Heavy Flavor Physics Theory Perspectives Matthias Neubert Mainz - - PowerPoint PPT Presentation

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01.02.2010

• ERC Advanced Grant (EFT4LHC)

An Effective Field Theory Assault on the Zeptometer Scale: Exploring the Origins of Flavor and Electroweak Symmetry Breaking Cluster of Excellence Precision Physics, Fundamental Interactions and Structure of Matter

Matthias Neubert Mainz Institute for Theoretical Physics Johannes Gutenberg University

• 11th ICFA Seminar

Institute of High-Energy Physics Beijing, China, 27-30 October 2014

Heavy Flavor Physics

Theory Perspectives

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Introductory remarks

The extensive experimental and theoretical explorations of flavor- changing processes in the past decades have taught us a great deal about the structure of the fundamental interactions and the properties of elementary particles at and beyond the electroweak scale. While the discovery of the massive electroweak gauge bosons W and Z (1983), of the last missing third-generation fermions t and ντ (1995 and 2000), and of the Higgs boson (2012) have confirmed the particle content

• f the Standard Model (SM), precision measurements of couplings (in

particular the Yukawa couplings) have confirmed the deeper structure of the SM as the correct (effective) quantum theory of the weak scale. Today, and even more so in the coming decades, flavor physics and precision collider physics (LHC, ILC and beyond) provide complementary and competitive tools to probe for physics beyond the SM.

1

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Flavor physics in the Standard Model

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Flavor physics in the Standard Model

The SM description of flavor and CP violation originating only from the weak charged-current interactions and described by the Cabibbo- Kobayashi-Maskawa (CKM) quark-mixing matrix has been spectacularly confirmed by the B-factory program (ARGUS, CLEO, BaBar, Belle, CDF , D0, LHCb, ATLAS, CMS):

• 2

ui

L → U ij u uj L

di

L → U ij d dj L

) VCKM = U †

uUd 6= 1

SLIDE 5

Flavor physics in the Standard Model

The SM description of flavor and CP violation originating only from the weak charged-current interactions and described by the Cabibbo- Kobayashi-Maskawa (CKM) quark-mixing matrix has been spectacularly confirmed by the B-factory program (ARGUS, CLEO, BaBar, Belle, CDF , D0, LHCb, ATLAS, CMS):

• 2

Sides and εK Angles only

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Flavor physics in the Standard Model

The CKM mechanism explains all flavor phenomena studied so far, often with incredible precision. A few ~3σ “anomalies” exist and should be studied seriously; often such anomalies have disappeared with more data and improved theoretical analyses.

• 3

3.7σ

B → K∗l+l−

1308.1707

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Flavor physics in the Standard Model

The CKM paradigm does not explain:

• the hierarchies of fermion masses and mixing angles
• the origin of fermion generations
• the mechanism of baryogenesis
• the matter-antimatter asymmetry in the Universe

We do not understand the SM before we have an answer to these questions, which call for a deeper theory of flavor. The flavor puzzle is one of the few robust reasons (besides the existence

• f dark matter) for why we need to keep searching for new physics!
• 4

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Flavor physics in the Standard Model

But we have learned much more! The minimal model of electroweak symmetry breaking via the vacuum expectation value of a single scalar doublet φ predicts the absence of tree-level flavor-changing neutral currents (FCNCs), since the couplings of the neutral bosons Z and H (and, more trivially, of γ and g) are automatically flavor diagonal! FCNCs in the SM are small due to their loop and GIM suppression — a wonderful protection mechanism!

• 5

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Flavor physics in the Standard Model

Extensions of the SM such as two-Higgs doublet models, SUSY models, extended gauge models (Z’), … tend to predict large FCNCs and can thus give rise to visible effects in many observables:

• This is a huge constraint on BSM model building!

In fact, flavor data and the existence of dark matter are the most robust constraints we have on model building (the role of “naturalness” is currenty being questioned in view of the absence of new colored particles at the LHC).

• 6

✏K, B → Xs, Bs → µ+µ−, K → ⇡⌫¯ ⌫, D− ¯ D mixing, ...

