1 / 21

A. Drutskoy, University of Cincinnati

B physics at U (5S). A. Drutskoy, University of Cincinnati. ITEP Meeting. on the Future of Heavy Flavor Physics. July 24 – 26, 2006, Moscow, Russia. ITEP Meeting B physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy. Outline.

jacoba
Télécharger la présentation

A. Drutskoy, University of Cincinnati

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. B physics at U(5S) A. Drutskoy, University of Cincinnati ITEP Meeting on the Future of Heavy Flavor Physics July 24 – 26, 2006, Moscow, Russia. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  2. Outline Introduction. Recent Belle measurements at the Y(5S). Future searches for BSM using Bs decays at Y(5S). Conclusion. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  3. CLEO PRL 54, 381 (1985) CLEO PRL 54, 381 (1985) (5S) (5S) Introduction (4S) Asymmetric energy e+e- colliders (B Factories) running at Y(4S) : Belle and BaBar 1985: CESR (CLEO,CUSB) ~116 pb-1 at Y(5S) 2003: CESR (CLEO III) ~0.42 fb-1 at Y(5S) 2005: Belle, KEKB ~ 1.86 fb-1 at Y(5S) 2006, June 9-31: Belle, KEKB ~21.7 fb-1 at Y(5S) _ e+ e- ->Y(4S) -> BB, where B is B+ or B0 meson _ _ _ _ _ _ _ _ e+ e- -> Y(5S) -> BB,B*B, B*B*, BBp, BBpp, BsBs, Bs*Bs, Bs*Bs* where B* -> B gandBs* -> Bsg G(Y(5S)) = 110  13MeV/c2 (PDG) M(Y(5S)) = 10865  8 MeV/c2 (PDG) Bs rate is ~10-20% => high lumi e+e- collider at the Y(5S) -> Bs factory. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  4. First Y(5S) runs at the KEKB e+e- collider Belle Electron and positron beam energies were increased by 2.7% (same Lorentz boost bg = 0.425) to move from Y(4S) to Y(5S). 8 GeVe- 3.5 GeV e+ No modifications are required for Belle detector, trigger system or software to move from Y(4S) to Y(5S). Integrated luminosity of ~1.86 fb-1 at 2005 and ~21.6 fb-1 at 2006 was taken by Belle detector at Y(5S). The same luminosity per day can be taken at Y(4S) and Y(5S). Very smooth running ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  5. Belle integrated luminosity at Y(4S) • Integrated luminosity reached 600 fb-1 on May 31st . ~630fb-1 Belle May-31st Babar ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  6. Inclusive analyses : Y(5S) -> Ds X , Y(5S) -> D0X points:5S hist: cont points:5S hist: cont Y(5S) P/Pmax<0.5 Ds-> fp+ Ds-> fp+ 3775 ± 100 ev D0 -> K-p+ After continuum subtraction and efficiency correction: L = 1.86 fb-1 Bf (Y(5S) -> Ds X) 2 = (23.6 ± 1.2 ± 3.6) % Nbb(5S) = 561,000 ± 3,000 ±29,000 events Bf (Y(5S) -> D0 X) 2 = (53.8 ± 2.0 ± 3.4) % fs = N(Bs(*) Bs(*)) / N(bb) => = (18.0 ± 1.3 ± 3.2 )% N(Bs) / fb-1 = 108,000 ± 21,000 events ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  7. Signature of fully reconstructed exclusive Bs decays BsBs , Bs*Bs, Bs*Bs* MC Zoom Mbc vs DE Mbc vs DE whereBs* -> Bsg e+ e- -> Y(5S) -> BsBs, Bs*Bs,Bs*Bs*, Reconstruction: Bsenergy and momentum, photonfrom Bs* is not reconstructed. Mbc = E*beam2 – P*B2 , DE = E*B – E*beam Two variables calculated: Figures (MC simulation) are shown for the decay mode Bs -> Ds-p+ with Ds- -> fp- . The signals for BsBs, Bs*Bs and Bs* Bs* can be separated well. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  8. Exclusive Bs -> Ds(*)+p-/r- and Bs-> J/y f/h decays Data at Y(5S), 1.86 fb-1 Bs -> Ds+p- Bs -> J/y f/h Bs -> Ds*+p- Bs -> Ds(*)+r- 9 evnts in Bs* Bs* 4 evnts in Bs* Bs* 7 evnts in Bs* Bs* 3 evnts in Bs* Bs* N(Bs*Bs*) / N(Bs(*)Bs(*))= (94± 69)% 5.408<MBC<5.429GeV/c2 Potential models predict Bs* Bs* dominance over Bs*Bs and BsBs channels, but not so strong. Bs* Bs* Nev=20.0 ± 4.8 Conclusions: 1. Belle can take ~30 fb-1 per month ( x2 soon). 