1. B physics at Belle (and beyond) Aurelio Bay LPHE/IPEP o CP violation and B physics, introduction o KEK-B and the BELLE detector o Results from Belle: constraining the UT oBeyond 2007 (LHCb) Summary: v2 Colloquium, PSI January 2004

2. A. Bay 30 I 20042 CP violation K 0 L    e      e   CP MIRROR { CP symmetry implies identical rates. Instead... K 0 L is its own antiparticle K 0 L S. Bennet, D. Nygren, H. Saal, J. Steinberg, J. Sunderland (1967): July 1964: J. H. Christenson, J. W. Cronin, V. L. Fitch et R. Turlay small CP violation with K 0 mesons    e   N    e   N     e   N    e   N +    % provides an absolute definition of + charge Asymmetry =

3. A. Bay 30 I 20043 K0K0 K0K0 Processes should be identical but CPLear finds that neutral kaon decay time distribution  anti-neutral kaon decay time distribution Other experiments: NA48, KTeV, KLOE  factory in Frascati,... CPLear

4. A. Bay 30 I 20044 Baryogenesis 1)  processes which violate baryonic number conservation: B violation is unavoidable in GUT. 2) Interactions must violate C and CP. C violated in Weak Interactions. CP violation observed in K and B decays. 3) System must be out of thermal equilibrium OK : Universe expands. Starting from a perfectly symmetric Universe: 3 rules to induce matter- antimatter asymmetry during evolution Andrej Sakarov 1967 B(t=0) = 0 B(today)>0 e + e  annihilation from the center of the Galaxy rate compatible with secondary production !

5. A. Bay 30 I 20045 How to generate CPV Hamiltonian H = H 0 + H CPV with H CPV responsible for CP violation. Let's take H CPV = gH + g*H † where g is some coefficient. The second term is required by hermiticity. CP H CPV CP † = CP (gH + g*H † ) CP † = gH † + g*H CP is violated, H CPV  CP H CPV CP † if gH + g*H †  gH † + g*H The conclusion is that CP is violated if g  g* CP violation is associated to the existence of a complex component in the hamiltonian.

6. A. Bay 30 I 20046 CPV and the Standard Model.2 L = L W,Z + L H + L Fermions + L interaction L Fermions contains the (Yukawa) mass terms: M U and M D complex matrices, diagonalized by a couple of non-singular matrices, to get the physical mass values:

7. A. Bay 30 I 20047 CPV and the Standard Model.3 After the transformation (idem for D quarks) e.m. and neutral currents unaffected. The charged currents are modified: "mixing matrix" V unitary s u W VusVus

8. A. Bay 30 I 20048 CPV and the SM.4 Parameters V ij are used to calculate the transitions quark(i)  quark(j) first introduced by N. Cabibbo for i,j=u, d, s In 1972 Kobayashi & Maskawa show that, in order to generate CP violation (i.e. to get a complex phase), V must be (at least) 3x3  prediction of the three quark families of the SM: (u, d), (c, s), (t, b) V Cabibbo is real. CPV implies that some of the V ij are complex ! s u W VusVus V Cabibbo = The c introduced in 1970 (GIM), discovered in 1974.  Cabibbo ~ 12°

9. A. Bay 30 I 20049 downstrange beauty up 0.97 0.22 0.002 charm 0.22 0.97 0.03 top 0.004 0.03 1 CKM matrix + O( 4 )  = sin(  Cabibbo ) ~ 0.22 phase: change sign under CP parametrized by 4 real numbers (not predicted by the SM). Need to measure them. Magnitude ~ Wolfestein (1983)

10. A. Bay 30 I 200410 downstrange beauty up 0.1% 1% 17% charm 7% 15% 5% top 20% ?% 29% CKM matrix  V ij  )/  V ij  ~ From direct measurements, no unitarity imposed:

11. A. Bay 30 I 200411 CKM matrix.2 + O( 4 ) downstrange beauty up 0 0 115° charm 0 0 0 top 25° 0 0 Phase ~ downstrange beauty up 0 0  115° charm 0 0 0 top  25° 0 0 Wolfestein (1983)

