Federico Mescia. Review of Flavour Physics. ECM & ICC, Universitat de Barcelona. FFP14, July 17 th 2014 Marseille. - Outline

Transcription

1 Review of Flavour Physics Federico Mescia ECM & ICC, Universitat de Barcelona - Outline What is Flavour Physics?: CKM, Higgs Flavour Physics What do we understand about New Physics so far? Results from Babar, Belle, Tevatron & LHC Future perspectives for New Physics via the Flavour Window F= processes: ϵ K, M s & Flavour Problem F=1 processes: b s FCNC transitions from LHCb FFP14, July 17 th 014 Marseille

2 Introduction: Flavour Physics: What is Flavour Physics? 1937 β decay: n p e - v p n int = CKM u Lγ Vu d dlw W mediates Flavour (CKM) d u, s u, b u, 6 types of quarks and leptons 1964 K K mixing W interaction violates CP (complex CKM)

3 Introduction: Flavour Physics: What is Flavour Physics? Flavour Transitions: - W interactions violate Flavour and CP: complex CKM matrix int =... CK t Lγ V M blw b W V CKM t CKM V = (unitarity) 3 angles and 1 Phase - Z interactions conserve Flavour and CP.

4 Introduction: Flavour Physics: What is Flavour Physics? Flavour Transitions: - W interactions violate Flavour and CP: complex 3x3 matrix (CKM) int =... CK t Lγ V M blw b W V CKM t But this is only macroscopic picture (phenomenogical couplings at low scales)

5 Introduction: Flavour Physics: What is Flavour Physics? Flavour Transitions: - W interactions violate Flavour and CP: complex 3x3 matrix (CKM) int =... CK t Lγ V M blw b W V CKM t Microscopic picture Higgs mediator 1973 ( ) int, = + + gauge Ai Qi QLYUU RH QLYDDRH Higgs gives rise to CKM and Masses by Yukawa interactions Y = ˆ U VCKM M Y ˆ u D V V =1 CKM CKM = M d

6 Flavour Physics Today Thanks to modern experiments (Babar, Belle, KLOE, NA48, Tevatron & LHC), the Yukawa interaction has been confirmed with high accuracy: CKM is the dominant source of Flavour and CP violation at low energy. = (, ) + + SM gauge Ai Qi QLYUU RH QLYDDRH Two of 9 unitarity relations of CKM, tested at percent level 1) Vud + V us + Vub = 1 ) * * * VcdVcb + VudVub + V td Vtb =0 Only 4 parameters V us, V cb, ρ and η, control a large set of Flavour observables to a high accuracy! Only 1 parameter η controls CP violation! V CKM ( ρ iη) λ 3 1 λ Aλ λ = λ 1 Aλ 3 Aλ ( 1 ρ iη) Aλ 1 V us = λ, V cb = Aλ

7 V us and V ud - unitarity test ( V ) V V + V + V = 1 CKM CKM uu ud us ub V ud ( ) + V + V 1 = us ub 1 angle to fit 3 measurements V ud from β nuclear decays V us from K πlv decays V us / V ud from K v decays V ud = () V us = 0.50(7) Δ CKM = (6) V ud = cosθ c = (13) V us = sinθ c = 0.5(6)

8 Unitarity triangle Analysis: * ( ) V V V V + V V + V V t = * * CKM CKM db cd cb ud ub td b see also Laiho, E. Lunghi & R. Van de Water 0 V V + V V + V V = * * * cd cb ud ub td tb V V V V t 0 V V + = * * ud ub td b * * cd cb VcdVc b All exp. band overlap in a common area VudV V V cd * ub * cb ρ + η V V td cd V V * tb * cb ( 1 ρ ) + η

9 Unitarity triangle Analysis: * ( ) V V V V + V V + V V t = * * CKM CKM db cd cb ud ub td b 0 ρ = ± % η = 0.35 ± % 4 CKM parameters to fit more than 11 measurements

10 Unitarity triangle Analysis: closer look I. Remarkable consistency between tree-level processes γ, α, V ub, V cb and loop induced observables (FCNC) sin(β), m ds, ε K, b->sγ... II. Remarkable consistency between CPC and CPV observables m ds, ε K V V + V V + V V = * * * cd cb ud ub td tb 0

