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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 1 Radiative and EW Penguin B-Decays with the Belle Detector Tom Ziegler Beauty 2003 Pittsburgh, Pennsylvania 13-18 th Oct 2003 Introduction Rare/Radiative Decays Purely Leptonic Decays Status & Perspective
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 2 Introduction and Motivation b -> s and b -> sl + l - decays proceed via lflavour changing neutral current (FCNC) box and penguin diagrams b -> s penguin: BR(b->s 3.5 10 -4 Not so rare actually…
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 3 b -> sl + l - penguin:b -> sl + l - box: + BR(b->sl + l - em BR(b->s ) 10 -6 !!! New particles can/will contribute quite significantly to the decay rates and various asymmetries quite significantly via the loops! => Ideal testing ground for SM and extensions (2HDM, MSSM, GUT, …?)
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 4 The KEK-B collider 3.5 GeV e + on 8 GeV e - L > (1.0 x 10 34 )/cm 2 /sec L dt = 158 fb -1 140 fb -1 on resonance! Y (4S)
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 5 The Belle Detector 3 layer Silicon Vertex Detector Central Drift Chamber 8 GeV e - 3.5 GeV e + Aerogel Cherenkov Counter ToF counter Electromagnetic. Cal. (CsI crystals) 1.5T SC solenoid and K L detection system
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 6 Continuum suppression BB and qq have different topologies! Typical variables for Bkg suppression: - Modified Fox Wolfram moments - Sphericity cos sph ) - Thrust, cos( thr ) - … => Build Fisher discriminant F for correlated variables => Form Likelihood for uncorrelated variables: L ( F,cos B ) => Build Likelihood ratio: LR = L B / ( L B + L qq ) E = E * B – E * beam Kinematic Variables: M bc = E *2 beam – |p * B | 2
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 7 B -> K * Photon with 1.8 < E * < 3.4 GeV, 0 / veto K*(892) reconstructed in 4 final states: K + -, K 0 s 0, K + 0, K 0 s + with |M(K ) – M(K * ) r | < 75 MeV/c 2 BKG suppression against e + e - -> qq( ) -> LR(F,cos( * B ))
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 8 BR(B -> K * ) BR(B 0 -> K *0 ) = (40.9 2.1 1.9) 10 -6 SM (69 21) 10 -6 BR(B + -> K *+ ) = (44.0 3.3 2.4) 10 -6 SM (74 23 ) 10 -6 Based on 78 fb -1 ( 85 M BB-pairs) E = E * B – E * beam M bc = E *2 beam – |p * B | 2
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 9 A IS (B -> K * ) Investigate Isospin asymmetry between B0 and B+: 0+ = BR(B 0 ->K *0 ) – BR(B + ->K *+ ) BR(B 0 ->K *0 ) + BR(B + ->K *+ ) B0B0 B+B+ B+B+ B0B0 0+ = (+0.3 4.5 1.8)% SM predicts +(5-10)%! B0B0 B+B+ = 1.083 0.017 [PDG2002] Assumes f + / f 0 = 1! f + / f 0 = 1.072 0.057 [PDG2002]
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 10 A CP (B -> K * ) A CP = (-0.1 4.4 0.8)% In SM A CP should be smaller than 1% ! A CP = 1/(1-2w) N(B->K * ) - N(B->K * ) N(B->K * ) + N(B->K * ) M bc = E *2 beam – |p * B | 2
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 11 B -> K Photon with 2.0 < E * < 2.7 GeV, 0 / veto Select 2 charged K + charged/neutral K ID: |M(KK) – M( ) r | < 10 MeV/c 2 BKG suppression against e+e- -> qq( ) -> LR( F,cos( *B)) | E|<400MeV M bc = E *2 beam – |p * B | 2 B + -> K + yield = 21.6 5.6 B + -> K +
