1 Highlights from Belle Jolanta Brodzicka (NO1, Department of Leptonic Interactions) SAB 2009

2 Plan CPV studies → Nobel Prize for Kobayashi and Maskawa B decays with „missing energy”: New Physics probe D s meson spectroscopy D 0 -  D 0 mixing: charm highlight B s 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 = GeV =  (4S) mass e + e -   (4S)   BB  Operating since 1999  Peak luminosity: 1.71  cm -2 s -1  1M  BB/day  Integ. luminosity: 860 fb  (4S)  Upgrade to Super KEKB approved  Super Belle collaboration formed

3 The Nobel Prize for Kobayashi and Maskawa: the crown of CPV studies K-M idea: 3 rd 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) B-Factories have verified predictions of the K-M mechanism CPV in B system: observed in several processes Relations between CKM parameters: tested CPV studies: goal reached d u V ud W + V ud V us V ub d L ~ ( u c t ) L γ μ V cd V cs V cb s W + μ V td V ts V tb b L V CKM V ub V td: complex

4 CPV: observations, out of many K-M predicted two types of CPV violations: both observed Time dependent CPV. Golden mode: B 0 → J/ψKs + B 0 -  B 0 mixing: time dependent B 0  K -  + Direct CP violation: difference in decay rates for B 0  K +  - and  B 0  K -  + + A CP =  (stat)  (syst) B 0  K    _ B 0  K    A CP (  t) = S sin(  m d  t) S=  (stat)  (syst)

5 V CKM is unitary matrix: V CKM V † CKM =1  From unitarity relation:  Angles and sides of the Untarity Triangle: fundamental SM parameters Measure both angles and sides  UT over-constrained consistency Confirmed: UT is a triangle (within ~10% accuracy) Next step: any effects beyond KM mechanism? Tests of Unitarity Triangle    A CP in B 0  J/  K 0  β A CP in B 0 , ,    A CP in B  D (*) K (*)   semileptonic B decays B -  B oscillations  UT sides Directly measured: β = (21 ± 1) o α = (92 ± 7) o γ = (78 ± 12) o From UT sides: β = (24 ± 2) o α = (92 ± 4) o γ = (64 ± 4) o 2008

6 Theoretically clean (small hadronic effects) Sensitive to New Physics: charged Higgs effects at tree level Experimentally challenging: multiple neutrinos in final states B decays with „missing energy” beyond SM amplitudes

7 Decay chain: B 0 → D* - τ + ν τ D* → D 0 π D 0 → K π, K ππ 0 τ → eν e ν τ, π ν τ Signal side Tagging side First observation of exclusive semi-tauonic B decay Analysis performed entirely in Krakow Study continued: other channels B →D τν, polarization analysis Important topic at SuperB Factory B 0 →D* - τ + ν τ : highlight of B decays 2007 A. Matyja, M. Różańska et al. PRL 98, (2007) Signal yield: (5.2σ with syst.) -11 BF(B 0 → D *- τ + ν)=( (stat) ±0.37 (syst) )

8 Study of B + →  D 0 D 0 K + Dalitz plot Observation of new meson: D sJ (2700) + →D 0 K + Radial excitation of D s * or L=2 orbital excitation? Toward interpretation: resonances in D*K studied D s spectroscopy J. Brodzicka, H. Pałka et al. PRL 100, (2008)  J P =1 - cosθ hel D sJ (2700) M(D 0 K + ) D sJ (2700) ? M(D* + K s 0 ) Signal yield / 40 MeV On the PRL cover M = 2708  9  11 MeV Γ = 108  MeV -31

9 D 0 -  D 0 mixing : most unexpected result of 2007 Mixing observed in K 0 (1958), B 0 d (1987) and B 0 s (2006) Unique for D 0 : only d,s,b quarks enter the box  mixing suppressed New Physics can enlarge x and y Mixing „modifies” decay time distribution  perform time dependent study of produced D 0 and  D 0 Measure D 0 lifetime from its decay length D 1, D 2 : mass eigenstates  D 0, D 0 : flavor eigenstates Mixing governed by x and y |x|, |y| ~ O (10 -2 )|x| ~ O (10 -5 )

10 D 0 → K + K - and π + π - : CP even eigenstates D 1  τ=1/Γ 1 D 0 → K - π + : not CP eigenstate  τ=f(1/Γ 1, 1/Γ 2 ) Lifetime difference between non-CP and CP eigenstates  access to mixing if y CP ≠0  D 0 -  D 0 mixing Measured proper decay time distributions: y CP from D 0 →K + K -,π + π - Significance:3.2σ  First evidence for D 0 mixing no CPV found Belle PRL 98, (2007) y CP = -1 = y τ (K - π + ) τ (K + K - or π + π - ) + = t (fs) t (fs) if no CPV (in SM: CPV<10 -3 )

11 D 0 -  D 0 mixing: status World average mixing parameters from HFAG-charm (all existing measurements included): Statistics of SuperB Factory needed for precision measurements and searches for New Physics effects No mixing (x=0 and y=0) excluded at ~7σ y= ( 0.73 ± 0.18 )% x= ( 0.91 ± 0.26 )%

12 KEKB increased beam energies: Y(4S) → Y(5S) E(e + ): GeV → GeV, E(e - ) : GeV → GeV No modification of the detector, trigger, software e + e - → Y(5S) → B s B s,  B s *B s,  B s *B s * (with BF ~20%)  access to B s (  bs mesons ) Advantages of B s physics at B-Factory versus hadronic machines: +low background +final states with π 0 / γ +absolute BF measurements More than B u,d at B-Factory: B s physics World Y(5S) data: 1985:CESR (CLEO,CUSB): 0.1fb :CESR (CLEO III): 0.4fb -1 KEKB (Belle): : ~23 fb : ~80 fb -1 Y(4S) Y(5S) Y(6S)

13 Cabibbo favored decay: B s → D s + π - with 21.7 fb -1 (2.8M B s ) Rare decay: B s → φγ (b → s electroweak penguin) B-Factory competitive in B s physics Precision BF for normalization modes  callibration for LHCb BF(B s → D s + π - )  to reduce error of BF(B s → μ + μ - ) B s →  5.5 σ B s decays with first data M(B s *)=  0.4  0.5 MeV Bs→Ds-π+Bs→Ds-π+ 163  13 ev First observation of rare B s decay BF(B s → φγ)=( ) BF(B s → D s + π - )=( ) Belle PRL 102, (2008) Belle PRL 100, (2008)

14 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