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Prospect of Particle Physics in China

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Prospect of Particle Physics in China Outline Prospect of Particle Physics in China • Introduction • BEPC and its results • BEPCII • Non-Accelerator Physics Experiments Hesheng Chen • Medium and long term plan of particle physics in China. Institute of High Energy Physics Beijing 100049, China 2 1 Particle Physics in China Prof. Sanqiang Qian, • Chinese Nuclear physics and Particle physics researches the founder of Chinese have long tradition: – Zhongyao Zhao : discovery of Positron Nuclear Physics and – Ganchang Wang: neutrino search Particle Physics, was a – Sanqiang Qian and Zehui He: students of Curie student of Mr and – …… • Institute of Modern Physics established 1950. Madam Curie . He was • JINR Dubna: the director of the Inst. – Jointed 1956 of Modern Physics – Discovery of anti-Σ by the group led by Ganchang since March 1951. Wang – Withdraw 1965 • Chinese Government deided to use the money to build the Prof. Sanqiang Qian Chinese HEP center 4 2 Particle Physics in China Institute of High Energy Physics • Independent Institute for High Energy Physics: Feb. 1973 • OfOpen door after cultural revolut ion: sent phys iiicists to Comprehensive and largest fundamental research Mark-J @ DESY 1978 center in China • HE physicists worked at DESY,CERN and US Major research fields : • China –US HEP agreement – Particle physics: Charm physics @ BEPC, LHC exp., • Beijing Electron Positron Collider (BEPC): milestone . ν constructed 1984-1988 cosmic ray, particle astrophysics, physics … • Provide big scientific platforms: – Accelerator technology and applications – Synchrotron Radiation Light Sources: – Synchrotron radiation technologies and applications • Beijing synchrotron radiation facility (2.5GeV) 1030 emppyloyees, ~ 670 p pyhysicists and eng ineers, • Hefei national synchrotron radiation light source (800MeV) 400 PhD Students and postdoctors • Shanghai Light source(3.5GeV, underconstruction) – Chinese Spallation Neutron Source 3 Particle physics experiment group Particle Physics Experiments in China • Univ. of Science and Technology of China, Hefei • BEPC & BEPCII: BESII/BESIII • Peking Univ. • Non-accelerator experiments • Tsinghua Univ. – Yangbajing cosmic-ray observatory (Tibet) • Shandong Univ. • China-Japan Air Shower Array • HuuogNoUv.azhong Normal Univ. • China-Italy Argo RPC carpet project • Chinese Inst. of Atomic Energy – L3cosmic (finished) • Nanjing Univ. – AMS • …… – Gamma Ray Burst Detector (flown 2001) – ChangEr Moon project: X ray spectrometer Dozens of PP and NP theory groups in institutes and – Hard X-ray modulated telescope universities. – Daya Bay reactor neutrino experiment 4 Particle Physics Experiments in China Bird’s Eye View of BEPC • International collaborations: – MkMark-J (IHEP, USTC. fin is he d) – LEP: L3, ALEPH (IHEP, USTC. finished) – Tristan: Amy (finished) – Tevatron: D0 (USTC, IHEP) – LHC：ATLAS, CMS, LHCb, Alice – AMS (IHEP, IEE, Southeast Univ…) – KEKB: BELLE (IHEP,Peking, USTC) – Kamland (IHEP), SuperK(Tsinghua). – RHIC: Star, Phenoix – ILC R&D – … 5 BEPC constructed in 1984 –1988 with beam energy: 1 – 2.8 GeV ψ J/ψ – Physics Run：Luminosity 1031cm-2s-1 @ 1.89GeV, 5 month/year J/ decays: Light hadron spectroscopy ： – Synchrotron Radiation Run 140mA @ 2.2 GeV, 3 month/year search for new particles J/ψ Physics Running finished March 2004 ψ × 6 World J/ Samples ( 10 ) • Gluon rich J/ψ Synchrotron Radiation Running finished June 2005 BESII • Very high production 58M J/ψ cross section 60 • Higher BR to hadrons than that of 50 J/ψ ψ 40 ’ (“12% rule”). 30 • Larger phase space to 1-3 GeV 20 hadrons than that of Y 10 0 • Clean background environment CBAL MKII MKIII DM2 BESI BESII compared with hadron collision experiments, e.g., “JP, I” filter 6 Main Physics Results from BES Impact of BES’s New R Values on the 2 SM Fit for α (Mz ) and Higgs mass • Precision measurement of τ mass: world average value changed by 3σ, accuracy improved by factor of 10, and approved τ lepton universality. 1995 before BES R data • R Measurement at 2-5GeV: ΔR/R 15-20% →6.6% α 2 −1 = ± (M Z ) 128.890 0.090 – Higgs mass prediction from SM 2001 with BES R data – g-2it2 experiment 2 −1 α 2 -1 α(M ) =128.936 ± 0.046 – (Mz ) : 128.890±0.090 → 128.936 ± 0.046 Z • Systematic study of ψ(2S) and J/ψ decays. • Resonance X(1835) inJ /ψ → γη'π +π − with mass and width are consistent with that of the S-wave resonance X(1860) g – 2 experiment indicated by the pp mass threshold enhancement. • > 400 results from BES quoted by PDG 2006. 7 Observation of an anomalous enhancement near the ψ γ threshold of p p mass spectrum Fit to J/ Æ pp including FSI ψ γ M = 1830.6 ± 6.7 MeV Include FSI curve from acceptance BES II J/ Æ pp A.Sirbirtsev et al.