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Re sults from B Factories II

Re sults from B Factories II. Peter Kri ž an University of Ljubljana and J. Stefan Institute. Contents. CKM: V ub measurements D 0 mixing Hadron spectroscopy FCNC B decays Summary (Only a very modest part of the harvest at B factories.). Belle spectrometer at KEK-B.

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Re sults from B Factories II

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  1. Results from BFactories II Peter Križan University of Ljubljana and J. Stefan Institute LHC Days in Split

  2. Contents CKM: Vub measurements D0 mixing Hadron spectroscopy FCNC B decays Summary (Only a very modest part of the harvest at B factories.) LHC Days in Split

  3. Belle spectrometer at KEK-B  and KL detection system Aerogel Cherenkov Counter 3.5 GeV e+ Silicon Vertex Detector Electromagnetic. Cal.(CsI crystals) 8 GeV e- Central Drift Chamber 1.5T SC solenoid ToF counter Accumulated luminosity:258 fb-1. LHC Days in Split

  4. BaBar spectrometer at PEP-II Accumulated luminosity:221 fb-1. LHC Days in Split

  5. CKM matrix measurements VudVub* VcdVcb* VtdVtb* VcdVcb* qi W± Vij qj Al3(r-ih) r h Al3(1-r-ih) BaBar & Belle main task:CP violation in the system of B mesons specifically: various measurements of complex elements of Cabbibo-Kobayashi-Maskawa matrix CKM matrix is unitary deviations could signal processes not included in SM Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb 1-l2/2 l -l 1-l2/2 Al2 = 1 -Al2 f2(a) f3(g) f1(b) (0,1) (0,0) LHC Days in Split

  6. h |Vub| measurements |Vub| r l W n B Xc, Xu From semileptonic B decays b c,u |Vub|, |Vcb| |Vcb| known to ~1.4%, becoming as precise as |Vus|=l (~1%) need to pin-down |Vub|, present world average ~10% b→cln background typically order of magnitude larger. LHC Days in Split

  7. Inclusive |Vub| measurement • Traditional inclusive method: use semileptonic decays, fight the background from b→cln decays by using only events with electron momentum above the b→cln kinematic limit. Problem: extrapolation to the full phase space→ large theoretical uncertainty. • New: fully reconstruct one of the B mesons, check the properties of the other (semileptonic decay, low mass of the hadronic system) • Very good signal to noise • Low yield (full reco efficiency is 0.3-0.4%) LHC Days in Split

  8. |Vub| measurement g p K q2 D fully reconstructed (Mbc) p B1 B2 U(4s) l p l n El n p MX p Xu B Babar,88M BB high p lepton Mbc[GeV] Variables separatingb → uln from b → cln: lepton energy El; hadronic inv. mass Mx; leptonic inv. mass q2; Full reconstruction Belle: B→D(*)-p+/r+/a1+/Ds(*)+ e ~0.25% BaBar: B→D(*)- n1pn2K … e ~0.4% LHC Days in Split

  9. Inclusive |Vub| measurement Extract signal in high q2 low Mx region (reduce theo. error): Mx<1.7 GeV q2>8 GeV2 signal b→cln Nsig~115 Nsig=174 Babar |Vub|= (4.98± 0.40 ± 0.39 ± 0.47)x10-3 (stat.) (syst.) (th.) Belle |Vub|= (5.54± 0.42 ± 0.50 ± 0.55)x10-3 LHC Days in Split

  10. D0 mixing in D0→Kp and Klndecays • The method: search for D mixing in the decay sequence: D*+→ D0p+, D0→flavour specific final state. • Semileptonic decay: • K- e+ n : no mixing(RS, Right Sign) • K+ e- n : mixing (WS, Wrong Sign) • measure WS rate • Hadronic decay: • K-p+ : no mixing • K+p- : mixing or doubly Cabbibo suppressed (DCSD) • measureWS time evolution LHC Days in Split

  11. D0 mixing in D0→Kp decays D0→Kptime evolution dN/dt a {RD +RD1/2y’ t + (x’2 + y’2) t2/4} e-t interference mixing • x’ = x cos d + y sin d • y’ = y cos d - x sin d • x = DM/G y = DG/2G • = strong phase difference SM: x <10-3, y<10-3 (long dist. effects); new physics: x>>y, CPV LHC Days in Split

  12. D0 mixing in D0→Kp decays Signal extraction LHC Days in Split

  13. D0 mixing in D0→Kp decays Freefit RD=(0.287 0.037)%, y’=(2.54+1.11-1.02)%, x’2=-(0.153+0.08-0.10)% Physicalregion R=(0.343+0.027-0.026)%, y’=(0.60 0.33)%, x’2=0% LHC Days in Split