11 What's Next? Despite all its successes, the SM is likely to be an effective theory, the low-energy limit of a more fundamental theory, with new degrees of freedom above the electroweak scale

12 What's Next? Despite all its successes, the SM is likely to be an effective theory, the low-energy limit of a more fundamental theory, with new degrees of freedom above the electroweak scale. Already many hints for physics beyond SM: gravity, neutrino oscillations, dark matter, matter/anti-matter asymmetries no clear clues to NP model but n.o.f at high scale looks necessary! Moreover, key open questions within Flavour dynamics itself What is the origin of Yukawa couplings in the SM? new degrees of freedom at unification scale TeV, M planck? Yukawa int.: large loop corrections to the higgs mass NP at O(1 TeV)? mh = y top Λ 16 Λ cutoff cutoff log π mtop

13 What's Next? Despite all its successes, the SM is likely to be an effective theory, the low-energy limit of a more fundamental theory, with new degrees of freedom above the electroweak scale Potential new degrees of freedom can modify Flavour decays through quantum fluctuations B 5 GeV X? Quantum Fluctuation (sensitive to Λ>>5 GeV) l K 900 MeV l MeV twofold role of Flavour physics in the LHC era Identify BSM mechanism of Flavour-breaking Probe physics at energy scale not accessible at LHC Are the Yukawa couplings the only source of Flavour?

14 Twofold role of Flavour for BSM - Example ϵ K and SUSY - NATURAL SUSY Constraints from ϵ K : [Mescia, Virto, ] i. 1 st & nd gen. squarks has to be heavy to escape current LHC bounds ii. But stop, sbottom and Higgsinos need to be light to avoid tuning in m h NATURAL SUSY: non-trivial flavor spectrum: 3 rd gen. of squarks lighter than others Dimopulos, Giudice 95 Cohen, Kaplan, Nelson 96 ϵ K mediated by 3 rd generations of squarks!!

15 Twofold role of Flavour for BSM - Example ϵ K and SUSY - NATURAL SUSY Constraints from ϵ K : [Mescia, Virto, ] s ~ b d s ~ b d ϵ K SM ϵ K ~ + g~ g~ + g~ g~ d ~ b s - d ~ b s - New sources of Flavour-breaking on SUSY Two scenarios and twofold role of Flavour: = ~ CKM 1 ~ CKM, =0

16 Twofold role of Flavour for BSM - Example ϵ K and SUSY - NATURAL SUSY Constraints from ϵ K : [Mescia, Virto, ] = ~ CKM s ~ b d ϵ K ~ g~ g~ d ~ b - s Excluded Twofold role of Flavour 1 Either NP too heavy and not directly accessible at LHC: m sbottom >3 TeV but still accessible by Flavour observables through loops

17 Twofold role of Flavour for BSM - Example ϵ K and SUSY - NATURAL SUSY Constraints from ϵ K : [Mescia, Virto, ] = ~ CKM s ~ b d ϵ K ~ g~ g~ d ~ b - s Excluded Powerful role of Flavour 1 Natural SUSY hypothesis (m sbottom <1 TeV?) built in to pass LHC searches excluded by Flavour breaking 1

18 Twofold role of Flavour for BSM - Example ϵ K and SUSY - NATURAL SUSY Constraints from ϵ K : [Mescia, Virto, ] ~ CKM, =0 s ~ b d ϵ K ~ g~ g~ d ~ b - s Excl. Powerful role of Flavour OK Natural SUSY spectrum (m sbottom <1 TeV?) - Flavour helpful to fix BSM symmetries. =0

19 Future perspective for New Physics via Flavour Window What is the origin of Yukawa couplings in the SM? In many observables theoretical errors still larger than exp. ones 1. Refined CKM fits to 1% by Belle II and LHCb: new physics in B d, B s and K mixing! 00 Past studies on FCNC mainly involve b d (and s d) transitions. b s transitions: possible rich ground for surprises! already some anomalies in B d K *! NOW LHCb 3. Rare Kaon decays: s d penguins >00,NA6, JPARC..