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 12 B -> K BR(B + -> K + ) = (3.4 0.9 0.4) 10 -6 -> 5.5 BR(B -> K* ) 10 BR(B + -> K + ) BR(B 0 -> K 0 ) = (4.6 2.4 0.6) 10 -6 -> 3.3 < 8.3 10-6 (@90% C.L.) B 0 -> K 0 is around the corner! and is a very promising candidate for time-dependent CPV analysis! Based on 90fb -1 ( 96 M BB-pairs) significance = -2 ln( L 0 / L max )
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 13 Belle Status of b->s in Belle ChannelBR ( 10 -6 ) L dtRef. =================================================== B -> X s 336 53 42 +50/-54 6 fb -1 [1] B 0 -> K *0 40.9 2.1 1.978 fb -1 [2] B + -> K *+ 44.0 3.3 2.478 fb -1 [2] B + -> K + 3.4 0.9 0.490 fb -1 [3] B + -> K + + - 24 5 +4/-229 fb -1 [3] B 0 -> K *0 2 (1430) 13 5 1 29 fb -1 [4] --------------------------------- B + -> + < 2.7 (@ 90% C.L.)78 fb -1 [5] B 0 -> 0 < 2.6 (@ 90% C.L.)78 fb -1 [5] B 0 -> (783) < 4.4 (@ 90% C.L.)78 fb -1 [5]
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 14 BaBar Status of b->s ChannelBR ( 10 -6 ) L dt =================================================== B -> X s 388 36 37 +43/-2354.6 fb -1 B 0 -> K *0 42.3 4.0 2.220.7 fb -1 B + -> K *+ 38.3 6.2 2.220.7 fb -1 B 0 -> K *0 2 (1430) 12.2 2.5 1.181.4 fb -1 B + -> K *+ 2 (1430) 14.4 4.0 1.381.4 fb -1
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 15 Status of BR(b->s ) B -> K * (892) (12.5%) B -> K * 2 (1430) (4%) B -> K * (9%) B -> K (9%) B -> K (1%) Rest of b->s (65±6%) K n (n>=3) Baryons + ( 13%) Mode with resonances, e.g. , ’ KKK n ( K ) …
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 16 Future of b->s Large theoretical uncertainties on BR! In ratios like A CP or Isospin asymmetries systematic uncertainties are expected to cancel (th./exp.) Current measurements are statistically limited! Also more modes accessible with more data! e.g. B 0 -> K 0 S promising candidate for time-dependent CPV analysis! Energy spectrum analysis -> transition dynamics (CKM) b->d transitions not yet observed, large CPV effects could be expected!
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 17 B -> K l + l - & B -> K * l + l - K: charged or neutral K*: K + -, K 0 s +, K + 0 with |M(K )-M(K * ) r |<75 MeV/c 2 Lepton pair: e or p(e)>0.4 GeV/c, p( )>0.7 GeV/c veto on J/ , (2S) M bc = E *2 beam – |p * B | 2 yield = 35.8 +7.6+0.9 -6.9-1.1 yield = 37.9 +7.6+1.3 -6.9-1.2
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 18 B -> K l + l - & B -> K * l + l - BR(B -> Kl + l - ) = (4.8 +1.0/-0.9 0.3 0.1) 10 -7 BR(B -> K * l + l - ) = (11.7 +2.6/-2.4 0.8 0.4) 10 -7 Based on 140 fb -1 ( 152 M BB-pairs)
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 19 BaBar Belle Status of B -> s l + l - ChannelBR ( 10 -7 ) L dtRef. =================================================== B -> X s ll 61 14 +14/-11 60 fb -1 [6] B -> Kll4.8 +1.0/-0.9 0.3 0.1 140 fb -1 [7] B -> K * ll 11.5 +2.6/-2.4 0.8 0.2 140 fb -1 [7] ---------------------------------- B -> X s ll 63 16 +18/-15 82 fb -1 B -> Kll6.5 +1.4/-1.3 0.4 113 fb -1 B -> K * ll 8.8 +3.3/-2.9 1.0 113 fb -1 B -> K 7.0 10 -5 (@90% C.L.)51/80 fb -1
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 20 Status and Perspective: B -> s l + l - Next target: precise measurement of X s l + l - increase precision in q 2 A FB measurement
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 21 B0 l+l-B0 l+l- => Helicity suppressed 2-body decay in SM + BR in SM:B-> : (1.00 0.14) 10 -10 B->ee : (2.34 0.33) 10 -15 B->e forbidden in SM, but possible in SUSY or Lepto-Quark models! Not observable, but enhancement by 2-3 orders of magnitude in 2HDM or Z mediated FCNC models.
