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Results on Charmonium and Bottomonium

Results on Charmonium and Bottomonium. Tom Browder (University of Hawaii). Will cover results from BESII, CLEO(-c), BaBar and Belle. Apologies: Not an expert but a backup speaker. Can only cover a small subset of interesting results in the available time.

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Results on Charmonium and Bottomonium

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  1. Results on Charmonium and Bottomonium Tom Browder (University of Hawaii) Will cover results from BESII, CLEO(-c), BaBar and Belle Apologies: Not an expert but a backup speaker. Can only cover a small subset of interesting results in the available time. Thanks: I have borrowed from talks by Pedlar, Shepard, Olsen, Muramatsu, Mussa, CZ Yuan, Skwarnicki. I have benefitted from correspondence with Soren Prell and others.

  2. Charmonium S. Olsen mesons formed from c- and c-quarks r c c c-quarks are heavy: mc ~ 1.5 GeV  2mp velocities small: v/c~1/4 (for b b, v/c ~0.1) non-relativistic QM applies _ What is V(r) ??

  3. “Cornell” potential c c r slope~1GeV/fm ~0.1 fm “confining” large distance component V(r) 1/r “coulombic” short distance component G.S.Bali hep-ph/0010032 2 parameters: slope & intercept

  4. Charmonium spectrum

  5. 1-- Charmonium states Important BES contribution to R Directly accessible via e+e- annihilation J/y e+ y y’ e- s(e+e-hadrons) Y(4160) Y(4040) y” Y(4415) D-meson + anti-D meson mass threshold “narrow” (G~300KeV) “narrow” (G~100KeV) “wide” (G~25 MeV) y”  DD decay channel is open G(DD)25MeV

  6. (3770), (4040), (4160), (4415) In 1998 and 1999, BES scanned 91 energy points between 2 and 5 GeV to determine R. Phys. Rev. Lett. 84, 594 (2000) and 88, 101802, (2002).

  7. Results from the new R analysis (2007) hep-ex: 0705.4500

  8. Resonance parameters (PLB660, 315 (2008))

  9. Current J/ and (2S) Samples (×106) Note: B( ψ(2S)->+-J/ψ)~32% one can tag J/ψ events very cleanly and efficiently. BESII : J/ 2001 – 58 M; CLEO-c: (2S) 2006 -27 M CLEO-c has CsI(Tl) crystals, BESII does not but BESIII will .

  10. Inclusive photon signal for ψ’γηc B(ψ(2S)->γηc(1S)) = (4.32+-0.16+-0.60)*10^-3B(J/ ψ->γηc(1S)) = (1.98+-0.09+-0.30)% B(J/ ψ->γηc(1S))/B( ψ(2S)->γηc(1S)) = 4.59+-0.23+-0.64. Renormalize ηc BF scale arXiv:0805.0252

  11. Signal for J/ψγηc Discrepancy between ηc properties (especially widths) in different processes is unresolved.

  12. P-wave states Gamma energy spectrum from y’g X decays accessible via E1 transitions from y’ Gaiser et al (Crystal Ball) PRD 34 711 E1 Transition Partial width 23S1 (y’)13P2 (cc2) 17 keV Calculable from”1st principles” Good agreement with measurements 23S1 (y’)13P1 (cc1) 24 keV 23S1 (y’)13P0 (cc0) 24 keV 13P2 (cc2) 13S1(J/y) 420 keV 13P1 (cc1) 13S1(J/y) 290 keV 13P0 (cc0) 13S1(J/y) 120 keV

  13. Hadronic transitions G(y’p+p-J/y) 70 keV “allowed” “reasonable” agreement between measurement & theory c.f. Kuang & Yan PRD 41 155 G(y”p+p-J/y) 50 keV “allowed” G(y’hJ/y)  5 keV allowed G(y’p0J/y)  0.3 keV isospin violating p0 h p+p- p+p-

  14. CLEO 2005 +2007 update The hcand ηc(2S) have been observed ψ0 hc0γηc Belle 2002 Charmonium table below D Dbar threshold is complete

