Physics Case Theory Summary

1. Physics CaseTheory Summary Matthias Neubert – Cornell University Super B Factory Workshop Honolulu, Hawaii

2. Outline • Introductory Remarks • CKM Measurements [Hazumi, Soffer, Stewart, Yamada, Hashimoto, Swain, Pirjol, Golowich, Ligeti, Eigen] • Searching for New Physics [Nakao, Berryhill, Robertson, Soni, Yoshikawa, Kagan, Sinha, Gershon, Hara, Matsumori] • Interpreting New Physics [Hou, Kolda, Okada, Wang, Mishima, Shimizu]

3. Acknowledgements • My thinking about Super-B has been shaped over the past years (since the Michigan workshop in 2000) in many discussions with colleagues • It has also been influences by the great performance of BaBar/PEP-2 and Belle/KEK-B • Thanks to all of you!

4. Introductory Remarks Hopes and Certainties (ignoring political realities and budgetary constraints)

5. Setting the Scene • Physics potential of a super B-factory must be evaluated on the basis of a vision of the HEP arena in >2010 • BaBar and Belle completed (>500 fb-1 each) • Hadronic B-factories have logged several years of data taking • Many UT parameters determined with great precision; many tests for New Physics done in rare decays

6. Super-B is the logical continuation and completion of the B-factory program • Will provide superb measurements of SM parameters and perform a broad sets of test for New Physics • Can exhaust the potential of many measurements in the quark flavor sector

7. But … it comes in the LHC era! • Most likely (hopefully …), LHC will have discovered new particles: • SUSY partners of SM particles • Kaluza-Klein partners of SM particles • One or more Higgs bosons • New fermions and gauge bosons of a dynamical EWSB sector • Etc.

8. Crucial Questions • Can Super-B complement the measurements at the energy frontier? • Can it do fundamental measurements that cannot be done elsewhere? (including earlier B-factories) • Is it an indispensible part of our goal to comprehensively explore the physics at the TeV scale?

9. In Zoltan’s words: “Will you be able to attract the best graduate students in our field to work on Super-B?”

10. Big Questions in Flavor Physics • Dynamics of flavor? • Origin of baryogenesis? • Connections between flavor physics and the physics of electroweak symmetry breaking and/or SUSY breaking?

11. 1. Dynamics of Generations? • Gauge forces in SM do not distinguish betw. fermions of different generations: • e, μ have same electrical charge • Quarks have same color charge • All equal, but not quite equal … • Why generations? Why 3? • Why hierarchies of masses and mixings?

12. To obtain a fundamental description of the origin of fermion generations remains one of the big, unsolved problems in particle physics • Deep, difficult question, whose answer may provide access to physics at much higher energy scales New symmetries, forces, dimensions?

13. 2. Origin of Baryogenesis? • The cosmic connection linking particle physics with the evolution of the Universe Matter Antimatter Early Universe 10,000,000,000 10,000,000,000

14. The Big Annihilation Today: us 1 Sakharov criteria: • Baryon-number violation • CP violation • Non-equilibrium

16. SM has the prerequisites for baryogenesis: • Baryon number violation at high temperatures (DB=DL) • Non-equilibrium during phase transitions (phase transitions) • CP violation in the quark and lepton sector • But, the CKM phase is not sufficient! • Need additional CP phases, or a new mechanism of CP violation (leptogenesis)

17. 3. Connections with the TeV Scale • What can flavor physics tell us about the origin of electroweak symmetry breaking and/or SUSY breaking? • Whereas progress on the first two “big flavor questions” is not guaranteed (though it would be most significant), we can hardly loose on this third question!

18. Any extension of the SM that can solve the gauge hierarchy problem naturally contains many new flavor parameters, e.g.: • SUSY (hundreds of flavor- and CP-violating couplings, even in MSSM) • Extra dimensions (flavor parameters of KK states) • Technicolor (couplings of techni-quarks) • Little Higgs models (new gauge bosons W’, Z’ and fermions t’) • Multi-Higgs models (CP-violating Higgs couplings) • Etc.

