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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.

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Presentation on theme: "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."— Presentation transcript:

1 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct Radiative and EW Penguin B-Decays with the Belle Detector Tom Ziegler  Beauty 2003  Pittsburgh, Pennsylvania th Oct 2003  Introduction  Rare/Radiative Decays  Purely Leptonic Decays  Status & Perspective

2 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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  Not so rare actually…

3 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct b -> sl + l - penguin:b -> sl + l - box: + BR(b->sl + l -  em  BR(b->s  )  !!! 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, …?)

4 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct The KEK-B collider 3.5 GeV e + on 8 GeV e - L > (1.0 x )/cm 2 /sec  L dt = 158 fb fb -1 on resonance! Y (4S)

5 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct The Belle Detector 3 layer Silicon Vertex Detector Central Drift Chamber 8 GeV e GeV e + Aerogel Cherenkov Counter ToF counter Electromagnetic. Cal. (CsI crystals) 1.5T SC solenoid  and K L detection system

6 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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

7 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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 ))

8 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct BR(B -> K *  ) BR(B 0 -> K *0  ) = (40.9  2.1  1.9)  SM  (69  21)  BR(B + -> K *+  ) = (44.0  3.3  2.4)  SM  (74  23 )  Based on 78 fb -1 (  85 M BB-pairs)  E = E * B – E * beam M bc =   E *2 beam – |p * B | 2

9 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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 *+  ) B0B0 B+B+ B+B+ B0B0  0+ = (+0.3  4.5  1.8)% SM predicts +(5-10)%! B0B0 B+B+ =  [PDG2002] Assumes f + / f 0 = 1! f + / f 0 =  [PDG2002]

10 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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

11 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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 + 

12 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct B ->  K  BR(B + ->  K +  ) = (3.4  0.9  0.4)  > 5.5  BR(B -> K*  )  10  BR(B + ->  K +  ) BR(B 0 ->  K 0  ) = (4.6  2.4  0.6)  > 3.3  < 8.3  10-6 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 )

13 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct Belle Status of b->s  in Belle ChannelBR (  )  L dtRef. =================================================== B -> X s  336  53  /-54 6 fb -1 [1] B 0 -> K *0  40.9  2.1  fb -1 [2] B + -> K *+  44.0  3.3  fb -1 [2] B + ->  K +  3.4  0.9  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 + ->  +  < % C.L.)78 fb -1 [5] B 0 ->  0  < % C.L.)78 fb -1 [5] B 0 ->  (783)  < % C.L.)78 fb -1 [5]

14 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct BaBar Status of b->s  ChannelBR (  )  L dt =================================================== B -> X s  388  36  / fb -1 B 0 -> K *0  42.3  4.0  fb -1 B + -> K *+  38.3  6.2  fb -1 B 0 -> K *0 2 (1430)  12.2  2.5  fb -1 B + -> K *+ 2 (1430)  14.4  4.0  fb -1

15 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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  ) …

16 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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!

17 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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 = yield =

18 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct B -> K l + l - & B -> K * l + l - BR(B -> Kl + l - ) = ( /-0.9  0.3  0.1)  BR(B -> K * l + l - ) = ( /-2.4  0.8  0.4)  Based on 140 fb -1 (  152 M BB-pairs)

19 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct BaBar Belle Status of B -> s l + l - ChannelBR (  )  L dtRef. =================================================== B -> X s ll 61  / fb -1 [6] B -> Kll /-0.9  0.3  fb -1 [7] B -> K * ll /-2.4  0.8  fb -1 [7] B -> X s ll 63  / fb -1 B -> Kll /-1.3  fb -1 B -> K * ll /-2.9  fb -1 B -> K  7.0  C.L.)51/80 fb -1

20 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct Status and Perspective: B -> s l + l - Next target: precise measurement of X s l + l - increase precision in q 2 A FB measurement

21 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct B0  l+l-B0  l+l- => Helicity suppressed 2-body decay in SM + BR in SM:B->  : (1.00  0.14)  B->ee : (2.34  0.33)  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.

22 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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

23 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct ChannelBR C.L.)  L dt =================================================== B->ee< 1.9  fb -1 Belle B->  < 1.6  fb -1 Belle B->e  < 1.7  fb -1 Belle ChannelBR C.L.)  L dt =================================================== B->ee< 1.9  fb -1 Belle B->  < 1.6  fb -1 Belle B->e  < 1.7  fb -1 Belle B->  < 2.5  pb -1 CDF B s ->  < 9.5  pb -1 CDF B s ->  < 16  pb -1 D B->e < 5.4  fb -1 Belle B->  < 6.8  fb -1 Belle B->  < 6.6  fb -1 Babar B->  < 4.1  fb -1 Babar Status of B  ll

24 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct SM prediction for purely leptonic/radiative B-decays: B->  :  3  B->  : > 3  B->  :  1  B->  :  few  B->ee :  3  B->ee  :  few  B->  :  7  B->  : > 7  B->  :  3  B->  :  few  B->e  :  7  B->e  :  few  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(  )

25 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct What have we achieved? Radiative B-Decays in PDG 2000: charged modesneutral modes K * (892)  (5.7±3.3) (4.0±1.9) K 1 (1270)  < < K * 2 (1400)  < < K * 2 (1430)  < < K * (1680)  < < K * 3 (1780)  < < K * 4 (2045)  < < Quite dramatic improvement in our knowledge of radiative B-decays

26 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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…

27 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct There are lots of them…

28 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct List of References [1] Phys.Lett. B511, 151 (2001) [2] Abs.537, BELLE-CONF-0319 Preliminary [3] Phys.Rev.Lett 98, (2002) [4] Abs.542, BELLE-CONF-0322 Preliminary [5] Moriond 2003 Preliminary [6] PRL 90, (2003) [7] hep-ex/ , submitted to PRL [8] hep-ex/ , submitted to PRD

29 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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 |

30 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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

31 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct 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

32 Radiative and EW Penguin Decays  Tom Ziegler  Beauty 2003  Pittsburgh, th Oct


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