Radiative and Rare B-Decays Fabrizio Salvatore  IoP Meeting  Manchester, 19 th November, 2003  Introduction  Radiative Decays B->K *  X s   Limits on b->d  decays  B->K (*) ll Decays  B->K Decays  B->X s ll Decays Many thanks to: Tom Ziegler – Belle Jeff Berryhill - BaBar Mark Convery -BaBar Eugeni Grauges – BaBar Carsten Hast – BaBar

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Introduction and Motivation b -> s  and b -> sl + l - decays proceed via flavor changing neutral current (FCNC) box and penguin diagrams b -> s  penguin: b -> sl + l - penguin: + b -> sl + l - box:

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov New particles can/will contribute quite significantly to the decay rates and various asymmetries via the loops! => Ideal testing ground for SM and extensions (2HDM, MSSM, GUT, …?) BR(b->sl + l -  em  BR(b->s  )  !!! BR(b->s  3.5  Not so rare actually… Study of such decay modes of the B meson are of extreme interest in B- Factory experiments (BaBar/Belle)

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov PEP-II Collider Peak luminosity: 6.58 x cm -2 s -1 (exceeded design goal 3.0 x ) PEP-II delivered 143 fb -1 BaBar recorded 136 fb -1 For analysis: On peak82 fb -1 ~90M BB pairs Off peak10 fb -1 Peak luminosity: 6.58 x cm -2 s -1 (exceeded design goal 3.0 x ) PEP-II delivered 143 fb -1 BaBar recorded 136 fb -1 For analysis: On peak82 fb -1 ~90M BB pairs Off peak10 fb -1

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov The BaBar Detector DIRC (PID) 144 quartz bars PMs 1.5 T solenoid Drift Chamber 40 stereo layers Silicon Vertex Tracker 5 layers, double sided strips e + (3.1 GeV) e - (9 GeV) EMC 6580 CsI(Tl) crystals Instrumented Flux Return iron / RPCs (muon / neutral hadrons)

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov The KEK-B collider 3.5 GeV e + on 8 GeV e - L > (1.0 x ) cm -2 sec -1  L dt = 158 fb fb -1 on resonance Y (4S)

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov 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

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Continuum suppression and Signal selection BB and qq have different topologies! Typical variables for Bkg suppression: - Modified Fox Wolfram moments - Sphericity cos  sph ) - Thrust, cos(  thr ) - … Signal candidates are selected using two Kinematic Variables:  Build Fisher discriminant F or Neural Network N from event shape variables  Form Likelihood for uncorrelated variables: L ( F,cos  B )  Build Likelihood ratio: LR = L B / ( L B + L qq ) VS BaBar

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B -> K *  in BaBar Photon with 2.30 < E *  < 2.85 GeV,  0 /  veto K*(892) reconstructed in 4 final states: K +  -, K 0 s  0, K +  0, K 0 s  + K+-K+- Continuum suppression: |M(K  ) – M(K * )| < 100 MeV/c <  E * <100 MeV

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov BR(B -> K *  ) in BaBar B(B 0  K *0  ) = (42.3 ± 4.0 (stat) ± 2.2 (syst))·10 -6 B(B ±  K *±  ) = (38.3 ± 6.2 (stat) ± 2.2 (syst))·10 -6 B 0  K 0 *  K 0 *  K +  - B ±  K ±*  K ±*  K ±   B 0  K 0*  K 0 *  K s 0   B ±  K ±*  K ±*  K s 0  ± 20.7 fb -1 of data ~22.7 M BR(K 0*  ) SM  (69  21)  BR(K +*  ) SM  (74  23)  PRL (2002)

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B -> K *  in Belle 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 ))

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov BR(B -> K *  ) in Belle BR(B 0 -> K *0  ) = (40.9  2.1  1.9)  BR(B + -> K *+  ) = (44.0  3.3  2.4)  Based on 78 fb -1 (  85 M BB-pairs) Belle-Conf-0319 (preliminary)

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov A CP (B -> K *  ) In SM A CP should be smaller than 1% ! Belle A CP = (-0.1  4.4  0.8)% Belle A CP = (-4.4  7.6  1.2)% BaBar K 0  0 mode not used for A cp

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B 0  K 2 * 0 (1430)  and B +  K 2 * + (1430)  BaBar Preliminary Br(B 0  K 2 *0 (1430)  ) Br(B +  K 2 *+ (1430)  ) BaBar ( ) x ( ) x Belle ( ) x Cleo ( ) x fb -1 hep-ex/ K 2 * 0 -> K +  - only K 2 * + -> K +  0, K 0  + +-+-