19. If new Physics exists at or below a TeV, its effects should show up (at some level) in flavor physics • Flavor- and/or CP-violating couplings can only be studied using precision measurements at high luminosity • Advantage that mass scales will be known (hopefully …) from the LHC

20. Top quark: Direct production proves existence und determines mass and spin Mass prediction based on electroweak precision measurements Couplings |Vts|~0.04 and |Vtd|~0.003 as well as their CP-violating phase can only be measured in B and K physics Neutrinos: Existence known since long, but only discovery of flavor-changing interactions (neutrino oscillations) has led to revolutionary discoveries Possibility of CP violation in the lepton sector; leptogenesis Hierarchy of mixing matrix very different from that in the quark sector! Examples: Top & Neutrinos

21. Exploring flavor aspects of New Physics is not just meant to fill the Particle Data Book! • Rather, it is of crucial relevance to answer some fundamental, deep questions about Nature

22. Do non-standard CP phases exist? • Clues about baryogenesis • Is the EWSB sector flavor blind (MFV)? • Insights into the mechanism of SUSY breaking • Do right-handed currents exist? • Hints about new gauge interactions (left-right symmetry) at very high energy

23. Will see that the interpretation of New Physics signals at Super-B can be tricky • But since it is our hope to answer some very important questions, we must try as hard as we can! • The Super-B workshops have shown that a very strong physics case can be made for such a machine

24. Killer Applications and the “Worst Case Scenario” • During these workshops it has become clear (to me) that a strength of Super-B it precisely that it’s success will not depend on a single measurement • Several first-rate discoveries are possible and often likely • It is the breadth of possibilities and the reach of Super-B that make a compelling physics case, and that make it superior to hadronic B-factories

25. Like in electroweak precision measurements, New Physics effects must show up at some level of precision in flavor physics • In the worst case that we would not see any large signals in B physics, Super-B would play a similar role as LEP played for the understanding of EWSB • It would then impose most severe constraints on model building for the post LHC era

26. CKM Measurements Sides and Angles

27. The Goals • Achieve what is theoretically possible! • Can savely assume steady theoretical advances: • Ever more clever amplitude methods • Progress in effective field theory (heavy-quark expansions) • Progress in lattice QCD

28. Sides: |Vub | and |Vtd | • Precision (~5%) measurements of |Vub | require progress in theory • Exclusive determinations need precise predictions for Blight form factors from lattice QCD [Yamada, Hashimoto] or effective field theory [Pirjol] • Inclusive determinations need optimized cuts and study of power corrections in the heavy-quark expansion

29. Super-B can provide high-precision data on the q2 dependence of form factors, and on the B Xs γ photon spectrum down to 1.8 GeV, which helps to eliminate shape-function effects[Nakao] • Precision (~5%) measurements of |Vtd | require progress in lattice QCD [Yamada, Hashimoto]

30. Angles: γ=Φ3 , β+γ = Φ1+Φ3 , and 2β+γ =2Φ1+Φ3 • Many presentations at this workshop • Super-B would allow us to exploit the full theory potential of model-independent measurements of various methods [Hazumi, Soffer, Soni, Swain, Ligeti] • Could finally realize the methods that require no theoretical input

31. It’s all about γ, really… • All methods measure combinations of γ and β • Importance is that “γ measurements” measure γ from pure tree processes, whereas “α measurements” measure γ in processes where penguins are present • Probes New Physics in penguin modes

