ExplainingtheFlavourAnomalies withnew Physics

Transcription

1 WIR SCHAFFEN WISSEN HEUTE FÜR MORGEN Andreas Crivellin Theory Group of the Laboratory for Particle Physics ExplainingtheFlavourAnomalies withnew Physics Corfu,

2 Outline Introduction: New Physics and Flavouranomalies b sμμ b cτν a μ Z explanations for b sμμ Simultaneous explanations with LQs Conclusions Andreas Crivellin Page 2

3 Finding NP in FlavourObservables At colliders one produces many (up to ) heavy quarks or leptons and measures their decays into light flavours Andreas Crivellin Experiment Standard Model New Physics Direct searches Flavour observables Flavour observables are sensitive to higher energy scales than collider searches Page 3

4 Hints for LFUV Electron channels: SM like τ µνν 2σ LFUV b sµµ 5-6σ Lepton Flavour Universality Violation (LFUV) a µ 3σ R(D ( * ) ) 4σ Andreas Crivellin Page 4

5 a µ explanations MSSM tan(ß) enhanced slepton loops Scalars Z Light scalars with enhanced muon couplings Very light with τμcouplings (m τ enhancement) Leptoquarks e.g. D. Stockinger, hep-ph/ e.g. A. Broggio et at. arxiv: A.C. et al. arxiv: e.g. W. Altmannshofer, C. Chen, P.S.B. Dev, A. Soni, arxiv: , m t enhanedeffects e.g. A. Djouadi, T. Kohler, M. Spira, J. Tutas, Z.Phys. C46 (1990) E. Leskow, A.C., G. D'Ambrosio, D. Müller arxiv: Chiral enhancement or very light particles 8 Page 5

6 Scalar Leptoquarksin a µ Chirallyenhanced effects via top-loops L, R λ µ Left-, righthanded muons-top coupling E. Leskow, A.C., G. D'Ambrosio, D. Müller arxiv: Z μμat future colliders 8 Page 6

7 R(D) & R(D*) Charged scalars Problems with q 2 distributions and B c lifetime W Strong constraints from direct LHC searches See talk of Roman Leptoquark Strong signals in qq ττsearches Large tree-level effect needed Explanation difficult Faroughy et al. arxiv: Page 7

8 R(D ( * ) ) and b sττ(model-independent) Large couplings to the second generation needed in order avoid collider and EW precision bounds Cancellation in b sννneeded: C (1) C (3) LHCb limit B s ττ very strongly enhanced

9 b sμμmodel-independent analysis Several 2-3σ deviations in more than 130 observables P5 R(K) R(K*) B s ϕμμ 6 NP operators (') µ ( 5 ) µ = µ O sγ P bµγ γ µ 9 L See talk of Nazila Model independent fit 4-6 σ better than SM B. Capdevila, AC, S. Descotes-Genon, J. Matias and J. Virto, arxiv: [hep-ph]. Page 9

10 b sμμexplanations Z See talk of Stephen King U. Haisch et al , Buras et al W. Altmannshofer et al , AC. et al ,.. Leptoquarks Gudrun Hiller, Martin Schmaltz arxiv: B. Gripaios, M. Nardecchia, S.A. Renner. arxiv: D. Bečirević, N. Košnik, O. Sumensari, R. Zukanovich Funchal, arxiv: L. Calibbi, AC. T. Ota, PRL 2015 Loop effects µ B. Gripaios, M. Nardecchia, S. Renner, arxiv: b LQ µ s Even high scale NP explanations possible Page 10

11 R(K), R(K*) and µ eγwith LQs Three LQs give a good fit Scalar triplet Vector singlet Vector triplet Simultaneous effect in b sμμ and b see generate μ eγ AC, D. Mueller, A. Signer, Y. Ulrich, arxiv:1505.xxxx Page 11

12 New Scalars and Fermions in b sµµ Possible representations 2x6x4 possibilities Pere Arnan, A.C., Lars Hofer and Federico Mescia, arxiv: Page 12

13 b sµµand B s mixing B s mixing requires Majorana Fermions b sμμ 1σ 3σ 2σ Explanation with O(1) couplings Page 13