SLIDE 10

Flavor physics beyond the Standard Model

SLIDE 11

Flavor structure beyond the SM

FCNCs provide prime tools to probe the SM at the quantum level and search for (even minute) hints of new interactions or the existence of new virtual particles:

• 7

Heff = HSM

eff +

X

i

Ci Λ2 Oi

Isidori, Nir, Perez (2010)

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Flavor structure beyond the SM

FCNCs provide prime tools to probe the SM at the quantum level and search for (even minute) hints of new interactions or the existence of new virtual particles:

• 8

101 102 103 104 105

(b → d) (s → d) (b → s) (c → u)

∆md, sin 2β ∆mK, K ∆ms, As

SL

CP

D – ¯ D

ΛUV/gX [TeV] LSM + g2

X

Λ2

UV

¯ QiQj ¯ QiQj

• Heff = HSM

eff +

X

i

Ci Λ2 Oi Λ/|Ci|1/2 [TeV]

SLIDE 13

Example 1: Rare leptonic decays Bs/d→μ+μ-

Generically, very large deviations from the SM predictions for the Bd,s→μ+μ- rates are expected in SUSY models, unless one imposes some ad hoc flavor structure such as MFV to keep these corrections small:

95% excl. û LHCb

2 4 6 8 10 12 5 10 15 20 BHBd Æ m+m-L @10-10D BHBs Æ m+m-L @10-9D

• 9

Much smaller corrections are predicted in dynamical flavor models such as warped extra dimensions (RS models), since the RS-GIM mechanism naturally suppresses flavor-changing interactions

• f light fermions:

RS model

BRs,SM

= (3.65 ± 0.23)×10-9

BRs

(exp) = (2.9 ± 0.7)×10-9

Straub (2012) Bauer, Casagrande, Haisch, MN (2009) Blanke et al. (2008)

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Example 1: Rare leptonic decays Bs/d→μ+μ-

Generically, very large deviations from the SM predictions for the Bd,s→μ+μ- rates are expected in SUSY models, unless one imposes some ad hoc flavor structure such as MFV to keep these corrections small:

95% excl. û LHCb

2 4 6 8 10 12 5 10 15 20 BHBd Æ m+m-L @10-10D BHBs Æ m+m-L @10-9D

9

Much smaller corrections are predicted in dynamical flavor models such as warped extra dimensions (RS models), since the RS-GIM mechanism naturally suppresses flavor-changing interactions

• f light fermions:

RS model

Constrained MSSM

“Mastercode” → talk by de Vries

Bauer, Casagrande, Haisch, MN (2009) Blanke et al. (2008) see also: Mahmoudi, Hurth (2012) Roszkowski et al. (2012) Altmannshofer et al. (2013) Buchmüller et al.

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Example 2: Split SUSY with PeV-scale sfermions

Generically large SUSY flavor effects can be tamed by raising the mass scale of scalar super-partners into the 1000-TeV range (which also helps explaining their non-observation at the LHC:-) This has several advantages:

• a 125 GeV Higgs can be accommodated

effortlessly

• heavy sfermions open up the possibility of

radiatively generating fermion mass hierarchies

• gaugino masses from anomaly mediation are a

loop factor below the gravitino mass Such split-SUSY models change the perspective on flavor physics, too!

10

Hall, Nomura; Arvanitaki et al.; Kane et al.; Yanagida et al.; Wells; Arkani-Hamed et al.

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Example 2: Split SUSY with PeV-scale sfermions

Generically large SUSY flavor effects can be tamed by raising the mass scale of scalar super-partners into the 1000-TeV range (which also helps explaining their non-observation at the LHC:-) For TeV-scale sfermions:

• SUSY flavor problem: extensive contributions

to many low-energy observables For PeV-scale (~1000 TeV) sfermions:

• SUSY flavor opportunities: a large number of

low-energy observables can be sensitive to sfermion masses far beyond the reach of LHC

10

Altmannshofer, Harnik, Zupan (2013)

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Example 2: Split SUSY with PeV-scale sfermions

Present constraints:

• Observations:
• PeV-scale squarks are probed in kaon mixing (εK )
• charm mixing and neutron EDM reach up to 100 TeV
• EDMs are particularly interesting, enhanced by

mτ/me (de) or mt/mu (dn)

11 Μe conv. ΜeΓ neutron EDM electron EDM Kaon mixing charm mixing Mh 125.51 GeV Μ3e

