for the BaBar and Belle Collaborations Miami 2008 Topical Conference on Elementary Physics, Astrophysics, and Cosmology Fort Lauderdale, FL, Dec 16-21, 2008 Bruce A. Schumm Santa Cruz Institute for Particle Physics University of California, Santa Cruz BaBar

Miami 2008: b  s(d)  Transition Rates 2 Bruce Schumm Effective Neutral Currents: General Motivation b  s  Penguins SUSY parameter space implications b  s  “Inclusive” approach B  X S  “Semi-Inclusive” approach b  d  Penguins and |V td /V ts | Motivation B →  (ρ,ω)  “Exclusive” approach B  →  X d “Semi-Inclusive” approach Status of |V td /V ts | Conclusions

BaBar Miami 2008: b  s(d)  Transition Rates 3 Bruce Schumm so new physics can enter at leading order: The SM b  s(d)  transition is high order (two weak plus one EM vertex) … + photon off any charged leg Although rare (~ 5x10 -4 for s  and ~10 -5 for d  ), the isolated high-energy photon is a powerful signature. V tb V t(s,d)

BaBar Miami 2008: b  s(d)  Transition Rates 4 Bruce Schumm Effective Neutral Currents: General Motivation b  s  SUSY parameter space implications Inclusive approach Other approaches b  d  and |V td /V ts | Motivation B →  (ρ,ω)  (“Standard” Approach) B  →  X d (“Semi-Inclusive” Approach) Status of |V td /V ts | Conclusions

BaBar Miami 2008: b  s(d)  Transition Rates 5 Bruce Schumm Direct searches (LEP) B  s  constraints MSSM Constraints b  s  has a significant impact on the tan  -m A plane…

BaBar Miami 2008: b  s(d)  Transition Rates 6 Bruce Schumm Fate of “Snowmass” MSSM study points … on some of our favorite scenarios …

BaBar Miami 2008: b  s(d)  Transition Rates 7 Bruce Schumm C.F. BergerC.F. Berger, J.S. Gainer, J.L. Hewett, T.G. Rizzo,J.S. GainerJ.L. HewettT.G. Rizzo “Supersymmetry Without Prejudice”, arXiv: v1 [hep-ph]arXiv: v1 Explore 10 7 points over 19- dimensional parameter space of CP-conserving MSSM b  s  most effective constraint (72% of models surviving prior constraints are eliminated; better than direct searches for SUSY partners) … and just in general.

BaBar Miami 2008: b  s(d)  Transition Rates 8 Bruce Schumm On-Peak Data Off-Peak Data (~10% of Sample)  (4S) resonance is ~1 nb at peak, competing with a “continuum” background of ~3 nb The  (4S) resonance is the lightest resonance that decays into “open Beauty” ( or )

BaBar Miami 2008: b  s(d)  Transition Rates 9 Bruce Schumm 700 fb fb -1

BaBar Miami 2008: b  s(d)  Transition Rates 10 Bruce Schumm qq + ττ BB XSγXSγ Most exacting approach (“Inclusive”) is aggressive: Use only high-energy  as signature Suppress continuum with event shapes, requirement of a high-energy lepton. Estimate remaining contribution by scaling off- peak data. Challenge: background from  0 (  )   decays (plus some fakes) in B decays

BaBar Miami 2008: b  s(d)  Transition Rates 11 Bruce Schumm To remove  0 (  )  background: Veto event if you find the 2 nd photon (~45% efficient for  0 (  ) fakes) Estimate and subtract out cases for which 2 nd photon is missed (S/B ~ 1/1) Requires knowledge of second photon efficiency to < 1%; measure using, e.g.,  0 s from e + e -   ;    +  -  0 Becoming limiting experimental uncertainty No s  signal here; provides test of  0 subtraction BELLE: (3.37  0.43)x10 -4 arXiv: fb -1 BaBar: (3.92  0.56)x10 -4 PRL97, fb -1 NOTE: Measurements scaled to E  cms = 1.6 GeV

BaBar Miami 2008: b  s(d)  Transition Rates 12 Bruce Schumm This “Semi-Inclusive” approaches employs a fit to the mass distribution, for which backgrounds tend to be self-calibrating… Reconstruct a total of 38 exclusive b  s  final states that comprise about 55% of the total width Fit to reconstructed mass of exclusive final state to determine signal yield

