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Highlights from Belle Jolanta Brodzicka (NO1, Department of Leptonic Interactions) SAB 2009 Plan • • • • • • CPV studies → Nobel Prize for Kobayashi and Maskawa B decays with „missing energy”: New Physics probe Ds meson spectroscopy D0 -D0 mixing: charm highlight Bs Physics: also possible at Belle The Future Belle experiment at KEKB KEKB: asymmetric e+e- collider e+: 3.5 GeV e-: 8.0 GeV √s = 10.58 GeV = (4S) mass e+e- (4S) BB Operating since 1999 Peak luminosity: 1.711034cm-2s-1 1MBB/day Integ. luminosity: 860 fb-1 @ (4S) Upgrade to Super KEKB approved Super Belle collaboration formed CPV studies: goal reached • The Nobel Prize for Kobayashi and Maskawa: the crown of CPV studies • K-M idea: 3rd quark family (b,t) introduced irreducible phase in quark mixing matrix (complex couplings between quarks) CP violation (in processes with interference sensitive to the complex phase) u Vud W+ d VCKM L ~ ( u c t )L γμ Vud Vus Vub d Vcd Vcs Vcb s W+μ Vtd Vts Vtb b Vub Vtd: complex L • B-Factories have verified predictions of the K-M mechanism CPV in B system: observed in several processes Relations between CKM parameters: tested CPV: observations, out of many • K-M predicted two types of CPV violations: both observed Time dependent CPV. Golden mode: B0→J/ψKs + B0 -B0 mixing: time dependent ACP (t ) d dt d dt ( B fCP ) ddt ( B fCP ) ( B fCP ) ddt ( B fCP ) ACP(t) = S sin(mdt) S= 0.642 0.031(stat) 0.017(syst) Direct CP violation: difference in decay rates for B0K+- andB0K-+ _ B0 K B0 K + ACP ( B f ) ( B f ) ( B f ) ( B f ) ACP= -0.094 0.018(stat) 0.008 (syst) Tests of Unitarity Triangle • VCKM is unitary matrix: VCKM V†CKM=1 From unitarity relation: Vud* Vub Vcd* Vcb Vtd*Vtb 0 Angles and sides of the Untarity Triangle: fundamental SM parameters • Measure both angles and sides UT over-constrained ACP in B0J/K0 β • ACP in B0, , ACP in BD(*)K(*) semileptonic B decays B -B oscillations UT sides Directly measured: β = (21 ± 1)o β = (24 ± 2)o α = (92 ± 7)o α = (92 ± 4)o γ = (78 ± • • From UT sides: 12)o consistency γ = (64 ± 4)o Confirmed: UT is a triangle (within ~10% accuracy) Next step: any effects beyond KM mechanism? 2008 B decays with „missing energy” beyond SM amplitudes • • • Theoretically clean (small hadronic effects) Sensitive to New Physics: charged Higgs effects at tree level Experimentally challenging: multiple neutrinos in final states B0→D*-τ+ντ : highlight of B decays 2007 • Decay chain: B0→D*-τ+ντ D*→D0π D0 →Kπ, Kππ0 τ→eνeντ , πντ Signal side Tagging side Signal yield: 60+12 -11 (5.2σ with syst.) -2 BF(B0→D*-τ+ν)=(2.02 +0.40 -0.37 (stat) ±0.37(syst)) 10 • • • • First observation of exclusive semi-tauonic B decay Analysis performed entirely in Krakow Study continued: other channels B→Dτν, polarization analysis Important topic at SuperB Factory A. Matyja, M. Różańska et al. PRL 98, 211803 (2007) Ds spectroscopy • • Study of B+→ D0D0K+ Dalitz plot Observation of new meson: DsJ(2700)+→D0K+ DsJ(2700) On the PRL cover M = 2708 9 11 MeV Γ = 108 23 +36 -31 MeV JP=1- M(D0K+) Signal yield / 40 MeV • • cosθhel Radial excitation of Ds* or L=2 orbital excitation? Toward interpretation: resonances in D*K studied DsJ(2700) ? M(D*+Ks0) J. Brodzicka, H. Pałka et al. PRL 100, 092001 (2008) D0 -D0 mixing : most unexpected result of 2007 • • Mixing observed in K0 (1958), B0d (1987) and B0s (2006) Unique for D0: only d,s,b quarks enter the box mixing suppressed Mixing governed by x and y |x| ~ O(10-5) • • |x|, |y| ~ O(10-2) New Physics can enlarge x and y Mixing „modifies” decay time distribution D1, D2 : mass eigenstates D0, D0 : flavor eigenstates perform time dependent study of produced D0 andD0 • Measure D0 lifetime from its decay length yCP from D0→K+K-,π+π• D0→K+K- and π+π- : CP even eigenstates D1 τ=1/Γ1 • • D0→K-π+ : not CP eigenstate τ=f(1/Γ1 , 1/Γ2) Lifetime difference between non-CP and CP eigenstates access to mixing τ(K-π+) yCP= -1 = y τ(K+K- or π+π-) • • if no CPV (in SM: CPV<10-3) if yCP≠0 D0 - D0 mixing Measured proper decay time distributions: = + t (fs) t (fs) yCP (1.31 0.32 0.25)% t (fs) t (fs) Significance:3.2σ First evidence for D0 mixing A (0.01 0.30 0.15)% no CPV found Belle PRL 98, 211803 (2007) D0 -D0 mixing: status • World average mixing parameters from HFAG-charm (all existing measurements included): y= ( 0.73 ± 0.18 )% x= ( 0.91 ± 0.26 )% No mixing (x=0 and y=0) excluded at ~7σ • Statistics of SuperB Factory needed for precision measurements and searches for New Physics effects More than Bu,d at B-Factory: Bs physics • • KEKB increased beam energies: Y(4S)→Y(5S) E(e+): 3.500 GeV → 3.595 GeV, E(e-) : 7.996 GeV → 8.211 GeV No modification of the detector, trigger, software KEKB (Belle): 2005-2006: ~23 fb-1 2008-2009: ~80 fb-1 Y(4S) Y(5S) Y(6S) World Y(5S) data: 1985:CESR (CLEO,CUSB): 0.1fb-1 2003:CESR (CLEO III): 0.4fb-1 • e+e-→Y(5S)→ BsBs, Bs*Bs,Bs*Bs* access to Bs (bs mesons ) • Advantages of Bs physics at B-Factory versus hadronic machines: + low background + final states with π0/γ + absolute BF measurements (with BF ~20%) Bs decays with first data • Cabibbo favored decay: Bs→Ds+π- with 21.7 fb-1 (2.8M Bs ) Bs→Ds-π+ 163 13 ev M(Bs*)=5417.6 0.4 0.5 MeV -3 BF(Bs→Ds+π-)=(3.41 +0.33+0.70 -0.31 -0.67 ) 10 Belle PRL 102, 021801 (2008) • Rare decay: Bs→φγ (b→s electroweak penguin) Bs →f 5.5 σ BF(Bs→φγ)=(5.7 +1.8+1.2 ) 10-5 -1.5 -1.1 First observation of rare Bs decay Belle PRL 100, 121801 (2008) • • B-Factory competitive in Bs physics Precision BF for normalization modes callibration for LHCb BF(Bs→ Ds+π-) to reduce error of BF(Bs→μ+μ-) Future: KEKB upgrade approved Physics prospects for Super KEKB • Krakow activity toward Super KEKB: Physics analyses: important in physics program of SuperBelle SVD and Pixel Detector • B Physics in Department of Leptonic Interaction: (Super)Belle and LHCb: lots of synergies ab-1 •