10 102 103 104 105 1 3 10 30

m q

m l Μ TeV

tanΒ m B

m W 3 TeV , m g 10 TeV

◮ all relevant flavor mixing |δij| = 0.3 ◮ all relevant phases sin φi = 1 ◮ no large cancellations between the various contributions

uR uL ˜ uR ˜ uL ˜ tR ˜ tL ˜ g mt γ, g

Altmannshofer, Harnik, Zupan (2013) McKeen, Pospelov, Ritz (2013)

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Example 2: Split SUSY with PeV-scale sfermions

Future constraints:

• Observations:
• neutron EDM will probe 1000 TeV squarks
• electron EDM and μ→e conversion will be sensitive

to slepton masses above 100 TeV

11

uR uL ˜ uR ˜ uL ˜ tR ˜ tL ˜ g mt γ, g

Μe conv. ΜeΓ neutron EDM e l e c t r

• n

E D M Kaon mixing charm mixing M

h

• 1

2 5 . 5

• 1

G e V Μ3e

10 102 103 104 105 1 3 10 30

m q

m l Μ TeV

tanΒ m B

m W 3 TeV , m g 10 TeV

◮ CPV in D mixing : factor 10 ◮ dn : factor 300 ◮ de : factor 90 ◮ µ → e conv. : factor 104

Expected improvements:

Altmannshofer, Harnik, Zupan (2013)

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Flavor structure beyond the SM

Flavor violation is a generic feature of any BSM physics, since a priori there is no reason why the flavor orientation of the couplings of some new particle(s) should be aligned with the CKM matrix! The concept of minimal flavor violation (MFV) is often invoked to tame flavor effects in BSM models. Without an underlying theory based on flavor symmetries and their dynamical breaking, MFV is a only paradigm but not a well motivated model.

12

Y d Y u

misalignment

• new sources of

flavor breaking CKM matrix

• flavor space

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Flavor structure beyond the SM

Simple example:

• with:
• This gives rise to flavor-changing Higgs couplings and top-quark FCNCs,

unless the matrix λij is by chance aligned with the SM Yukawa matrix yij!

13

L = LSM + λij Λ2

• φ†φ

¯ Qi

Luj R ˜

φ + h.c.

EWSB & rotation to mass basis

Yij = √ 2mi v + v2 Λ2 ¯ λij ; ¯ λ = ULλ U †

R

L 3 X

ij

Yij H¯ ui

Luj R + h.c.

Agashe, Contino (2009) Azatov, Toharia, Zhu (2009)

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Flavor structure beyond the SM

In the SM, FCNC decays of the top-quark are strongly loop, CKM and GIM suppressed:

• Observing these decays would be a clear signal of new physics,

presumably of TeV-scale origin. h t c b W

M 3 32

• 2π2 V ∗

tbVcb yt

m2

b

v2 ¯ cLtRh Br(t ch) 3 · 10−15 , Br(t uh) 2 · 10−17

14

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Flavor structure beyond the SM

Concrete models offering a compelling approach to the flavor problem (Froggatt-Nielsen, warped extra dimensions, partial compositeness, …) typically predict some departures from the MFV paradigm due to additional sources of flavor and CP violation not encoded in the SM Yukawa couplings! It is important to probe as many flavor observables as possible, without assuming model-dependent correlations!

• 15

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Flavor structure beyond the SM

16

Randall-Sundrum (RS) models as an example:

• The localization of fermions along the extra dimension depends exponen-

tially on O(1) parameters related to the 5D masses. As a result, the overlap integrals with the Higgs profile are exponentially small for light quarks.

warped extra dimension AdS5 geometry

37 7 14 21 28

Kaluza-Klein (KK) modes light quarks heavy quarks

ln(z/R)

ds2 = ⇤R z ⌅2 ηµνdxµdxν − dz2⇥

Higgs sector

Randall, Sundrum (1999) Grossman, MN (1999); Ghergetta, Pomarol (2000)

SLIDE 24

Flavor structure beyond the SM

∼ g2

s

M 2

KK

L F(Q1L)F(dR) F(Q2L)F(sR) F(Q2L) d d s s g(1) gs √ L gs √ L F(Q1L) F(dR) F(sR)

This mechanism suffices to suppress most

• f the dangerous FCNC couplings!

17

Tree-level quark FCNCs are induced by the virtual exchange of Kaluza- Klein (KK) resonances (including gluons). The resulting FCNC couplings depend on the same exponentially small

• verlap integrals F(QL), F(qR) that generate the fermion masses.

