Unitary Triangle Analysis: Past, Present, Future

Transcription

1 Unitarity Triangle Analysis: Past, Present, Future INTRODUCTION: quark masses, weak couplings and CP in the Standard Model Unitary Triangle Analysis: PAST PRESENT FUTURE Dipartimento di Fisica di Roma I Guido Martinelli HANOI August 5th-9th 2004

2 C, CP and CPT and their violation are related to the foundations of modern physics (Relativistic quantum mechanics, Locality, Matter-Antimatter properties, Cosmology etc.) Although in the Standard Model (SM) all ingredients are present, new sources of CP beyond the SM are necessary to explain quantitatively the BAU Almost all New Physics Theories generate new sources of CP

3 Quark Masses, Weak Couplings and CP Violation in the Standard Model

4 In the Standard Model the quark mass matrix, from which the CKM Matrix and CP originate, is determined by the Yukawa Lagrangian which couples fermions and Higgs L quarks = L kinetic + L weak int + L yukawa CP invariant CP and symmetry breaking are closely related!

5 QUARK MASSES ARE GENERATED BY DYNAMICAL SYMMETRY BREAKING Charge +2/3 L yukawa i,k=1,n [ Y i,k (q i L HC ) U k R + X i,k (qi L H ) D k R + h.c. ] Charge -1/3 i,k=1,n [ m u i,k (ui L uk R ) + md i,k (di L dk R ) + h.c. ]

6 Diagonalization of the Mass Matrix Up to singular cases, the mass matrix can always be diagonalized by 2 unitary transformations u i L Uik L uk L M = U L M U R u i R Uik R uk R (M ) = U R (M) U L L mass m up (u L u R + u R u L ) + m ch (c L c R + c R c L ) + m top (t L t R + t R t L )

7 N(N-1)/2 angles and (N-1)(N-2) /2 phases N=3 3 angles + 1 phase KM the phase generates complex couplings i.e. CP violation; 6 masses +3 angles +1 phase = 10 parameters V ud V us V ub V cd V cs V cb V tb V ts V tb

8 NO Flavour Changing Neutral Currents (FCNC) at Tree Level (FCNC processes are good candidates for observing NEW PHYSICS) CP Violation is natural with three quark generations (Kobayashi-Maskawa) With three generations all CP phenomena are related to the same unique parameter ( δ )

9 V ud ~1 V us ~ λ V ub ~ λ 3 V cd ~ λ V cs ~1 V cb ~ λ 2 V tb ~ λ 3 V ts ~ λ 2 V tb ~1 β-decays W down up Neutron Proton V ud Quark masses & Generation Mixing e - ν e V ud = (8) V us = (23) V cd = 0.224(16) V cs = 0.970(9)(70) V cb = (8) V ub = (32) V tb = 0.99(29) (0.999)

10 c 12 c 13 s 12 c 13 s 13 e -iδ -s 12 c 23 -c 12 s 23 s 13 e iδ c 12c 23 -s 12 s 23 s 13 e iδ s 23 c 13 s 12 s 23 -c 12 c 23 s 13 e iδ -c 12s 23 -s 12 c 23 s 13 e iδ c 23 c 13 c ij = Cos θ ij s ij = Sin θ ij c ij 0 s ij 0 0 δ 2 π s 12 ~ Sin θ c for small angles s ij ~ V ij

11 The Wolfenstein Parametrization 1-1/2 λ 2 λ A λ 3 (ρ - i η) - λ 1-1/2 λ 2 A λ 2 + O(λ 4 ) A λ 3 (1- ρ - i η) -A λ 2 1 λ ~ 0.2 A ~ 0.8 η ~ 0.2 ρ ~ 0.3 Sin θ 12 = λ Sin θ 23 = A λ 2 Sin θ 13 = A λ 3 (ρ-i η)

12 d 1 The Bjorken-Jarlskog Unitarity Triangle a 1 a 2 b 1 b 2 V ij is invariant under phase rotations a 1 = V 11 V 12 * = V ud V us * a 2 = V 21 V 22 * a 3 = V 31 V 32 * e 1 a 3 b 3 a 1 + a 2 + a 3 = 0 (b 1 + b 2 + b 3 = 0 etc.) c 3 γ Only the orientation depends on the phase convention α a 3 a 1 a 2 β

13 From A. Stocchi ICHEP 2002

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15 sin 2β is measured directly from B decays at Babar & Belle J/ψ K s Γ(B d 0 J/ψ K s, t) - Γ(B d 0 J/ψ K s, t) A J/ψ Ks = Γ(Bd 0 J/ψ K s, t) + Γ(B d 0 J/ψ K s, t) A J/ψ Ks = sin 2β sin (Δm d t)

16 DIFFERENT LEVELS OF THEORETICAL UNCERTAINTIES (STRONG INTERACTIONS) 1) First class quantities, with reduced or negligible uncertainties 2) Second class quantities, with theoretical errors of O(10%) or less that can be reliably estimated 3) Third class quantities, for which theoretical predictions are model dependent (BBNS, charming, etc.) In case of discrepacies we cannot tell whether is new physics or we must blame the model

