Download presentation

Presentation is loading. Please wait.

Published byClement Duane Mills Modified about 1 year ago

1
Andreas Crivellin ITP Bern Non-minimal flavor violation in the MSSM

2
Outline: The SUSY flavor and CP problem The SUSY flavor and CP problem Self-energies in the MSSM Self-energies in the MSSM Resummation of chirally enhanced corrections Resummation of chirally enhanced corrections Effective Higgs vertices Effective Higgs vertices Chirally enhanced corrections to FCNC processes Chirally enhanced corrections to FCNC processes Flavor from SUSY Flavor from SUSY Right-handed W-coupling and the determination of V ub and V cb. Right-handed W-coupling and the determination of V ub and V cb. Constraints on the squark mass splitting from Kaon and D mixing Constraints on the squark mass splitting from Kaon and D mixing

3
Introduction Sources of flavor violation in the MSSM

4
Quark masses Top quark is very heavy: Top quark is very heavy: Bottom quark rather light, but Y b can be big at large tan(β) Bottom quark rather light, but Y b can be big at large tan(β) All other quark masses are very small sensitive to radiative corrections All other quark masses are very small sensitive to radiative corrections

5
CKM matrix CKM matrix is the only source of flavor and CP violation in the SM. CKM matrix is the only source of flavor and CP violation in the SM. No tree-level FCNCs No tree-level FCNCs Off-diagonal CKM elements are small Off-diagonal CKM elements are small Flavor-violation is suppressed in the Standard Model. Flavor-violation is suppressed in the Standard Model.

6
SUSY flavor (CP) problem The squark mass matrices are not necessarily diagonal (and real) in the same basis as the quark mass matrices. The squark mass matrices are not necessarily diagonal (and real) in the same basis as the quark mass matrices. Especially the trilinear A-terms can induce dangerously large flavor- mixing (and complex phases) since they don’t necessarily respect hierarchy of the SM. Especially the trilinear A-terms can induce dangerously large flavor- mixing (and complex phases) since they don’t necessarily respect hierarchy of the SM. The MSSM possesses two Higgs-doublets: Flavor-changing charged and (loop-induced) neutral Higgs interactions. Why is the observed flavor violation so small? The MSSM possesses two Higgs-doublets: Flavor-changing charged and (loop-induced) neutral Higgs interactions. Why is the observed flavor violation so small? Possible solutions: Possible solutions: - MFV D’Ambrosio, Giudice, Isidori, Strumia hep-ph/ Flavor-symmetries - effective SUSY Barbieri et at hep-ph/ Radiative flavor violation

7
Squark mass matrix involves only bilinear terms (in the decoupling limit) hermitian: The chirality-changing elements are proportional to a vev

8
Mass insertion approximation (L.J. Hall, V.A. Kostelecky and S. Raby, Nucl. Phys. B 267 (1986) 415.) flavor indices 1,2,3 chiralitys L,R off-diagonal element of the squark mass matrix Useful to visualize flavor-changes in the squark sector

9
Self-energies in the MSSM

10
SQCD self-energy: Finite and proportional to at least one power of decoupling limit

11
Decomposition of the self-energy Decompose the self-energy into a holomorphic part proportional to an A-term non-holomorphic part proportional to a Yukawa Define dimensionless quantity which is independent of a Yukawa coupling

12
Chargino self-energy:

13
Finite Renormalization and resummation of chirally enhanced corrections AC, Ulrich Nierste, arXiv: AC, Ulrich Nierste, arXiv: AC, arXiv: AC, Lars Hofer, Janusz Rosiek arXiv:

14
tan(β) is automatically resummed to all orders Renormalization I All corrections are finite; counter-term not necessary. Minimal renormalization scheme is simplest. Mass renormalization

15
Renormalization II Flavour-changing corrections important two-loop corrections A.C. Jennifer Girrbach 2010

16
Renormalization III Renormalization of the CKM matrix: Decomposition of the rotation matrices Corrections independent of the CKM matrix CKM dependent corrections

17
Effective gaugino and higgsino vertices No enhanced genuine vertex corrections. No enhanced genuine vertex corrections. Calculate Calculate Determine the bare Yukawas and bare CKM matrix Determine the bare Yukawas and bare CKM matrix Insert the bare quantities for the vertices. Insert the bare quantities for the vertices. Apply rotations to the external quark fields. Apply rotations to the external quark fields. Similar procedure for leptons (up-quarks) Similar procedure for leptons (up-quarks)

18
Chiral enhancement For the bottom quark only the term proportional to tan(β) is important. tan(β) enhancement For the bottom quark only the term proportional to tan(β) is important. tan(β) enhancement For the light quarks also the part proportional to the A-term is relevant. For the light quarks also the part proportional to the A-term is relevant. Blazek, Raby, Pokorski, hep-ph/

19
Flavor-changing corrections Flavor-changing A-term can easily lead to order one correction. Flavor-changing A-term can easily lead to order one correction.