BaBar Miami 2008: b  s(d)  Transition Rates 13 Bruce Schumm But need to rely on models to correct for the 45% of states that are not measured (depends on mass M(X s ) that photon recoils against). Mass Recoiling Against  RESULT BF(B  s  ) = (3.49  0.57)x10 -4 PRD72: fb -1 analyzed is less than 10% of world sample Has systematics independent of those of inclusive approach

BaBar Miami 2008: b  s(d)  Transition Rates 14 Bruce Schumm Experimental accuracy commensurate with theoretical control, but work continue on both ends Inclusive Semi-Inclusive Inclusive A. Limosani, Melbourne Most of BaBar data set still unanalyzed

BaBar Miami 2008: b  s(d)  Transition Rates 15 Bruce Schumm Effective Neutral Currents: General Motivation b  s  SUSY parameter space implications Inclusive approach Other approaches b  d  and |V td /V ts | Motivation B →  (ρ,ω)  (“Standard” Approach) B  →  X d (“Semi-Inclusive” Approach) Status of |V td /V ts | Conclusions

BaBar Miami 2008: b  s(d)  Transition Rates 16 Bruce Schumm (d) V t(s,d) Note: In both cases, hadronic uncertainties minimized by comparing to corresponding V ts process (B s mixing, b  s  )  Observable is | V td / V ts | B Mixing Radiative Penguins Two independent diagrams provide sensitivity to CKM parameter V td

BaBar Miami 2008: b  s(d)  Transition Rates 17 Bruce Schumm ICHEP ’08 B Mixing Results [Farrington(CDF), Moulik(D0), averaged by DeLodovico(BaBar)]: How do penguins fit into the picture? Mixing: x d =  m B /  B ~ 1   m B ~  B Penguins: Br(b  d  ) ~   d  ~  B “These [b  d  ] vertices are CKM-suppressed in the standard model, but new physics contributions may not follow the CKM pattern in flavor- changing-neutral-current transitions and hence new physics effects may become more easily discernible in B  X d +  (and its charge conjugate) than in the corresponding CKM-allowed vertices b  s  and b  sg” Furthermore (Ali, Asatrian, Greub, Phys. Lett B 429, 87): With |V td /V ts | precisely constrained by mixing, b  d  is a compelling testbed for new physics. SM effects suppressed by relative to mixing

BaBar Miami 2008: b  s(d)  Transition Rates 18 Bruce Schumm “Traditional” Approach: measure exclusive rate Br(B   (  )  ); normalize with Br(B  K *  ) (and  ) Values of  2 and  R are state (  +,  0,  ) dependent and are available from Ali, Parkhomenko, arXiv:hep-ph/ Ball, Zwicky, J. High. Energy Phys. 0604, 046 (2006); Ball, Jones, Zwicky, Phys. Rev. D (2007) at approximately 8% overall accuracy. Annihilation Diagram

BaBar Miami 2008: b  s(d)  Transition Rates 19 Bruce Schumm Belle: New result this Spring 351 fb -1 (2006)  598 fb -1 (April 2008) BaBar: New result this Summer 316 fb -1 (April 2007)  423 fb -1 (July 2008) Challenge: BRs are small (<10 -6 ); backgrounds are high  continuumNeural Net with event shape, B tagging information, …  B → K*  ; K *  K  Require excellent particle ID  B → (      Veto if  found such that M  ~ M ( ,  )

BaBar Miami 2008: b  s(d)  Transition Rates 20 Bruce Schumm Remaining separation achieved by two-dimensional fit to the largely independent kinematic variables “Energy-substituted mass”; since E beam ~ M B, largely a measurement of momentum balance * In e + e - CMS frame E B = E beam for properly reconstructed candidate; total energy measurement Example: BaBar B 0   0   “self-calibrating” continuum background subtraction  efficiencies (~5-15%) estimated with control samples Signal Continuum b  s  Feedthrough

BaBar Miami 2008: b  s(d)  Transition Rates 21 Bruce Schumm ModeBaBar ’07 (x10 -7 )BaBar ’08 (x10 -7 ) + +  0 0     ModeBelle ’06 (x10 -7 )Belle ’08 (x10 -7 ) + +  0 0     BELLE:  598 fb -1 BaBar:  423 fb -1 Phys.Rev.D78:112001,2008 Phys.Rev.Lett.101:111801,2008, Erratum-ibid.101:129904,2008

