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Recent Bottomonium Results from BaBar and Belle

1. Recent Bottomonium Results from BaBar and Belle. Veronique Ziegler (SLAC) Representing the BaBar Collaboration 13 th International Conference on B-Physics at Hadron Machines Amsterdam, 4 – 8 April 2011. 2. U (nS) Data Sets. 3.

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Recent Bottomonium Results from BaBar and Belle

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  1. 1 Recent Bottomonium Results from BaBar and Belle Veronique Ziegler (SLAC) Representing the BaBar Collaboration 13th International Conference on B-Physics at Hadron Machines Amsterdam, 4 – 8 April 2011

  2. 2 U(nS) Data Sets

  3. 3 Radiative transition studies from inclusive spectra for converted photons U(2S, 3S) data samples

  4. Radiative bottomonium transitions from U(3S) events using g→e+e- conversions 4 Reconstructed Vertices Energy in C.M. frame Significantly improves energy resolution Efficiency ~(0.1 – 1)%

  5. 5 Inclusive photon energy regions for U(3S) events • Resolution dominated • Small Doppler broadening

  6. 6 Inclusive photon energy regions for U(3S) events from U(3S) to U(1S)

  7. 7 Inclusive photon energy regions for U(3S) events Search for the Bottomonium Ground State hb(1S) g U(3S)→ g hb(1S) photons from calorimeter  hb significance < 3s

  8. Inclusive photon energy regions for U(3S) events 8 Search for the Bottomonium Ground State hb(1S) g hb significance < 3s

  9. 9 Inclusive photon energy regions for U(2S) events g hb significance < 3s ISR hb (1S)

  10. 10 Inclusive photon energy regions for U(2S) events hb significance < 3s g

  11. 11 • Summary of BF measurements from U(2S,3S) radiative decays using converted photons • Precise measurements of • cbJ(nP) n=1,2→ g U(mS)m=1,2 BFs • Good agreement with theory • (e.g. Kwong & Rosner, PRD38, 279 • (1988)) • Measurements of BFs for • U(3S)→ g cbJ(1P) transitions • -- transition to cb1(1P) not seen •  in general inconsistent with • theoretical predictions ?

  12. The search for the hb(1P) state in U(3S) data 12

  13. 13 U(3S) Search for a peak in invariant mass of system recoiling against p0 or p+p- p0 pp Hyperfine splitting for L=1 states M [c.o.g.(13PJ)] – M(11P1) hb(1P) cbJ(1P) hb(1S)

  14. background-subtracted result: 14 Evidence for the hb(1P) in the decay U(3S) pohb arXiv:1102.4565 yield as a fcn of assumed hb mass: • 9145 ± 2804 signal events • M(hb) = 9902+/-4(stat) +/-1(syst) MeV/c2 • consistent with predictions • Stat. Signif = 3.2s (i.e. √Dc2), including systematic errors = 3.0s(evaluated with the hb mass fixed at expected value of 9.9 GeV/c2) • B(U(3S)p0hb(1P) = (3.7±1.1±0.4)10-4 • B(U(3S)p0hb(1P)< 5.810-4 (@ 90% CL)

  15. Search for the hb(1P) in the decay U(3S)p+p-hb 15 background-subtracted result: hb ? • No hb observation: -1106 ± 2432(stat.) signal events (mass fixed at 9.9 GeV/c2) • BF(U(3S)p+p-hb)<1.0x10-4 (@90% C.L.) --suppressed by a factor >3 compared to p0 mode • BFs improved w.r.t. current PDG values: -- BF(U(3S)p+p-U(2S))=(3.00 ± 0.02 ± 0.14)% -- di-pion transition between cbJ states -- BF(U(3S)X(U(2S)p+p-U(1S))=(1.78±0.02±0.11)%

  16. 16 The search for the hb(nP) states in U(5S) data

  17. 17 • Motivation to take data at the U(5S) resonance • Studies of Bs decays 2 orders of magnitude larger indicate stronger coupling • Anomalous production of • U(nS)n=1,2,3p+p- • Possibly explained by the • presence of exotic resonance • Yb, bottomonium analog of • charmonium Y(4260), • responsible for high transition • rates • Belle scan of the Y(5S) region to • search for the Yb • discrepancy between U(nS)p+p- cross sectionlineshape and hadronic cross section (BaBar) at the 2s level • B(U(5S)→BB*p)=(7.3+2.3±0.8)% > one order of magnitude larger than expected -2.1 ? 17

  18. 18 • Measured e+e-→p+p- MM transitions at U(5S) energy arXiv:1103.3419 Observation of the hb(1P) and hb(2P) states background-subtracted results • Signal lineshapes • from calibration channels • U(5S)→U(nS) p+p- • →m+m- • measured hb(1P,2P) mass values • consistent with calculated values • no info. on p0 transitions as yet • observed hb production rate • enhancement may be indicative • of exotic process violating HQ • spin-flip suppression • hb not seen in U(4S) data

  19. 19 • Conclusions • Bottomonium Spectroscopy at the U(2S, 3S) • Precision measurements of radiative transitions between known bottomonium states using g→ e+e- • Searches for predicted states • BaBar: Evidence for U(3S)→p0 hb(1P) arXiv:1102.4565 No evidence for U(3S)→p+p- hb(1P) • Bottomonium Spectroscopy at the U(5S) • Belle: observation of the hb(1P) and hb(2P) states arXiv:1103.3419 • Measured mass values consistent with C.o.G. of partner cbJ states • Unexpectedly large production rates • Possibility for the existence of a Yb exotic bottomonium candidate, the analog of the Y(4260) in the charmonium sector • TOPICS COVERED ELSEWHERE • Bottomonium Spectroscopy above the U(4S) targeted for studies of Bs decays • Belle: observation of Bs→J/y f0(980) and evidence for Bs→J/y f0(1370) arXiv:1102.2759 • BaBar: measurement of inclusive BF for Bs→X l nland Bs production rate

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