17 Quantities used in the Standard UT Analysis

18 THE COLLABORATION M.Bona, M.Ciuchini, E.Franco, V.Lubicz, G.Martinelli, F.Parodi, M.Pierini, P.Roudeau, C.Schiavi, L.Silvestrini, A.Stocchi Roma, Genova, Torino, Orsay NEW 2004 ANALYSIS IN PREPARATION New quantities e.g. B -> DK will be included Upgraded experimental numbers after Bejing THE CKM

19 PAST and PRESENT (the Standard Model)

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21 Results for ρ and η & related quantities With the constraint fromδm s 68% and 95% C.L. ρ = ± η = ± [ ] [ ] at 95% C.L. sin 2 α = ± 0.25 sin 2 β = ± [ ] [ ]

22 Comparison of sin 2 β from direct measurements (Aleph, Opal, Babar, Belle and CDF) and UTA analysis sin 2 β measured = ± sin 2 β UTA = ± sin 2 β UTA = ± prediction from Ciuchini et al. (2000) Very good agreement no much room for physics beyond the SM!!

23 Theoretical predictions of Sin 2 β in the years predictions exist since '95 experiments

24 Crucial Test of the Standard Model Triangle Sides (Non CP) compared to sin 2 β and ε K From the sides only sin 2 β=0.715 ± 0.050

25 PRESENT: sin 2α from B -> ππ & ρρ γ and (2β+γ) from B -> DK & B -> D(D*) π FROM UTA

26 Δm s Probability Density Without the constraint fromδm s Δm s = (20.6 ± 3.5 ) ps -1 [ ] ps -1 at 95% C.L. With the constraint fromδm s +1.7 Δm s = ( ) ps -1 [ ] ps -1 at 95% C.L.

27 Hadronic parameters f Bs B Bs = 276 ± 38 MeV 14% f Bs B Bs = 279 ± 21 MeV 8% 6% 4% lattice UTA f Bd B Bd = 223 ± 33 ± 12 MeV lattice f Bd B Bd = 217 ± 12 MeV UTA B K = 0.86 ± 0.06 ± 0.14 lattice B K = 0.69 (+0.13) (-0.08) UTA

28 Limits on Hadronic Parameters f Bs B Bs

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30 PRESENT (the Standard Model) NEW MEASUREMENTS

31 sin 2α from B -> ππ B π π B π π B π π

32 φ could be extracted by measuring sin 2α from B -> ππ

33 sin 2α from B -> ππ

34 PRESENT & NEAR FUTURE I cannot resist to show the next 3 trasparencies

35 MAIN TOPICS Factorization (see M. Neubert talk) What really means to test Factorization B ππ and B Kπ decays and the determination of the CP parameter γ Results including non-factorizable contributions Asymmetries Conclusions & Outlook From g.m. qcd@work martinafranca 2001

36 CIUCHINI ET AL 2001 Contrary to factorization we predict large Asymmetries for several of the particleantiparticle BRs, in particular BR(B + -> K + π 0 ) and BR(B 0 -> K + π - ). This open new perspectives for the study of CP violation in B systems. From g.m. qcd@work martinafranca 2001

37 CHARMING PENGUINS GENERATE LARGE ASYMMETRIES A = BR(B) - BR(B) BR(B) + BR(B) BR(K + π 0 ) typical A 0.2 (factorized 0.03) BR(K + π - ) Large uncertainties BR(π + π - ) From g.m. qcd@work martinafranca 2001

38 BABAR ± ± sigma effect (last Monday!!)

39 B -> Kπ DECAYS (III)

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43 Tree level diagrams, not influenced by new physics

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45 FUTURE: FCNC & CP Violation beyond the Standard Model

46 CP beyond the SM (Supersymmetry) Spin 1/2 Quarks q L, u R, d R Spin 0 SQuarks Q L, U R, D R Leptons l L, e R SLeptons L L, E R Spin 1 Gauge bosons Spin 1/2 Gauginos W, Z, γ, g w, z, γ, g Spin 0 Higgs bosons Spin 1/2 Higgsinos H 1, H 2 H 1, H 2

47 In general the mixing mass matrix of the SQuarks (SMM) is not diagonal in flavour space analogously to the quark case We may either Diagonalize the SMM z, γ, g FCNC q j L Q j L or Rotate by the same matrices the SUSY partners of the u- and d- like quarks (Q j L ) = U ij L Q j L U i L d k L g U j L

48 In the latter case the Squark Mass Matrix is not diagonal (m 2 Q ) ij = m 2 average 1 ij + Δm ij 2 δ ij = Δm ij 2 / m 2 average

49 Deviations from the SM? Model independent analysis: Example B 0 -B 0 mixing (M.Ciuchini et al. hep-ph/ )

50 Second solution also suggested by BNNS analysis of B ->Kπ, π π decays SM solution

51 TYPICAL BOUNDS FROM ΔM K AND ε K x = m 2 g / m 2 q x = 1 m q = 500 GeV Re (δ 122 ) LL < Re (δ 122 ) LR < Re (δ 12 ) LL (δ 12 ) RR < from ΔM K

