1. DOE SITE VISIT Monday, July 27, 2011 Bruce A. Schumm Santa Cruz Institute for Particle Physics University of California, Santa Cruz BaBar

2. 2010 DOE Site Visit2 Bruce Schumm Senior Al Eisner (volunteer) Bruce Schumm Student Joel Martinez (B   Ph.D. expected 9/2011) Post-doc William Panduro-Vazquez (volunteer; now an ATLAS postdoc at)

3. BaBar 2010 DOE Site Visit3 Bruce Schumm Effective Neutral Currents: General Motivation b  s  Penguins SUSY parameter space implications b  s  “Inclusive” approach b  d  Penguins and |V td /V ts | Motivation B  →  X d “Semi-Inclusive” approach Status of |V td /V ts | CP Violation in B →  ρ o  Conclusions

4. BaBar 2010 DOE Site Visit4 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) (d)

5. BaBar 2010 DOE Site Visit5 Bruce Schumm Effective Neutral Currents: General Motivation b  s  SUSY parameter space implications Inclusive approach b  d  and |V td /V ts | Motivation B  →  X d (“Semi-Inclusive” Approach) Status of |V td /V ts | CP Violation in B 0  0  Conclusions

6. BaBar 2010 DOE Site Visit6 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:0812.0980v1 [hep-ph]arXiv:0812.0980v1 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)

7. BaBar 2010 DOE Site Visit7 Bruce Schumm 700 fb -1 440 fb -1

8. BaBar 2010 DOE Site Visit8 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 continuum by scaling off- peak data. Challenge: background from  0 (  )   decays (plus some fakes) in B decays

9. BaBar 2010 DOE Site Visit9 Bruce Schumm B/Bbar background control region BB Cont. Signal Sig. Region Most prominent SCIPP Contributions:  0,  rejection and backgrounds Anti-neutron backgrounds BAD editor (Eisner)

10. BaBar 2010 DOE Site Visit10 Bruce Schumm Collaborating with SLAC, Notre Dame; SCIPP playing central role since 2003 (Schmitz thesis, Winstrom candidacy project) Inclusive Semi-Inclusive Inclusive A. Limosani, Melbourne BaBar Result on 360 fb -1 is finalized:

11. BaBar 2010 DOE Site Visit11 Bruce Schumm Branching Fraction Results (x 10 4 ) Quoted errors: (stat%)  (syst%) BABAR Runs I-V E  * > 2.02.80  0.12  0.14   6.6% E  * > 1.93.00  0.14  0.19   7.9% E  * > 1.83.20  0.15  0.29   10.2% BELLE 605 fb -1 E  * > 1.83.24  0.17  0.24   9.1 % Expect to quote preliminary result for E  * > 1.8 this summer (ICHEP)

12. BaBar 2010 DOE Site Visit12 Bruce Schumm E*E* Signal Photons per 0.1 GeV NOT YET PUBLIC SIGNAL REGION Runs I-V But: Predictions are in B rest frame  unfold detector smearing and boosts…

13. BaBar 2010 DOE Site Visit13 Bruce Schumm Largest effect is boost at kinematic edge.  Nearing review-board approval (!!)  Phys. Rev. D article in prepartation Signal Photons per 0.1 GeV E  cms Procedure: An iterative, dynamically-stabilized method of data unfolding, B. Malaescu, ArXiv 0907:3791

14. BaBar 2010 DOE Site Visit14 Bruce Schumm Effective Neutral Currents: General Motivation b  s  SUSY parameter space implications Inclusive approach b  d  and |V td /V ts | Motivation B  →  X d (“Semi-Inclusive” Approach) Status of |V td /V ts | CP Violation in B 0  0  Conclusions

15. BaBar 2010 DOE Site Visit15 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

16. BaBar 2010 DOE Site Visit16 Bruce Schumm ICHEP ’08 B Mixing Results [Farrington(CDF), Moulik(D0), averaged by Di Lodovico (BaBar)]: How do penguins fit into the picture? Mixing: x d =  m B /  B ~ 1   m B ~  B Penguins: Br(b  d  ) ~ 10 -5   d  ~ 10 -5  B With |V td /V ts | precisely constrained by mixing, b  d  is a compelling testbed for new physics. SM effects suppressed by 10 -5 relative to mixing

