Precision measurement of t mass(1992) 1776918=0MeV Y 10 2s4 World average value 2 003 changed by 3o 0.176 01B3 I. Accuracy improved by a factor of 10 051 t lepton universality together with measurements of lifetime leptonic decay branch 17 ratios LKHD- MT-EFT
11 Precision measurement of mass (1992) 1776.9 – 0.19 – 0.16 MeV +0.18+0.20 • World average value changed by 3 • Accuracy improved by a factor of 10 • lepton universality together with measurements of lifetime & leptonic decay Branch ratios
BESI New results R Measurement at 2-5Gev(91 points 1 441 BESI 199(PrellmInary) BESII 1998, PAL 84(2000)594 c&10> mm扫之 □Mark Iuto A 时中 △R/R(%) Before bes 15-20 BES 6.6 12
12 R/R(%) Before BES 15-20 BES 6.6 BESII New Results R Measurement at 2-5GeV (91 points)
Impact of BES's New r Values on the SM Fit for a(M2) and Higgs mass 2.5 1995 before bes r data:: PREL. Suner 200 a(M2)=128890±0.0905 standard 7.5 2001 with besr data 5 5 a(MZ)=128936±0046 2.5 2.5 2 experiment 170210 10 500 [Gev] 6890
13 Impact of BES’s New R Values on the SM Fit for α (Mz 2 ) and Higgs mass ( ) 128.890 0.090 2 1 = − MZ ( ) 128.936 0.046 2 1 = − MZ 1995 before BES R data 2001 with BES R data g-2 experiment
Threshold enhancement of J/y-y pbar, BW fit -narrow resonance below 2m location J/y→yp acceptance weighted bw M=1859 Mev/c2 10-25 T<30 Mev/cl(90% cl) 100 r J/v→>Ypp x2/dof=56/56 0.1 0.2 0.3 3-body pr hase space M(pp)-2m,(GeV a acceptance m
14 Final fit M=1859 MeV/c2 < 30 MeV/c2 (90% CL) J/→pp M(pp)-2mp (GeV) 0 0.1 0.2 0.3 3-body phase space acceptance 2 /dof=56/56 fitted peak location acceptance weighted BW +3 +5 −10 −25 Threshold enhancement of J/Ψ→γ p pbar, BW fit →narrow resonance below 2mp J/ → pp
Other Majorresearch fields in HEP 1. Particle physics experiment A Particle-Astrophysics experiments L3 Cosmic: ray measurement E. Yangbajing Argo RPC carpet project Hard X ray modulated telescope M. Alpha Magnetic Spectrometer y ray burst detector. s ntl collaboration of HEPexperiments CMS and Atlast LHC Belle and babar Kamland he Kloe 15
15 Other Major research fields in IHEP 1. Particle physics experiment – Particle-Astrophysics experiments • L3 Cosmic ray measurement • Yangbajing - Argo RPC carpet project • Hard X ray modulated telescope • Alpha Magnetic Spectrometer • ray burst detector. – Intl. collaboration of HEP experiments • CMS and Atlas at LHC • Belle and Babar • Kamland • Kloe