12. A. Bay 30 I 200412 CKM Matrix and the Unitary Triangle(s) + O( 4 ) SM  Unitarity V ji *V jk =  ik  V ud V ub  + V cd V cb  + V td V tb  = 0 V ud V ub V cd V cb V td V tb * * *          Re Im The Unitary Triangle Triangle

13. A. Bay 30 I 200413 CKM Matrix and the Unitary Triangle(s) + O( 4 ) SM  Unitarity V ji *V jk =  ik  V ud V ub  + V cd V cb  + V td V tb  = 0 Area   CPV ! The Unitary Triangle Triangle after normalization by V cd V cb *=A 3          Re Im  1 

14. A. Bay 30 I 200414 Experimental program: measure sides and angles * CP violated in the SM => the area of triangle  0 * Any inconsistency could be a signal of the existence of phenomena not included in the SM    ~V ub ~V td ~V cb Use B mesons phenomenology t quark oscillations CP asymmetries b quark decays

15. A. Bay 30 I 200415 The B mesons family + antiparticles M (B  ) ≈ M (B 0 ) ≈ ≈ 5279 MeV/c 2 lifetime ≈ 1.5 10  12 s mixing/oscillation bs,dq u,c,t W q B0B0 B0B0 d b W W b d W b u,c direct decay loop decay B factories u,c,t

16. A. Bay 30 I 200416 New Physics...may modify rates and inject new phases in the processes. For instance: d b W W b d d b b d New FCNC V ts V tb * B0B0 b d s s d K0K0  s W t ??? b d s s d K0K0  s  squark + ? + ? ( MSSM has 43 additional CP violating phases ! )

17. A. Bay 30 I 200417 (Open a parenthesis: masses & mixings In the SM, CPV is related to the mass generation mechanism for the fermions. The fermionic system is far to be understood. Is there any "periodicity" in the mass spectrum? Similar question for the mixing matrices.

18. A. Bay 30 I 200418 Any horizontal symmetry ? CPV, mix., baryogenesis: hep-ph/0108216v2 * Neutrino mix and CPV in B: hep-ph/0205111v2 Bs-Bs mixing in SO(10) SUSY GUT linked to    mix. hep-ph/0312145 A. Buras, J. Ellis, M.K. Gaillard and D.V. Nanopoulos, Nucl. Phys. B135 (1978) 66 Lepton-quark mass relations first (?) discussed by...close the parenthesis) V H ( CKM ) ( NMS ) ?

19. A. Bay 30 I 200419 KEK-B 8 GeV electrons 3.5GeV positron IP:  x  77 µm  y  2 µm  z  4 mm  E* beam ) = 2.6 MeV  L dt ~ 180 fb –1 at  (4S)+off res(~10%)  production of  (4s) (10.58GeV/c 2 )  = 0.425  (4s)  B 0 B 0  B + B  24% Y(4s) 76% continuum

20. A. Bay 30 I 200420 KEK-B year 2003: crossing the (psychological) barrier of 10 34 cm -2 s -1 Luminosity trend in the last 30 years Peak luminosity cm  s  24 I 20004: 24h integrated lumi record: 730.3 pb 

21. A. Bay 30 I 200421 Belle experiment Central Drift Chamber He/C 2 H 5 (  Pt/Pt) 2 =(0.0019 Pt) 2 +(0.0030) 2 CsI(Tl) 16X 0  E/E ~ 1.8% @1GeV Aerogel Cherenkov n=1.015~1.030 Si Vertex detector 3 layers  mid 2003 now 4 layers Impact parameter resolution  55  m for p=1GeV/c TOF counter SC solenoid 1.5T 8GeV e  3.5GeV e  Started in 1999 ~300 physicists from ~60 institutes in 14 countries. Has collected ~150 million BB pairs Particle ID : dE/dx in CDC  dE/dx =6.9% TOF  TOF = 95ps Aerogel Cerenkov ACC Efficiency = ~90%, Fake rate = ~6%  3.5GeV/c  / K L detection 14/15 layers of RPC+Fe   : efficiency > 90% 1GeV/c