As a result, FCNCs involving light quarks are strongly suppressed: RS-GIM mechanism

Huber (2003); Burdman (2003) Agashe et al. (2004); Casagrande et al. (2008) Agashe et al. (2004)

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Flavor structure beyond the SM

Predictions for top-quark FCNCs in the RS model with custodial protection:

• 18

95 CL CDF 95 CL ATLAS 5Σ ATLAS

2 4 6 8 10 1017 1015 1013 1011 109 107 105 103 101 MKK TeV t cZ

95 CL LHC 3Σ LHC

2 4 6 8 10 1015 1013 1011 109 107 105 103 101 MKK TeV t ch

Casagrande et al. (2010)

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Hints of new physics?

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Anomalies: angular distributions

A few “anomalies” exist in the LHCb data on FCNC processes of the type a and in the global unitarity-triangle fit. Their status is currently under intense debate. New data will help, but also some theory questions need to be addressed.

19

B → K∗l+l−

0.5 1 1.5 2 2.5 3 3.6 3.8 4 4.2 4.4 4.6

dBr d√ q2 [B+ → K+µµ]/10−7GeV−1

p

q2/GeV Ψ(3770) Ψ(4040) Ψ(4160) Ψ(4400) Factorisation LHCb

Ψ(4415) Ψ(2S)

b → s l+l−

3.7σ

B → K∗l+l−

Quark-hadron duality violations

Matias, Mescia, Ramon, Virto (2012) Descotes-Genon, Matias, Ramon, Virto (2012) Lyon, Zwicky (2014)

1308.1707

SLIDE 28

Anomalies: Lepton non-universality in

20

B → Kl+l−

2.6σ

R

K

= B r ( B

+

→ K

+

µ

+

µ

−

) B r ( B

+

→ K

+

e

+

e

−

)

2.6σ

R

K

= B r ( B

+

→ K

+

µ

+

µ

−

) B r ( B

+

→ K

+

e

+

e

−

)

Naive account of QED radiative corrections based on inclusive decay:

RSM

K

= 1 + O ⇣ α ln m2

b

m2

µ

⌘

RXs

LHCb-TALK-2014-108 Huber, Misiak, Lunghi, Wyler (2005) Bobeth, Hiller, Piranishvili (2007)

• U. Haisch (priv. com.)

A few “anomalies” exist in the LHCb data on FCNC processes of the type a and in the global unitarity-triangle fit. Their status is currently under intense debate. New data will help, but also some theory questions need to be addressed. b → s l+l−

SLIDE 29

Anomalies: Tension in global UT fit (εK vs. sin2β)

21

SM fit, no εK |Vub|

• Errors from lattice QCD ?
• Problems in the determination
• f |Vub| ?

UT fit without εK A few “anomalies” exist in the LHCb data on FCNC processes of the type a and in the global unitarity-triangle fit. Their status is currently under intense debate. New data will help, but also some theory questions need to be addressed. b → s l+l−

SLIDE 30

The path to new physics

SLIDE 31

Exploring terra incognita … the tedious way

In the absence of new-physics signals in the form of light (i.e. TeV-scale) new particles, BSM effects can be parame- terized model independently in terms

• f higher-dimensional operators

composed of the known (SM) fields:

• 59 dimension-6 operators for one fermion generation
• 2499 operators for three generations

Flavor observables are crucial in order to explore this enormous parameter space! The lepton sector plays a special role, because any signal of lepton flavor violation (such as neutrino oscillations) is an effect of BSM physics!

22

SLIDE 32

Exploring terra incognita … the tedious way

The effective Lagrangian encoding BSM effects up to operator dimension d=6 reads:

23

LSM = L(4)

SM + 1

Λ

• k

C(5)

k Q(5) k

+ 1 Λ2

• k

C(6)

k Q(6) k

+ O 1 Λ3

• ,

unique operator (neutrino masses):

Qνν = ( ϕ†lp)TC( ϕ†lr)

Weinberg (1979)

SLIDE 33

Exploring terra incognita … the tedious way

The effective Lagrangian encoding BSM effects up to operator dimension d=6 reads:

23

LSM = L(4)

