On the status of flavor anomalies Diego Guadagnoli LAPTh Annecy - - PowerPoint PPT Presentation

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On the status of flavor anomalies Diego Guadagnoli LAPTh Annecy - - PowerPoint PPT Presentation

Jul 21, 2023 42 likes •802 views

On the status of flavor anomalies Diego Guadagnoli LAPTh Annecy (France) Recap of flavor anomalies: b s LHCb and B factories measured several key b s and b c modes. Agreement with the SM is less than perfect. D. Guadagnoli,

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SLIDE 1

Diego Guadagnoli

LAPTh Annecy (France)

On the status of flavor anomalies

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SLIDE 2

Recap of flavor anomalies: b → s LHCb and B factories measured several key b → s and b → c modes. Agreement with the SM is less than perfect.

  • D. Guadagnoli, Status of flavor anomalies
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SLIDE 3

Recap of flavor anomalies: b → s LHCb and B factories measured several key b → s and b → c modes. Agreement with the SM is less than perfect.

R K = BR(B

+→K +μμ)[1,6]

BR(B

+→K +ee)[1,6 ]

= 0.745⋅(1±13%)

  • D. Guadagnoli, Status of flavor anomalies
slide-4
SLIDE 4

Recap of flavor anomalies: b → s LHCb and B factories measured several key b → s and b → c modes. Agreement with the SM is less than perfect.

R K = BR(B

+→K +μμ)[1,6]

BR(B

+→K +ee)[1,6 ]

= 0.745⋅(1±13%)

muons are among the most reliable

  • bjects within LHCb

the electron channel would be an

  • bvious culprit (brems + low stats).

But disagreement is rather in muons

  • D. Guadagnoli, Status of flavor anomalies
slide-5
SLIDE 5

Recap of flavor anomalies: b → s LHCb and B factories measured several key b → s and b → c modes. Agreement with the SM is less than perfect.

R K = BR(B

+→K +μμ)[1,6]

BR(B

+→K +ee)[1,6 ]

= 0.745⋅(1±13%)

muons are among the most reliable

  • bjects within LHCb

the electron channel would be an

  • bvious culprit (brems + low stats).

But disagreement is rather in muons

  • D. Guadagnoli, Status of flavor anomalies

➋

BR(Bs → φ μμ): >3 below SM prediction. Same kinematical region m2

μμ ∈ [1, 6 ] GeV2

Initially found in 1/fb of LHCb data, then confirmed by a full Run-I analysis (3/fb)

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SLIDE 6

Recap of flavor anomalies: b → s LHCb and B factories measured several key b → s and b → c modes. Agreement with the SM is less than perfect.

R K = BR(B

+→K +μμ)[1,6]

BR(B

+→K +ee)[1,6 ]

= 0.745⋅(1±13%)

muons are among the most reliable

  • bjects within LHCb

the electron channel would be an

  • bvious culprit (brems + low stats).

But disagreement is rather in muons

  • D. Guadagnoli, Status of flavor anomalies

➋

BR(Bs → φ μμ): >3 below SM prediction. Same kinematical region m2

μμ ∈ [1, 6 ] GeV2

Initially found in 1/fb of LHCb data, then confirmed by a full Run-I analysis (3/fb)

B → K* μμ angular analysis: discrepancy in one combination of the angular expansion coefficients, known as P'5

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  • D. Guadagnoli, Status of flavor anomalies

B → K* μμ angular analysis: discrepancy in P'5

arXiv:1604.04042

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SLIDE 8
  • D. Guadagnoli, Status of flavor anomalies

B → K* μμ angular analysis: discrepancy in P'5

arXiv:1604.04042

Effect is again in the same region: m2

μμ ∈ [1, 6 ] GeV2

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SLIDE 9
  • D. Guadagnoli, Status of flavor anomalies

B → K* μμ angular analysis: discrepancy in P'5

arXiv:1604.04042

Effect is again in the same region: m2

μμ ∈ [1, 6 ] GeV2

Compatibility between 1/fb and 3/fb LHCb analyses.

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SLIDE 10
  • D. Guadagnoli, Status of flavor anomalies

B → K* μμ angular analysis: discrepancy in P'5

arXiv:1604.04042

Effect is again in the same region: m2

μμ ∈ [1, 6 ] GeV2

Compatibility between 1/fb and 3/fb LHCb analyses. Supported also by recent Belle analysis.

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SLIDE 11
  • D. Guadagnoli, Status of flavor anomalies

B → K* μμ angular analysis: discrepancy in P'5 Significance of the effect is debated. Effect is again in the same region: m2

μμ ∈ [1, 6 ] GeV2

Compatibility between 1/fb and 3/fb LHCb analyses. Supported also by recent Belle analysis.

arXiv:1604.04042

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SLIDE 12

Recap of flavor anomalies: b → s LHCb and B factories measured several key b → s and b → c modes. Agreement with the SM is less than perfect.

