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Prospects of Probing Rare and Forbidden Processes at BES-III

Prospects of Probing Rare and Forbidden Processes at BES-III. Haibo Li Institute of High Energy Physics, Beijing . International Workshop on Heavy Quarkonium QWG4 – June 27-30 2006, BNL, USA. BESIII Detector. Two rings, 93 bunches: Luminosity 10 33 cm -2 s -1 @1.89GeV

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Prospects of Probing Rare and Forbidden Processes at BES-III

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  1. Prospects of Probing Rare and Forbidden Processes at BES-III Haibo Li Institute of High Energy Physics, Beijing. International Workshop on Heavy Quarkonium QWG4 – June 27-30 2006, BNL, USA Haibo Li

  2. BESIII Detector • Two rings, 93 bunches: • Luminosity • 1033 cm-2 s-1@1.89GeV • 6 1032 cm-2 s-1@1.55GeV • 6 1032 cm-2 s-1@ 2.1GeV Magnet: 1 T Super conducting MDC: small cell & He gas xy=130 m sp/p = 0.5% @1GeV dE/dx=6% TOF: T = 100 ps Barrel 110 ps Endcap Muon ID: 9 layer RPC Data Acquisition: Event rate = 3 kHz Thruput ~ 50 MB/s EMCAL: CsI crystal E/E = 2.5% @1 GeV z = 0.6 cm/E Trigger: Tracks & Showers Pipelined; Latency = 6.4 ms The detector is hermetic for neutral and charged particle with excellent resolution ,PID, and large coverage. Haibo Li

  3. Charm Productions at BEPCII Average Lum:L = 0.5×Peak Lum.; One year data taking time: T = 107s Nevent/year = exp L T Huge J/ and (2S) sample at BESIII; Largest D/DS sample near the threshold. Haibo Li

  4. Physics Topics at BESIII I will not talk the lists below, but they are the main motivation of BESIII! • Charmonium: J/, (2S), C(1S) in J/ decay, • C{0,1,2} , C(2S) and hC(1P1) in (2S) decay , (1D) and so on • Exotics : hybrids, glueballs and other exotics in J/ and (2S) radiative decays; • Baryons and excited baryons in J/ and (2S) hadronic decays; • Mesons and mixing of quark and gluon in J/ and (2S) decays; • Open charm factory : Absolute BR measurements of D and Ds decays, • Rare D decay, D0-D0bar mixing, CP violation, • f D+, fDs , form factors in semi-leptonic D decays, • precise measurement of CKM (Vcd, Vcs) • CP violation and strong phase in D Dalitz Decays, • light spectroscopy in D0 and D+ Dalitz Decays. • Electromagnetic form factors and QCD cross section; • New Charmonium states above open charm threshold---R values ...; • t physics near the threshold. Haibo Li

  5. Search for Rare Processes at BES-III No any evidence beyond SM is found in the lab based on the accelerators. No any indication beyond SM in Quarkonium happened. But I will present my own personal selection of highlights on very rare processes in Charm and Charmonium decays, from an experimentalist’s points of view. • Opportunity to probe rare and unusual processes which • are sensitive to new physics at BES-III? • Rare and forbidden Charmonium decays : • (1)Weak decays of y ; • (2) Invisible decays of quarkonium; • (3) Lepton Flavor/baryon number violated decays; • (4) CP violation in y decays; • New Physics probe in Charm meson decays: • (5) Rare decays of Charm meson • (6) D0-D0bar mixing • (7) CP violation in D meson decays • Lepton flavor Violated tau Decays Haibo Li

  6. Weak decay ofy s  c c dp0() d u S u c c c D0 c D0 l+ n l+ n c d s J/y D- DS c c c l+ l- g New Physics in loop! c u u D0 D0 c c c One estimated the total weak decay rate of J/y: M.A.Sanchis-Lozano FTUV:93-10 Haibo Li

  7. New Physics in flavor Changing Decays of J/ c  u quark transition: J/   D/Dbar +Xu : In the Standard Model, these processes are predicated to be unobservable. They are sensitive to New Physics: For example: In top color model: [C.T. Hill: Phys. Lett. B 345, 483 (1995)] BR(J/   D/Dbar +Xu)  10-5 – 10-6 (mp = 100 – 200 GeV) Also the following papers: A. Datta hep-ph/9903461 A. Datta, P. O'Donnell, S. Pakvasa, X. Zhang, Phys.Rev.D60:014011,1999 Haibo Li

