1 1 D. Hitlin SLAC B-Day March 20, 2003 David Hitlin Caltech March 20, 2003

2 2 D. Hitlin SLAC B-Day March 20, 2003 Parsing the title of the talk Physics Challenges The improvement of measurement precision is a sufficient motivation for a machine, if and only if the improved precision takes us into discovery territory There are indeed areas in which large data samples (10-50 ab -1 ) can lead, with reasonable certainty, to measurable new physics effects, by increasing precision or making certain measurements possible The context is also important What new physics potential exists with a ab -1 sample that doesn’t exist with a ab -1 sample? What can an asymmetric e + e - machine at contribute beyond what can be done at hadron experiments ( ATLAS, CMS, LHCb, BTeV )? What is the time window for ? Detector Challenges What do we need in a detector to do physics at a machine? Should there be an upgrade of B A B AR, or a totally new detector? What R&D is required on new detector subsystems?

3 3 D. Hitlin SLAC B-Day March 20, 2003 The New Physics Bible according to Nir CP violation is an excellent probe of new physics The Standard Model CKM mechanism has a single source of CPV and makes quantitative predictions New sources of flavor and CP violation can induce large deviations from the Standard Model predictions, many of which are not obscured by hadronic uncertainties Henceforth in this discussion, I will emphasize the supersymmetric Standard Model as an example, although other extensions of the Standard Model can also produce observable effects The supersymmetric SM has 124 independent parameters, 44 of which are CP- violating What are the constraints of existing measurements of CPV on SUSY model building? What are the prospects that future CPV measurements will uncover deviations from the SM predictions? H aving found that A CP in agrees with CKM prediction, we are beyond the era of seeking alternatives to the CKM phase and must now search for new physics by finding loop corrections to the CKM picture

4 4 D. Hitlin SLAC B-Day March 20, 2003 New CP Violating effects must be there CP effects in the flavor sector that are not accounted for by the CKM phase must exist If they do not exist, SUSY and other models constructed with the same motivation will be ruled out The sensitivity required to see these effects can be reached It is possible, though not likely, that SUSY could be discovered through loop effects before there is explicit production of new particles at LHC Assume that evidence for SUSY is found at the LHC or NLC What will we actually know? The masses of some of the SUSY partners: gluino, squark, …….. Something about coupling constants Perhaps the identity of the LSP Even if the first evidence for SUSY comes from LHC, it will be important to study CPV in flavor physics at the scale of to B decays

5 5 D. Hitlin SLAC B-Day March 20, 2003 SUSY mass spectra for the 9 Snowmass points & slopes SPS-9 SPS-8SPS-7 SPS-6 SPS-5 SPS-4 SPS-3 SPS-2 SPS-1 Ghodbane and Martyn

6 6 D. Hitlin SLAC B-Day March 20, 2003 Many SM extensions yield measurable effects in B physics Little Higgs w MFV UV fix Extra dim w SM on brane Supersoft SUSY breaking Dirac gauginos SM-like B physics New Physics in B data MSSM MFV low tan b Generic Little Higgs Generic extra dim w SM in bulk SUSY GUTs Effective SUSY MSSM MFV large tan b after G. Hiller

7 7 D. Hitlin SLAC B-Day March 20, 2003 Mapping SUSY-breaking schemes to flavor models MSUGRA GMSB AMSB ĞMSB Exact Universality Approximate Universality No Universality Approximate CP MFV Extended MFV SUSY GUTS J. Hewett

8 8 D. Hitlin SLAC B-Day March 20, 2003 Constraints on SUSY from existing measurements In order to obey the constraints from K decay: Indirect CPV in and decays: |e| = (2.28  0.02) x Direct CPV in decays: Re |e/e|= (1.66  0.16) x it is necessary to invoke one or more of the following: Heavy squarks: Universality: Alignment: Approximate CP: CPV phases are small All viable models of SUSY-breaking use one or more of these mechanisms Two other measurements: A CP in decay: Im l  K =  Limits on EDM’s (through T violation and CPT ) impose serious additional constraints For example, A CP effectively kills Approximate CP models EDM limits imply that the source of CPV beyond the Standard Model in models with minimal flavor violation is Yukawa couplings, which can be flavor dependent