  14. D0 mixing in D0→Kp decays Results: 95% contour in x’2 and y’ plane (with 90 fb-1) LHC Days in Split

  15. D0 mixing in D0→Kp decays Results: 95% contour in x’2 and y’ plane (with 57.1 fb-1) LHC Days in Split

  16. D0 mixing in D0→Ken decays • Selection criteria: • c.m.s. momentum of the Ke system > 2 GeV (bb, comb. backgr.) • Invariant mass of e-e+ (e+→p+) > 0.15GeV (g conversions) • Cut on decay time (backgrounds d(t) + e-t, signal t2 e-t) • Neutrino reconstruction: hermiticity of the spectrometer, kinematic constraints. • Main observable: Dm = m(psKen) - m(Ken) LHC Days in Split

  17. D0 mixing in D0→Ken decays   NRS = 40198329 NWS = 1967 rD = (NWS/ NRS) (eRS/eWS) = (0.20  0.70) 10-3 rD < 1.4 10-3 (90% conf. level) rD = (x2 + y2)/2 LHC Days in Split

  18. D0 mixing in D0→Ken decays BaBar: employs neural net techniques to reconstruct the D0 momentum vector (including again the neutrino), and to reject background events. Yield: fit to Dm, t distributions. NRS = 49620265 NWS = 11461 rD = (2.3  1.2(stat)) 10-3 rD < 4.2 10-3 (90% conf. level) LHC Days in Split

  19. Hadron spectroscopy – X(3872) Belle observed a new state decaying into J/yp+p- B+→K+ X(3872) 35±7 events M=3872.0±0.8 MeV G<2.3MeV (90%) J/yp+p- X(3872) y’ l+l- M(J/yp+p-)- M(J/y) [GeV] confirmed by CDF,D0,BaBar LHC Days in Split

  20. Hadron spectroscopy – X(3872) < 1 MeV/c2 hc’’ cc1’ hc2Y2 Y3 hc’ X(3872) MD*+MD 2MD Y’ cc2 hc cc1 cc0 Decay to J/Yp+p- Isospin 0++ allowed J/Y Isospin 1-- violating hc LHC Days in Split

  21. Hadron spectroscopy – X(3872) Search for other decay modes of X(3872): 90% C.L. upper limits (most from Belle): BaBar Non-observation of DD modes: JP=0+, 1-, 2+,…, is ruled out. LHC Days in Split

  22. What kind of state is X(3872)? M too low and G too small angular distribution rules out 1+- G(gJ/y) too small G(gcc1) too small; (PRL 93, 2003) pp hc should dominate over ppJ/y G( gcc2 & DD) too small No good cc candidates for X(3872): hc” hc’ cc1’ y2 hc2 y3 - Isospin violating decays to J/Yp+p- LHC Days in Split

  23. Hadron spectroscopy – X(3872) Search for B+→K+ X(3872) Belle,274M BB F.Fang,ICHEP’04 J/yp+p-p0 N=10.0±3.6 S/N=5 in accordance with DD* molecule model w mass region M(w)+M(J/y)=3879 MeV X(3872)→w J/y can occur via virtualw G(w J/y)/G(J/yp+p-)=0.8±0.3±0.1 LHC Days in Split Swanson,PLB 588,189(2004)

  24. Hadron spectroscopy – DsJ(2317) andDsJ(2460) mesons BaBar - DsJ(2317) CLEO Belle DSJ(2317) DSJ(2317) DSJ(2460) DSJ(2460) DSJ(2460) LHC Days in Split

  25. Hadron spectroscopy – DsJ mesons Properties studied e.g. helicity in B→DDsJ DsJ(2317)+ → Ds+p0 J=1 J=1 DsJ(2460)+ → Ds*+g J=0 J=2 Belle,280M BB, M.Danilov,ICHEP’04 Apart from low masses,all properties in accordancewith lowest level P states JP=0+,1+ LHC Days in Split

  26. Hadron spectroscopy – DsJ mesons Belle,152M BB,A.Drutskoy,ICHEP’04 First observation of B0→DsJ(2317)+K- Measured branching fractions for comparison Br(B0→ Ds K-)= (2.93±0.55±0.79)x10-5 Br(B0→ Dsp-)= (1.94±0.47±0.52)x10-5 Events in Mbc,DE signal region B0→DsJ(2317)+K- B0→DsJ(2317)-p+ M(Dsp0)-M(Ds) [GeV] Br(B0→DsJ(2317)+K-) x Br(DsJ(2317)+->Ds+p0) =(5.3±1.4±0.5±1.4)x10-5 LHC Days in Split

  27. FCNC B decays Flavour changing neutral current (FCNC) processes (like bs, bd) are fobidden at the tree level in the Standard Model. Proceed only at low rate via higher-order loop diagrams. Ideal place to search for new physics. LHC Days in Split

  28. b  sg inclusive b  sg rate: sensitive to deviations from the SM, world average in good agreement with SM predictions. Photon energy Eg distribution: depends on mband Fermi motion parameter in the B system (parameters of HQE); also important for the determination of Vub in semileptonic B decays. Previous measurement by CLEO: Eg > 2.0GeV. Belle: extend the energy range to Eg > 1.8GeV to cover >95% of the rate. LHC Days in Split

