WIR SCHAFFEN WISSEN HEUTE FR MORGEN Andreas Crivellin

WIR SCHAFFEN WISSEN – HEUTE FÜR MORGEN Andreas Crivellin Theory Group of the Laboratory for Particle Physics Explaining the flavour anomalies with Leptoquarks Obergurgel, 16. 04. 2018

Outline • Introduction: The flavour anomalies - b→sμ+μ- Talks of Uli, Regis, Stefano, Vincenzo, … - b→cτν - Anomalous magnetic moment of the muon aμ • Simultaneous explanations with leptoquarks - 2 scalar leptoquarks - Vector leptoquark; gauged - Vector leptoqaurk; composite • Conclusions and outlook Andreas Crivellin Page 2

Physics Beyond the Standard Model • Dark Matter existence established at cosmological scales New Thursday session particles - New weakly interacting particles and • Neutrinos not exactly massless interactions Talk of Frank Deppisch exist! - Right-handed (sterile) neutrinos • Matter anti-matter asymmetry - Additional CP violating interactions writescience. wordpress. com The SM must be extended! What is the underlying fundamental theory? Andreas Crivellin Page 3

Finding New Physics with Flavour • At colliders one produces many (up to 1014) heavy quarks or leptons and measures their decays into light flavours New Physics a l F u o v b o r r e s b a v s e l PSI Talk of Uli Standard Model Direct searches Experiment Talk of Adrian Flavour observables are sensitive to higher energy scales than collider searches Andreas Crivellin Page 4

New Physics in the Flavour Sector Hints for New Physics in flavour observables Andreas Crivellin Page 5

P 5’ and Bs→ϕμμ n n n LHCb 3σ deviation from the SM Confirmed by BELLE 2σ tension in the Bs→ϕμμ branching ratio Hadronic uncertainties or NP? 4 Page 6

R(K) = B→Kµµ/B→Kee n Lepton flavour universality violation n 2. 6σ deviation from theoretically rather clean SM expectation C. Bobeth, G. Hiller, and G. Piranishvili, 0709. 4174 Lepton Flavour Violation in B decays? LHCb 1406. 6482 5 Page 7

R(K*) = B→K*µµ/B→K*ee n 2. 2 -2. 4 σ in two bins Page 8

Global fit to b→sμμ data n n Global analyses give a very good fit to data Good fit to data: n n n 1501. 04239 B. Capdevila, AC, S. Descotes-Genon, J. Matias and J. Virto, ar. Xiv: 1704. 05340 [hep-ph]. Fit is 5 -6 σ better than the SM Page 9

b→cτν processes All measurements above the SM prediction ≈4σ deviation Page 10

Muon Anomalous Magnetic Moment • Single measurement from BNL • Theory prediction sound but challenging because of hadronic effects. • Soon new experimental results from Fermilab 3 σ deviation (order of SM-EW contribution) Page 11

Leptoquarks n n Scalars or Vectors 5 gauge representations each which are invariant under the SM gauge group Couple quarks to leptons Maybe also quarks to quarks Ø n Proton decay Are present in Grand Unified Theories Page 12

aμ: Leptoquarks mt/mμ enhancement 8 Page 13

Leptoquarks in aμ n Chirally enhanced effects via top-loops Left-, righthanded muons-top coupling E. Leskow, A. C. , G. D'Ambrosio, D. Müller ar. Xiv: 1612. 06858 Z→μμ at future colliders 8 Page 14

R(K), R(K*) and μ→eγ with LQs n Three LQs give a good fit Scalar triplet n Vector singlet n Vector triplet n b→sμμ & b→see generate μ→eγ AC, D. Mueller, A. Signer, Y. Ulrich, ar. Xiv: 1706. 08511 Page 15

R(D(*)) and b→sττ • Large couplings to the second generation • Cancelation in b→sνν needed: C(1)=C(3) Capdevila, AC, Descotes-Genon, Matias 1712. 01919, accepted for PRL b→sττ very strongly enhanced See also R. Alonso, B. Grinstein and J. Martin Camalich, 1505. 05164 Page 16

Two Scalar Leptoquarks for b→cτν • • scalar leptoquark singlet with Y=-2/3 scalar leptoquark triplet with Y=-2/3 AC, D. Mueller, T. Ota arxiv: 1703. 09226 Constructive in R(D(*)) Destructive in b→sνν Page 9

R(D(*)), b→sνν with 2 Scalar LQs

R(D(*)), b→sμμ and aμ with 2 scalar LQs • Scalar leptoquark singlet + triplet with Y=-2/3 • Cancelation in b→sνν imposed 2 out of 3 can be explained

Vector Leptoquark SU(2) Singlet • • • 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-renormalizable without Higgs mechanism - Pati Salam not possible at the Tev scale because of KL→μe and K→πμe Good solution, but difficult UV completion

Pati-Salam + vector-like fermions L. Calibbi, AC and T. Li, A model of vector leptoquarks in view of the B-physics anomalies ar. Xiv: 1709. 00692

Pati-Salam + vector-like fermions - 3 light generation (SM fermions) - 3 heavy generation (vector like) Only the LQ couples flavour violating

R(D(*)) and b→sμμ LHCb bounds require additional heavy neutral fermions Simultaneous explanation possible! Can also account for the AMM of the muon

Pati-Salam + Randall-Sundrum M. Blanke, AC, ar. Xiv: 1801. 07256 broken to the SM via boundary conditions on a compact extra dimension • Zero modes: SM fermions • KK modes: Vector-like fermions and massive gauge bosons • No zero mode for the Leptoquark • Flavour alignment to the down-sector • PS + RS naturally accounts for a vector LQ + VLFs

Flavour effects • b→cτν + • b→sμμ • τ → μμμ & D mixing τ→μμμ and cannot be avoided

PS+RS Phenomenology Modell well motivated + limited but sizable effect

Outlook • P 5’ b→dμμ • R(D) & R(D*) b→sττ • R(K) & R(K*) μ→eγ NP • R(D), R(D*) & aμ τ → μγ • R(D), R(D*) & b → sμμ b → sτμ Interesting experimental prospects Andreas Crivellin Page 27

Conclusions Electron channels: SM-like τ→Kν >2σ Lepton Flavour Universality Violation (LFUV) aµ >3σ Andreas Crivellin b→sµµ >5σ Leptoquarks provide a very promising solution to the flavour anomalies b→cτν >4σ Page 28

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R(K) & R(K*) ar. Xiv: 1704. 05438 Combined ≈4 σ evidence for LFUV Page 30