  8. Access to Semileptonic Weak Decay of  Semileptonic decays: based on heavy quark spin symmetry: Z.Phys.C62:271-280,1994 M. Sanchis-Lozano One can easily get the Cabibbo-suppressed mode from the following relation: One got the following clean prediction based on HQET: G (  DS*+l ) R = ------------  1.5 G(  DS+l ) G (  D*+l ) R = ------------  1.5 G(  D+l ) Haibo Li

  9. Look for Search for Weak decay of J/y at BES-II 58 million J/y data at BES-II Accepted by PLB: hep-ex/0604005 Haibo Li

  10. Access to Weak J/ Decay at BESIII (1) hep-ph/9801202, K. Sharma • J/   DS (DS*) M (M = p, r, ,,’,K, K*,) < G (  DS*+p- ) R = ------------  3.5 G(  DS+p-) G (  DS*+r- ) R = ------------  1.4 G(  DS+r-) Sensitive to new physics if larger BRs measured. Haibo Li

  11. Access to Weak J/ Decay at BESIII (2) • The rate of weak decay of J/ is at • 10-8 level, and the inclusive search • at BESIII may be available: • J/  D*+S X • D*+S  DS+g (soft g ) • D+S p+ • K*0K+ • KSK+ The sensitivity at BESIII: 10-7 – 10-8 Haibo Li

  12. CPV Processes, VectorQuarkonium Decay to KSKS , KLKL Within Standard Model, the possible CPV processes 1-- KSKS, KLKL are due to K0K0 oscillation! KSKL KLKS KSKS KLKL K0 K0 t1 t0 t2 CPV processes Time evolution of the K0K0 system produced in vector QQ decay can tell us the possibilities to find KSKL, KLKS, KSKS and KLKL Haibo Li

  13. The Decay Widths of CPV Processes The Partial widths of the   KSKS, KLKL, KSKL are: where C is the phase space factor. The ratio RSS and RLL are defined as: In the ratios, the phase space factor C and the strong matrix element square are completely canceled, which insure that the ratios are completely free from uncertainty caused by strong interaction in the decay. Haibo Li

  14. Prediction for CPV Processes • The ratio of RSS (RLL) of KSKS (KLKL and KSKL production rates has • been constructed in a model-independent way: Haibo Li and Maozhi Yang Phys. Rev. Lett. 96 (2006) 192001 • Simultaneous measurements of vector quarkonium decays to both KSKS • and KSKL pairs are suggested at higher luminosity e+e- machines (BEPC-II, • DA NE-II, and Super-B). So many systematic errors can be canceled in the • ratio RSS measurements. Haibo Li

  15. The Predicted Results for CPV Quarkonium  KSKS Processes BESII: PRD, 69, 012003 (2004) BESII: PRL, 92, 052001 (2004) From PDG 2004 We gotthe following predicted branching factions for CPV processes : Haibo Li

  16. BESII 58M J/ , J/  KSKS Search for CPV Quarkonium  KSKS Processes at BES-II BESII: PLB 589 (2004) 7 BESII 14M (2S), (2S)  KSKS The main backgrounds are due to J/ gKSKS which will dilute the CP of KSKS final states. At BESIII, 1010 J/ sample can be produced per year ! The sensitivity will be 10-8 – 10-9 level for J/y KSKS Haibo Li

  17. CPV in J/y  Decays at BESIII The measurement of the electric dipole moment of the particles is very promising as a place to look for further source of CPV, X-H. He, J.P.Ma and B. Mckellar PRD 47, R1744 (1993); PRD 49 4548 (1994). The decay amplitude can be parameterized as: CP term Define the observables : <A> as large as 10-2 current limit of dipole moment: d < 1.510-16 e cm With 10 billion J/y sample d upper bounds  1.510-18 e cm p is the three momentum of ; q1 and q2 are the momentum of proton and antiproton from  and  decays in their rest frame. Haibo Li

  18. CPV in J/yg Decays J.P.Ma. R.G.Ping and B.S.Zou PLB, 580, (2004) 163 Assuming CP is introduced by the electric- and chromo-dipole moment of charm quark, the CP asymmetry can be predicted. Experimentally, the decay J/yg is easy to be reconstructed. The CP term in Lagrangian is defined : And one can get the density matrix of the decay: If CP not violated, we had: To test CP, one defined the observable at BES-III : K+ is the direction e+ beam and p1 and p2 are the direction of the two s, where |p1|>|p2| to distinguish two phi from each other. With 1010 J/y at BES-III, we expect: Haibo Li