SM + 1

Λ

• k

C(5)

k Q(5) k

+ 1 Λ2

• k

C(6)

k Q(6) k

+ O 1 Λ3

• ,

59 operator (× flavor quantum numbers)

X3 ϕ6 and ϕ4D2 ψ2ϕ3 QG f ABCGAν

µ GBρ ν GCµ ρ

Qϕ (ϕ†ϕ)3 Qeϕ (ϕ†ϕ)(¯ lperϕ) Q

G

f ABC GAν

µ GBρ ν GCµ ρ

Qϕ (ϕ†ϕ)(ϕ†ϕ) Quϕ (ϕ†ϕ)(¯ qpur ϕ) QW εIJKW Iν

µ W Jρ ν W Kµ ρ

QϕD

• ϕ†Dµϕ

⋆ ϕ†Dµϕ

• Qdϕ

(ϕ†ϕ)(¯ qpdrϕ) Q

W

εIJK W Iν

µ W Jρ ν W Kµ ρ

X2ϕ2 ψ2Xϕ ψ2ϕ2D QϕG ϕ†ϕ GA

µνGAµν

QeW (¯ lpσµνer)τ IϕW I

µν

Q(1)

ϕl

(ϕ†i

↔

Dµ ϕ)(¯ lpγµlr) Qϕ

G

ϕ†ϕ GA

µνGAµν

QeB (¯ lpσµνer)ϕBµν Q(3)

ϕl

(ϕ†i

↔

D I

µ ϕ)(¯

lpτ Iγµlr) QϕW ϕ†ϕ W I

µνW Iµν

QuG (¯ qpσµνT Aur) ϕ GA

µν

Qϕe (ϕ†i

↔

Dµ ϕ)(¯ epγµer) Qϕ

W

ϕ†ϕ W I

µνW Iµν

QuW (¯ qpσµνur)τ I ϕ W I

µν

Q(1)

ϕq

(ϕ†i

↔

Dµ ϕ)(¯ qpγµqr) QϕB ϕ†ϕ BµνBµν QuB (¯ qpσµνur) ϕ Bµν Q(3)

ϕq

(ϕ†i

↔

D I

µ ϕ)(¯

qpτ Iγµqr) Qϕ

B

ϕ†ϕ BµνBµν QdG (¯ qpσµνT Adr)ϕ GA

µν

Qϕu (ϕ†i

↔

Dµ ϕ)(¯ upγµur) QϕW B ϕ†τ Iϕ W I

µνBµν

QdW (¯ qpσµνdr)τ Iϕ W I

µν

Qϕd (ϕ†i

↔

Dµ ϕ)( ¯ dpγµdr) Qϕ

W B

ϕ†τ Iϕ W I

µνBµν

QdB (¯ qpσµνdr)ϕ Bµν Qϕud i( ϕ†Dµϕ)(¯ upγµdr)

Buchmüller, Wyler (1986) Hagiwara et al. (1987 & 1993) Grzadkowski, Iskrzynski, Misiak, Rosiek (2010)

Operators other than four-fermion operators

SLIDE 34

Exploring terra incognita … the tedious way

The effective Lagrangian encoding BSM effects up to operator dimension d=6 reads:

23

LSM = L(4)

SM + 1

Λ

• k

C(5)

k Q(5) k

+ 1 Λ2

• k

C(6)

k Q(6) k

+ O 1 Λ3

• ,

59 operator (× flavor quantum numbers)

(¯ LL)(¯ LL) ( ¯ RR)( ¯ RR) (¯ LL)( ¯ RR) Qll (¯ lpγµlr)(¯ lsγµlt) Qee (¯ epγµer)(¯ esγµet) Qle (¯ lpγµlr)(¯ esγµet) Q(1)

qq

(¯ qpγµqr)(¯ qsγµqt) Quu (¯ upγµur)(¯ usγµut) Qlu (¯ lpγµlr)(¯ usγµut) Q(3)

qq

(¯ qpγµτ Iqr)(¯ qsγµτ Iqt) Qdd ( ¯ dpγµdr)( ¯ dsγµdt) Qld (¯ lpγµlr)( ¯ dsγµdt) Q(1)

lq

(¯ lpγµlr)(¯ qsγµqt) Qeu (¯ epγµer)(¯ usγµut) Qqe (¯ qpγµqr)(¯ esγµet) Q(3)

