稀有衰变模式的寻找

报告主要内容 § 北京谱仪实验发现一系列新粒子或新共振结构 § psi’ 衰变的12％ 规则检验 § psi(3770)非DDbar衰变模式的寻找研究 § J/psi 稀有衰变模式的寻找

New observations at besi A possible pp bound state: ppmass threshold enhancement in J/vpp and new observation of X(1835) pA mass threshold enhancement in Jly>pKA KA mass threshold enhancement in J/y> pKA ooo mass threshold enhancement in J/y→γo New observation of a broad 1-- resonance in J/y→K+K-0

New Observations at BESII § A possible bound state: mass threshold enhancement in and new observation of X(1835). § mass threshold enhancement in § mass threshold enhancement in §  mass threshold enhancement in J/   § New observation of a broad 1- - resonance in J/  K+K- 0 p p J / p p     J / pK  K p    J / pK p p

A possible ppbar bound state

A possible ppbar bound state

Observation of an anomalous enhancement near the threshold of pp mass spectrum at BES lI BEsJ∧+pp acceptance weighted BW M=1859+3+5MeV/c2 10-25 T<30 Mev/c2(90% cl 100 却地 x/dof=5656 0.1 0.2 0.3 Phys. Rev. Lett. 91,022001(2003) Mpp)-2mp(GeV) 3-body phase space acceptance

Observation of an anomalous enhancement near the threshold of mass spectrum at BES II M=1859 MeV/c 2 G < 30 MeV/c 2 (90% CL) J/pp M(pp)-2mp (GeV) 0 0.1 0.2 0.3 3-body phase space acceptance c2 /dof=56/56 acceptance weighted BW +3 +5 10 25 pp BES II Phys. Rev. Lett. 91, 022001 (2003)

Features of the enhancement near the threshold of pp mass spectrum at BES II BEs‖J∧+γpp Peak position: 0 Mev above threshold 150 “ Width 100 60M eV 8p Strong(“ Height") (s+B)B~2 The above features may 00.10.20.3 help us easily to judge whether it is observed in Mpp)-2m,(GeV) other processes

Features of the enhancement near the threshold of mass spectrum at BES II J/pp M(pp)-2mp (GeV) 0 0.1 0.2 0.3 pp BES II § Peak position: ~ 0 MeV above threshold § “Width”: ~ 60M eV § Strong (“Height”): (S+B)/B ~ 2 The above features may help us easily to judge whether it is observed in other processes

This narrow threshold enhancement is NOT observed in qqyX) explained by pure FSl effect, since fsl is a universal effect <0.7%@90%CL FSI interpretation of the narrow and strong ppar threshold enhancement is 10 disfavored This indicates that X(1860) has a production property 192.12.32 27293.1 similar to n meson M(pp)(GeVIc- c.f. FIG.7:Inyariant mass of pp from T(1s) Br(Y(1S)→ym)Br(/y→ym) No enhancement near threshold <049@90%CL

§ This result cannot be explained by pure FSI effect, since FSI is a universal effect. FSI interpretation of the narrow and strong ppbar threshold enhancement is disfavored. § This indicates that X(1860) has a production property similar to ’ meson. c.f.: This narrow threshold enhancement is NOT observed in pp  ) S1( at CLEO No enhancement near threshold CL Br S Br J 0.7% @ 90% ( (1 ) X)/ ( / X)      CL Br S Br J 0.4% @ 90% ( (1 ) ')/ ( / ')       

This narrow threshold enhancement is NOT observed in qqo)/Br(Jly>y X) and indicates that X(1860) <0.5@95%Cl has a production 25829.58 eom2.534E- property similar to n' or 40-.. bcaie C.L.=1.9% Minos -0000+0.00 meson. 0.000 0 0000 +.000 0. 0.00 000 +0.000 0.000 +0.000 c.f.: 9.5157E-02-0 0000 0.000 + Br(Jy→n)/Br(Jy→yn) 60 ≈0.04 40 ≌ .This also indicates X(1860) may have strong 0 005 mpp-2mp(Gev/c).15 0.10 0.20 coupling to gluons as n' meson. No narrow strong enhancement near threshold

§ This again disfavors FSI and indicates that X(1860) has a production property similar to ’ meson. c.f.: § This also indicates X(1860) may have strong coupling to gluons as ’ meson. This narrow threshold enhancement is NOT observed in pp  / Jat BESII No narrow strong enhancement near threshold CL Br J Br J 0.5 @ 95% ( / X)/ ( / X)      0.04 ( / ')/ ( / ')  Br J   Br J   

Pure Fsi disfavored =0 S-wave FSI CANNOT fit the bes data 150 FSI curve from A. sirbirtsev et al.( Phys. Rev. D71: 054010 2005)in the fit(O) x2d.0.,f=192/58 100 9>0o8°9 FS|· PS* eff+bck 0.00 0.10 0.20 0.30 n P

Pure FSI disfavored I=0 S-wave FSI CANNOT fit the BES data. M pp mp  2 / . . 192 / 58 2 c d o f  FSI * PS * eff + bck FSI curve from A.Sirbirtsev et al. ( Phys.Rev.D71:054010, 2005 ) in the fit (I=0)