R K = BR(B

+→K +μμ)[1,6]

BR(B

+→K +ee)[1,6 ]

= 0.745⋅(1±13%)

muons are among the most reliable

  • bjects within LHCb

the electron channel would be an

  • bvious culprit (brems + low stats).

But disagreement is rather in muons

 ➊ (+ ➋ + ➌)

⇒

There seems to be BSM LFNU and the effect is in µµ, not ee

  • D. Guadagnoli, Status of flavor anomalies

➋

BR(Bs → φ μμ): >3 below SM prediction. Same kinematical region m2

μμ ∈ [1, 6 ] GeV2

Initially found in 1/fb of LHCb data, then confirmed by a full Run-I analysis (3/fb)

B → K* μμ angular analysis: discrepancy in P'5 Again same region m2

μμ ∈ [1, 6 ] GeV2

Compatibility between 1/fb and 3/fb LHCb analyses. Supported also by recent Belle analysis. Significance of the effect is debated.

slide-13
SLIDE 13
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

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SLIDE 14
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

adapted from Y. Sato, talk at ICHEP16

R(D*) state-of-the-art

ICHEP '16 updates

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SLIDE 15
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

First discrepancy found by BaBar in 2012 in both R(D) and R(D*)

adapted from Y. Sato, talk at ICHEP16

R(D*) state-of-the-art

ICHEP '16 updates

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SLIDE 16
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

First discrepancy found by BaBar in 2012 in both R(D) and R(D*)

2015: BaBar's R(D*) confirmed by LHCb

adapted from Y. Sato, talk at ICHEP16

R(D*) state-of-the-art

ICHEP '16 updates

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SLIDE 17
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

First discrepancy found by BaBar in 2012 in both R(D) and R(D*)

2015: Belle finds a more SM-like R(D*) (hadronic tau's)

2015: BaBar's R(D*) confirmed by LHCb

adapted from Y. Sato, talk at ICHEP16

R(D*) state-of-the-art

ICHEP '16 updates

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SLIDE 18
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

First discrepancy found by BaBar in 2012 in both R(D) and R(D*)

2015: Belle finds a more SM-like R(D*) (hadronic tau's)

2015: BaBar's R(D*) confirmed by LHCb Early 2016: Belle also sees an R(D*) excess (semi-lep. tau's)

adapted from Y. Sato, talk at ICHEP16

R(D*) state-of-the-art

ICHEP '16 updates

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SLIDE 19
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

First discrepancy found by BaBar in 2012 in both R(D) and R(D*)

2015: Belle finds a more SM-like R(D*) (hadronic tau's)

2015: BaBar's R(D*) confirmed by LHCb Early 2016: Belle also sees an R(D*) excess (semi-lep. tau's)

 

adapted from Y. Sato, talk at ICHEP16

R(D*) state-of-the-art

Summer '16: SM-like R(D*) in new had.-tag Belle analysis

ICHEP '16 updates

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SLIDE 20
  • D. Guadagnoli, Status of flavor anomalies

There are long-standing discrepancies in b → c transitions as well.

R(D

(*)) = BR(B→D (*)τ ν)

BR(B→D

(*)ℓν) (with ℓ=e,μ)

Recap of flavor anomalies: b → c

First discrepancy found by BaBar in 2012 in both R(D) and R(D*)

2015: Belle finds a more SM-like R(D*) (hadronic tau's)

2015: BaBar's R(D*) confirmed by LHCb Early 2016: Belle also sees an R(D*) excess (semi-lep. tau's)

 

adapted from Y. Sato, talk at ICHEP16

R(D*) state-of-the-art

Summer '16: SM-like R(D*) in new had.-tag Belle analysis

ICHEP '16 updates All in all: Simultaneous fit to R(D) & R(D*) about 4σ away from SM

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  • D. Guadagnoli, Status of flavor anomalies

Each of the mentioned effects needs confirmation from Run II to be taken seriously

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SLIDE 22
  • D. Guadagnoli, Status of flavor anomalies

Each of the mentioned effects needs confirmation from Run II to be taken seriously Q1: Can we (easily) make theoretical sense of data? Q2: What are the most immediate signatures to expect ?

Yet, focusing for the moment on the b → s discrepancies

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Concerning Q2: most immediate signatures to expect

  • D. Guadagnoli, Status of flavor anomalies
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SLIDE 24

Concerning Q2: most immediate signatures to expect Basic observation:

  • D. Guadagnoli, Status of flavor anomalies

If RK is signaling LFNU at a non-SM level, we may also expect LFV at a non-SM level.