lq

(¯ lpγµτ Ilr)(¯ qsγµτ Iqt) Qed (¯ epγµer)( ¯ dsγµdt) Q(1)

qu

(¯ qpγµqr)(¯ usγµut) Q(1)

ud

(¯ upγµur)( ¯ dsγµdt) Q(8)

qu

(¯ qpγµT Aqr)(¯ usγµT Aut) Q(8)

ud

(¯ upγµT Aur)( ¯ dsγµT Adt) Q(1)

qd

(¯ qpγµqr)( ¯ dsγµdt) Q(8)

qd

(¯ qpγµT Aqr)( ¯ dsγµT Adt) (¯ LR)( ¯ RL) and (¯ LR)(¯ LR) B-violating Qledq (¯ lj

per)( ¯

dsqj

t )

Qduq εαβγεjk

• (dα

p)TCuβ r

(qγj

s )TClk t

• Q(1)

quqd

(¯ qj

pur)εjk(¯

qk

sdt)

Qqqu εαβγεjk

• (qαj

p )TCqβk r

(uγ

s)TCet

• Q(8)

quqd

(¯ qj

pT Aur)εjk(¯

qk

sT Adt)

Q(1)

qqq

εαβγεjkεmn

• (qαj

p )TCqβk r

(qγm

s )TCln t

• Q(1)

lequ

(¯ lj

per)εjk(¯

qk

sut)

Q(3)

qqq

εαβγ(τ Iε)jk(τ Iε)mn

• (qαj

p )TCqβk r

(qγm

s )TCln t

• Q(3)

lequ

(¯ lj

pσµνer)εjk(¯

qk

sσµνut)

Qduu εαβγ (dα

p)TCuβ r

(uγ

s)TCet

• Buchmüller, Wyler (1986)

Hagiwara et al. (1987 & 1993) Grzadkowski, Iskrzynski, Misiak, Rosiek (2010)

Four-fermion operators

SLIDE 35

Global fits of Wilson coefficients in

24

b → sγ, sl+l−

Flavor observables are crucial in order to explore the enormous parameter space of the effective BSM Lagrangian! A global analysis of the experimental data on and d decay distributions provides information about various

• perator coefficients (all defined to vanish in the SM):

B → Xsγ, B → K∗γ, B → K(∗)µ+µ−

Altmannshofer, Straub (2013)

CNP

9

= −1.0 ± 0.3 C′

9 = +1.0 ± 0.5

A first hint?

SLIDE 36

Exploring terra incognita … the pleasant way

In the fortunate case of the discovery

• f any new particle, this will directly
• pen up a new territory for flavor

physics! In the past years, we have performed extensive searches for flavor-changing Z-boson couplings and probed the flavor-changing top-quark couplings with great accuracy. After the Higgs discovery, the study of flavor-changing Higgs couplings is of great importance — this includes lepton-flavor violating modes! The discovery of new particles would open the door to new flavor and CP-violating phenomena!

25

Z0, ˜ t, χ±, H±, . . .

Drey, Efrati, Hochberg, Nir (2013)

SLIDE 37

Exploring terra incognita … the pleasant way

A first promising study of the lepton-flavor violating H→τμ decay has recently been reported by CMS:

), % τ µ → 95% CL Limit on Br(h

2 4 6 8 10

1.57% (obs.) 0.75% (exp.)

τ µ → h

3.84% (obs.) 3.77% (exp.)

, 2 Jets

e

τ µ

2.38% (obs.) 1.66% (exp.)

, 1 Jet

e

τ µ

2.04% (obs.) 1.32% (exp.)

, 0 Jets

e

τ µ

3.29% (obs.) 1.95% (exp.)

, 2 Jets

had

τ µ

2.11% (obs.) 2.10% (exp.)

, 1 Jet

had

τ µ

2.94% (obs.) 2.35% (exp.)