17. BaBar 2010 DOE Site Visit17 Bruce Schumm Standard (“Exclusive”) Approach: measure exclusive rate Br(B   (  )  ); normalize with Br(B  K *  ) (and  ) Values of  2 and  R are available from Ali, Parkhomenko, arXiv:hep-ph/0610149 Ball, Zwicky, J. High. Energy Phys. 0604, 046 (2006); Ball, Jones, Zwicky, Phys. Rev. D 75 054004 (2007)  8% uncertainty on extraction of |V td /V ts |. Annihilation Diagram

18. BaBar 2010 DOE Site Visit18 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) ] Alternative Approach (Runs I-V): Reconstruct seven exclusive final states X d  in range 0.6 GeV/c 2 < M Xd < 1.8 GeV/c 2 ( now published in PRL 102:161803,2009 Collaborating with I.C. London & SLAC New: Include Run VI, re-optimize event selection; extend M Xd to 2.0 GeV/c 2

19. BaBar 2010 DOE Site Visit19 Bruce Schumm K * Region 1.0 < M had < 2.02.0 < M had XSXS XdXd MEASURED UNMEASURED  and X d analyses X d analysis only M had (M Xd ) #  0 # bodies #  0 # bodies MEASURED UNMEASURED 0.6 < M had < 1.0

20. BaBar 2010 DOE Site Visit20 Bruce Schumm Fit in high-mass X d  region 1.0 < M had < 2.0 GeV/c 2 EEM ES B A B AR PRELIMINARY First significant observation of b  d  above resonant region Primary Exptl Result (prior result: 0.033  0.013  0.009); Submitted to PRL

21. BaBar 2010 DOE Site Visit21 Bruce Schumm Submitted to PRL Ali Asatrian Greub Expt. Theory Ratio of partial widths related to |V td /V ts | with very small uncertainty B A B AR PRELIMINARY

22. BaBar 2010 DOE Site Visit22 Bruce Schumm No evidence for non-Standard-Model contribution to the b  d  decay width. Starting to receive attention from theory community: Crivellin, Mecolli,“B  X d  and Constraints on New Physics” arXiv:1106.5499 Published Sept 2010: Phys.Rev.D82:051101

23. BaBar 2010 DOE Site Visit23 Bruce Schumm Invited review: Radiative Penguin transition rates (published in Modern Physics Letters A, August 2010) Invited talk: 2011 Lake Louise Winter Institute

24. BaBar 2010 DOE Site Visit24 Bruce Schumm Separate out B 0 (“+”) and anti-B 0 (“-”) decays; look at asymmetry in time-evolution: Standard Model expectation: C = -0.1 and S = 0 (due to phase cancellation between mixing and t-quark-dominated decay)

25. BaBar 2010 DOE Site Visit25 Bruce Schumm Significant signal- region backgrounds are: Continuum Generic B K  - Small fraction of non- truth-matched signal (no special treatment) MODEExpected # events (440 fb -1 ) Truth-matched signal41.6 Non-truth-matched signal8.7 Continuum1734 + +  0.5    0.7 K+ -K+ - 17.6 K+ 0K+ 0 0.3 K0S -K0S - 15.2 K0S 0K0S 0 0.0 B0B0B0B0 59.0 B+B-B+B- 44.2

26. BaBar 2010 DOE Site Visit26 Bruce Schumm ttdEM ES

27. BaBar 2010 DOE Site Visit27 Bruce Schumm ttdEM ES K+-K+- K0S-K0S- Displaced; broad Broader tail

28. BaBar 2010 DOE Site Visit28 Bruce Schumm Significant dEM ES tt B+B-B+B- B0B0B0B0

29. BaBar 2010 DOE Site Visit29 Bruce Schumm tt dE M ES Fit components: Signal Continuum Generic B K +  - K 0 S  -

30. BaBar 2010 DOE Site Visit30 Bruce Schumm Plan to employ a two-stage fit: 1)Fit over full region in dE and M ES (ignore  t) to establish continuum and normalization and shape and signal normalization 2)Fit over signal region (including  t) to extract S, C, fixing continuum and signal parameters to the values obtained in 1).

