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

A. Bay 30 I 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 =

A. Bay 30 I 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

A. Bay 30 I 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 !

A. Bay 30 I 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.

A. Bay 30 I 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:

A. Bay 30 I 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

A. Bay 30 I 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  Cabibbo ~ 12°

A. Bay 30 I downstrange beauty up charm top 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)

A. Bay 30 I 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:

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

A. Bay 30 I 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

A. Bay 30 I 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 

A. Bay 30 I 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

A. Bay 30 I The B mesons family + antiparticles M (B  ) ≈ M (B 0 ) ≈ ≈ 5279 MeV/c 2 lifetime ≈  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

A. Bay 30 I 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 ! )

A. Bay 30 I (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.

A. Bay 30 I Any horizontal symmetry ? CPV, mix., baryogenesis: hep-ph/ v2 * Neutrino mix and CPV in B: hep-ph/ v2 Bs-Bs mixing in SO(10) SUSY GUT linked to    mix. hep-ph/ 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 ) ?

A. Bay 30 I 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 )  =  (4s)  B 0 B 0  B + B  24% Y(4s) 76% continuum

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

A. Bay 30 I Belle experiment Central Drift Chamber He/C 2 H 5 (  Pt/Pt) 2 =( Pt) 2 +(0.0030) 2 CsI(Tl) 16X 0  E/E ~ 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

A. Bay 30 I Micro-vertex detector

A. Bay 30 I event Belle x z 1 mm

A. Bay 30 I 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

A. Bay 30 I 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

A. Bay 30 I 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 cut

A. Bay 30 I How to find a B meson? Kinematics variables at the Y(4S) M bc 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  

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

A. Bay 30 I Determination of Vub W b u Vub bcbc bubu 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/ , 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

A. Bay 30 I Determination of Vtd B0B0 B0B0 t d b t W W b d Vtd 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

A. Bay 30 I 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 

A. Bay 30 I  m d from di-lepton events 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)

A. Bay 30 I  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  z (mm) SS  z (mm) OS  z (mm)

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

A. Bay 30 I 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

A. Bay 30 I  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

A. Bay 30 I 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

A. Bay 30 I  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

A. Bay 30 I 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

A. Bay 30 I A large CP asymmetry has been observed! Belle: S CP = ± ± BABAR: S CP = ± ± World average: S CP = ± 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

A. Bay 30 I 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°

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

A. Bay 30 I 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:

A. Bay 30 I 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 GeV/c 2 BaBar Beam-Energy Constrained Mass sin2  (ccs)

A. Bay 30 I  from B  D 0 K D 0  Ks  +  - See A.Giri, Yu.Grossman, A.Soffer, J.Zupan hep-ph/ 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

A. Bay 30 I  from B  D 0 K D 0  Ks  +  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° ±12°±24°  = 95° ±13°±10° 90%CL: 61°<  < 142° very preliminary

A. Bay 30 I Belle: very, very preliminary

A. Bay 30 I  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:

A. Bay 30 I B0  B0   Submitted to Phys Rev from ~231     : A  =  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/

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

A. Bay 30 I 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) (hep-ph/ gives 74° <  < 132°... )

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

A. Bay 30 I 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

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

A. Bay 30 I BEYOND 2007

A. Bay 30 I ~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:

A. Bay 30 I ~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:

A. Bay 30 I ~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: 

A. Bay 30 I  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 ….

A. Bay 30 I  B physics at LHC(b)   bb  ~500  b, bb / year at L=2  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:

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

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

A. Bay 30 I 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 [ps]

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

A. Bay 30 I 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      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

A. Bay 30 I LHCb after 10 7 seconds Parameter Channels N untagged   B d  +    P/T = 30°, |P/T|=0.20  0.02,  =90° 2  -5  B d 0     =50° 5  2  +  B d  D*   +  =0 12   B d  J/  K s 200k <0.6   -2  B s  D s K  m s =20ps   B d  D(KK)K* 600  =55°-105° <8   B s  J/  120k 0.6   B d   +   / K + K -  =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

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

A. Bay 30 I 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 bb / year at 2  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.