32. sin2γ with BD(flavor+CP)K l2e-idD [Soffer] Gronau, Wyler, PLB 265, 172 (GW) Atwood, Dunietz, Soni, PRL 78, 3257 (ADS) s Amplitude K+ u bc b c K+p- 1 B+ D0 u u l CPES (CP eigenstate) l(1rei(dB+g)) l g b u K-p+ bu D0 rei(dB+g) rei(dB+g)+l2e-idD c B+ s K+ u u Initial a2/a1 ~ 0.25:r~ 0.1 B0 D0p0, etc., suggestr~ 0.2 (l2~ 0.05) cos dDmeasurable @ charm factory A.S., hep-ex/9801018 Gronau, Grossman, Rosner, PLB508, 37, 2001 Atwood, Soni, hep-ph/0304085

33. New Developments [Soffer] • More modes & methods – more statistics • New methods reduce ambiguity to 2-fold • More experimental experience Each of these methods satisfies theNIMSBHO principle: Not Inherently More Sensitive But Helps Overall (despite possible claims to the contrary…)

34. sin(2b+g) with BD(*)+h- d d t b b t u B0 B0 d b ~0.02 g reid d u c d D(*)+ h- [Soffer] p,r,a1 Dunietz, hep-ph/9712401 b d c h- D(*)+ S = sin(2b+gd)

35. [Soffer] gwith 10 ab-1 • Use all methods: • Will measure g to ~ 2° (%) (stat) or less! • Only gg+p ambiguity is left • Excluded theoretically? • The error is so small that ambiguities won’t matter ~2% g

36. History of App and Spp [Hazumi] Belle This result Belle 140fb1 BaBar Difference still at ~2.0s level

37. 2) Evidence for direct CP violation 3.2s for App=0 and any Spp App 3.3s for “superweak” case Spp Belle 140fb1 Significance [Hazumi] 1) Observation of CP violation (5.2s)

38. Overview [Hazumi] • Time-dependent CP asymmetries in b g uud tree transition (assuming no penguin)  sin2f2 • Penguin is not negligible in general, need to trap it out • Methods that have been studied so far • B 0gpp Isospin analysis • B 0grp quasi 2-body method • B 0grp“full” Dalitz analysis • B 0grr Isospin analysis for a given polarization, which can be determined experimentally

39. f2“banana” in r-h plane (5 ab-1) [Hazumi] Super KEKB

40. Constraints on New Physics (NP) in mixing [Hazumi] Super KEKB

41. Removal of Penguins … • A revolutionary new proposal:

42. Searching for New Physics Never Stop Exploring

43. Probing new Physics with CKM Measurements • In general, if different determinations of unitarity triangle parameters were inconsistent, this would imply the presence of new Physics • E.g., interesting to confront the “standard analysis” of the UT (sensitive to B-B and K-K mixing) with mixing-independent constructions [Eigen]

44. Constraint from B πρ CP asym. [Beneke, Neubert] BBNS Fit of B πK and B ππ CKM parameters: β=(24±2)o γ=(67±15)o ρ=0.15±0.08 η=0.36±0.09 [Beneke, Buchalla, Neubert, Sachrajda] • Establishes CP violation in the b sector (ImVub=0) • Leaves room for New Physics in b s FCNC processes!

45. Also interesting to confront different measurements of βand γ with each other, e.g.: Belle data

46. Status of sin2β Measure-ments

47. Many more tests for New Physics can be done outside the realm of CKM measurements • Several involve rare hadronic B decays • Others make use of inclusive decays • General strategy: look for niches where the “SM background” is small (importance of “null measurements”)

48. Theory of Exclusive B Decays • Much progress has been made (and continues to be made) in this field • Great challenge to theory community • Rigorous methods based on heavy-quark expansions and/or flavor symmetries (isospin or SU 3)

49. d π - W u b u B0 π+ d W d t,c,u π - b u u B0 π+ d Flavor Topologies Tree: Penguin: Electroweak! g Z

50. Until few years ago such nonleptonic decays were believed to be theoretically intractable Recent developments: QCD factorization pQCD [Mishima, Matsumori] Soft-Collinear Effective Theory [Stewart, Pirjol] Systematic treatment (ΛQCD/mb expansion) d π - W u b u π+ B0 d Reality is Far More Complicated