9 9 D. Hitlin SLAC B-Day March 20, 2003 Effects of SUSY breaking on CPV in flavor physics Specific models produce specific CPV patterns There are a variety of models of SUSY breaking on the market Many of these models generate specific, calculable CP -violating effects in hadronic and rare B decays Other extensions (extra dimensions, Little Higgs,….) have the same sorts of effects, although they often have distinguishable patterns In order to exploit CP violation as a tool to search for physics beyond the Standard Model we must do two things: Achieve the highest meaningful precision on CPV ( a, b, g ) measurements of the B unitarity triangle This requires several x 10 ab -1 Measure kinematic distributions and CP -violating (and sometimes CP - conserving) asymmetries in very rare decays with branching fractions of <10 -5, both inclusive and exclusive These are decay modes such as where we have at present only a handful of events

10 10 D. Hitlin SLAC B-Day March 20, 2003 Probes of new physics - I 1)Measure the CP asymmetry in modes other than that measure sin2 b in the Standard Model Precision of benchmark sin2 b in can improve to the  1% level Expect the same value for “sin2 b ” in “, but different SUSY models can produce different asymmetries A great deal of luminosity is required to make these measurements to meaningful precision

11 11 D. Hitlin SLAC B-Day March 20, 2003 From the B A B AR Physics Book (SLAC ‑ R ‑ 504)

12 12 D. Hitlin SLAC B-Day March 20, 2003 Variations from SM predictions can be substantial Goto, et al. Three examples mSUGRA SU(5) SUSY GUT with n R U(2)

13 13 D. Hitlin SLAC B-Day March 20, 2003 Many CP asymmetries can be changed by SUSY Ciuchini, Franco, Martinelli, Masiero, & Silvestrini r SM r 500 r 250

14 14 D. Hitlin SLAC B-Day March 20, 2003 SUSY models are already constrained by A CP, D m, EDM U(2) model of Masiero, et al. There are two real parameters, j and y  j = -0.25, y = 0 j = -0.25, y = x j = -0.5, y = -0.25

15 15 D. Hitlin SLAC B-Day March 20, 2003 Other Standard Model extensions also change CPV Correction to SM prediction Effective SUSY Enhanced chromo- magnetic dipole SUSY without R-parity Grossman and Worah

16 16 D. Hitlin SLAC B-Day March 20, 2003 An example: CP in The fact that the CP asymmetry in is so close to the Standard Model prediction tells us that new CP -violating contributions to b  d transitions (via ) are small The fact that is close to the Standard Model value tells us that the helicity-conserving part of is small. The helicity-changing part of, i.e., and could still be large and enter the supersymmetric gluonic penguin that contributes to This produces a series of inter-related constraints: Chang, Masiero, Murayama: Change in B(b  s g ) A CP f K S D m s

17 17 D. Hitlin SLAC B-Day March 20, 2003 B A B AR f K S results N cand = 66 Purity = 50% 81.3 fb -1

18 18 D. Hitlin SLAC B-Day March 20, 2003 Current A CP ( f K s ) has large errors, but opposite sign Interesting, but not yet a persuasive case for new physics Pure CKM forbidden penguin amplitude

19 19 D. Hitlin SLAC B-Day March 20, 2003 CP violation in modes that measure “ sin2 b ” ” Decay modeB x Decay process SC  | l |=0.95         0.46 | l |=0.98  0.27 It is certainly premature to draw any conclusions about disparities. One mode is clean: f K S. Branching ratio is small. Could a statistically persuasive case for a different A CP from J/ y K S be made?

20 20 D. Hitlin SLAC B-Day March 20, 2003 What level of precision is required ? Statistical/systematic error on sin2 b from will improve to somewhat beyond the 1% level. More than adequate SUSY effects on sin2 b in other modes can be quite large, tens of percent of the CKM value With what precision must one measure sin2 b in other, more difficult decay modes in order to establish an effect? An example: sin2 b ( ) = 0.75 (its current value), but the error is reduced to 1%, s = , sin2 b ( ) = 0.60, i.e., the SUSY contribution to is 20% For a 5 sigma effect: D sin2 b = 0.15/5 = 0.03, a 5% measurement This requires a data sample of the size provided by a asymmetric B Factory

21 21 D. Hitlin SLAC B-Day March 20, 2003 Extrapolated statistical errors on CP asymmetries 10 to 50 ab -1 are required for a meaningful comparison Current precision B A B AR measurement errors