20 1. CKM fits to 1% by tree-level modes (00) Experimental error on B and K mixings are already below 1% _ ϵ K : K 0 -K 0 mixing exp. err 0.5% th.err 10% Μ d : B 0 d-b 0 d mixing exp. err 0.7% th.err 6% _ Μ s : B 0 s-b 0 _ s mixing exp. err 0.1% th.err 6% By reducing the theory error we become more sensitive to NP: sources of th. error hadronic + parametrical (CKM, masses)

21 1. CKM fits to 1% by tree-level modes (00) Experimental errors on B and K mixing are already below 1% _ ϵ K : K 0 -K 0 mixing exp. err 0.5% th.err 10% Μ d : B 0 d-b 0 d mixing exp. err 0.7% th.err 6% _ Μ s : B 0 s-b 0 _ s mixing exp. err 0.1% th.err 6% By reducing the theory errors we become more sensitive to NP: sources of th. error: hadronic + parametrical (CKM, masses) ones ρ~15% - - η~10% - ρ~1% η~1% Belle 50ab -1 50fb -1 Drastic reduction of CKM parametrical uncertainties

22 Tension in CKM fits: ϵ K -sin(β), V ub UTfit Collaboration - + fit vs. exp.4σ Exp SM Weak evidence of ϵ K - ϵ K > 0 A positive contribution to ϵ K is common to MFV-like SUSY models Barbieri, Buttazzo, Sala, Straub 13

23 . b s transitions: possible rich ground for surprises! Large amount of observables: a rich anatomy of b s couplings LHCb TASK

24 b s transitions: Β s SM operators ( bγ L s) ( γ ) O = b σ s F, O = b s ν 7 R L ν 9 L O = γ γ 10 5 γ SUSY at large tanβ BSM operators ν ( bs R L), ( Rσ sl) ν O = O = b σ S( P) S( P) T 7,9,10, S,P 7,9,10, S,P ( R) O = O L GOLDEN MODE at LHCb enhanced C S(P) ~tan 3 β Γ 0 F m 3 Bs + ( Bs ) G α ~ 64 π f ( ) + ( ) ( ) Bs tb ts m C10 C 10 mbs CP C P + m C C Bs S S VV Special Mode double suppressed! No SM tree-level contributions Helicity suppression hadronic uncertainties under control Only one hadronic parameter: f Bs

25 b s transitions: Β s SM operators ( bγ L s) ( γ ) O = b σ s F, O = b s ν 7 R L ν 9 L O = γ γ 10 5 γ BSM operators ν ( bs R L), ( Rσ sl) ν O = O = b σ S( P) S( P) T 7,9,10, S,P 7,9,10, S,P ( R) O = O L PANIC: July 13, LHCb-CMS results Br exp (Β s ) = (.9 ± 0.7)10 9 Br SM (Β s ) = (3.3 ± 0.3)10-9 NO NEW PHYISICS? update of D. Straub 1

26 b s transitions: Β s + Β Κ ( ) + Β s ττ SM operators ( bγ L s) ( γ ) O = b σ s F, O = b s ν 7 R L ν 9 L O = γ γ 10 5 γ BSM operators ν ( bs R L), ( Rσ sl) ν O = O = b σ S( P) S( P) T 7,9,10, S,P 7,9,10, S,P ( R) O = O L PANIC: Br exp (Β s ) = (.9 ± 0.7)10 9 Br SM (Β s ) = (3.3 ± 0.3)10-9 NO NEW PHYISICS? NO PANIC: Β Κ, Β Κ & Β ττ sensitive to different b s couplings 3 ways out to overcome the B s constraints

27 b s transitions: Β s + Β Κ ( ) 1 SM operators ( bγ L s) ( γ ) O = b σ s F, O = b s ν 7 R L ν 9 L O = γ γ 10 5 γ BSM operators ν ( bs R L), ( Rσ sl) ν O = O = b σ S( P) S( P) T 7,9,10, S,P 7,9,10, S,P ( R) O = O L Γ 0 F m 3 Bs + ( Bs ) G α ~ 64 π f ( ) + ( ) ( ) Bs tb ts m C10 C 10 mbs CP C P + m C C Bs S S VV No contribution from O 9 C 9 couplings unconstrained by B s J. Matias, S Descotes-Genon, J. Virto 13 1 However, O 9 gives contribution to Β Κ, Β Κ, and non-sm effects can be possible

28 b s transitions: Anomaly on Β Κ ( ) 1 July 013, LHCb found a deviation of about 4σ w.r.t the SM in the P 5 observable, one of the coefficients of the B K * angular distribution July 013 4σ Warning: LHCb analysis low statistics -- about 800 events B K * see Sam Cunliffe talk at HEP parallel session on Friday