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B ->  K  from Belle 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 )) BR(B + ->  K +  ) = (3.4  0.9  0.4)x > 5.5  BR(B 0 ->  K 0  ) = (4.6  2.4  0.6)x10 -6 (-> 3.3  ) < 8.3x10 C.L. |  E|<400MeV B + ->  K +  yield = 21.6  fb -1 (  96 M BB-pairs) hep-ex/

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov known at 10% level at NLO B  X s  analysis HQET: Quark-Hadron Duality B(b -> s  ) = B(B -> X s  ) Model dependent assumptions on E  result from the confinement of b quark in B meson Better to impose as few requirements as possible on X s  Inclusive approach Large Backgrounds B -> X s  BB qq BaBar

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B  X s  results (BaBar) Data sample 54.6 fb -1 Significant component of bg removed by making requirements on the other B meson Lepton tag: p e(  * >1.3 (1.55) GeV/c Signal events in the region: 2.1 < E   < 2.7 GeV ~6fb -1 off-resonance used for continuum subtraction Dominant Syst error from BB bkgnd subtraction B  X d  events subtracted using SM prediction: Data Total expected bg Preliminary 543 signal events hep-ex/ From PDG

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Penguin B decays: A leading indicator of new physics at the EW scale CLEO B → X s  LEP 2 direct limit Gambino and Misiak, hep-ph/ b → s  provides a very powerful constraint on two-Higgs doublet models W H  t tt ~   Neubert, hep-ph/ CMSSM

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B   analysis Experimentally very challenging:  Low branching ratios: ~10 -6 Large continuum background contribution   from ISR and  0 /   use  veto  Continuum BG  Use NN trained with event shape variables BB bkgnd from B    decays   resonance wider (149 MeV) than K*  Use MC simulation Large background from B  K* 

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov fb -1 B   results B 0   0 ,  0   +  - B ±   ± ,  ±   +   B 0  ,    +  -   BaBar (preliminary): (hep-ex/ submitted to PRL) Use a multi-dimensional maximum likelihood fit to m ES and  E to extract yields: No Evidence found B(B 0   0  ) < 1.2·10 90%CL B(B ±     ) < 2.1·10 90% CL B(B 0   ) < 1.0·10 90% CL

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov |V td /V ts | from B   BaBar (preliminary) B   limit Isospin symmetry:  (B   ) =  (B ±     ) = 2x  (B 0     ) B(B   ) < 1.9x 10 90% CL Using Ali & Parkhomenko (Eur. Phys. J. C.23, 89 (2002)) |V td /V ts 90% CL B(B   )/B(B  K*  ) = |V td /V ts | 2  2 |1+  R| (1-m  2 /M B 2 ) 3 /(1-m K* 2 /M B 2 ) 3  =0.76±0.10  R=0.0±0.2 <  B + /  B 0 = 1.083±0.017

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Future of b->s,d  Large theoretical uncertainties on BR ! Quite dramatic improvement of our knowledge on radiative decays in the last few years, thanks to the results from B-Facotry experiments; Current measurements are still statistically limited ! More modes could be accessible with more data ! B 0 ->  K 0 S  promising candidate for time-dependent CPV analysis b->d  transitions may have contribution from physics beyond the SM (SUSY) and still have to be observed

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B -> K l + l - & B -> K * l + l - Reconstruct: K +, K s   +  -, K *0  K +  -, K *+  K s  + For B -> K * l + l < M(K  ) < 1.1 GeV/c 2 Lepton pair: e or  with p(e)>0.5 GeV/c, p(  )>1.0 GeV/c Veto on J/ ,  (2S) b->sll penguin diagrams b->sll box diagram BaBar In SM: B( B->K l + l - )~5x10 -7 B( B->K*l + l - )~3xB( B->K l + l - ) with  th ~35% +

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B -> K l + l - & B -> K * l + l - 2-D unbinned maximum LH fit to m ES and  E on all 4 decays K + ee/  and K s 0 ee/  8.4  excess over background 3-D unbinned maximum LH fit to m ES,  E and m K  Br(B  K* ll) = ( /- 1.0 )  excess over background Br(B  K ll) = ( /- 0.4 ) BaBar hep-ex/ (sub. to PRL) 113 fb -1

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov 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) yield = 37.9 yield = BR(B -> Kl + l - )=( /-0.9  0.3  0.1)  BR(B -> K * l + l - )=( /-2.4  0.8  0.2)  Based on 140 fb -1 (  152 M BB-pairs) Belle hep-ex/ (sub. to PRL) binned ML fit