22. A. Bay 30 I 200422 Micro-vertex detector

23. A. Bay 30 I 200423 event Belle x z 1 mm

24. A. Bay 30 I 200424 Particle ID in Belle Particle ID uses information from ACC, TOF, dE/dx( CDC) Barrel ACC Endcap ACC dE/dx TOF p (GeV/c) cut

25. A. Bay 30 I 200425 Analysis and results Continuum rejection Kinematics at the Y(4s) The Unitary triangle: determination of Vub " Vcb " Vtd "  "  "  No time for other topics    ~V ub ~V td ~V cb

26. A. Bay 30 I 200426 Continuum rejection 24% Y(4s) 76% continuum from event topology which is ~spherical for BB, jet like for continuum and angular distributions BB qq Build Likelihood L for B and qq hypothesis using event shape variables and cos  B 0 0.2 0.4 0.6 0.8 1 cut

27. A. Bay 30 I 200427 How to find a B meson? Kinematics variables at the Y(4S) M bc 5.2 5.24 5.28 GeV/c 2 0 EE 0.2  0.2 GeV/c 2 Gather candidates B daughters and calculate its (p B,E B ) Boost to c.m. "beam constrained mass" Example: B   D 0  

28. A. Bay 30 I 200428 Determination of Vcb WW b c Vcb World Average: |Vcb| (inclusive) (42.0  0.6  0.8) 10 -3 |Vcb| (exclusive) (40.2 +2.1 ) 10 -3 -1.8 (Moriond excl. D*: CLEO: 46.9 10 -3 BABAR: 48.2 10 -3 ) D0D0 g(y) known function of y d D* + B0B0 q F(y) hadronic form factor plus ~5% error on F(1)

29. A. Bay 30 I 200429 Determination of Vub W b u Vub bcbc bubu 0 1 2 3 GeV/c Lepton momentum (in c.m.) Exemple: use lepton momentum distribution from inclusive semileptonic decays Less than 10% of the spectrum background free hep-ex/0305037, with neutrino reconstruction |Vub| (10 -3 ) = 3.96  0.17(stat)  0.44(syst)  0.29(theo)  0.34(b  c)  0.26(b  u) Average(inclusive) Vub=(4.12±0.13±0.60)10 -3

30. A. Bay 30 I 200430 Determination of Vtd B0B0 B0B0 t d b t W W b d Vtd 0 3 6 9 ps Probability 1 B0B0 B0B0 Starting from a pure sample of B 0, for instance, a B 0 component builds up in a time scale of a few ps: measure oscillation frequency

31. A. Bay 30 I 200431 region of B 0 & B 0 coherent evolution  m d with di-lepton events * KEK-B boost   cβγ  ~ 200  m  (4s) z z1z1 z2z2 zz e+e+  * Tag B flavour from semileptonic B 0  X  l   B 0  X  l  X Y * B 0 and B 0 oscillate coherently (QM entangled state). When the first decays, the other is known to be of the opposite flavour. t ~  z/c 

32. A. Bay 30 I 200432  m d from di-lepton events.2 -12 -8 -4 0 GeV 2 N Missing mass Background: B +  X  l   B   X  l  Selection strategy of the "soft pion tag" B 0  D*  l  Br  3%  D 0   Br  70% Event selection: - 1 st lepton P*> 1.8 GeV - 1 pion of opposite sign P* < 1 GeV - 2 nd lepton P*> 1.3 GeV - cut on M 2 (Frederic Ronga, PhD thesis, 2003)

33. A. Bay 30 I 200433  m d from di-lepton events.3 Get  z distributions for "Same Sign" and "Opposite Sign" leptons couples and fit for  m d... OS SS J/   l + l  to infer resolution -2 -1 0 1 2  z (mm) SS -2 -1 0 1 2  z (mm) OS 0 1 2  z (mm)

34. A. Bay 30 I 200434 F. Ronga average  m d and Vtd HEP-PH/0206171 From: F. Ronga, PhD Thesis, Lausanne XII 2003 Bag parameter B decay constant  |V td | ~ (8±2)10 -3 ~20% error ! {

