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Decays of Y(5S) to B0 and B+ Mesons

This workshop explores the decays of Y(5S) particle to B0 and B+ mesons, studying their properties and searching for possible new physics beyond the Standard Model.

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Decays of Y(5S) to B0 and B+ Mesons

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  1. (5S) decays to B0 and B+ mesons and scan around (5S) A. Drutskoy, University of Cincinnati Mt.Tsukuba: Nyotai-san 877m, Nantai-san 871m Workshop on Heavy Quarkonium, Fermilab, May 18-21,2010 QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  2. e+ e-hadronic cross section 2 - - - - - + bb (cc,ss,uu,dd) (5S) (6S) e+ B (4S) _ ¡ (4S) B e- Belle took data at E=108671MeV BaBar PRL 102, 012001 (2009) 2M(Bs) _ M( (5S)) = 10876  2 MeV/c2 e+ e- ->(4S) -> BB, whereBisB+orB0meson G( (5S)) = 43  4 MeV/c2 (BaBar) _ _ _ _ _ e+ e- -> bb ((5S)) ->B(*)B(*), B(*)B(*)p, BBpp, Bs(*)Bs(*), (1S)pp, X … CLEO: 2003: ~0.42 fb-1 Belle: 2005 1.86 fb-1, 2006 21.7 fb-1, 2008 ~27 fb-1, 2009 ~71 fb-1 where B* -> B gandBs* -> Bsg QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  3. CLEO PRL 54, 381 (1985) (5S) Hadronic event classification at (5S) 3 hadronic events at (5S) u,d,s,c continuum (5S) events b continuum N(bb events) = N(hadr, 5S) - N(udsc, 5S) bb cross-section bb events Bs events B0, B+ events  X ISR ISR B* B B* B* B* B p B* B*p B B p B B B B p p QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  4. Belle cavity e+ source Belle data taking at (5S) 4 Belle detector 8 GeVe- 3.5 GeV e+ E(e+): 3.500 GeV -> 3.595 GeV, E(e-) : 7.996 GeV -> 8.211 GeV. No modifications are required for Belle detector, trigger system or software to move (4S) -> (5S). Electron and positron beam energies are increased by 2.7% (same Lorentz boostbg =0.425) to move from (4S) to (5S). QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  5. _ Theoretical model for (5S) decays to BB pairs 5 Cornell model modified for bottomonium arXiv:0812.4402 [hep-ph] Decay rate of (5S) with spin s=1 and mass M to B(*)B(*)-pair with spins s1+s2: G= (1/8p) (P/M) E1 E2C(ss1s2) |A5S(P)|2 where P, E1, E2 – momentum and energies of final B mesons in CM. _ _ _ C(ss1s2) spin counting factor => 1/3 : 4/3 : 7/3 for BB, B*B , B*B* Decay amplitude: A5S(P) = 4p fq InLl (P) _ where fq includes only quark masses BB _ Problem: amplitude oscillates fast, nodes B*B _ B*B* Two heavy quarks: calculations should be reliable 3-body final states: ratio s(3)/s(2): pion form-factor, large model and parameter uncertainties, not very reliable QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  6. Signature of fully reconstructed B decays 6 _ B+->J/y K+ e+ e- -> (5S) -> B(*)B(*)(p)(p), BBpp _ Bs*Bs* 23.6 fb-1 whereB* -> B g _ _ Mbc Bs*Bs B(*)B(*)p _ Data BsBs _ Mbc+DE-5.28 MC B*B* _ B*B _ BB Mbc vs DE Only one B meson is reconstructed Mbc = E*beam2 – P*B2 , DE = E*B – E*beam Two variables calculated: * B energy (E*B) and momentum (P*B) are reconstructed; no rec.gfrom B QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  7. DE vs Mbc distributions 7 L=23.6 fb-1 B+->J/yK+ B+->D0p+ D0->Kp Five B modes are studied: only charged tracks in final state, PDG branching fraction errors are 3-5% => small systematic errors Clear B signals are seen insignal regions for all 5 studied B decays. B+->D0p+ B0->J/yK*0 B0->D-p+ D0->K3p QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  8. Mbc+DE–5.28 projections 8 B+->J/yK+ B+->D0(Kp)p+ B+->D0(K3p)p+ B0->J/yK*0 B0->D-(K+p-p-)p+ f(X)=N(X)/N(bb) B+ B+->J/yK+ 89.0±6.3±8.0 % 72.1±3.9±5.0 % 6.1 3.8 B0 B+->D0(Kp)p+ 64.0±6.2±4.9 % 77.0±5.8±6.1 % 5.6 B+->D0(K3p)p+ 68.3±8.0±6.4 % S 8.1 73.7± 3.2±5.1 % B0->J/yK*0 85.3±9.2 ±8.8 % 8.8 58.9 ± 10.0 ± 9.2 % (CLEO 2006) B0->D-(K+p-p-)p+ 72.9±7.4±6.4 % Sum Bs: 19.5±3.0 % (PDG, Belle+CLEO). 