, 0 Jets

had

τ µ

Observed Expected σ 1 ± Expected σ 2 ± Expected

= 8 TeV s ,

• 1

19.7 fb CMS preliminary

Limit on BR(h → μτ ) = 1.57% (0.75 expected)!

|

τ µ

|Y

• 4

10

• 3

10

• 2

10

• 1

10 1

|

µ τ

|Y

• 4

10

• 3

10

• 2

10

• 1

10 1

= 8 TeV s ,

• 1

19.7 fb CMS preliminary

BR<0.1% BR<1% BR<10% BR<50%

τ τ → LHC h

• bserved

expected τ µ → h

µ 3 → τ γ µ → τ

2

/v

τ

m

µ

|=m

µ τ

Y

τ µ

|Y

CMS PAS HIG-14-005

26

SLIDE 38

Complementarity

SLIDE 39

Complementary ways of probing new physics …

In the 1990s and even well into the era of the B-factories, flavor physics and physics at the energy frontier were too often seen as different branches of particle physics. Fortunately, this is no longer the case. Now flavor physics is (and should remain) a crucial component of a comprehensive high-energy program! Flavor observables provide complementary and often competitive indirect probes of BSM effects, which complement precision studies at the energy frontier. Examples:

• generic probes
• triple gauge-boson couplings (TGCs)
• ttZ vertex
• EDMs

27

SLIDE 40

Complementary ways of probing new physics …

28

µh→γγ 1 ± N v2 Λ2 h γ γ Λ

• N

0.1 v

• 0.8 TeV ,

N = 1 3 TeV , N = 4π b s µ+ µ− Z µBs→µ+µ− 1 ± 4π g2|V ∗

tbVts|2

v2 Λ2

Λ v

• 0.2

    

• 4π

g |V ∗

tbVts|

• 

    50 TeV , anarchic tree

µHiggs = 1.1 ± 0.1 µBs→µ+µ− = 0.8 ± 0.2

SLIDE 41

Complementary ways of probing new physics …

28

µHiggs = 1.1 ± 0.1

µh→γγ 1 ± N v2 Λ2 h γ γ Λ

• N

0.1 v

• 0.8 TeV ,

N = 1 3 TeV , N = 4π b s µ+ µ−

Z µBs→µ+µ− 1 ± v2 Λ2

Λ v

• 0.2

    

• 4π

g |V ∗

tbVts|

1

• 

    50 TeV , anarchic tree 0.6 TeV , MFV loop

µBs→µ+µ− = 0.8 ± 0.2

Even in the most pessimistic scenario, the sensitivity to the NP scale in flavor physics at LHCb is comparable to that of the Higgs-couplings measurements by ATLAS and CMS.

SLIDE 42

Precision measurements of Z-boson couplings

29

C ¯ bLZ / sL Z bL sL bL ¯ bL Z C ¯ bLZ / bL + O(M 2

Z)

∆C = −0.04 ± 0.26 ∆C = (−0.16 ± 0.53) ∪ (−2.15 ± 0.08)

In many NP models (MFV, SUSY, partial compositeness, …), flavor- changing and flavor-conserving Z-penguin effects are closely related:

• Pre LHC, flavor constraints were often not competitive with EWP data.

Bobeth et al. (2005) Haisch, Weiler (2007)

SLIDE 43

Precision measurements of Z-boson couplings

29

C ¯ bLZ / sL Z bL sL bL ¯ bL Z C ¯ bLZ / bL + O(M 2

Z)

In many NP models (MFV, SUSY, partial compositeness, …), flavor- changing and flavor-conserving Z-penguin effects are closely related:

• Today, flavor data often provide stronger constraints!

∆C = 0.28 ± 0.30 ∆C = −0.11 ± 0.11

Haisch, Weiler (2007) Guadagnoli, Isidori (2013) Freitas (2012)

SLIDE 44

Triple gauge-boson couplings

30

W ± W γ ∆κγ, λγ Z ∆gZ

1 , λγ

W ± W

Modifications of the non-abelian gauge vertices (coupling 3 or 4 bosons) from d=6 operators such as could provide subtle hints about NP:

• These couplings can be probed “indirectly” in flavor physics and

“directly” in di-boson production at colliders.

LW W V = −igW W V

• gV

1

• W +

µν W −µV ν − W + µ Vν W −µν

• + κV W +

µ W − ν V µν + λV

m2

W

W +

µν W −νρVρ µ

• (Dµφ)†(DνΦ) Bµν, . . .

SLIDE 45

Triple gauge-boson couplings

31

b

s u, c, t W W γ

b

s u, c, t W W Z µ+ µ−

Z → b¯ b ∆C10 ∆C9 ∆C7

• SM

Anomalous TGCs contribute to FCNC processes such as d and : B → Xsγ, B → K∗µ+µ−, Bs → µ+µ−, ✏0/✏, Z → b¯ b

Bobeth, Haisch (priv. com.)