35. A. Bay 30 I 200435 UT sides The Unitary Triangle inferred from its sides and from K 0 data Vub/Vcb From K 0  m d &  m s 1 0 Excluded area has <0.05 CL

36. A. Bay 30 I 200436  from B 0  J/  Ks b d B0B0 Vcb c c s KsKs J/  d B0B0 Vcb c s KsKs J/  VtdVtb VtdVtb c b Interference between the 2 amplitudes gives a "time-dependent CPV" CKM phase  0 ! CKM phase = 0 sin2  } SM: B0B0 d Golden Channel

37. A. Bay 30 I 200437 Any "direct" CP violation ? b d B0B0 Vcb c c s KsKs J/  d B0B0 Vtbc KsKs J/  c b s No "direct CPV" expected in SM in B  J/  Ks, but who knows ?... CKM phase = 0 t Vts sin2  } SM: } 0

38. A. Bay 30 I 200438  ime dependent asymmetry measurement  (4s) z z1z1 z2z2 zz J/  Ks f CP e D region of B 0 & B 0 coherent evolution Need to "tag" the flavour: B 0 or B 0. B 0 and B 0 oscillate coherently (QM entangled state)  use the other side to infer the flavour t ~  z / c  f tag

39. A. Bay 30 I 200439 b  ccs reconstruction 140 fb  1, 152M BB pairs B 0  J/  K L b  ccs (J/  K L excluded) 5417 events are used in the fit. p B GeV/c

40. A. Bay 30 I 200440 A large CP asymmetry has been observed! Belle: S CP = 0.733 ± 0.057 ± 0.028 BABAR: S CP = 0.741 ± 0.067 ± 0.033 World average: S CP = 0.736 ± 0.049 J/  K L A CP ~ 0, compatible with no direct CPV SM: S CP = sin(2  ) =>   or 66.3°) mainly tag and vtx reconstruction J/  K Lv is OK

41. A. Bay 30 I 200441 SM & KM model is verified ! sin2  (Belle, 140 fb -1 ) = 0.733±0.057±0.028 sin2  (BaBar, 81 fb -1 ) = 0.741±0.067±0.033 sin2  (World Av.) =0.736±0.049  = 23.7°± 2.1° = 66.3°± 2.1°

42. A. Bay 30 I 200442 UT with sin2  The Unitary Triangle fit including sides, K 0 data, and sin2 

43. A. Bay 30 I 200443 b  sss, a B 0   Ks puzzle ? b to s transition is second order (gluonic penguin). Prediction from SM: ~ same value of sin(2  ) as in ccs because no additional phase from the loop. V ts V tb * B0B0 b d s s d Ks  s W t ??? B0B0 b d s s d  s  squark unless new physics enters the loop. For instance:

44. A. Bay 30 I 200444 B 0   Ks.2 68  11 signals 106 candidates in the fit purity = 0.64  0.10 efficiency = 27.3% B 0  KSB 0  KS 5.2 5.4 5.28 GeV/c 2 BaBar Beam-Energy Constrained Mass sin2  (ccs)

45. A. Bay 30 I 200445  from B  D 0 K D 0  Ks  +  - See A.Giri, Yu.Grossman, A.Soffer, J.Zupan hep-ph/0303187 u u B+B+ b c s D0D0 Ks ++ -- K+K+ u B+B+ c s D0D0 ++ -- b u K+K+ D 0 and D 0 decay to same final state  mixed state is produced: Dalitz's analysis with variables and a, ,  unknown

46. A. Bay 30 I 200446  from B  D 0 K D 0  Ks  +  -.2 0.5 1 1.5 2 2.5 3 3 2 1 D 0  Ks  +  - as a sum of 2 body decays Fit Dalitz plot with a, ,  as free parameters a = 0.33±0.10±0.03±0.03  = 162° +20 -25 ±12°±24°  = 95° +25 -20 ±13°±10° 90%CL: 61°<  < 142° very preliminary