22 22 D. Hitlin SLAC B-Day March 20, 2003 Probes of new physics - II 2) Measure branching ratios and kinematic distributions in rare decays that are sensitive to new physics, particularly those involving b  s transitions Requires tens of ab -1

23 23 D. Hitlin SLAC B-Day March 20, 2003 Kinematic distributions and CP asymmetries in rare decays ® Bauer, Stech & Wirbel ® Ball and Braun ® Melihov, Nikitin and Simula ® SM, …… > SUGRA with  C 7,  MIA with suppressed Br,  MIA with enhanced Br Ali, et al. Standard Model predictions are robust In SUGRA, sign of C 7 determines sign of A FB

24 24 D. Hitlin SLAC B-Day March 20, 2003 Probe of SUSY in and Ali and Safir SM SUGRA Standard Model predictions are robust

25 25 D. Hitlin SLAC B-Day March 20, 2003 CPV in exclusive radiative decays Ali and Lunghi

26 26 D. Hitlin SLAC B-Day March 20, 2003 Bartl, Gajdosik, Lunghi, Masiero, Porod, Stremnitzer and Vives, hep:ph/ MSSM: CP asymmetry in b  s  · No EDM constraint · Obey EDM constraint

27 27 D. Hitlin SLAC B-Day March 20, 2003 The effect of extra dimensions on UT parameters Buras, et al.

28 28 D. Hitlin SLAC B-Day March 20, 2003 Probes of new physics - III 3)Measure sides and angles of the Unitarity Triangle to best possible precision a b g Improve measurements of |V ub | and |V cb | essentially independent of new physics Super B Factory using the recoil technique Measure D m s Hadron machine Improve measurement of D m d Super B Factory Measure sin2 a Super B Factory using p 0 p 0 Measure sin2 a eff Super B Factory Hadron machine Measure g Super B Factory Hadron machine Measure sin2 b Super B Factory Hadron machine Test a + b +g =p to ~5-10% Improve calculations of |V ub |, |V cb |, Lattice

29 29 D. Hitlin SLAC B-Day March 20, 2003 The B beam technique Reconstruct a very large sample of of hadronic decays at the Y(4S) In 10 ab -1, there are 4 x 10 7 fully reconstructed B ’s in which the four momentum of the recoil is known Use this sample to study semileptonic decays and rare (inclusive) decays The B beam technique, unique to e + e -, sacrifices statistics, but Improves kinematics – reducing model dependence in | V ub | and | V cb | studies Reduces background for rare decays, especially those involving photons and neutrinos

30 30 D. Hitlin SLAC B-Day March 20, 2003  (radians) Luminosity (fb -1 ) measure  ’  for B ( B ) from L = 10 ab -1  (radians)  (radians) L = 2 ab -1 … but there is a 4-fold ambiguity!  ’’ With 10 ab -1, the Gronau-Wyler construction can place a stringent limit on penguin amplitudes Isolating the penguin contribution to sin2 a using sin2  eff = 0.02 ±0.34 ± 0.05 with 2  eff = 2  s(Da) = 4 to 10   Cahn, Roodman

31 31 D. Hitlin SLAC B-Day March 20, 2003 An independent estimate of the Gronau-Wyler construction Uses current central values

32 32 D. Hitlin SLAC B-Day March 20, 2003 Measuring g with B  DK Gronau-Wyler, Atwood, Dunietz and Soni method: Comparison of BR’s for B  DK modes can allow extraction of g There is an 8-fold ambiguity With sufficient luminosity, it is possible to resolve the ambiguity: with 10 ab -1, it appears that a precision of Dg  1  -2.5  can be achieved Study was done with 600 fb -1, scaled to 10 ab -1 Soffer

33 33 D. Hitlin SLAC B-Day March 20, 2003 Eigen, Kronfeld, Mackenzie Snowmass 2001 scenario for improvement in the precision of CKM matrix elements

34 34 D. Hitlin SLAC B-Day March 20, 2003 A projection to 2010 by the CKM Fitter group b b