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SLIDE 25

Concerning Q2: most immediate signatures to expect Basic observation:

  • D. Guadagnoli, Status of flavor anomalies

If RK is signaling LFNU at a non-SM level, we may also expect LFV at a non-SM level. In fact:

Consider a new, LFNU interaction above the EWSB scale, e.g. with

ℓ Z'ℓ

new vector bosons:

ℓ φ q

  • r leptoquarks:

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SLIDE 26

Concerning Q2: most immediate signatures to expect Basic observation:

  • D. Guadagnoli, Status of flavor anomalies

If RK is signaling LFNU at a non-SM level, we may also expect LFV at a non-SM level. In fact:

Consider a new, LFNU interaction above the EWSB scale, e.g. with

ℓ Z'ℓ

new vector bosons:

ℓ φ q

  • r leptoquarks:

In what basis are quarks and leptons in the above interaction? Generically, it's not the mass eigenbasis. (This basis doesn't yet even exist. We are above the EWSB scale.)

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SLIDE 27

Concerning Q2: most immediate signatures to expect Basic observation:

  • D. Guadagnoli, Status of flavor anomalies

If RK is signaling LFNU at a non-SM level, we may also expect LFV at a non-SM level. In fact:

Consider a new, LFNU interaction above the EWSB scale, e.g. with

ℓ Z'ℓ

new vector bosons:

ℓ φ q

  • r leptoquarks:

In what basis are quarks and leptons in the above interaction? Generically, it's not the mass eigenbasis. (This basis doesn't yet even exist. We are above the EWSB scale.)

 

Rotating q and ℓ to the mass eigenbasis generates LFV interactions.

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SLIDE 28

Frequently made objection: what about the SM? It has LFNU, but no LFV

  • D. Guadagnoli, Status of flavor anomalies
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SLIDE 29

Frequently made objection: what about the SM? It has LFNU, but no LFV

  • D. Guadagnoli, Status of flavor anomalies

Take the SM with zero ν masses.

Charged-lepton Yukawa couplings are LFNU, but they are diagonal in the mass eigenbasis (hence no LFV)

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SLIDE 30

Frequently made objection: what about the SM? It has LFNU, but no LFV

  • D. Guadagnoli, Status of flavor anomalies

Take the SM with zero ν masses.

Charged-lepton Yukawa couplings are LFNU, but they are diagonal in the mass eigenbasis (hence no LFV) Or more generally, take the SM plus a minimal mechanism for ν masses.

Physical LFV will appear in W couplings, but it's suppressed by powers of ( mν / mW )2

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SLIDE 31

Frequently made objection: what about the SM? It has LFNU, but no LFV

  • D. Guadagnoli, Status of flavor anomalies

Take the SM with zero ν masses.

Charged-lepton Yukawa couplings are LFNU, but they are diagonal in the mass eigenbasis (hence no LFV) Bottom line: in the SM+ν there is LFNU, but LFV is nowhere to be seen (in decays) Or more generally, take the SM plus a minimal mechanism for ν masses.

Physical LFV will appear in W couplings, but it's suppressed by powers of ( mν / mW )2

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SLIDE 32

Frequently made objection: what about the SM? It has LFNU, but no LFV

  • D. Guadagnoli, Status of flavor anomalies

Take the SM with zero ν masses.

Charged-lepton Yukawa couplings are LFNU, but they are diagonal in the mass eigenbasis (hence no LFV) Bottom line: in the SM+ν there is LFNU, but LFV is nowhere to be seen (in decays) But nobody ordered that the reason (=tiny mν) behind the above conclusion be at work also beyond the SM

Or more generally, take the SM plus a minimal mechanism for ν masses.

Physical LFV will appear in W couplings, but it's suppressed by powers of ( mν / mW )2

slide-33
SLIDE 33

Frequently made objection: what about the SM? It has LFNU, but no LFV

  • D. Guadagnoli, Status of flavor anomalies

Take the SM with zero ν masses.

Charged-lepton Yukawa couplings are LFNU, but they are diagonal in the mass eigenbasis (hence no LFV) Bottom line: in the SM+ν there is LFNU, but LFV is nowhere to be seen (in decays) But nobody ordered that the reason (=tiny mν) behind the above conclusion be at work also beyond the SM

So, BSM LFNU BSM LFV (i.e. not suppressed by mν )

⇒

Or more generally, take the SM plus a minimal mechanism for ν masses.