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B + -> K + A rare flavor changing neutral current SM prediction: Br (B  K )  4  10 –6 (summed over all neutrino species) The best upper limits CL): CLEO: Br (B  K )  2.4  10 – 4 BaBar: Br (B  K )  9.4  10 – 5 ( Semi-Leptonic B-tags: B  Dl X (X  ,  0 or nothing)) (50.7 fb -1 ) hep-ex/ PRL (2001) New search (80 fb -1 ) with hadronic B-tags B   D 0(*) (   ) (K  ) (K 0 s ) (  0 ) (D*  D 0  and D 0  K , K  0, K3 , K s  ) Use kinematic variables  E and m ES BaBar

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B + -> K + BR(B -> K )<1.05  10  90% CL BaBar Identify tag B in  E and m ES region All remaining tracks and neutrals belong to the recoiling signal-side B One well identified Kaon with p K > 1.5 GeV/c Missing momentum within the detector acceptance no  0 ; “extra” neutral Energy < 300 MeV Data B  K MC B + B  MCB 0 B 0 MCcc MCu,d,s MC Selected events: 3 Exp. Bg events: 2.7  0.8 hep-ex/ BR(B -> K )<7.0  10  90% CL combined with previous Sub. to PRL Signal region: -1.8<  E<0.6 GeV 5.273<m ES <5.288 GeV/c 2

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B -> X s l + l - analysis l Semi-Inclusive analysis: 10 modes: 1 K ± or K 0 s (      ), (   +  0 )  2,  0  1, ~50% of BR(B  X s l + l - ) l Same analysis procedure as B -> K l + l -, but higher combinatorial bkgnd → m Xs < 1.8 GeV/c 2 B  X s e + e - B  X s  +  -  =2.5%  =1.2% 82 fb -1 on-reso Recent calculations: B(B->X s e + e - )=6.9±1.0x10 -6 B(B->X s     )=4.2±0.7x10 -6 (A.Ali et al. PRD (2002) m(e + e - ) > 0.2 GeV/C 2 BaBar preliminary

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov B -> X s l + l - analysis Br(B  X s e + e - ) = (6.6 ± 1.9 ± ) Br(B  X s     ) = (5.7 ± 2.8 ± ) Br(B  X s l + l - ) = (6.3 ± 1.6 ± ) Mode N sig (  stat) Significance (stat) B  X s e  e  29.0  B  X s     12.4  Sum 41.4 

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Status and Perspective: b -> s l + l - Next target: precise measurement of X s l + l - q 2 distribution A FB measurement

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Summary Many new (and updated) results have become available during the last year from B-Factory experiments: new measurement of B -> X s  and B -> X s l + l - updated results on B -> K (*) l + l - B -> K  and B -> X s l + l - updated results on B -> K *  and first observation of B ->  K  limits on b->dg transitions (B ->  ) and |V td /V ts | BR and asymmetries are in good agreement with SM many results are still statistically limited We are entering the exciting phase of precision measurements A FB, q 2 dependence in K (*) ll, E  distribution in B ->  K  B -> X s  Radiative Penguin decays are ideal testing ground for SM and new physics … Need more data to fix some of the important parameters in EW/radiative penguin transitions Many interesting discoveries are still ahead…

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Stay tuned !

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Backup slides

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov 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)  < <

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov BaBar Status of b->s,d  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  fb -1 B + -> K *+ 2 (1430)  14.4  4.0  fb B + ->  +  < % C.L.)78 fb -1 B 0 ->  0  < % C.L.)78 fb -1 B 0 ->  (783)  < % C.L.)78 fb -1

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Belle Status of b->s,d  ChannelBR (  )  L dt =============================================== B -> X s  336  53  /-54 6 fb -1 B 0 -> K *0  40.9  2.1  fb -1 B + -> K *+  44.0  3.3  fb -1 B + ->  K +  3.4  0.9  fb -1 B + -> K +  +  -  24  5 +4/-229 fb -1 B 0 -> K *0 2 (1430)  13  5  1 29 fb B + ->  +  < % C.L.)78 fb -1 B 0 ->  0  < % C.L.)78 fb -1 B 0 ->  (783)  < % C.L.)78 fb -1

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov Status of BR(b->s  )

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov BaBar Belle Status of b -> s l + l - ChannelBR (  )  L dt =================================================== B -> X s ll 61  / fb -1 B -> Kll /-0.9  0.3  fb -1 B -> K * ll /-2.4  0.8  fb 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

Radiative and Rare B-Decays  Fabrizio Salvatore  IoP Meeting  Manchester 19 th Nov % CL on M H + from B → X s  as a function of the world average of its error