14 Implications for New Particles a μ Higgses Scalars and fermions R(D ( * ) ) Leptoquarks b sμμ Extension of the SM is required! Z gauge boson What is the underlying theory? Andreas Crivellin Page 14

15 Simultaneous Explanation of R(D), R(D*), a µ and b sμμunsing Leptoquarks

16 Two Scalar Leptoquarks AC, D. Mueller, T. Ota arxiv: Φ 1 scalar leptoquark singlet with Y=-2/3 scalar leptoquark triplet with Y=-2/3 Φ 3 Constructive in R(D ( * ) ) Destructive in b sμμ

17 R(D ( * ) ), b sννwith 2Scalar LQs λ λ L jk λ 1L jk 3L = e i π j λ L jk jk

18 R(D ( * ) ), b sμμand a μ with 2 scalar LQs Scalar leptoquark singlet + triplet with Y=-2/3 Cancelation in b sνν imposed 2 out of 3 can be explained

19 Vector LeptoquarkSU(2) Singelet C 9 =-C 10 effect in b sμμ Left handed vector current in R(D) and R(D*) No effect in b sνν No proton decay Contained within the Pati-Salam model Massive vector bosons Non-renormalizablewithout Higgs mechanism PatiSalam not possible at the Tevscale because of K L μeand K πμe Good solution, but difficult UV completion

20 Pati-Salam + vector-like fermions L. Calibbi, AC and T. Li, A model of vector leptoquarks in view of the $B$-physics anomalies arxiv:

21 Pati-Salam + vector-like fermions Q R QL ql YR =, YL, X L L = = R L L l L i i i ( Q Q ) ( L L ) L m q + M Q Q M L + m l L ij il ij il jr ij il ij il jr 3 light generation (SM fermions) 3 heavy generation (vector like) Only the LQ couples flavour violating

22 R(D ( * ) ) and b sμμ s Q i = m M 1+ Q ii Q ii m M Q ii Q ii s 1 = s = 2 = 1.5 TeV Q L 3 3 M Simultaneous explanation possible! Can also account for the AMM of the muon

23 Outlook P5 R(D) & R(D*) R(K) & R(K*) R(D), R(D*) & a μ R(D), R(D*) & b sμμ b dμμ b sττ μ eγ NP τ μγ b sτμ Interstingexperimental prospects Andreas Crivellin Page 23

24 Conclusions Intriguing hints for Lepton FlavourUniversality violating New Physics Leptoquarksare prime candidates for a solution Confirming or disproving the anomalies makes a model selection Predictions for flavor and LHC observables Flavour LHC NP Dark Matter Exciting times in particle physics are ahead of us! Andreas Crivellin Page 24

25 L µ -L τ model for a µ L μ -L τ flavoursymmetry Flavoncouples to μand τ τ µγ Effects in is protected is not protected a µ h µµ W. Altmannshofer, M. Carena, AC, Explanation of a μ and b sμμ 30 Page 25

26 Solution with horizontal U(1) charges Avoid vector-like quarks by assigning charges to baryons as well Same mechanism in the quark and lepton sector L μ -L τ in lepton sector Good symmetry for the PMNS matrix ee Effect in but not C C µµ 9 9 First two quark generations must have the same charges because the large Cabibboangle would lead to huge effect in Kaon mixing Anomaly freedom Q B = a, a,2a ( ) ( ) Q(L)=(0,1,-1) Q(B)=(a,a,-2a) Page 26

27 F=2: Z contribution R B R ε q K m = m = ε ε K SM K B q q SM B Necessarily constructive, but Higgs effects and be destructive. Page 27

28 Dynamical explanation of the charges A.C., J. Fuentes-Martin, A. Greljo and G. Isidori arxiv: Quark Sector Lepton Sector ( 3) ( 3) ( 3) SU SU SU Q U D ( 3) ( 3) ( 3) SU SU O l E ν R Energy scale Symmetry ( 2) ( 2) ( 2) ( 1) SU ( 2) U ( 1) SU SU SU U Q U D q U ( ) 1 q breaking U E l ( 1) l Standard Model Page 28

29 Solution with two Z s 2 Z bosons Z 1 coupling mainly to leptons Z 2 coupling mainly to quarks Low energy phenonenology unchanged Different collider signatures 8 Page 29