  15. Recent results on non-exotic charmonia 21S0(ηc(2S)) found by Belle S.K.Choi et al PRL 89 102001 properties as expected 23P2 found by Belle hep-ex/0507033 properties as expected 11P1(hc) found by CLEO hep-ex/0508037 properties as expected 13D1 g 13P1 g 11P0 seen by CLEO, Phys.Rev.D74:031106,2006. G(meas) = 75  18 keV G(theor)  ~59-77 keV

  16. The potential model for (ccbar) charmonium mesons is robust and reliable. The old “missing states” (hc and ηc(2S)) have now been observed Declare victory May 1, 2003

  17. Problems with strong decays of charmonium MARK-II Old unsolved mystery K*K X-H Mo et al, review in hep-ph/06011214 (>10 proposals) W. S Hou’s idea, glueball-J/ψ mixing, seems to be ruled out ρπ Rosner One possible explanation

  18. ’ Ξ-Ξ+p2π-p2π+ ΞΞ-bar ’ ΛΛpπ-pπ+ ’ Σ0Σ0 pπ-pπ+ ’  pp ’  Baryon Anti-baryon OK First measurements by BESI, remeasure BR with BESII data sample. ΣΣ-bar ΛΛ-bar pp-bar Consistent with “12% rule”.

  19. Bottomonium Data Samples BaBar, 30.3 fb-1, ~120 M Y(3S) Belle 2.9 fb-1 (2006) , 11 M Y(3S) ~14.4fb-1 on the Y(2S)

  20. Bottomonium: Some mysteries in strong decays “QCD Multipole Expansion” What is special about the case m-n > 1 ?

  21. Most famous ancient mystery (1994-2000)

  22. Possible Theoretical Explanations: High statistics data and sophisticated analysis may provide some clues (CLEO)

  23. The matrix element for Υ(mS)Υ(nS) The amplitudes A, B could be complex In the above, ε, ε’ are the polarization vectors of the Υ(nS), Υ(mS) q1, q2 are the pion 4-vectors while E1, E2 are their energies in the Υ rest frames. q2 is the invariant mass of the two pions

  24. CLEO High Statistics Analysis of di-pion matrix element M, θX

  25. CLEO High Statistics Analysis of di-pion matrix element A, B are complex. B was previously neglected C is consistent with zero (spin flip and breakdown of QCD multipole expansion not present). PRD 76, 072001 (2006)

  26. Recent data for Υ(4S)Υ(1S,2S) + - Non-B Bbar decay Belle data BaBar data PRL 96 (2006) 232001 PRD 071103 (R) 2007

  27. CLEO’s first evidence for (2S)(1S) η preliminary 4.6σ One candidate is found, Expect this is 16% of the η mode

  28. BaBar discovers Υ(4S)(1S)η These are examples of non-B Bbar decays that have been observed by BaBar and Belle. preliminary

  29. Could related transitions provide a way to discover the elusive hb or ηb ? Two suggestions: (Voloshin, Mod. Phys. Lett. A 19, 2895 (2004)) (Godfrey, Rosner, PRD66, 014012 (2002) like CLEO’s hc search )

  30. Where is the ground state bottomonium ηb ? Tests theory and is the highest priority of the quarkonium working group (QWG) Direct M1 transitions Which Upsilon(nS) is best ? Inclusive or exclusive ? What are the hadronic modes of the ηb ?

  31. Second mystery or big problem in the field: Where is the ηb, the ground state bottomonium state ?

  32. Search for a Y(4260) analogue in the bottomonium sector Y(4260) → J/yp+p- Is there a corresponding bb state Ub→ U(1S) p+p- ? “Searching for the bottom counterparts of X(3872) and Y(4260) via +-Υ(1S)”, Wei-Shu Hou, PR D74, 017504 (2006) → theory inspiration (experimental work by Kai-Feng Chen and Anatoly Sokolov) Resonant structure is rather complicated above BB threshold. E.g. Y(10860) is commonly assumed to be a radially excited 1-- b b bound state a.k.a the Y(5S), but we do not really know that. World wide Y(10860) data: 1985 CLEO 0.1/fb 2003 CLEO III 0.43/fb 2005 Belle 1.9/fb 2006 Belle 21.7/fb Total cross-section Collected mainly for Bs physics, ≈105 Bs / fb Use this data to measure+-Υ(1,2,3S) production at the (10860)