47. A. Bay 30 I 200447 Belle: very, very preliminary

48. A. Bay 30 I 200448  from B 0   W u d   A  = 0 S  = sin(2  +2  )=  sin(2  ) without penguin contributions: Isospin analysis needed for the extraction of . Need to measure also  B 0      B +      W t g d  - This is not the case: large "penguin pollution" expected (but intrinsically interesting..!) Consider B 0     first:

49. A. Bay 30 I 200449 B0  B0   Submitted to Phys Rev from ~231     : A  = +0.58  0.15  0.07 S  =  1.00 ± 0.21 ± 0.07 charmless 3-body B decay  KK continuum syst. primarily from background fraction BABAR: A  = 0.30 ± 0.25 ± 0.04 S  = .02 ± 0.34 ± 0.05 A  0 hep-ex/0401029

50. A. Bay 30 I 200450 B 0        Belle BaBar direct CVP

51. A. Bay 30 I 200451 First signal from B 0      M bc [GeV/c 2 ] using 152 M BB: Br(B 0      ) = (1.7 ± 0.6 ± 0.2)10 -6 B+ B+   continuum BABAR: Br(B 0      ) = (2.1 ± 0.6 ± 0.3)10 -6 Phys. Rev. Lett. 91 (2003) 261801 (hep-ph/0306058 gives 74° <  < 132°... )

52. A. Bay 30 I 200452 Other topics (a few hep-ex) sin(2  ) from J/   hep-ex/0308053 hep-ex/0308053  from B  D*  hep-ex/0308048 hep-ex/0308048 Rare B decays: B  hh { , K , KK,  } hep-ex/0307077, hep-ex/0306007 hep-ex/0307077hep-ex/0306007 B  Khh {K  } hep-ex/0307082 hep-ex/0307082 B  pph, p  hep-ex/0302024 hep-ex/0302024 B  K ( * ) ,  K ( * )  K ( * ) ll hep-ex/0308044 hep-ex/0308044 B   K hep-ex/0305068 hep-ex/0305068 B   c p Phys. Rev. Lett. 90 (2003) 121802 CPV results: EPR & Bell test of QM: hep-ex/0310192 Phys. Rev. Lett. 91 (2003) 262001 New charmonium X(3871):

53. A. Bay 30 I 200453 downstrange beauty up 0.1% 1% 5% charm 2% 2% 3% top 5% 5% 29% CKM matrix 2007 *  V ij  )/  V ij  ~ CDF + D0: 4 fb -1 each BABAR + Belle: 500–1000 fb -1 CLEO-C  (sin(2  )) ≈ 0.03 from B 0  J/  K S * no precise measurement of other angles

54. A. Bay 30 I 200454 CKM triangle in 2007 (SM) Picture will be already inconsistent ?      from  m from b  c from b  u  from B  J/  Ks

55. A. Bay 30 I 200455 BEYOND 2007

56. A. Bay 30 I 200456 ~V ub     from B  X u +  B0B0 B0B0 B0B0 J  K s WW t t CP Asym ~ sin{ 2  } t d b t W W b d ~     ~V td SM view of the unitary triangle from  m:

57. A. Bay 30 I 200457 ~V ub     from B  X u +   new B0B0 B0B0 B0B0 J  K s WW t t CP Asym ~ sin{2(  new )} t d b t W W b d ~     d b b d NEW FCNC Unchanged   r new NEWNEW Im Re ~V td SM + New FCNC from  m:

58. A. Bay 30 I 200458 ~V ub     from B  X u +   new B0B0 B0B0 B0B0 J  K s WW t t CP Asym ~ sin{2(  new )} t d b t W W b d ~     d b b d NEW FCNC Unchanged   r new NEWNEW Im Re ~V td SM + New FCNC (bis) from  m: 

59. A. Bay 30 I 200459  and new physics from B d  D*  n  +, D* + n  , etc. Idem with B s decays:    s new  from CP in B s  J     s new   from CP in B s  D s  K , D s  K  compare the two  determinations (then combine them) B d  D*  n  vs B d  D*  n  B d  D*  n  vs B d  D*  n  From 2(  new ) +    CP in B  J/  K s ~ 2(  +  new )  need to trigger and select hadronic decay channels, need to study the B s system, have K/  separation, access to Br < 10  7 ….