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 22 B0 l+l-B0 l+l- Tight cut on leptons (e/ ): L > 0.9 BKG suppression with LR( F,cos( * B )) Signal box: 5.27<M bc <5.29 GeV/c 2, | E|<0.05GeV E = E * B – E * beam M bc = E *2 beam – |p * B | 2
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 23 ChannelBR (@90% C.L.) L dt =================================================== B->ee< 1.9 10 -7 78 fb -1 Belle B-> < 1.6 10 -7 78 fb -1 Belle B->e < 1.7 10 -7 78 fb -1 Belle ChannelBR (@90% C.L.) L dt =================================================== B->ee< 1.9 10 -7 78 fb -1 Belle B-> < 1.6 10 -7 78 fb -1 Belle B->e < 1.7 10 -7 78 fb -1 Belle B-> < 2.5 10 -7 113 pb -1 CDF B s -> < 9.5 10 -7 113 pb -1 CDF B s -> < 16 10 -7 100 pb -1 D0 --------------------------------------------------- B->e < 5.4 10 -6 60 fb -1 Belle B-> < 6.8 10 -6 60 fb -1 Belle B-> < 6.6 10 -6 81 fb -1 Babar B-> < 4.1 10 -4 81 fb -1 Babar Status of B ll
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 24 SM prediction for purely leptonic/radiative B-decays: B-> : 3 10 -8 B-> : > 3 10 -8 B-> : 1 10 -10 B-> : few 10 -10 B->ee : 3 10 -15 B->ee : few 10 -10 B-> : 7 10 -5 B-> : > 7 10 -5 B-> : 3 10 -7 B-> : few 10 -6 B->e : 7 10 -12 B->e : few 10 -6 Any significant increase in these BR might give hint for new physics Some of these modes should be accessible with the B-factories! Future? B ll( )
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 25 What have we achieved? Radiative B-Decays in PDG 2000: charged modesneutral modes ----------------------------------------------------- K * (892) (5.7±3.3) 10 -5 (4.0±1.9) 10 -5 K 1 (1270) < 7.3 10 -3 < 7.0 10 -3 K * 2 (1400) < 2.2 10 -3 < 4.3 10 -3 K * 2 (1430) < 1.4 10 -3 < 4.0 10 -4 K * (1680) < 1.9 10 -3 < 2.0 10 -3 K * 3 (1780) < 5.5 10 -3 < 1.0 10 -2 K * 4 (2045) < 9.9 10 -3 < 4.3 10 -3 Quite dramatic improvement in our knowledge of radiative B-decays
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 26 Summary Since last year new modes to B -> X s and B -> X s l + l - added -> first observation of B -> K and B -> K * l + l - BR and asymmetries are in good agreement with SM, but many results are statistically limited We are entering the exciting phase of precision measurements (e.g. A FB, q 2 dependence in K (*) ll ) just started Radiative Penguin decays are ideal testing ground for SM and new physics … but you knew that… Need more data to fix some of the important parameters in EW/radiative penguin transitions Many interesting discoveries are still ahead…
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 27 There are lots of them…
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 28 List of References [1] Phys.Lett. B511, 151 (2001) [2] Abs.537, BELLE-CONF-0319 Preliminary [3] Phys.Rev.Lett 98, 231801 (2002) [4] Abs.542, BELLE-CONF-0322 Preliminary [5] Moriond 2003 Preliminary [6] PRL 90, 021801 (2003) [7] hep-ex/0309032, submitted to PRL [8] hep-ex/0309069, submitted to PRD
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 29 Low energy eff. Hamiltonian H eff 10 i=1 C i ( ) O i ( ) (b->s ) = 1/32 4 G 2 F em m 5 b |V* ts V tb | 2 (|C 7 eff | 2 + O(1/m b,1/m c ))) => Access to |C 7 |
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 30 Low energy eff. Hamiltonian H eff 10 i=1 C i ( ) O i ( ) (b->s ) |V* ts V tb | 2 |C 7 eff | 2 => Access to |C 7 | Interesting observables: BR, A CP, spectrum (b->s + - )/ds |V * ts V tb | 2 O(s, |C 7 eff | 2, |C 8 eff | 2,|C 10 eff | 2, C 7 effR Re(C 9 eff )) => Access to |C 7 |, |C 9 |, |C 10 |, sgn(C 7 ) Interesting observables: BR, A FB, q 2 distribution s = q 2 /m 2 b = (M( + - )/m b ) 2
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 31 Particle ID & Kinematic Variables E = E * B – E * beam K/ separation: - dE/dx from CDC - light yield from ACC - t from ToF e ID: - dE/dx from CDC - light yield from ACC - t from ToF - CsI (ECL) ID: - hits in KLM ID: - 16X 0 CsI (ECL) Kinematic Variables: M bc = E *2 beam – |p * B | 2
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Radiative and EW Penguin Decays Tom Ziegler Beauty 2003 Pittsburgh, 13-18 th Oct 2003 32
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