35 35 D. Hitlin SLAC B-Day March 20, 2003 Improvement of UT measurements can test the SM (Buras) Optimal Unitarity Triangle Test Improve measurements of | V ub | and | V cb |, which are essentially independent of new physics contributions This is best done at a B Factory using the “ B beam” technique Measure D m s – domain of hadron machines Improve theory estimates: | V ub |, | V cb |, and This yields a prediction for g, which is measurable both at a B Factory and in hadron experiments Test of the mixing matrix element With the above and with improved knowledge of e K and D m d, we have the best possible prediction of the mixing matrix element and thus of m t, which can be compared with improved direct measurements

36 36 D. Hitlin SLAC B-Day March 20, 2003 Simulations of more of these measurements are needed Calculations needed at 10 and 50 ab -1 How well can we measure V ub with the recoil technique f B with recoil technique a g A FB in s + - or K (*) + - vs B ( B  rg ) mixing B( t  mg ) PRAVDA Monte Carlo tool with a capable detector is nearly ready for these studies

37 37 D. Hitlin SLAC B-Day March 20, 2003 Statistics and systematics Nearly all important CPV measurements will remain statistics limited Certain measurements, such as A CP in will be systematics limited at below the ~1% level Other measurements, such as the extraction of sin2 a or V ub will be limited by theory Many of the most interesting measurements will be limited by statistics and backgrounds This leads to the question of whether an upgraded detector can do better than a extrapolation would indicate Does improved momentum resolution and improved particle ID lead to a better measurement of S pp by improving S/B ? Does improved photon energy and angular resolution lead to a better measurement of tagged ? Does longitudinal segmentation in the EMC lead to better p / e separation and thus better tagging?

38 38 D. Hitlin SLAC B-Day March 20, 2003 Comparison of e + e - B Factories and hadronic experiments Wűrthwein

39 39 D. Hitlin SLAC B-Day March 20, 2003 What is the future of experimental flavor physics? Total B A B AR, Belle data samples will amount to ~ fb -1 each CDF (DØ), in areas which overlap e + e -, are being calibrated with TeV-II data Würthwien(SSI02): for untagged B  h + h - : 2 fb -1 (CDF)  500 fb -1 ( B A B AR, Belle) CDF/DØ can, of course, study B s decay, but is unlikely, in general, to markedly improve on e + e - results in other areas LHC experiments will bring statistics to the next level In this context, is a new, very high luminosity e + e - effort warranted? e + e - experimentsHadron experiments The current lineup: B A B AR, BelleCDF, DØ The situation in ~2010Super BABAR or SuperBelle ATLAS, CMS, LHC b B TeV

40 40 D. Hitlin SLAC B-Day March 20, 2003 LHC b physics performance Sensitivity Relative to LHCb 1 year operation Atlas/CMS (1 year) B A B AR 0.5ab BTeV (1 year) LHCb (Value)  (Sin2  Expt  (Sin2  LHCb 0.9/  (Sin2  Expt  (Sin2  LHCb 1.8/ ???  (  Expt  (  LHCb   (-2  Expt  (-2  LHCb  1.6/ K 1.2/

41 41 D. Hitlin SLAC B-Day March 20, 2003 SLAC-PUB-8970 * * Two arm BTeV At 10 36, e + e - is fully competitive in rare decay studies

42 42 D. Hitlin SLAC B-Day March 20, 2003 Comparison of 1 year yields – B Tev and Super B Factory Mode BTeV Super B YieldTaggedYieldTagged BsJ/yBsJ/y B-K-B-K B0KsB0Ks B 0  K*  +  ~1000 Bs +-Bs + B0+-B0+ D *+   + D 0, D 0  K -  + ~ x10 7

43 43 D. Hitlin SLAC B-Day March 20, 2003 A BTeV -generated comparison (updated from ) Number of flavor tagged B 0   +  - (B = 0.45x10 -5 ) Number of B -   D 0   (Full product B = 1.7x10 -7 ) B s, B c and  b studies are not done at U (4S) e + e - machines ag

44 44 D. Hitlin SLAC B-Day March 20, 2003 Comparison of hadronic and reach A comparison from the Snowmass E2 Group summary:

45 45 D. Hitlin SLAC B-Day March 20, 2003 Main concerns Machine-related backgrounds synchrotron radiation particle backgrounds, due primarily to continuous injection Radiation dose Physics backgrounds – hadronic split-offs, ….. The environment 7MRad/ y 100% Occupancy 25MHz >10 hits/crystal/event SVT DCH DIRC EMC