2. Number of produced Bs at Y(5S) is ~105/fb-1. 3. Bs*Bs* channel dominates over all Bs(*)Bs(*). 4. Backgrnds in exclusive modes are not large. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  9. DGs/Gs measurement from Bf (Bs -> Ds+(*) Ds-(*)) MBs = (MH + ML)/ 2 Gs = (GH + GL)/ 2 Dms = MH – MLDG = GL- GH>0 in SM ( ) ( ) d Bs Bs “ i - Schrodinger equation i = ( M – / 2 G ) d t Bs Bs Matrices M and G are t-dependent, Hermitian 2x2 matrices Assuming CPT: M11 = M22G11 = G22 | BH,L(t) > = exp( - ( iMH,L+GH,L/ 2)t ) | BH,L> SM: bs=arg(-Vts Vtb*/ Vcs/ Vcb*) =O(l2) - no CP-violation in mixing BSM : fs = arg (- M12/ G12) 2qs = fsDGs = 2 | G12| cos 2qs ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  10. DGs/Gs measurement from Bf (Bs -> Ds+(*) Ds-(*)) DGs = 2 | G12| cos fs DGsSM = DGCPs = 2 | G12| Since DGCPs is unaffected by NP, NP effects will decrease DGs. DGCPs = S G(CP=+) – SG(CP= –) Bs->Ds(*) + Ds(*) - decays have CP- even final states with largest BF’s of ~ (1-3)% each, saturating DGs/Gs . DGCPs Bf(Bs->Ds(*) + Ds(*) - ) ~ ~ Gs 1- Bf(Bs->Ds(*) + Ds(*) - ) / 2 To prove this formula experimentally : a) Contribution of Bs -> Ds+(*) Ds-(*) np is small b) Most of Bs -> Ds+ Ds- * and Bs -> Ds+* Ds- * states are CP- even. Assuming corrections are small (~5-7%), Bf measurement will provide information about DGCPs or |G12|. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  11. DGs/Gs measurement from Bf (Bs -> Ds+(*) Ds-(*)) Expected with 100 fb-1 at Y(5S): Y(5S), 1.86 fb-1 N ~ 107 x 2x10-4 x 10-2~ 20 ev Eff(Bs->Ds+ Ds-) ~ 2x10-4 N ~ 107 x 10-4 x 2x10-2~ 20+20 ev Eff(Bs->Ds*+ Ds-) ~1x10-4 N ~ 107 x 5x10-5 x 3x10-2~ 15 ev Bs-> Ds+ Ds- Eff(Bs->Ds*+ Ds*-) ~5x10-5 Bs-> Ds*+ Ds- Bs-> Ds*+ Ds*- =>Accuracy ofBf (Bs->Ds(*)+Ds(*)-) has to be ~15%. Ds+ -> fp+ , K*0 K+, Ks K+ DGCPs Bf(Bs->Ds(*) + Ds(*) - ) should be compared with direct DGs/Gs measurement to test SM. ~ <= ~ Gs 1- Bf(Bs->Ds(*) + Ds(*) - ) / 2 DGs/Gs lifetime difference can be measured directly with high accuracy at Y(5S) and also at Tevatron and LHC experiments. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  12. Semileptonic Bs decays At the Y(5S) we can measure precisely semileptonic decays: Bf (Bs->X+l-n) Accuracy is expected to be ~5% with 100 fb-1 at Y(5S) Bf (Bs->Ds+l-n) Bf (Bs->Ds*+l-n) Difficult to measure in hadron-hadron colliders. These Bf’s have to be compared with corresponding B meson Bf’s. This comparison provides important test of SU(3) symmetry and quark-qluon duality. Motivations: 1. t(B0) > t(Bs) - 2.9s difference (in contrast with theory). 2. Measured B0 semileptonic Bf is a bit lower than theoretical prediction. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  13. Exclusive Bs -> g gdecay Bs -> g g 1.86 fb-1 MC Natural mode to search for BSM effects, many theoretical papers devoted to this decay. PDG limit : Bf (Bs -> gg ) < 1.48 x 10-4 90% CL UL with 1.86 fb-1 :Bf (Bs -> gg ) < 0.56 x 10- 4. Expected UL with 100 fb-1 :Bf (Bs -> gg ) < 1. x 10- 6. SM:Bf (Bs -> gg ) = (0.5-1.0) x 10- 6. BSM can increase Bf up to two orders of magnitude. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  14. Exclusive Bs -> g gdecay Many “conventional” BSM models can be better constrained by B -> K* g and B->s g g processes, however not all. In some BSM models Bs -> gg provides the best limit, in particular in 4-generation model (VTs) and R- parity violating SUSY ( x M(gg)). VTb hep-ph/0302177 (Huang et al) : limits on four-generation matrix elements VTb and VTs were obtained from B decays. Bf(Bs->gg) can increase up to one order of magnitude under specific conditions. Decay B-> gg is not affected. VTs hep-ph/0404152 (Gernintern et al): within R-parity violation SUSY, diagram with sneutrino will increase Bf(Bs->gg) up to one order of magnitude. b _ t g n _ s g ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  15. Exclusive Bs -> K+ K-, Bs -> K-p+ and Bs->f g decays Direct CP-violation => non-zero charge asymmetry parameter A = (Bf (+) – Bf (-) ) / (Bf (+) – Bf (-) ). Expected number of events with 100 fb-1: Bs -> K+ K- : ~40 events ; Bs -> K-p+ : ~6 events. Larger statistics is required to observe direct CP-violation on the level of 10%. New Physics can contribute in penguin decay loops. Bs ->f g Estimated number of events with 100 fb-1 : ~20 ev. Partner of B -> K* g penguin decay . Bf’s have to be compared. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  16. Conclusions Bs decays with branching fractions down to 10-6 can be studied with statistics of ~100 fb-1 at e+e- colliders running at Y(5S) . Many important SM tests can be done with statistics of the order of (100-500) fb-1. Bs studiesat e+ e- colliders running atY(5S) have many advantages comparing with hadron-hadron colliders: high efficiency of photon reconstruction; 100% trigger efficiency; good K/p PID. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  17. Background slides ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  18. CLEO PRL 54, 381 (1985) (5S) Hadronic event classification hadronic events at U(5S) u,d,s,c continuum U(5S) events b continuum N(bb events) = N(hadr, 5S) - N(udsc, 5S) bb events B0, B+ events Bs events fs = N(Bs(*) Bs(*)) / N(bb) Bs* Bs* channel Bs* Bs Bs Bs ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  19. Number of bb events, number of Bs events Y(5S) : Lumi = 1.857 ± 0.001 (stat) fb-1 Cont (below 4S) : 3.670 ± 0.001 (stat) fb-1 Nbb(5S) = 561,000 ± 3,000 ±29,000 events => 5% uncertainty ( from luminosity ratio) How to determine fs =N(Bs(*) Bs(*)) / N(bb)? bb at Y(5S) _ _ B B Bs Bs = fs + (1-fs) Bf (Y(5S) -> Ds X) / 2 Bf (Bs -> Ds X) Bf (B -> Ds X) x x 1. Bf (Bs -> Ds X) can be predicted theoretically, tree diagrams, large. 2. Bf (B -> Ds X) is well measured at the Y(4S). ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  20. Feasibility of Bs lifetime measurement with same sign leptons Lifetime can be measured using two fast same sign lepton tracks and beam profile. To remove secondary D meson semileptonic decays: P(l)>1.4 GeV. Y(5S) : Bs(l +) Bs(l +) / Bs(l +) Bs(l -) = 100% Y(5S) : B(l +) B(l +) / B(l +) B(l -) ~ 10% m+ m+ Beam profile Dz = bgc Dt Bs Y(5S) Bs Z beam ~ 3 mm; Dz ~ 0.1- 0.2 mm. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

  21. Comparison with Fermilab Bs studies. There are several topics, where Y(5) running has advantages comparing with CDF and D0: 1) Model independent branching fraction measurements. 2) Measurement of decay modes with g, p0 and h in final state (Ds+r-). 3) Measurement of multiparticle final states (like Ds+ Ds-). 4) Inclusive branching fraction measurements (semileptonic Bs). 5) Partial reconstruction (Bf (Ds+ l-n) using “missing- mass” method). There are also disadvantages: 1) We have to choose between running at Y(4S) or Y(5S). 2) Number of Bs is smaller than in Fermilab experiments. 3) Vertex resolution is not good enough to measure Bs mixing. Running at Y(5S) is a new tool to study Bs physics. First Belle results are very promising. Collider exists => relatively low price. ITEP MeetingB physics at Y(5S) , July 24 - 25, 2006 , Moscow, Russia A. Drutskoy

More Related