2.2 QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  9. ϒ(5S) decays to B0 and B+ mesons 9 _ Backgr. subtracted Data B+->J/y K+ MC BB _ _ Sum of 5 modes 23.6 fb-1 BBpp fit BB* _ Mbc B*B* 2-body thresh. _ B(*)B(*)p Mbc+DE-5.28 Simultaneous fit of 5 B modes in Mbc<5.35GeV/c2 region Channel fractions per bb-pair: _ _ BB: 5.5±1.0 ±0.4 % _ Theory: channel B*B* is dominant, 30-69% 0.9 B*B: 13.7 ± 1.3 ±1.1 % _ Results should be used to adjust theory B*B*: 37.5±2.1±3.0 % 1.9 => not 2-body channels, why so large? Mbc>5.35 GeV/c: 17.5±1.8±1.3 % 1.6 QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  10. Decomposition of 3-body channels 10 _ We reconstruct directly produced pion in B(*)B(*)p+ channels. Then we calculate parameters ( all in CM system): rec. B Reconstructed B meson: Mbc, DE ; DX(rec) = Mbc+ DE-5.28 rec. p (5S) B miss. Missing B meson: use momentum P(Bp) and energy E(Bp) of reconstructed B and p: Mbcmiss = sqrt( E2beam– P(Bp)2 ) , because P(Bmiss)=P(Bp) DEmiss= Ebeam – E(Bmiss) = E(Bp) – Ebeam DX(miss) = Mbcmiss + DEmiss – 5.28 DX(corr) = DX(miss) + DX(rec) -> to decrease uncertainty QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  11. Decomposition of 3-body channels 11 Sum of 5 B modes _ BBp _ Data MC B*Bp _ B*B*p _ BBpp Only B candidates from signal region with Mbcrec>5.37 MeV/c2 We assume Clebsch-Gordan coefficients: Fr(p±)/Fr(p0)=2:1 QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  12. Decomposition of 3-body channels 12 Fractions for different components averaged over 5 studied B decays (assuming equal B+ and B0 production): _ Events Fraction over M>5.37 Fraction over bb _ BBp+ 0.2 ± 7.2 (0.2 ± 6.8 )% (0.0 ± 1.2 ± 0.3) % 6.9 6.5 _ B*Bp+ 38.3 ± 10.5 (41.6 ± 12.1 )% (7.3 ± 2.3 ± 0.8) % 9.8 11.4 2.1 _ B*B*p+ 4.8 ± 6.4 (5.9 ± 7.8 )% (1.0 ± 1.4 ± 0.4) % 5.9 7.2 1.3 Residual (52.3 ± 15.9 )% (9.2 ± 3.0 ± 1.0) % 15.0 2.8 228.7 ± 22.9 All (17.5 ± 1.8 ± 1.3) % 100% 22.3 1.6 _ _ Channel B*Bp decays in S-wave (1-0-0-), BBp decays with 2 P-waves (0-0-0-) _ Theory, 3-body fractions: ~0.3% : L.Lellouch et al Nucl Phys B405:55,1993 ~0.03% : Yu.Simonov et al hep-ph:0805.4518 Large fraction of 3-body B*Bp+ => not predicted by theory _ Residual is too large for BBpp channel. We calculated probability of ISR and got ~10% (~4% to (4S) and ~6% above (4S)). Reasonable agreement with residual. QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  13. Observation of ϒ(5S) ϒ(1S)p+p-, ϒ(2S)p+p- 13 K.-F. Chen et al. (Belle coll), PRL 100, 112001 (2008) (2S) L= 21.7 fb-1 m+m-h+h- -> look for: (3S) (2S) e+e- -> (1S) p+p-X e+e- -> (2S) p+p-X (1S) e+e- -> (3S) p+p-X In contrast to expectations significant fraction of (5S) (bb) decays to non-BB states. (1S) _ _ QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  14. larger by > 102 ϒ(5S) decays to bottomonium 14 4 modes seen : (5S) -> (nS) h+h- Possible explanations: 1.Rescattering mechanism(5S)->B’B’pp->(1S)pp,suppressed at(4S) (Simonov) 2. It comes not from (5S), but from near Yb- analog of hybrid Yc(4260) (Hou) QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  15. Energy scans 15 Motivated by large Bf((5S)->(1S)pp), Belle performed energy scan to search for non-(5S) resonance (Yb hybrid?) decaying into (1S)p+p-, (2S)p+p- and (3S)p+p-. Belle Belle: arXib:0808.2445 BaBar also did energy scan (Rb:b-events) Belle Y(5S) Mass (MeV) Width (MeV) Belle(comb) 10888.4±3.0 30.7± 8.7 2.9 7.7 Belle(hadr, Rb) 10879 ± 3 46 ± 9 7 BaBar(hadr,Rb) 10876 ± 2 43±4 (nS)pppeak is shifted by 3.2s from Rb Rb BaBar (nS)pphas zero level, Rb level is ~0.2 Yb : difference in shapes is very small ? BaBar: PRL 102,012001(2009) (5S)->B’B’pp->(1S)pp : why zero level? QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  16. Conclusions 16 Y(5S) decays to B0 and B+ mesons are studied (preliminary results). Two-body fractions are precisely measured. Theory should be adjusted using these results. Three-body fractions are measured. Large fraction is obtained for B*Bp channel. Theory predicted very small fractions for 3-body channels. Contradiction should be resolved. Unexpectedly large fractions for ϒ(5S)->ϒ(1S,2S,3S)p+p- decays are observed. Energy scan was performed around ϒ(5S). Difference in shapes is found for ϒ(5S) peak in hadronic bb cross section and peaks in ϒ(1S,2S,3S)p+p- final states. No clear explanation. Theory cannot predict well behaviors of (“simple”) bb-system _ _ _ BB: 5.5±1.0±0.4 % B*B: 13.7 ± 1.3 ±1.1 % B*B*: 37.5±2.1±3.0 % 0.9 1.9 _ _ _ _ (1.0±1.4±0.4)% BBp+ : (7.3±2.3 ±0.8)% B*B*p+ : (0.0±1.2±0.3)% B*Bp+ : 2.1 1.3 QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  17. 17 Background slides QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

  18. Decomposition of 3- and 4-body channels 18 BBp B*Bp B*B*p MC MC BBp B*Bp B*B*p QWG 2010, Y(5S) decays to B0 and B+ mesons and scan around Y(5S), Fermilab, Batavia, May 18 - 21 A. Drutskoy

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