BaBar Miami 2008: b  s(d)  Transition Rates 22 Bruce Schumm BELLE: assuming the world-average Combining, for exclusive radiative decay overall: BaBar: yielding Assuming startic quark model, SU(3) F symmetry, can combine to get “isospin-averaged” BF, and then |V td /V ts |:

BaBar Miami 2008: b  s(d)  Transition Rates 23 Bruce Schumm |V td /V ts | 2 related to  (b  d  )/  (b  s  ) with ~1% theoretical uncertainty [ Ali, Asatrian, Greub, Phys. Lett. B 429, 87 (1998) ] However, must correct for unmeasured regions: Higher-multiplicity final states Higher-mass hadronic component (i.e. M Xd > 1.8 GeV/c 2 ) “New” Approach (BaBar): Reconstruct seven exclusive final states X d  in range 0.6 GeV/c 2 < M Xd < 1.8 GeV/c 2

BaBar Miami 2008: b  s(d)  Transition Rates 24 Bruce Schumm ( , ,K * ) 1.0 < M had < < M had XSXS XdXd MEASURED UNMEASURED  and X d analyses X d analysis only M had (M Xd ) #  0 # bodies

BaBar Miami 2008: b  s(d)  Transition Rates 25 Bruce Schumm Fit in high-mass X d  region (first time measured): Yields and partial branching fractions: High-mass b  X d  Continuum background X s , MisID background B A B AR PRELIMINARY

BaBar Miami 2008: b  s(d)  Transition Rates 26 Bruce Schumm  Dominant systematic error for 1.0 < M X < 1.8 GeV/c 2  Most difficult for B  X d  (not constrained by data)  Can improve with statistics (internal constraints) Errors: Statistical  Experimental Systematic Try several models: M X given by “ KN Model ” Kagan & Neubert, Phys. Rev. D 58, (1998), with phase-space fragmentation As above, but with 50% replaced by mix of resonances Fix to measured b  s  fragmentation Primary experimental result B A B AR PRELIMINARY

BaBar Miami 2008: b  s(d)  Transition Rates 27 Bruce Schumm arXiv: [hep-ex]; submitted to PRL Precise (~1%) expression for |Vtd/Vts| [Ali, Asatrian, Greub] is based on ratio of full widths  (b  d  )/  (b  s  ) Measured region 0.6 < M X < 1.8 is ~50% of width Extrapolate to full mass region via “KN Model”; KN calculation suggests negligible difference and uncertainty in extrapolation of the ratio (because m s,m d << 1.8 GeV/c 2 ?) Ali Asatrian Greub Expt. Theory B A B AR PRELIMINARY

BaBar Miami 2008: b  s(d)  Transition Rates 28 Bruce Schumm No evidence for non-Standard Model contribution to the decay width. * PRELIMINARY *

BaBar Miami 2008: b  s(d)  Transition Rates 29 Bruce Schumm  Radiative measurements of |V td /V ts | are becoming precise: | V td /V ts | rad =   Semi-inclusive approach works, and is independent of exclusive approach, with small theoretical uncertainty  Agreement with SM (as constrained by B mixing) is good In principle, the severe SM suppression of this radiative process (x10 -6 of B mixing) should make it very sensitive to new physics contributions. Have we fully thought through the meaning of this constraint?  B  s  continues to be leading constraint on MSSM parameter space  More data exists (~80% of BaBar sample) to improve measurement, but “inclusive” approach starting to be limited by difficult systematics  “Semi-inclusive” approach has systematics independent of inclusive approach; very little of existing sample has been analyzed in this way.

BaBar Miami 2008: b  s(d)  Transition Rates 30 Bruce Schumm Backup Slides

BaBar Miami 2008: b  s(d)  Transition Rates 31 Bruce Schumm Assuming SU 3 (F) symmetry [B(B  0  ) ~ B(B  )] and (approximately true by static quark model) we can write from which it follows  Can combine  +,  0,  results to derive |V td /V ts | from

BaBar Miami 2008: b  s(d)  Transition Rates 32 Bruce Schumm

BaBar Miami 2008: b  s(d)  Transition Rates 33 Bruce Schumm