Physical LFV will appear in W couplings, but it's suppressed by powers of ( mν / mW )2

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SLIDE 34
  • D. Guadagnoli, Status of flavor anomalies

Concerning Q1: can we easily make theoretical sense of these data?

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SLIDE 35
  • D. Guadagnoli, Status of flavor anomalies

Concerning Q1: can we easily make theoretical sense of these data?

Yes we can. Consider the following Hamiltonian

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

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SLIDE 36
  • D. Guadagnoli, Status of flavor anomalies

Concerning Q1: can we easily make theoretical sense of these data?

Yes we can. Consider the following Hamiltonian

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

About equal size & opposite sign in the SM (at the mb scale)

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SLIDE 37
  • D. Guadagnoli, Status of flavor anomalies

Advocating the same (V – A) x (V – A) structure also for the corrections to C9,10

SM

(in the µµ-channel only!) would account for: RK lower than 1 B → K µµ & Bs → µµ BR data below predictions Concerning Q1: can we easily make theoretical sense of these data?

Yes we can. Consider the following Hamiltonian

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

the P5' anomaly in B → K* µµ

About equal size & opposite sign in the SM (at the mb scale)

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SLIDE 38
  • D. Guadagnoli, Status of flavor anomalies

Advocating the same (V – A) x (V – A) structure also for the corrections to C9,10

SM

(in the µµ-channel only!) would account for: RK lower than 1 B → K µµ & Bs → µµ BR data below predictions

A fully quantitative test requires a global fit.

[Altmannshofer, Straub, EPJC '15]

Concerning Q1: can we easily make theoretical sense of these data?

For analogous conclusions, see also [Ghosh, Nardecchia, Renner, JHEP '14]

Yes we can. Consider the following Hamiltonian

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

the P5' anomaly in B → K* µµ

About equal size & opposite sign in the SM (at the mb scale)

slide-39
SLIDE 39
  • D. Guadagnoli, Status of flavor anomalies

As we saw before, all b → s data are explained at one stroke if: Model example: Glashow et al., PRL 2015 (V – A) x (V – A) structure

C9

(ℓ) ≈ −C10 (ℓ)

LFNU

|C9,NP

(μ) | ≫ |C9, NP (e) |

slide-40
SLIDE 40
  • D. Guadagnoli, Status of flavor anomalies

As we saw before, all b → s data are explained at one stroke if:

This pattern can be generated from a purely 3rd-generation interaction of the kind Model example: Glashow et al., PRL 2015 (V – A) x (V – A) structure

C9

(ℓ) ≈ −C10 (ℓ)

LFNU

|C9,NP

(μ) | ≫ |C9, NP (e) |

HNP = G ¯ b' Lγ

λb' L ¯

τ' Lγλ τ' L

expected e.g. in partial-compositeness frameworks

with G = 1/ΛNP

2

≪ GF

slide-41
SLIDE 41
  • D. Guadagnoli, Status of flavor anomalies

As we saw before, all b → s data are explained at one stroke if:

This pattern can be generated from a purely 3rd-generation interaction of the kind Model example: Glashow et al., PRL 2015 (V – A) x (V – A) structure

C9

(ℓ) ≈ −C10 (ℓ)

LFNU

|C9,NP

(μ) | ≫ |C9, NP (e) |

HNP = G ¯ b' Lγ

λb' L ¯

τ' Lγλ τ' L

expected e.g. in partial-compositeness frameworks

Fields are in the “gauge” basis (= primed) Note: primed fields

 

with G = 1/ΛNP

2

≪ GF

slide-42
SLIDE 42
  • D. Guadagnoli, Status of flavor anomalies

As we saw before, all b → s data are explained at one stroke if:

This pattern can be generated from a purely 3rd-generation interaction of the kind Model example: Glashow et al., PRL 2015 (V – A) x (V – A) structure

C9

(ℓ) ≈ −C10 (ℓ)

LFNU

|C9,NP

(μ) | ≫ |C9, NP (e) |

HNP = G ¯ b' Lγ

λb' L ¯

τ' Lγλ τ' L

expected e.g. in partial-compositeness frameworks

Fields are in the “gauge” basis (= primed) They need to be rotated to the mass eigenbasis Note: primed fields

b 'L ≡ (d' L)3 = (U L

d)3i (d L)i

τ' L ≡ (ℓ' L)3 = (U L

ℓ)3i (ℓL)i

mass basis

☞

 

with G = 1/ΛNP

2

≪ GF

slide-43
SLIDE 43
  • D. Guadagnoli, Status of flavor anomalies

As we saw before, all b → s data are explained at one stroke if:

This pattern can be generated from a purely 3rd-generation interaction of the kind Model example: Glashow et al., PRL 2015 (V – A) x (V – A) structure