20
Chirally enhanced Corrections to FCNC processes AC, Ulrich Nierste, arXiv:

21
Improvement of FCNC analysis necessary if A-terms are big: Self energies can be of Ο(1) in the flavor conserving case, and have to be resummed. M.S.Carena, D.Garcia, U.Nierste and C.E.M.Wagner, [arXiv:hep-ph/ ]. They are still of Ο(1) in the flavor violating case, when the mixing angle is divided out. Two- or even three-loop processes can be of the same order as the LO process!

22
Inclusion of the self-energies We treat all diagrams in which no flavor appears twice on an external leg as one particle irreducible. We treat all diagrams in which no flavor appears twice on an external leg as one particle irreducible. Use of the MS-bar scheme allows for a direct relation between the parameters in the squark mass matrices and observables. Use of the MS-bar scheme allows for a direct relation between the parameters in the squark mass matrices and observables. Computations are easiest if one includes the chirally enhanced self-energies into a renormalized quark-squark-gluino vertex: Computations are easiest if one includes the chirally enhanced self-energies into a renormalized quark-squark-gluino vertex:

23
b→sγ Behavior of the branching ratio for Two-loop effects enter only if also m b μ tan(β) is large.

24
Constraints on δ 23 from b→sγ

25
Effective Higgs vertices AC, arXiv:

26
Higgs vertices in the EFT I new Flavour-diagonal case M. Spira et al arXiv:

27
Higgs vertices in the EFT II Non-holomorphic corrections Non-holomorphic corrections Holomorphic corrections Holomorphic corrections The quark mass matrix is no longer diagonal in the same basis as the Yukawa coupling Flavor-changing neutral Higgs couplings The quark mass matrix is no longer diagonal in the same basis as the Yukawa coupling Flavor-changing neutral Higgs couplings

28
Effective Yukawa couplings with Final result: Final result: Diagrammatic explanation in the full theory:

29
Higgs vertices in the full theory Cancellation incomplete since Part proportional to is left over. A-terms generate flavor-changing Higgs couplings Cancellation incomplete since Part proportional to is left over. A-terms generate flavor-changing Higgs couplings

30
Radiative generation of light quark masses and mixing angels AC, Ulrich Nierste, arXiv: AC, Jennifer Girrbach, Ulrich Nierste, arXiv: AC, Ulrich Nierste, Lars Hofer, Dominik Scherer arXiv:

31
SU(2)³ flavor-symmetry in the MSSM superpotential: CKM matrix is the unit matrix. CKM matrix is the unit matrix. Only the third generation Yukawa coupling is different from zero. Only the third generation Yukawa coupling is different from zero. All other elements are generated radiatively using the trilinear A-terms! Radiative flavor-violation

32
Features of the model Additional flavor symmetries in the superpotential. Additional flavor symmetries in the superpotential. Explains small masses and mixing angles via a loop- suppression. Explains small masses and mixing angles via a loop- suppression. Deviations from MFV if the third generation is involved. Deviations from MFV if the third generation is involved. Solves the SUSY CP problem via a mandatory phase alignment. (Phase of μ enters only at two loops) Borzumati, Farrar, Polonsky, Thomas Solves the SUSY CP problem via a mandatory phase alignment. (Phase of μ enters only at two loops) Borzumati, Farrar, Polonsky, Thomas The SUSY flavor problem reduces to the elements The SUSY flavor problem reduces to the elements Can explain the B s mixing phase Can explain the B s mixing phase

33
CKM generation in the down-sector: Allowed regions from b→sγ. Chirally enhanced corrections must be taken into account. A.C., Ulrich Nierste 2009 Allowed regions from b→sγ. Chirally enhanced corrections must be taken into account. A.C., Ulrich Nierste 2009

34
Non-decoupling effects Non-holomorphic self- energies induce flavour- changing neutral Higgs couplings. Non-holomorphic self- energies induce flavour- changing neutral Higgs couplings. Effect proportional to ε b Effect proportional to ε b

35
Higgs effects: B s →μ + μ - Constructive contribution due to Constructive contribution due to

36
Higgs effects: B s mixing Contribution only if due to Peccei-Quinn symmetry Contribution only if due to Peccei-Quinn symmetry

37
Correlations between B s mixing and B s →μ + μ - Br[B s →μ + μ - ]x10 -9 Br[B s →μ + μ - ]x10 -9

38
CKM generation in the up-sector: Constraints from Kaon mixing. Constraints from Kaon mixing. unconstrained from FCNC processes. unconstrained from FCNC processes. can induce a sizable right-handed W coupling. can induce a sizable right-handed W coupling.