(hep-ph/ weighted BW Γ = 0 ± 93 MeV 0411386) in the fit (I=0) X(1860) M=1859 +3 +5MeV/c2 −10 −25 2 Γ < 30 MeV/c (90% CL) BES II Preliminary χ2/dof=56/56 0 0.1 0.2 0.3 3-body phase space M(pp)-2mp (GeV) Phys. Rev. Lett. 91, 022001 (2003) acceptance 8 X(1860) has large BR to pp pp bound state (baryonium)? BES measured: There is lots & lots of literature about this possibility −5 BR(J /ψ → γX (1860)) • BR(X (1860) → pp) ~ 7 ×10 E. Fermi, C.N. Yang, Phys. Rev. 76, 1739 (1949) deuteron: … baryonium: For a 0-+ meson: I.S. Sharpiro, Phys. Rept. 35, 129 (1978) C.B. Dover, M. Goldhaber, PRD 15, 1997 (1977) −3 attractive nuclear force attractive force? BR (J /ψ → γX (1860 )) ~ 0.5 − 2 ×10 … A. Datta, P.J. O’Donnell, PLB 567, 273 (2003)] So we would have: + n M.L. Yan et al., hep-ph/0405087+ − B. Loiseau et al., hep-ph/0411218 BR ( X (1860 ) → pp) ~ 4 −14% … loosely bound 3- loosely bound (This BR to pp might be the largest among all PDG particles) q Ob3-qserva color ti ons o f this st 3-qruc t 3-qure colori n Considering that decaying into pp is only from singletsother with decay Md modes are singletsdesirable. with the tail of X(1860) and the phase space is very small, ε δ = 2mp- Mb = 2mp- ? such a BR indicates X(1860) has large coupling to pp ! 9 + − BES: X(1835) in J /ψ → γη'π π X(1835) could be the same structure as pp mass threshold enhancement. Statistical Significance 7. 7 σ 7.7σ It is like ly to be a pp boun d s ta te s ince X(1835) it dominantly decays to pp when its mass is above pp mass threshold. η’ππ mmpode is expected to be the m ost favorable decay mode for a pp bound state below pp mass threshold. N = 264 ± 54 obs Its spin-parity should be 0-+ Î BESIII M = 1833.7 ± 6.1± 2.7 MeV/c 2 may measure it w ith a fac tor o f 100 Γ = ± ± 2 67.7 20.3 7.7 MeV/c more statistics B(J ψ → γX )B( X → π +π −η′) = (2.2 ± 0.4 ± 0.4) ×10−4 PRL 95 (2005) 262001 10 Observation of non-DDbar decays of ψ(3770) BEPCII • ψ(3770) is believed to be a mixture of 1D and 2S states of cc-bar 2. BEPCII: High Lumi. Double–ring Collider systemIt is thought to decay almost entirely to pure DD-bar • From a measurement of DD-bar cross section and R value, BESII found for the first time a significant fraction of non-DD-bar Br. Hep-ex/0605105 • BESII also found for the first an exclusive channel of non-DDbar decays, which was confirmed later by CLEO-c: PLB 605 (2005) 63 Build new ring inside existing ring . Two half new rings and two half old rings cross at two IR’s, forming a double ring collider. 22 11 BEPC II Double ring Design e+--ee- Colliders: Past, Present and Future 1037 • In the existing BEPC tunnel, add another ring, cross over L (cm-2 s-1) L (cm-2 sec-1) SUPER atthdthittt south and north points, two equa lifltl rings for electrons 1036 FACTORIES and positrons. double-ring collision technology. KEK B and PEP II 1035 • 93 bunches，total current > 0.9A in each ring. GLC 1034 KEK B • Collision spacing：8 ns. DAFNE2 PEP II BEPCIII 1033 CESR FACTORIES • Collision with large horizontal cross-angle（±11 mr）. CESRc DAFNE LEP 33 -2 -1 1032 • Luminosity： 10 cm s @ 3.78GeV of C.M. energy. TRISTAN VEPP2000 PETRA DORIS + 31 VEPP4M • Linac upgrade: e 50mA/min. , Full energy injection up 10 BEPC SPEAR to 1.89GeV VEPP2M COLLIDERS 1030 ADONE • SR run performance upgrade：250mA @ 2.5 GeV. Hard E (GeV) 1029 cm E (GeV) X-ray flux ti be increased by one order of magnitude. 1 10 100 1000 + - • Major detector upgrade：BES III. 23 C. Biscari, Workshop on e e in 1-2 GeV Range, September 10-13, 2003, Italy24 12 Physics at BEPCII/BESIII Light hadron spectroscopy • Precision measurement of CKM matrix elements • Precision test of Standard Model • Baryon spectroscopy 1010 J/ψ events + LQCD are • QCD an d ha dron pro duct ion • Charmonium spectroscopy probably enough to pin down • Light hadron spectroscopy most of questions in of light • Glueball searches • Charmonium physics hadron spectroscopy • Search for new physics/new particles • Search for non-qqbar states Physics Energy Luminosity Events/year Channel (GeV) (1033 cm–2s –1) J/ψ 3.097 0.6 1.0×1010 τ 3.67 1.0 1.2×107 ψ’ 3.686 1.0 3.0 ×109 D* 3.77 1.0 2.5×107 Ds 4.03 0.6 1.0×106 Ds 4.14 0.6 2.0×106 25 26 Spectrum of glueballs from LQCD 13 Precision measurement of CKM Precision test of SM and Search for new Physics ---- Branching rations of charm mesons • DDbar mixing – DDbar mixing in SM ~ 10 –3 - 10 –10 • Vcd /Vcs: Leptonic and semi-leptonic decays – DDbar m ix ing sens it ive to “new phihysics” • Vcb: Hadronic decays – Our sensitivity : ~ 10-4 • Vtd /Vts: fD and fDs from Leptonic decays • Lepton universality • Vub: Form factors of semi-leptonic decays • Unitarity Test of CKM matrix • CP violation • Rare decays : FCNC, Lepton no.
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