C9

(ℓ) ≈ −C10 (ℓ)

LFNU

|C9,NP

(μ) | ≫ |C9, NP (e) |

HNP = G ¯ b' Lγ

λb' L ¯

τ' Lγλ τ' L

expected e.g. in partial-compositeness frameworks

Fields are in the “gauge” basis (= primed) They need to be rotated to the mass eigenbasis Note: primed fields This rotation induces LFNU and LFV effects

b 'L ≡ (d' L)3 = (U L

d)3i (d L)i

τ' L ≡ (ℓ' L)3 = (U L

ℓ)3i (ℓL)i

mass basis

☞

 

with G = 1/ΛNP

2

≪ GF

slide-44
SLIDE 44
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data

HSM+NP(¯ b→¯ sμμ) = −4GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

Recalling our full Hamiltonian

slide-45
SLIDE 45
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

Recalling our full Hamiltonian

kSM (SM norm. factor)

slide-46
SLIDE 46
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data the shift to the C9 Wilson coeff. in the µµ-channel becomes

kSM C9

(μ) = kSM C9,SM + G

2 (U L

d)33 * (U L d)32|(U L ℓ)32| 2

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

Recalling our full Hamiltonian

kSM (SM norm. factor)

slide-47
SLIDE 47
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data the shift to the C9 Wilson coeff. in the µµ-channel becomes

kSM C9

(μ) = kSM C9,SM + G

2 (U L

d)33 * (U L d)32|(U L ℓ)32| 2

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

Recalling our full Hamiltonian

kSM (SM norm. factor) The NP contribution has

  • pposite sign than the SM one if

G (U L

d)32 < 0

slide-48
SLIDE 48
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data the shift to the C9 Wilson coeff. in the µµ-channel becomes

kSM C9

(μ) = kSM C9,SM + G

2 (U L

d)33 * (U L d)32|(U L ℓ)32| 2

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

Recalling our full Hamiltonian

kSM (SM norm. factor) The NP contribution has

  • pposite sign than the SM one if

G (U L

d)32 < 0

On the other hand, in the ee-channel

kSM C9

(e) = kSM C9,SM + G

2 (U L

d)33 * (U L d)32|(U L ℓ)31| 2

slide-49
SLIDE 49
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data the shift to the C9 Wilson coeff. in the µµ-channel becomes

kSM C9

(μ) = kSM C9,SM + G

2 (U L

d)33 * (U L d)32|(U L ℓ)32| 2

HSM+NP(¯ b→¯ sμμ) = −4 GF

√2

V tb

* V ts

αem 4 π [¯ bL γ

λsL⋅(C9 (μ) ¯

μ γλμ + C10

(μ) ¯

μ γλ γ5μ)]