  19. Lepton flavor violating processes in J/ decays Lepton flavor violating (LFV) processes are strongly suppressed in the Standard Model by power of (small) neutrino masses. Such decays signal new physics. PRD63, 016003, S. Nussinov, R.D. Peccei and X.M. Zhang BESII upper limit BR(J/  e) < 1.110-6 BR(J/  et) < 8.310-6 BR(J/  mt) < 2.010-6 with 58M J/  sample BESII PLB561, 49 (2003) PLB598, 172(2004) m momentum distribution J/y e, et, t, the sensitivity can be 10-8 – 10-9 at BES-III with 1010 J/y events per year J/ye- proton +c.c, J/ym- proton +c.c can also be searched for. Haibo Li

  20. Invisible Quarkonium Decays With in SM, the invisible quarkonium decays are predicted by: hep-ph/9806487, L.N Chang, O.Lebedlev and J. N. Ng With 2-3% uncertainty! One get: Theoretical clean process can be used to test model and probe new physics! Br(Y(1S) ) = 110-5 Br(J/  ) = 2.69 10-8 New physics may enhance the production rate of the invisible Charmonium decays. Haibo Li

  21. P. Jean et al Astron. Asronphys 407(2003) L55 MeV Dark Matter Candidates C. Boehm et. al PRL 2004 511keV line Excess of 511 keV gamma ray line (SPI spectrometer on INTEGRAL ) could be due to scalar dark matter annihilation. Many studies had been done: e+e- U g, U e+e-, at B factory and phi factory, hep-ph/0510147, N. Borodatchenkova et al e+e-  U g, U  invisible, at B factory and phi factory,hep-ph/0509024, J.F. Gunion, Vector quarkonium or scalar quarkonium invisible decays,hep-ph/0506151 Bob McElrath hep-ph/0510147 hep-ph/0509024 Haibo Li

  22. Invisible Quarkonium Decays H(QQ)   : looking for invisible decay in Y(nS) and (ns) n = 1, 2,3 ; hep-ph/0506151 Bob McElrath  C J/y Decay rates were estimated with model independent way by considering the constraint from observation of WMAP: A C   hep-ph/0509024, J.F. Gunion, D. Hooper, B. McElrath: prediction by considering Light Neutralino Dark Matter : J/y A  ynS  s A (00) V=J/y or  Haibo Li

  23. Charmonium Invisible Decays at BES-III (2S)  p+p- J/ (2S)   J/ (2S)  0 J/ (2S)  gC J/ or C nn at BESIII Two body decay will be easy since the missing momentum is mono-energitic (2S)  p+p- J/ ,  J/ and 0 J/ (J/ m+m- ) can be used as control sample to understand the event shape and background of J/y  nnbar. Missing momentum of  pmiss mgg Distributions in (2S)   J/ (J/ m+m-) Missing momentum of p0 Distributions in (2S)  p0 J/ (J/ m+m-) mgg pmiss Haibo Li

  24. Sensitivities of Charmonium Invisible Decays at BES-III 3109 y(2S) events per year at BES-III The sensitivity at BESIII will be 10-6-10-7 for J/y, C and C Invisible. Haibo Li

  25. Looking for /’ Invisible Decays in J//’ • Reconstructing K+K , • looking at missing momentum of  decays • Fast  (1.2 GeV) will help us define the decay • direction of invisible decay of / (958) . Missing direction Tag direction No any hit information are required outside of the core of  decays. Signal MC 58 M J/  missing momentum distribution Preliminary at BES-II. Being Submitted to PRL. Haibo Li

  26. Study of invisible decays of , , ’,  and  in J/ two body decays 10X109 J/y events per year at BES-III The sensitivity at BESIII will be 10-5-10-6 for , ’ Invisible Haibo Li

  27. e-m (m-t) Universality Test in y and DS Decays e-m universality in y decays, current experiments: At BESIII, 1010 J/y sample, the error will be 10-4 ,namely : (xx  0.001) H+ s R relative error: 1% at BES-III with 20 fb-1 at 4170 MeV Haibo Li

  28. Probe New Physics in CharmDecaysD-mixing is the last chance to see New Physics in meson oscillations!!! Haibo Li

  29. D-Dbar mixing SM for |x| SM to |y| New Physics to |x| x, y in range of 10-7-10-2 : signal for New Physics? : Standard Model? A.A. Petrov hep-ph/0311371 Haibo Li