  29. b  sg inclusive -0.31 -0.07 Results Branching ratio: BR(bsg)=(3.550.32+0.30+0.11) 10-4 Photon energy Eg distribution: first moment: < Eg> = (2.292  0.0260.034) GeV second moment:< Eg2> - < Eg>2 = (0.0305 0.00740.0063) (GeV)2 LHC Days in Split

  30. B  K* l+ l- b  s l+l- was first measured in B K l+l- by Belle. With 140/fb of data, search for K* l+l-and update K l+l-. Important for further searches for the physics beyond SM: backward-forward asymmetry AFB in K* l+l- LHC Days in Split

  31. B  K* l+ l- • K*: K+p-, K0sp+, K+p0 with |M(Kp)-M(K*)|<75 MeV/c2 • K: charged or neutral • Lepton pair: e or m, p(e)>0.4 GeV/c, p(m)>0.7 GeV/cveto on J/Y, Y(2S) first observation Mbc = (E*2beam–|p*B|2) LHC Days in Split

  32. B  K* l+ l- Results based on 140 fb-1 • BR(B  K*l+l-) = (11.5+2.6  0.8  0.2) 10-7 observation • BR(B  K l+l-) = (4.8+1.0  0.3  0.1) 10-7update with more data -2.4 -0.9 q2 = Mll2c2 yellow: SM expect. LHC Days in Split

  33. B  K* l+ l-,K l+ l- Results based on 123 fb-1 • BR(B  K*l+l-) = (8.8+3.3  1.0) 10-7 • BR(B  K l+l-) = (6.5+1.4  0.4) 10-7 Belle+BaBar: All in good agreement with SM. -2.9 -1.3 With more statistics: measure backward-forward asymmetry AFB in K* l+l- -> determine sign of C7 LHC Days in Split

  34. Summary • CKM measurements: new measurements with the fully reco. sample, Vubwith less thoeretical uncertainty. • New upper limits for D0 mixing in D0→Kp andKlndecays. • BR and asymmetries in bsgand bsl+l-transitions are in good agreement with SM,but some interesting results (e.g. AFB) are statistically limited.We are entering an exciting phase of precision measurements. • New, exciting results from hadron spectroscopy • .... and much more, but could not be covered in this talk! LHC Days in Split

  35. More slides – if time left LHC Days in Split

  36. B  K*g • Photon candidates withp0/hveto • K*(892) reconstructed in 4 final states: K+p-, K0sp0, K+p0, K0sp+with |M(Kp) – M(K*)r| < 75 MeV/c2 • BKG suppression against e+e-qq(g) byevent shape var. data sample 78/fb LHC Days in Split

  37. B  K*g braching fractions BR(B0  K*0g) = (4.01 0.21  0.17) 10-5SM  (6.9  2.1) 10-5 BR(B+ K*+g) = (4.25 0.31  0.24) 10-5SM  (7.4  2.3 ) 10-5 Mbc = (E*2beam–|p*B|2) LHC Days in Split

  38. B  K*g asymmetries Isospin asymmetryD0+ = • (t B+ / t B0) BR(B0  K*0g) - BR(B+ K*+g) • (t B+ / t B0) BR(B0  K*0g) + BR(B+ K*+g) D0+ = +0.012 0.044(stat)  0.026(syst) Belle SM: 5-10% D0+ = +0.051 0.044(stat)  0.023(syst) BaBar CP asymmetrySM<<0.01 ACP =(G(B K*g)-G(B  K*g))/(G(B K*g)+G(B  K*g)) = 1 N(B K*g)-N(B  K*g) (1-2w) N(B K*g)+N(B  K*g) ACP =-0.015  0.044(stat)  0.012(syst) Belle ACP =-0.015  0.036(stat)  0.010(syst) BaBar (w= dilution due to imperfect tagging) LHC Days in Split

  39. |Vub| inclusive q2 Mx2 used in the measurement (q2cut,MXcut) 8 GeV2, 1.7 GeV DVub 6%-9% only q2cut 11.6 GeV2 DVub 12%-15% C.W.Bauer et al.,hep-ph/0111387 large non-perturbative corr. (large th. uncertainty) MX only Babar-CONF-04/11,ICHEP’04 |Vub|= (4.77 ± 0.28 ± 0.28 ± 0.690.39)x10-3 Mx-q2 |Vub|= (4.92 ± 0.39 ± 0.36 ± 0.46)x10-3 LHC Days in Split

  40. |Vub| inclusive Mx-q2 |Vub|= (4.92 ± 0.39 ± 0.36 ± 0.46)x10-3 BaBar (stat.) (syst.) (th.) |Vub|= (5.54 ± 0.42 ± 0.50 ± 0.55)x10-3 Belle BaBar syst.: largest from detector (tracking, ID) and b→cln modeling Belle syst.: MC statistics LHC Days in Split

  41. AFB for B  K(*)l+l- • Raw AFB in each q2 region is extracted from Mbc fit. • Dotted lines indicatecharmonium veto windows. • Kll has no asymmetry, hence a good control sample. • Curves (not fitted lines!)show theory including exp’tal efficiency. • Both are in agreement with data. LHC Days in Split

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