Recalling our full Hamiltonian

kSM (SM norm. factor) The NP contribution has

  • pposite sign than the SM one if

G (U L

d)32 < 0

On the other hand, in the ee-channel

kSM C9

(e) = kSM C9,SM + G

2 (U L

d)33 * (U L d)32|(U L ℓ)31| 2

The NP contrib. in the ee- channel is negligible, as

|(U L

ℓ)31| 2 ≪ |(U L ℓ)32| 2

slide-50
SLIDE 50
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data

So, in the above setup

RK ≈ |C9

(μ)| 2+|C10 (μ)| 2

|C9

(e)| 2+|C10 (e)| 2 ≃ 2|C10 SM+δC10| 2

2|C10

SM| 2

slide-51
SLIDE 51
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data

So, in the above setup

RK ≈ |C9

(μ)| 2+|C10 (μ)| 2

|C9

(e)| 2+|C10 (e)| 2 ≃ 2|C10 SM+δC10| 2

2|C10

SM| 2

factors of 2: equal contributions from |C9|2 and |C10|2

☞

slide-52
SLIDE 52
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data

So, in the above setup

RK ≈ |C9

(μ)| 2+|C10 (μ)| 2

|C9

(e)| 2+|C10 (e)| 2 ≃ 2|C10 SM+δC10| 2

2|C10

SM| 2

factors of 2: equal contributions from |C9|2 and |C10|2

☞

Note as well

0.77±0.20 = BR(Bs→μμ)exp BR(Bs→μμ)SM = BR(Bs→μμ)SM+NP BR(Bs→μμ)SM = |C10

SM+δC10| 2

|C10

SM| 2

slide-53
SLIDE 53
  • D. Guadagnoli, Status of flavor anomalies

Explaining b → s data

So, in the above setup

RK ≈ |C9

(μ)| 2+|C10 (μ)| 2

|C9

(e)| 2+|C10 (e)| 2 ≃ 2|C10 SM+δC10| 2

2|C10

SM| 2

factors of 2: equal contributions from |C9|2 and |C10|2

☞

Note as well

0.77±0.20 = BR(Bs→μμ)exp BR(Bs→μμ)SM = BR(Bs→μμ)SM+NP BR(Bs→μμ)SM = |C10

SM+δC10| 2

|C10

SM| 2

implying (within our model) the correlations

BR(Bs→μμ)exp BR(Bs→μμ)SM ≃ RK ≃ BR(B

+→K +μμ)exp

BR(B

+→K +μμ)SM

Another good reason to pursue accuracy in the Bs → µµ measurement

See also Hiller, Schmaltz, PRD 14

slide-54
SLIDE 54
  • D. Guadagnoli, Status of flavor anomalies

As mentioned: if RK is signaling BSM LFNU, then expect BSM LFV as well LFV model signatures

BR(B

+→K +μ e)

BR(B

+→K +μμ)

= |δC10|

2

|C10

SM+δC10| 2 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2 ⋅ 2

☑

slide-55
SLIDE 55
  • D. Guadagnoli, Status of flavor anomalies

As mentioned: if RK is signaling BSM LFNU, then expect BSM LFV as well LFV model signatures

BR(B

+→K +μ e)

BR(B

+→K +μμ)

= |δC10|

2

|C10

SM+δC10| 2 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2 ⋅ 2

☑

= 0.1592 according to RK

slide-56
SLIDE 56
  • D. Guadagnoli, Status of flavor anomalies

As mentioned: if RK is signaling BSM LFNU, then expect BSM LFV as well LFV model signatures

BR(B

+→K +μ e)

BR(B

+→K +μμ)

= |δC10|

2

|C10

SM+δC10| 2 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2 ⋅ 2

µ+e– & µ– e+ modes

☑

= 0.1592 according to RK

slide-57
SLIDE 57
  • D. Guadagnoli, Status of flavor anomalies

As mentioned: if RK is signaling BSM LFNU, then expect BSM LFV as well LFV model signatures

BR(B

+→K +μ e)

BR(B

+→K +μμ)

= |δC10|

2

|C10

SM+δC10| 2 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2 ⋅ 2

µ+e– & µ– e+ modes

BR(B

+→K +μe) < 2.2×10 −8 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2

☑

= 0.1592 according to RK

slide-58
SLIDE 58
  • D. Guadagnoli, Status of flavor anomalies

As mentioned: if RK is signaling BSM LFNU, then expect BSM LFV as well LFV model signatures

BR(B

+→K +μ e)

BR(B

+→K +μμ)

= |δC10|

2

|C10

SM+δC10| 2 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2 ⋅ 2

µ+e– & µ– e+ modes

BR(B

+→K +μe) < 2.2×10 −8 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2

The current BR(B+ → K+ µe) limit yields the weak bound

|(U L

ℓ)31/(U L ℓ)32| < 3.7

☑

= 0.1592 according to RK

slide-59
SLIDE 59
  • D. Guadagnoli, Status of flavor anomalies

As mentioned: if RK is signaling BSM LFNU, then expect BSM LFV as well LFV model signatures

BR(B

+→K +μ e)

BR(B

+→K +μμ)

= |δC10|

2

|C10

SM+δC10| 2 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2 ⋅ 2

µ+e– & µ– e+ modes

BR(B

+→K +μe) < 2.2×10 −8 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2

The current BR(B+ → K+ µe) limit yields the weak bound

|(U L

ℓ)31/(U L ℓ)32| < 3.7

☑ ☑

would be even more promising, as it scales with

BR(B

+→K +μ τ)

|(U L

ℓ)33/(U L ℓ)32| 2

= 0.1592 according to RK

slide-60
SLIDE 60
  • D. Guadagnoli, Status of flavor anomalies

As mentioned: if RK is signaling BSM LFNU, then expect BSM LFV as well LFV model signatures

BR(B

+→K +μ e)

BR(B

+→K +μμ)

= |δC10|

2

|C10

SM+δC10| 2 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2 ⋅ 2

µ+e– & µ– e+ modes

BR(B

+→K +μe) < 2.2×10 −8 ⋅ |(U L ℓ)31| 2

|(U L

ℓ)32| 2

The current BR(B+ → K+ µe) limit yields the weak bound

|(U L

ℓ)31/(U L ℓ)32| < 3.7

☑ ☑

would be even more promising, as it scales with

BR(B

+→K +μ τ)

|(U L

ℓ)33/(U L ℓ)32| 2

= 0.1592 according to RK

☑

An analogous argument holds for purely leptonic modes

slide-61
SLIDE 61
  • D. Guadagnoli, Status of flavor anomalies

More on LFV model signatures The most suppressed of the above modes is most likely Bs → μ e. (The lepton combination is the farthest from the 3rd generation, and it's chirally suppressed.)