39
Effects in K→ π νν Effects in K→ π νν Verifiable predictions for NA62 Verifiable predictions for NA62

40
A right-handed W coupling Effects on the determination of V ub and V cb in the MSSM AC, arXiv:

41
Motivation for a right-handed W coupling 2.2 σ discrepancy between the inclusive and exclusive determination of V cb 2.2 σ discrepancy between the inclusive and exclusive determination of V cb σ deviation from the SM expectation in B→ τν σ deviation from the SM expectation in B→ τν Tree-level processes. Commonly believed to be free of NP. (Charged Higgs contribution to B→τν is destructive.) Tree-level processes. Commonly believed to be free of NP. (Charged Higgs contribution to B→τν is destructive.) Notoriously difficult to explain the deviations from the SM

42
Effective field theory O (5) gives rise to neutrino masses O (5) gives rise to neutrino masses Focus on the dimension 6 operator which generates the anomalous W couplings Focus on the dimension 6 operator which generates the anomalous W couplings Buchmüller, Wyler Nucl. Phys. B268 (1986)

43
Possible size of V R strongly constrained from b→sγ Misiak et. al strongly constrained from b→sγ Misiak et. al also constrained from b→sγ (b→dγ) A.C. Lorenzo Mercolli arXiv: also constrained from b→sγ (b→dγ) A.C. Lorenzo Mercolli arXiv: No large effect for the first two generations possible because the CKM elements are big and the chirality violation is small. No large effect for the first two generations possible because the CKM elements are big and the chirality violation is small. Sizable effects possible in and Sizable effects possible in and

44
Genuine vertex- correction Corrections to the left-handed coupling suppressed because the hermitian part of the WFR cancels with the genuine vertex correction. Corrections to the left-handed coupling suppressed because the hermitian part of the WFR cancels with the genuine vertex correction. Right-handed coupling not suppressed! Right-handed coupling not suppressed!

45
Where are SUSY effects possible? strongly constrained from FCNC processes. strongly constrained from FCNC processes. less constrained from FCNC but constrained from the CKM renormalization. less constrained from FCNC but constrained from the CKM renormalization. constrained from D mixing constrained from D mixing nearly unconstrained from FCNCs and not involved in the CKM renormalization. nearly unconstrained from FCNCs and not involved in the CKM renormalization. Large possible if A b or tan(β) is large. Large possible if A b or tan(β) is large. V ud, V us, V cd, V cs are to large for observable effects Only V ub, V cb can be affected by SUSY effects. V ud, V us, V cd, V cs are to large for observable effects Only V ub, V cb can be affected by SUSY effects.

46
Biggest SUSY effect in V ub. Effect in V cb ≈10%

47
Right-handed W coupling in exclusive and inclusive B decays Exclusive leptonic B decays: ~|γ μ γ 5 |² V L =V+V R Exclusive leptonic B decays: ~|γ μ γ 5 |² V L =V+V R Exclusive semi-leptonic B decays to pseudo-scalar mesons ~|γ μ |² V L =V-V R Exclusive semi-leptonic B decays to pseudo-scalar mesons ~|γ μ |² V L =V-V R Exclusive semi-leptonic B decays to vector mesons ~|γ μ γ 5 |² at ω=1 Exclusive semi-leptonic B decays to vector mesons ~|γ μ γ 5 |² at ω=1 Inclusive B→u decay ~|1+γ μ γ 5 |²+|1-γ μ γ 5 |² V L ≈V Inclusive B→u decay ~|1+γ μ γ 5 |²+|1-γ μ γ 5 |² V L ≈V Inclusive B→c decay receive correction proportional to m c /m b Inclusive B→c decay receive correction proportional to m c /m b V L =V+0.56V R V L =V+0.56V R V = measured CKM element Dassinger, Feger, Mannel: Complete Michel Parameter Analysis of inclusive semileptonic b→c transition

48
Effects of a right-handed W- coupling on V ub inclusive CKM unitarity B→τν B→πlν

49
Connection to Single Top Production Plehn, Rauch, Spannowski: Feynman diagrams contributing to Single Top production Integrated luminosity necessary to discover Single Tops

50
Constraints on the mass splitting between left- handed squarks from D and K mixing AC, Momchil Davidkov, arXiv:

51
K and D mixing Mass difference is small: Mass difference is small: CP violation is tiny CP violation is tiny Constrains FCNCs between the first two generations in a stringent way.