  33. Anomalous U(1,2,3S) p+p-, U(1S) K+K- cross sections at U(5S) 3.2s PRL 100, 112001, 21.7 fb-1 14s Final state U(3S) U(2S) 20s Initial state U(1S) U(10860) 4.9s U(3S) U(2S) U(1S) U(10860) U(10860) decay or decay of new overlapping state Yb?Energy scan (7.9 / fb) around U(10860) : compare U(1S) p+p- and total hadronic cross sections. Results will be ready soon. U(1S)

  34. What about the dipion mass distributions for the Y(10860) ? (the state formerly known as the “Υ(5S)”) Phase space, Cahn-Brown model (B=0) There are hints of a low mass structure in a) and b) but statistics are low.

  35. Bottomonium: New Physics Potential Suppose those precision electroweak fits are taken literally, MH~76±30 GeV. Suppose nMSSM is correct, then there is a H and another light Higgs particle a1 (m(a1) <m(b)). Can avoid LEP limits and still have MH~100 GeV. (R. Dermisek, J. Gunion, B. McElrath) The dominant decay mode might be: Difficult at a hadron collider. But could find the light Higgs (a1) in bottomonium at B or Super B Factories.

  36. Bottomonium: New Physics Potential (cont’d) One motivation for BaBar’s 30 fb-1 Y(3S) run.

  37. Hunting dark matter or light Higgs in Υ(nS) decays High precision check of lepton universality in dilepton decays Light Higgs signature Can also search for the HYPER-CP particle using decays to aμ+μ-

  38. BaBar’s final run Kirkby Expect compelling results on bottomonium from BaBar (and perhaps Belle) in the near future.

  39. More New Results (but not enough time to cover)

  40. New Measurements of Upsilon(3S) Branching Fractions (CLEO)

  41. New Measurements of Upsilon(3S) Branching Fractions (CLEO)

  42. It looks like there may be a bbversion of the Y(4260)lurking around the (5S) W.-S. Hou PRD 74, 017504 (2007) If there are bb versions of the XYZ’s, why not ss versions as well?

  43. 1-- Ys states around 2 GeV? Y(2175)f0(980)f from BaBar (confirmed by BESII) e+e- g f0(980)h @ Ecm ~10.6 GeV confirmed by BESII M(f0(980)f GeV M.Ablikim et al (BES) PRL 100, 102003 (2008)

  44. Backup Slides

  45. The new 2007 improved results Comparison of the updated R value and the old results in Phys. Rev. Lett. 88 (2002) 101802 preliminary Differences in R values are due to the updated resonant parametersandinitial state radiative correction factor (1+obs). hep-ex: 0705.4500

  46. ’  Baryon antibaryon OK BESII – CLEOc comparison pp-bar ΛΛ-bar ΣΣ-bar ΞΞ-bar Consistent with SU(3) symmetry. Reduced Branching Ratios R = Br/(π p* /s½), p* is baryon momentum. R’s same under SU(3) symmetry. BES Phys. Lett. B648, 149 (2007)

  47. (4S)  (1S) p+p- 2S 3S 4S is Huge!! Belle: G((5S)pp(nS)) (4S)pp(1S) 477 fb-1 from Belle (1/20 times the data & ~1/10th the crosssection) 8 times as many events! “(5S)”pp(1S) 23.6 fb-1 from Belle 325±20 evts! 44±8 evts Belle 0710.2577 K.F. Chen et al (Belle) PRL 100, 112001 (2008) (2 weeks ago)

  48. Partial Widths Assume “(5S)” = (5S) PDG value taken for (nS) properties N.B. Resonance cross section 0.302 ± 0.015 nb at 10.87 GeV PRD 98, 052001(2007) [Belle] >100 times bigger!! Cf (2S)  (1S)p+p- ~ 6 keV (3S) 0.9 keV (4S)1.8 keV

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