  30. Quantum Correlations in D0D0 decays from the (3770) allow measurement of strong phases and mixing parameters from BESIII: Coherence simplifies study DCSD interfere away so not a background: Unmixed: mixing: Charm Mixing –Quantum Correlation at BES-III • BESIII PID system • dE/dx, resolution (6-7)% • Two layer barrel TOF, time resolution ~100ps, ~83% solid angle coverage • 1 layer endcap TOF, ~110ps • Selection efficiency is >20% with a K/π double mis-identification rate at < 10-4 level • Two missing neutrinos in events • Electron PID can suppress background • The selection efficiency is similar as the Kπ channel • Background level is also negligible while running a small MC data sample (~1% of 20fb-1). More detail study is needed. With 20fb-1(4-5 years running) at Ψ(3770) peak RM <10-4 Haibo Li

  31. Combined Sensitivity of Charm Mixing @BES-III The sensitivity of RM measurement a few 10-5 at BES-III with 20fb-1 data at y(3770). BESIII Fully using the Quantum correlation in y(3770)DDbar decays or data above 3770 MeV with final states DD* to extract mixing rate. Haibo Li

  32. Mixing parameters using Quantum Correlation From PRD 73 034024 (2006) by Asner and Sun Using single and double CP/flavor tags –complicated analyses Have to identify C=+1 ofgD0D0bar and gD0D0barπ0 from D*Dbar and D*D*bar decays Haibo Li

  33. CP eigenstate Tags • CP + • K+K- (3.89X10-3 ) • π+π-(1.38X10-3 ) • Ks π0π0 • π0π0(8.4X10-4) • KSKS (7.1X10-4) • ρ0 π0 (3.2x10-3) • CP – • KSπ0(0.012) • Ksη (3.9X10-3) • KSη’ (0.0094) • KSρ0 (0.0078) • Ksω (0.012) • KSφ (4.7X10-3) In 20fb-1Ψ(3770) data, we can get CP+ tags : 4.5x105 ; CP- tags : 3.6x105 With large sample of CP tags, we will definitely improve the measurements of strong phase, probe the direct CP, and other mixing parameters Haibo Li

  34. Find: CP Violation at ψ(3770) at BESIII • CP violating asymmetries can be measured by searching for events with two CP odd or two CP even final states: p+p-,K+K-, p0 p0, Ksp0 , ACP sensitivity 10-2 -10-3 K K vs pp Beam constraint Mass Haibo Li

  35. Rare and forbidden Charm Decays Estimation of sensitivity of the rare and forbidden decays of Charm meson at BES-III with 20 fb-1 at y(3770) Haibo Li, hep-ex/0605004 D+ D0 Haibo Li

  36. Brief Summary for Charm mixing • Charm provides great opportunities for New Physics studies • large available statistics (20 fb-1) • mixing: x, y = 0 in the SU(3) limit (as V*cbVub is very small) • mixing is a second order effect in SU(3) breaking • it is conceivable that y ~ x ~ 1%in the Standard Model • it is possible for y to be dominated by New Physics • Quantum coherence will allow BES-III to perform new measurements of strong phases in charm mixing studies • Quantum coherence will allow BES-III to perform new studies of mixing • no DCSD contamination in double-tag Kp studies • Observation of CP-violation or FCNC transitions in the current round of experiments provide “smoking gun” signals for New Physics - untagged asymmetries are more sensitive to CPV From Alexey Petrov Charm 2006 Haibo Li

  37. Lepton Flavor Violation in t Decays George Lafferty Charm 2006 Haibo Li

  38. George Lafferty Charm 2006 LFV experimental summary 90% CL Upper Limits on Br(l- X-) [BABAR / BELLE] Haibo Li

  39. Alex Bondar Charm 2006 LFV experimental summaryProspects at BES-III BES-III limit with 12 million tau pairs above the threshold ! Same sensitivity as current B factory 500 fb-1 data. BES-III range It is not a good place to study LFV in tau decay at BES-III New Physics Haibo Li

  40. Summary With 1010 J/y and 3.2 109y(2S) samples at BES-III, we can look for many rare and forbidden decays of Charm and charmonium, and challenge the SM. • Rare and forbidden Charmonium decay : • (1)Weak decays of y ; • (2) Invisible decays of quarkonia; • (3) Lepton Flavor/baryon number violated decays; • (4) CP violation in y decays; • New Physics probe in Charm meson decays: • (5) Rare decays of Charm meson • (6) D0-D0bar mixing • (7) CP violation in D meson decays We expect to locate the search of tiny contributions from new physics at heavy flavor sector after anything new can be found at LHC! Haibo Li

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