52
SUYS Contributions SU(2) L relation: SU(2) L relation: SUSY contributions to D and Kaon mixing can only be simultaneously avoided if is proportional to the unit matrix. elements are induced if the left- handed squarks of the first two generations are not degenerate. elements are induced if the left- handed squarks of the first two generations are not degenerate.

53
Electroweak contributions are important for In non-minimal flavor violation the main focus is on the gluino contributions, however: The gluino contributions suffer from cancellations between the crossed and uncrossed boxes for The gluino contributions suffer from cancellations between the crossed and uncrossed boxes for Chargino diagrams do not suffer from such a cancellation. Chargino diagrams do not suffer from such a cancellation. Winos couple directly to left-handed squarks with g 2. can contribute without small LR or gaugino mixing. Winos couple directly to left-handed squarks with g 2. can contribute without small LR or gaugino mixing. The wino mass is often assumed to be much lighter than the gluino mass. In most GUT scenarios: The wino mass is often assumed to be much lighter than the gluino mass. In most GUT scenarios:

54
Relative importance of the contributions to C 1 normalized to the chargino contribution:

55
Allowed mass splitting Maximally allowed mass-splitting Alignment to Y d Alignment to Y u Minimally allowed mass-splitting Non-degenerate squark masses are allowed. Non-degenerate squark masses are allowed. More space for models with abelian flavor symmetries. More space for models with abelian flavor symmetries. Interesting for LHC benchmark scenarios. Interesting for LHC benchmark scenarios.

56
Conclusions Self-energies in the MSSM can be of order one. Self-energies in the MSSM can be of order one. Chirally enhanced corrections must be taken into account in FCNC processes. Chirally enhanced corrections must be taken into account in FCNC processes. A-terms generate flavor-changing neutral Higgs couplings. A-terms generate flavor-changing neutral Higgs couplings. Radiative generations of light fermion masses and mixing angles solves the SUSY flavor and the SUSY CP problem. It can explain B s mixing and enhance B s →μ + μ -. Radiative generations of light fermion masses and mixing angles solves the SUSY flavor and the SUSY CP problem. It can explain B s mixing and enhance B s →μ + μ -. The first two generations of left-handed squarks can be non-degenerate. The first two generations of left-handed squarks can be non-degenerate. The MSSM can generate a sizeable right-handed W-coupling. Tree-level processes are not necessarily free of NP! The MSSM can generate a sizeable right-handed W-coupling. Tree-level processes are not necessarily free of NP!

57
Finite renormalization (general formalism) Corrections to the Mass: Flavor valued wave-function corrections: Decomposition of the self-energies: with

58
Fine-tuning constraints A small parameter is natural if a symmetry is gained if parameter is put to zero A small parameter is natural if a symmetry is gained if parameter is put to zero Large accidental cancellations, not enforced by a symmetry are unnatural Large accidental cancellations, not enforced by a symmetry are unnatural ‘t Hooft’s naturalness argument: The SUSY corrections to the masses and mixing angels should not exceed the measured values.

59
Constrains from fermion masses I:

60
Example: V ub Constrains from the CKM matrix:

61
Constraints on from V ub For large helicity flipping elements, for example m b μ tan(β), also can be constrained. Strongest for :

62
Constrains from fermion masses II:

63
Existing results: FCNC bounds (decoupling): M. Ciuchini et al. [arXiv:hep-ph/ ] F. Borzumati, C.Greub, T.Hurth and D.Wyler [arXiv:hep-ph/ ] D. Becirevic et al. [arXiv:hep-ph/ ] M. Ciuchini et al. [arXiv:hep-ph/ ] … Vacuum stability bounds (non-decoupling): J.A.Casas and S.Dimopoulos, Stability bounds on flavor-violating trilinear soft terms in the MSSM, Phys. Lett. B387 (1996) 107 [arXiv:hep-ph/ ]

64
quantity our bound bound from FCNC bound from vacuum stability , K mixing , B d mixing , b→sγ , B d mixing , D mixing Results and comparison Bounds calculated with m squark =m gluino =1000GeV

65
Allowed range for NP in ΔF=2 processes Results taken for: UTfit Collaboration: Example: B s mixing

66
Effect of including the self- energies in ΔF=2 processes for

67
Constraints on (δ LR ) 23 from B s mixing

68
Constraints on δ LR from D, B, and K mixing

69
Constraints on δ 23 from b→sγ

70

71
inclusive B→Dlν B→D*lν Effects of a right-handed W-coupling on V cb

Similar presentations

© 2016 SlidePlayer.com Inc.

All rights reserved.

Ads by Google