DG, Melikhov, Reboud, PLB 16

slide-62
SLIDE 62
  • D. Guadagnoli, Status of flavor anomalies

More on LFV model signatures The most suppressed of the above modes is most likely Bs → μ e. (The lepton combination is the farthest from the 3rd generation, and it's chirally suppressed.) What about Bs → μ e γ ?

DG, Melikhov, Reboud, PLB 16

 

γ = “hard” photon

(hard = outside of the di-lepton Invariant-mass signal window)

slide-63
SLIDE 63
  • D. Guadagnoli, Status of flavor anomalies

More on LFV model signatures The most suppressed of the above modes is most likely Bs → μ e. (The lepton combination is the farthest from the 3rd generation, and it's chirally suppressed.) What about Bs → μ e γ ?

Chiral-suppression factor, of O(mμ / mBs)2 replaced by αem / π suppression

DG, Melikhov, Reboud, PLB 16

 

☞

γ = “hard” photon

(hard = outside of the di-lepton Invariant-mass signal window)

slide-64
SLIDE 64
  • D. Guadagnoli, Status of flavor anomalies

More on LFV model signatures The most suppressed of the above modes is most likely Bs → μ e. (The lepton combination is the farthest from the 3rd generation, and it's chirally suppressed.) What about Bs → μ e γ ?

Chiral-suppression factor, of O(mμ / mBs)2 replaced by αem / π suppression

DG, Melikhov, Reboud, PLB 16

 

☞

BR(Bs → μ e γ) BR(Bs → μ e)

γ = “hard” photon

(hard = outside of the di-lepton Invariant-mass signal window)

Enhancement by ~ 30% Inclusion of the radiative mode more-than- doubles statistics of the non-radiative

slide-65
SLIDE 65

More signatures

Being defined above the EWSB scale,

  • ur assumed operator

G ¯ b' L γ

λb' L ¯

τ 'L γλ τ ' L

must actually be made invariant under SU(3)c x SU(2)L x U(1)Y

See: Bhattacharya, Datta, London, Shivashankara, PLB 15

  • D. Guadagnoli, Status of flavor anomalies
slide-66
SLIDE 66

More signatures

Being defined above the EWSB scale,

  • ur assumed operator

G ¯ b' L γ

λb' L ¯

τ 'L γλ τ ' L ¯ Q' L γ

λQ ' L ¯

L' Lγλ L'L ¯ Q' L

i γ λQ ' L j ¯

L'

j L γλ L' L i

 

[neutral-current int's only] [also charged-current int's]

must actually be made invariant under SU(3)c x SU(2)L x U(1)Y

See: Bhattacharya, Datta, London, Shivashankara, PLB 15

  • D. Guadagnoli, Status of flavor anomalies

SU(2)L inv.

slide-67
SLIDE 67

More signatures

Being defined above the EWSB scale,

  • ur assumed operator

G ¯ b' L γ

λb' L ¯

τ 'L γλ τ ' L ¯ Q' L γ

λQ ' L ¯

L' Lγλ L'L ¯ Q' L

i γ λQ ' L j ¯

L'

j L γλ L' L i

 

[neutral-current int's only] [also charged-current int's]

Thus, the generated structures are all of:

t't ' ν' τ ν' τ , t ' t ' τ' τ' , b' b' ν' τ ν' τ , b' b' τ ' τ' ,

must actually be made invariant under SU(3)c x SU(2)L x U(1)Y

See: Bhattacharya, Datta, London, Shivashankara, PLB 15

  • D. Guadagnoli, Status of flavor anomalies

SU(2)L inv.

slide-68
SLIDE 68

More signatures

Being defined above the EWSB scale,

  • ur assumed operator

G ¯ b' L γ

λb' L ¯

τ 'L γλ τ ' L ¯ Q' L γ

λQ ' L ¯

L' Lγλ L'L ¯ Q' L

i γ λQ ' L j ¯

L'

j L γλ L' L i

 

[neutral-current int's only] [also charged-current int's]

Thus, the generated structures are all of:

t't ' ν' τ ν' τ , t ' t ' τ' τ' , b' b' ν' τ ν' τ , b' b' τ ' τ' , t ' b ' τ ' ν' τ

must actually be made invariant under SU(3)c x SU(2)L x U(1)Y

See: Bhattacharya, Datta, London, Shivashankara, PLB 15

  • D. Guadagnoli, Status of flavor anomalies

SU(2)L inv.