60. A. Bay 30 I 200460  B physics at LHC(b)   bb  ~500  b, 10 12 bb / year at L=2  10 32 cm  2 s  B u (40%), B d (40%), B s (10%), B c, and b-baryons (10%) Many primary particles to determine b production vertex    bb /  inelastic  ~ 0.6% => triggering problem  Many particles not associated to b hadrons  No B 0 -B 0 entangled states: mixing dilutes tagging good things: not so good:

61. A. Bay 30 I 200461 LHCb Forward detector (1.9    4.9) ~ 50% acceptance for bb pairs 3 2 1  b [rad] 0 1 2 3 B shielding removed !

62. A. Bay 30 I 200462 LHCb — RICH detectors for PID —vertex detectors inside beam vacuum Magentic momentum analysis in the vtx detector

63. A. Bay 30 I 200463 VErtex LOcator (VELO) 21 stations, ~200k channels, analogue R/O (Beetle) r- and  -measuring stations with Si “striplets”  IP = 14  + 35  /p T From tracking:  p/p = 0.35% – 0.55% can observe 5  signal if  m s < 68 ps  1  m s = 25 ps  1 B s oscillation B s oscillation from B s  D s    sample 0 1 2 3 4 5 6 [ps]

64. A. Bay 30 I 200464 LHCb ATLAS 0 20 40 60 80 GeV/c Particle ID RICH1 RICH2 Aerogel & C 4 F 10 CF 4 prob (   K) K efficiency

65. A. Bay 30 I 200465 Triggers 1 MHz 40 MHz Detached vertex + IP of p T candidate Medium p T hadron, ,e,  + pileup veto (12.4 MHz of inelastic interactions) LHCb 40 kHz L0 L1 B 0  J/  K S B s  D s  K + B 0      0.880.540.76 0.900.700.72 0.790.380.55 Efficiencies for signal events accepted by offline selection  ln p T  ln IP/  IP L1 Signal Min. Bias B0  B0   B s  D s  K + Final state reconstruction 200 Hz HLT

66. A. Bay 30 I 200466 LHCb after 10 7 seconds Parameter Channels N untagged   B d  +   20k @  P/T = 30°, |P/T|=0.20  0.02,  =90° 2  -5  B d 0    4k @  =50° 5  2  +  B d  D*  200k @2  +  =0 12   B d  J/  K s 200k <0.6   -2  B s  D s K 5400 @  m s =20ps -1 14   B d  D(KK)K* 600  =55°-105° <8   B s  J/  120k 0.6   B d   +   / K + K - 20k/30k @  =55°- 105° <6   B d  Ks 0.8k <20  ?  m s B s  D s  80k s/b~3, up to 68 ps -1 (5  ) A few penguins : B s   1.2k B d  K +  - 135k B s  K + K - 37k B d  K *0  35k B s   9.3k B d  K *0  4.4k (Using PDG branching ratios or SM predictions) not possible at B factory

67. A. Bay 30 I 200467 CKM triangle in 2007+10 7 s ?      from B  J/  Ks from  m d,  m s from b  u  from LHCb Re Im

68. A. Bay 30 I 200468 Summary Measurements of B 0  hh,... Observation of X(3872), narrow   D 2  state or a DD* molecule ? Tests of QM, EPR&Bell. Many other results The main goal of Belle experiment is CPV study in B decays: sin2  = 0.733±0.057±0.028 Large CPV in B 0   (direct CPV ?)  S : sin2  = –0.96 ±0.50 ±0.11: hint of New Physics or statistical fluctuation? B physics at LHC will get a big boost from 10 12 bb / year at 2  10 32 cm  2 s  1 including Bs mesons LHCb is an experiment dedicated to B physics hadronic trigger and topological trigger, optimized particle ID and proper time resolution Precise determination of the Unitary Triangles angles,  in particular, with different methods. If new physics shows up, measure the relevant parameters.