SLIDE 46

Triple gauge-boson couplings

32

Direct searches for anomalous TGCs have been performed at Tevatron and LHC (WW, WZ, Wγ, Zγ, … production and H→ZZ, …):

W W

e−, q e+, ¯ q ν

• ν
• γ, Z

Z Z

h g g t t t

Corbett, Eboli, Gonzales-Fraile, Gonzales-Garcia (2013)

SLIDE 47

Triple gauge-boson couplings

32

Direct searches for anomalous TGCs have been performed at Tevatron and LHC (WW, WZ, Wγ, Zγ, … production and H→ZZ, …):

W W

e−, q e+, ¯ q ν

• ν
• γ, Z

Z Z

h g g t t t

flavor

SM

Corbett, Eboli, Gonzales-Fraile, Gonzales-Garcia (2013) Bobeth, Haisch (priv. com.)

SLIDE 48

Anomalous ttZ couplings

33

Searches for anomalous Z-boson couplings to the top-quark can be performed using flavor data and EWP tests …

−0.1 0.0 0.1

v2 Λ2 log( µW Λ ) Cφu,33

−0.2 −0.1 0.0 0.1

v2 Λ2 log( µW Λ ) C(1) φq,33

Current measurements

Bs →µ+µ− δgb

L

T

−0.1 0.0 0.1

v2 Λ2 log( µW Λ ) Cφu,33

−0.2 −0.1 0.0 0.1

v2 Λ2 log( µW Λ ) C(1) φq,33

Current measurements

Bs →µ+µ− δgb

L

T

−0.1 0.0 0.1

v2 Λ2 log( µW Λ ) Cφu,33

Future projections

Bs →µ+µ− KL →π0ν¯ ν K+ →π+ν¯ ν

Brod, Greljo, Stamou, Uttayarat (2014)

SLIDE 49

Anomalous ttZ couplings

34

… but also directly in production at the LHC: pp → t¯ t + Z

t t + Z e1 eb 13 TeV, NLO QCD 95 % C.L. limit 3000 fb-1 300 fb-1

• 0.2

0.0 0.2 0.4

• 0.2
• 0.1

0.0 0.1 v2 L2 Re Cf u

33

v2 L2 Re Cf q

H3,33L

Röntsch, Schulze (2014)

SLIDE 50

Anomalous ttZ couplings

34

… but also directly in production at the LHC: pp → t¯ t + Z

t t + Z e1 eb 13 TeV, NLO QCD 95 % C.L. limit 3000 fb-1 300 fb-1

• 0.2

0.0 0.2 0.4

• 0.2
• 0.1

0.0 0.1 v2 L2 Re Cf u

33

v2 L2 Re Cf q

H3,33L

flavor

SM

Röntsch, Schulze (2014) Brod, Greljo, Stamou, Uttayarat (2014)

SLIDE 51

Summary

The past years have taught us some lessons:

• It pays off to explore theoretically well motivated frontiers of high-

energy physics: Higgs (EWSB, unitarity), CKM, dark matter

• But discoveries are not always as easy as predicted by “simple” or

“natural” extensions of the SM (“weaker” theoretical motivation).

• Thus a broad and complementary program is of utmost

importance! It must include all aspects of high-energy physics, but also low-energy probes and astro-particle physics. Sometimes, breakthrough discoveries can come out of the blue:

• dark energy (who would have thought?)
• imagine we would discover or …

35

RK 6= RSM

K

Br(H → τ ¯ µ) = 1%

SLIDE 52

Summary

The past years have taught us some lessons:

• It pays off to explore theoretically well motivated frontiers of high-

energy physics: Higgs (EWSB, unitarity), CKM, dark matter

• But discoveries are not always as easy as predicted by “simple” or

“natural” extensions of the SM (“weaker” theoretical motivation).

• Thus a broad and complementary program is of utmost

importance! It must include all aspects of high-energy physics, but also low-energy probes and astro-particle physics. Sometimes, breakthrough discoveries can come out of the blue:

• dark energy (who would have thought?)
• imagine we would discover or …

35

RK 6= RSM

K

Br(H → τ ¯ µ) = 1%

We need to keep turning all stones to find the next piece of the puzzle!

SLIDE 53

Thank you!