46 46 D. Hitlin SLAC B-Day March 20, 2003 There is an upgrade path from B A B AR to Super B A B AR If it were feasible to modify the existing B A B AR detector for use at a machine, there would be substantial savings in time, money and effort over a completely new detector Upgrading the existing detector is beneficial in Reducing costs by reuse of detector components and existing IR infrastructure Use of existing software as a basis for new programs Packaging an attractive proposal for funding agencies An affordable, fast, radiation hard electromagnetic calorimeter is the key to the morphing of B A B AR into Super B A B AR An LXe EMC fits into the existing B A B AR solenoid/flux return There is a substantial cost saving over most crystals Tracking with pixels/strips and a compact readout DIRC are compatible with this design

47 47 D. Hitlin SLAC B-Day March 20, 2003 An upgrade path from B A B AR to Super B A B AR 1.IFR upgraded (ongoing) 2.Remove SVT, DCH, EMC, DIRC 3.New EMC – liquid Xe 4.New tracker – Two inner pixel layers Seven(?) thin double-sided Si-strip arch layers 5.New DIRC(s) with compact readout BABAR SuperBABAR

48 48 D. Hitlin SLAC B-Day March 20, 2003 The MSSM (Minimal Symbolic Straw Man) Upgrade Detector This B A B AR upgrade design has not been optimized It is certainly possible to improve upon this design This will be among the first orders of business when the physics foundation for has been solidified We are currently implementing this design into a fast Monte Carlo called PRAVDA Implementation includes the flexibility to Vary parameters within a detector subsystem Swap technologies for a given subsystem TRACKERR package (complete error matrix) for vertex/tracking with an all silicon tracker has been implemented Use parameterized descriptions for PID, EMC and IFR A shower library is also under development for the EMC

49 49 D. Hitlin SLAC B-Day March 20, 2003 Vertexing and Tracking Pixel layers needed near beampipe Double-sided strips for main tracking Drift chamber is unlikely to survive An all silicon tracker with two pixel layers + seven double-sided strip layers is a good candidate R outer = 60 cm It is crucial to have a thin silicon chips and a light mounting structure to have adequately small multiple coulomb scattering

50 50 D. Hitlin SLAC B-Day March 20, 2003 A silicon tracker with adequate momentum resolution is feasible Current DCH Double-sided 100 m m A proposal to INFN to develop very thin double- sided detectors is in preparation Forti – TRACKERR/PRAVDA

51 51 D. Hitlin SLAC B-Day March 20, 2003 Particle ID – a new kind of DIRC Barrel Fused silica radiator bars are adequately radiation hard Background in existing SOB is far too high at New non-SOB DIRC is under development in SLAC Group B Quartz is sufficiently radiation hard Need pixel readout to remove SOB Use pixelated PMT  readout outside the flux return Endcap Requires single photoelectron readout in a magnetic field An aerogel threshold counter would work, as would a RICH with an aerogel radiator

52 52 D. Hitlin SLAC B-Day March 20, 2003 Electromagnetic Calorimeter Requirements Good energy resolution Radiation hardness Excellent energy and position resolution Large dynamic range Uniformity and stability Can be met by new crystals – LSO, GSO, …, which are expensive Desirable attributes Longitudinal segmentation for best possible p /e separation Minimal interruption in barrel/endcap region These are features of a scintillating liquid xenon calorimeter, which is under development at Caltech

53 53 D. Hitlin SLAC B-Day March 20, 2003 Comparison of CsI(Tl), LSO, Liquid Xe CsI(Tl)LSOLXe Atomic number Z54 effective65 effective54 Atomic weight A131 Density (g/cc) Radiation length (cm) Molière radius (cm) l scint (nm) t scint (ns) 680, , 22, 45 Light yield (photons/MeV)56,000 (64:36)27,00075,000 Refractive index Liquid/gas density ratio519 Boiling point at 1 atmosphere (  K) 165 Radiation hardness (Mrad) Cost/cc3.2>7 (50 ???)2.5

54 54 D. Hitlin SLAC B-Day March 20, 2003 Unit cell of the LXe EMC Hexagonal cells of ~ 1 Molière radius in transverse dimension are formed from thin quadraphenyl butadiene (TPB)-coated eptfe sheets Cells are not load-bearing, thus thin Longitudinal segmentation is provided by TPB-coated optical separators, with WLS fibers sensitive only in a particular segment Three segments is probably optimal 1. Massless gap – ascertain whether there was an interaction in material in front of the EMC 2, Two larger segments, with division near shower max Fibers are read out by a pixelized APD, located in the LXe volume Clear fibers between coil segment and APD Redundant readout is simple and inexpensive All readout at rear, minimizing nuclear counter effect