52 from ε K x = 1 m q = 500 GeV Im (δ 122 ) LL < Im (δ 122 ) LR < Im (δ 12 ) LL (δ 12 ) RR <

53 ΔM B and A(B J/ ψ K s ) ΔB=2 ΔM Bd = 2 Abs B d H eff B d A(B J/ ψ K s ) = sin 2 β sin ΔM Bd t eff 2 β = Arg B d H B d eff ΔB=2 eff sin 2 β = ± BaBar & Belle & others from exps

54 TYPICAL BOUNDS ON THE δ-couplings A, B =LL, LR, RL, RR 1,3 = generation index A SM = A SM (δ SM ) B 0 H eff ΔB=2 B 0 = Re A SM + Im A SM + A SUSY Re(δ 13 d ) AB 2 + i A SUSY Im(δ 13 d ) AB 2

55 TYPICAL BOUNDS ON THE δ-couplings B 0 H eff ΔB=2 B 0 = Re A SM + Im A SM + A SUSY Re(δ 13 d ) AB 2 + i A SUSY Im(δ 13 d ) AB 2 Typical bounds: Re,Im(δ 13 d ) AB Note: in this game δ SM is not determined by the UTA From Kaon mixing: Re,Im(δ 12 d ) AB SERIOUS CONSTRAINTS ON SUSY MODELS

56 CP Violation beyond the Standard Model Strongly constrained for b d transitions, Much less for b s : BR(B X s γ) = (3.29 ± 0.34) 10-4 A CP (B X s γ) = ± 0.04 BR(B X s l + l - ) = (6.1 ± 1.4 ± 1.3) 10-6 The lower bound on B 0 s mixing Δm s > 14 ps - 1

57 b W SM Penguins s t s b g s s b s s

58 b W SUSY Penguins s t Recent analyses by G. Kane et al., Murayama et al.and Ciuchini et al. b g s b s s s Also Higgs (h,h,a) contributions s

59 A CP (B d -> φ K s ) (2002 results) Observable BaBar Belle Average SM prediction BR (in 10-6 ) ± ± ~ 5 S φks ± ±0.64 ± ± ± C φks _ 0.56±0.41 ± ± A φks = - C φks cos(δm B t) + S φks sin(δm B t ) [A CP (B d -> π K ) do not give significant constraints ] One may a also consider B s -> µµ (for which there is an upper bound from Tevatron, CDF BR < )

60 A CP (B d -> φ K s ) (2003 results) Observable BaBar Belle Average SM prediction S φks ± ± ± see M. Ciuchini et al. Presented at Moriond 2004 by L. Silvestrini A φks = - C φks cos(δm B t) + S φks sin(δm B t )

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62 FUTURE: who knows? This is what makes it Interesting!

63 WHY RARE DECAYS? Rare decays are a manifestation of broken (accidental) symmetries e.g. of physics beyond the Standard Model Proton decay baryon and lepton number conservation µ -> e + γ lepton flavor number ν i -> ν k

64 RARE DECAYS WHICH ARE ALLOWED IN THE STANDARD MODEL FCNC: q i -> q k + ν ν q i -> q k + l + l - these decays occur only via loops because of GIM and are suppressed by CKM q i -> q k + γ THUS THEY ARE SENSITIVE TO NEW PHYSICS

65 Why we like K π ν ν? For the same reason as A J/ψ Ks : 1) Dominated by short distance dynamics (hard GIM suppression, calculable in pert. theory ) 2) Negligible hadronic uncertainties (matrix element known) O(G 2 F ) Z and W penguin/box s d ν ν diagrams SM Diagrams

66 H eff =G 2 F α/ (2 2π s 2 W )[ V td V ts* X t + V cd V cs* X c ] ( s γ µ (1 - γ 5 ) d) ( ν γ µ (1 - γ 5 ) ν ) NLO QCD corrections to X t,c and O(G 3 F m 4 t) contributions known the hadronic matrix element π s γ µ (1 - γ 5 ) d K is known with very high accuracy from Kl3 decays sensitive to V td V ts * and expected large CP

67 A(s d ν ν ) O(λ 5 m 2 t ) + i O(λ 5 m 2 t ) O(λ m 2 c ) + i O(λ 5 m 2 c ) O(λ Λ 2 QCD ) CKM suppressed GIM CP conserving: error of O(10%) due to NNLO corrections in the charm contribution and CKM uncertainties BR(K + ) SM = (7.2 ± 2.0) BR(K + ) EXP = ( ) events observed by E787 - central value about 2 the value of the SM - E events in 2 years

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69 K + -> π + νν

70 CP Violating K L π 0 ν ν O(λ 5 m 2 t ) + i O(λ m 2 t ) O(λ m 2 c ) + i O(λ 5 m 2 c ) O(λ Λ 2 QCD ) dominated by the top quark contribution -> short distances (or new physics) theoretical error 2 % BR(K + ) SM = (m t (m t )/170GeV) 2.3 (Im(V ts* V td )/ λ 5 ) 2 = (2.8 ± 1.0) Using Γ(K L π 0 νν) < Γ(K + π + νν) One gets BR(K L π 0 νν) < (90% C.L.) 2 order of magnitude larger than the SM expectations

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