and

slide-69
SLIDE 69

More signatures

Being defined above the EWSB scale,

  • ur assumed operator

G ¯ b' L γ

λb' L ¯

τ 'L γλ τ ' L ¯ Q' L γ

λQ ' L ¯

L' Lγλ L'L ¯ Q' L

i γ λQ ' L j ¯

L'

j L γλ L' L i

 

[neutral-current int's only] [also charged-current int's]

Thus, the generated structures are all of:

t't ' ν' τ ν' τ , t ' t ' τ' τ' , b' b' ν' τ ν' τ , b' b' τ ' τ' , t ' b ' τ ' ν' τ

After rotation to the mass basis (unprimed), the last structure contributes to Γ(b  c τ ν) i.e. it can explain deviations on R(D(*)) must actually be made invariant under SU(3)c x SU(2)L x U(1)Y

See: Bhattacharya, Datta, London, Shivashankara, PLB 15

  • D. Guadagnoli, Status of flavor anomalies

SU(2)L inv.

☞

and

slide-70
SLIDE 70

More signatures

Being defined above the EWSB scale,

  • ur assumed operator

G ¯ b' L γ

λb' L ¯

τ 'L γλ τ ' L ¯ Q' L γ

λQ ' L ¯

L' Lγλ L'L ¯ Q' L

i γ λQ ' L j ¯

L'

j L γλ L' L i

 

[neutral-current int's only] [also charged-current int's]

Thus, the generated structures are all of:

t't ' ν' τ ν' τ , t ' t ' τ' τ' , b' b' ν' τ ν' τ , b' b' τ ' τ' , t ' b ' τ ' ν' τ

After rotation to the mass basis (unprimed), the last structure contributes to Γ(b  c τ ν) i.e. it can explain deviations on R(D(*)) must actually be made invariant under SU(3)c x SU(2)L x U(1)Y

See: Bhattacharya, Datta, London, Shivashankara, PLB 15

  • D. Guadagnoli, Status of flavor anomalies

SU(2)L inv.

☞

But this coin has a flip side. Through RGE running, one gets also LFU-breaking effects in τ → ℓ v v (tested at per mil accuracy) Such effects “strongly disfavour an explanation of the R(D(*)) anomaly model-independently”

F e r u g l i

  • ,

P a r a d i s i , P a t t

  • r

i , 2 1 6

and

slide-71
SLIDE 71
  • D. Guadagnoli, Status of flavor anomalies

Conclusions

In flavor physics there are by now several persistent discrepancies with respect to the SM.

slide-72
SLIDE 72
  • D. Guadagnoli, Status of flavor anomalies

Conclusions

In flavor physics there are by now several persistent discrepancies with respect to the SM. Experiments: Results are consistent between LHCb and B factories. Their most convincing aspects are the following:

slide-73
SLIDE 73
  • D. Guadagnoli, Status of flavor anomalies

Conclusions

In flavor physics there are by now several persistent discrepancies with respect to the SM. Experiments: Results are consistent between LHCb and B factories. Their most convincing aspects are the following: Data: Deviations concern two independent sets of data: b → s and b → c decays.

slide-74
SLIDE 74
  • D. Guadagnoli, Status of flavor anomalies

Conclusions

In flavor physics there are by now several persistent discrepancies with respect to the SM. Data vs. theory: Discrepancies go in a consistent direction. A BSM explanation is already possible within an EFT approach. Experiments: Results are consistent between LHCb and B factories. Their most convincing aspects are the following: Data: Deviations concern two independent sets of data: b → s and b → c decays.

slide-75
SLIDE 75
  • D. Guadagnoli, Status of flavor anomalies

Conclusions

In flavor physics there are by now several persistent discrepancies with respect to the SM. Data vs. theory: Discrepancies go in a consistent direction. A BSM explanation is already possible within an EFT approach. Experiments: Results are consistent between LHCb and B factories.

Early to draw conclusions. But Run II will provide a definite answer Their most convincing aspects are the following: Data: Deviations concern two independent sets of data: b → s and b → c decays.

slide-76
SLIDE 76
  • D. Guadagnoli, Status of flavor anomalies

Conclusions

In flavor physics there are by now several persistent discrepancies with respect to the SM. Data vs. theory: Discrepancies go in a consistent direction. A BSM explanation is already possible within an EFT approach. Experiments: Results are consistent between LHCb and B factories.

Early to draw conclusions. But Run II will provide a definite answer

Timely to propose further tests. One promising direction is that of LFV. Plenty of channels, many of which largely untested. Their most convincing aspects are the following: Data: Deviations concern two independent sets of data: b → s and b → c decays.