31. BaBar 2010 DOE Site Visit31 Bruce Schumm Fit for N sig : = 50  19 = -0.07  0.03

32. BaBar 2010 DOE Site Visit32 Bruce Schumm Fit for S,C: = 0.47 = 0.01  0.03

33. BaBar 2010 DOE Site Visit33 Bruce Schumm  SCIPP playing central role in key radiative penguin measurements  Inclusive b  s  measurement very challenging; drafting long PRD with  10% (E  * > 1.8 GeV) (prior result was  14.5% for E  * > 1.9 GeV)  Intensive focus on b  d  transition * Rates  Three PRL, one PRD in last three years * CP Violation  Expect result in ~6 months  First observation of non-resonant b  d  transition (Impact of b  d  signature may not yet be fully appreciated)  Schumm wrote s(d)  review article for World Scientific  5 PhD theses; 6 th on the way

34. BaBar 2010 DOE Site Visit34 Bruce Schumm Backup Slides

35. BaBar 2010 DOE Site Visit35 Bruce Schumm ObjectSourceControl RegionSignal Region 00 57.3%66.6%  17.1%15.7%  Other meson8.7%5.1%  e9.3%4.7%  Other0.4% Total  92.8%92.4% eAny4.8%3.7% n/n bar Any1.7%2.9% p + /p - Any0.0%0.1%  /K Any0.4%0.8% Total non-  7.2%7.6% Total100% Sources of B/Bbar Background (after full selection)

36. BaBar 2010 DOE Site Visit36 Bruce Schumm   If high-energy  passes selection, then look for low-energy  and veto event 0,0, ~50% of the time the low-energy photon is missing. Modeling of low-energy (30-80 MeV) photon efficiency to ~ 1% critical to lowering systematic error One example of SCIPP group contribution Also: Anti-neutron backgrounds, photon efficiency, … Major source of BB background due to high-energy photons from  0 (  )   (67% + 15% = 82% of total BB background according to MC)

37. BaBar 2010 DOE Site Visit37 Bruce Schumm cos  h Define cos  h  (E ,high - E ,low )/ (E ,high + E ,low ) = energy asymmetry Signal selection requirement of E  * > 1.8 GeV pushes asymmetry up, and energy of 2 nd photon down.  Sensitive to reconstruction efficiency for 30-80 MeV photons. Measurement of  0 reconstruction efficiency from (  )/(  ) Expected/Measured cos  h But: can bootstrap to lower E  with dedicated  0 sample

38. BaBar 2010 DOE Site Visit38 Bruce Schumm B  X (d,s)  : Correction for Missing Modes Missing modes with 0.6 < M X < 1.0 MC suggests this region is dominated by resonances (  and  ); confirmed by K* dominance of B  X s  Correction for missing modes well understood MC Simulation Two-body X s(d)  decay; mass spectrum of X s(d) system given by Kagan-Neubert model A.L. Kagan, M. Neubert, Phys. Rev. D 58, 094012 (1998) Fragment X s system via prior experimental constraint Fragment X d system via phase space

39. BaBar 2010 DOE Site Visit39 Bruce Schumm Missing Modes with 1.0 < M X < 1.8 Force 50% of decays to un-weighted mix of higher-mass resonances Force X d decay to be identical to X s decay up to substitution s  d B  X S  Resonances K 1 (1270) K 1 (1400) K * (1410) K 2 * (1430) K * (1680) B  X d  Resonances h 1 0 (1170) b 1 0 (1235) b 1 + (1235) a 1 0 (1260) a 1 + (1260) f 2 0 (1270) f 1 0 (1285) a 2 0 (1320) a 2 + (1320) B  X (d,s)  : Correction for Missing Modes