29 b s transitions: Anomaly on Β Κ ( ) 1 SM operators ( bγ L s) ( γ ) O = b σ s F, O = b s ν 7 R L ν 9 L O = γ γ 10 5 γ BSM operators ν ( bs R L), ( Rσ sl) ν O = O = b σ S( P) S( P) T 7,9,10, S,P 7,9,10, S,P ( R) O = O L LHCb SM A negative contribution to C 9 = C improves the agreement between LHCb and SM (4σ >1.8σ) J. Matias, S Descotes-Genon, J. Virto 13 Warning: LHCb analysis low statistics -- about 800 events B K * SM Warning: still some controversial! is hadronic effects? J. Lyon, R. Zwicky 14, S. Jäger, J. M. Camalich 1 NP ruled out by other modes? Straub et al 14 Experimental fluctuacions?

30 b s transitions: Β s + Β Κ ( ) SM operators ( bγ L s) ( γ ) O = b σ s F, O = b s ν 7 R L ν 9 L O = γ γ 10 5 γ BSM operators ν ( bs R L), ( Rσ sl) ν O = O = b σ S( P) S( P) T 7,9,10, S,P 7,9,10, S,P ( R) O = O L Γ 0 F m 3 Bs + ( Bs ) G α ~ 64 π f ( ) + ( ) ( ) Bs tb ts m C10 C 10 mbs CP C P + m C C Bs S S VV Β s (P=-1) ) Only contributions from axial combinations D. Becirevic, N. Kosnik, F. M, E. Scheider 1 However, orthogonal combinations of couplings enters Β Κ, Β Κ Β Κ ll (P=1) K bγ γ s B = K bγ s B = s 5 s ( C C ) ( C C ) ( C C ) ( C C ) Br +, +, +, P P S S

31 b s transitions: Β s + Β s ττ 3 SM operators ( bγ L s) ( γ ) O = b σ s F, O = b s ν 7 R L ν 9 L O = γ γ 10 5 γ BSM operators ν ( bs R L), ( Rσ sl) ν O = O = b σ S( P) S( P) T 7,9,10, S,P 7,9,10, S,P ( R) O = O L Γ 0 F m 3 Bs + ( Bs ) G α ~ 64 π f ( ) + ( ) ( ) Bs tb ts m C10 C 10 mbs CP C P + m C C Bs S S VV 1) Helicity suppression is not fully working for B->ττ 3 Smallish contributions to Β can still give sizeable deviations of the rate for Β ττ D. Becirevic, N. Kosnik, F. M, A. Tayduganov, A. Renau in progress 14

32 b s transitions: Β s + Β s ττ 3 SM All the points compatible with present constraints Blue Line with only C 10 not-vanishing Red points C 10, C S, C P free SM 3 Non-SM contributions to C 10 easily expected in SUSY

33 b s transitions: Resum 1 3 Br(Β s ) is genuinely sensitive to (pseudo)scalar operators S ( bprls ), and P ( b RL, ) O = O = P s γ, 5 Only one hadronic parameter enters, f Bs -> small th. error Br(Β Κll) & Br(Β Κ ll) are sensitive to scalar + vector operators (+ tensors) hadronic uncertainties -> still large th. error With respect to Β s & Β s X s γ, they probe the effective Hamiltonian in an orthogonal direction! Improvement of form factors calculation would make the observables a high resolution probe of scalar operators

34 Conclusions What about BSM effects? We learned a lot about Flavour physics during last years: Disentangling New Physics, it is mainly a question of precision and new modes Potential n.d.f at the TeV scale must have a rather sophisticated Flavour structure which we have not clearly understood yet Some tension emerging in several modes: B->K*, sin(β) vs ϵ K Multiple probes! Almost all channels are sensitive at NP at well motivated levels! Higgs couplings Rare K decays Rare B decays

35 THANKS VERY MUCH

36 Natural SUSY: no fine tuning on the the Higgs mass: stops, sbottoml and gluinos lights

37 1 pb L 1 fb stronger constraint for light squarks g g q ~ q ~ u ~ u ~ squarks σ pb (300 GeV/m) 6 Flavour Independent (TeV/m g ) Flavour Dependent:U/D PDF large