55 55 D. Hitlin SLAC B-Day March 20, 2003 Instrumented Flux Return High rate capability Good time resolution Stable response RPC’s, LST’s do not have adequate rate capability, at least in the end cap region Barrel will be upgraded with LST’s in 2004/5 Endcap may require MINOS-type scintillating strips

56 56 D. Hitlin SLAC B-Day March 20, 2003 EMC solid angle coverage could be substantially improved

57 57 D. Hitlin SLAC B-Day March 20, 2003 Thr road ahead There is discovery potential in 10 to 50 ab -1 data samples Is there an interested community ? Yes, drawn from the B A B AR and Belle communities + others Can we obtain funding for a collider and detector ? Not certain, but possible, given the appropriate circumstances What is the appropriate time window for a machine ? It should ideally take data on a time scale comparable to the LHC experiments ( ATLAS, CMS, LHCb ) and, potentially BTeV The HEPAP-mandated P5 is currently making decisions involving major new US facilities Its first round includes a decision on BTeV

58 58 D. Hitlin SLAC B-Day March 20, 2003 PEP-II – luminosity scenario through FY2008

59 59 D. Hitlin SLAC B-Day March 20, 2003 PEP-II/Super B Factory Peak and Integrated Luminosity

60 60 D. Hitlin SLAC B-Day March 20, 2003 Technically limited schedule Super B Factory PEP-II B A B AR

61 61 D. Hitlin SLAC B-Day March 20, 2003 Super B Factory activity at KEK, SLAC The Directors of SLAC and KEK have encouraged cooperation between B A B AR ians and Bellies on future activities, since they believe that “there will be at most one new high luminosity B Factory” Both Directors agree that “high luminosity” means The core of a Super B Factory effort will likely be drawn from the B A B AR and Belle Collaborations Accelerator and detector R&D is underway in both labs and at several of the collaborating institutions Workshops KEK has held four workshops (the most recent on February 4) There will be a workshop at SLAC on May 8-10 to explore in detail opportunities to probe physics beyond the Standard Model at a asymmetric B Factory There will be an ICFA Accelerator Workshop at SLAC in October, focusing on very high luminosity e + e - circular machines

62 62 D. Hitlin SLAC B-Day March 20, 2003 Workshop on the discovery potential of an asymmetric machine SLAC May 8-10

63 63 D. Hitlin SLAC B-Day March 20, 2003 The Physics Challenge There is a substantial difference in the discovery potential of a ab -1 data sample and a ab -1 data sample With this large data sample we will 1.by measuring CP asymmetries and kinematic distributions in rare decays: either find clear SUSY effects and make the first measurement of a SUSY phase, or place highly constraining limits on SUSY-breaking models 2.take the various overconstrained tests of the Standard Model using the Unitarity Triangle to their systematic limit 3. produce the most sensitive probes for new physics through mixing searches for lepton flavor violation in t  mg

64 64 D. Hitlin SLAC B-Day March 20, 2003 The Detector Challenge In order to do physics at 10 36, we must develop thin, rad hard pixel and double-sided strip detectors and associated readout a particle ID system, such as the DIRC with pixel PMT readout and no SOB, that can take high rates a high quality, fast, rad-hard electromagnetic calorimeter an IFR that can handle high rates an appropriate trigger/DAQ system R&D is either starting or is underway in many of these areas

65 65 D. Hitlin SLAC B-Day March 20, 2003 Conclusions Detailed studies of CP violation in B meson decay (and D and t decay) with samples of ab -1 provide a sensitive probe of to new physics such as SUSY These studies are vital to an understanding of the flavor sector of any extension of the Standard Model Estimates of physics capabilities of a Super B Factory are promising Detailed studies of machine and physics backgrounds and of limiting systematic errors for the experiment are underway Capabilities of a Super B Factory are complementary to those of hadronic experiments Both e + e - and hadronic experiments are needed to fully explore the realm of flavor physics

66 66 D. Hitlin SLAC B-Day March 20, 2003 WANTED Dead or Alive