Connecting b->s anomalies with neutrino masses, dark matter and - - PowerPoint PPT Presentation

Chandan Hati Laboratoire de Physique de Clermont

Based on: JHEP 1811 (2018) 011 arXiv:1806.10146 In collaboration with

• G. Kumar, J. Orloff, and A. M. Teixeira

Connecting b->s anomalies with neutrino masses, dark matter and charged LFV

16 to 23 March 2019

Electroweak Interactions and Unified Theories

Introduction

The Standard Model (SM): Highly successful but incomplete … Neutrino Oscillation-> neutrino masses (SM neutrinos are strictly massless) Matter-antimatter asymmetry Unification of interactions Flavour puzzle Dark matter candidate Hierarchy Problem … => New physics beyond the SM Hundreds of theoretical models with various motivations !

1

Guidance from experimental anomalies: B-decays, (g-2) , …

Beyond the Standard Model: for the hints

Hints of significant deviations from the SM predictions in B meson decays=> New physics ?

[JHEP 08 (2017) 055]

2

A phenomenological approach to LFUV: connection to available data and experimental prospects

Neutrino masses and

• scillation data

Motivation Constraints/Predictions

Unification? Baryogenesis? … Collider EDM? …

Some popular solutions to the LFUV:

Scalar leptoquark triplet: (3, 3, 1/3); Vector leptoquark singlet: (3,1,2/3); … SM+ Scalar LQ triplet+ ??

3

A working example: SM + 2 Scalar LQ + T riplet Majorana fermion (3 gen)

4

The symmetry gives a viable dark matter candidate The standard type III seesaw is forbidden!

Radiative neutrino masses and a parametrisation to fit oscillation data

νL νC

L

h−1/3

1

h−1/3

2

h−1/3

1

h−1/3

2

dC

L

dL dC

R

dR Σ0

Topologically similar to Krauss, Nasri, Trodden PRD 2013,

• rdinary scalars and singlet DM in the loop

see talk of Rachik Soualah

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Using this parametrisation one can can easily fit oscillation data!

is a complex orthogonal matrix

A parameterisation à la Casas-Ibarra

A viable dark matter candidate

Z2 symmetry => ΣR is odd =>Σ0 (the lightest "exotic" stable state) => a viable dark matter candidate

m(Σ±) − m(Σ0) ∼ 166 MeV

Electroweak radiative corrections:

ΣR co-annihilate via gauge interactions

Cirelli, Fornengo, Strumia NPB 2006

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s-channel t-channel

Neutral current anomalies: RK and RK*

Taking Relevant operators for: the 1σ best fit to RK and RK* data

Hiller, Nisandzic 2017, Capdevila et al. 2018 Hurth et al. 2016, Bečirević et al. 2015, …

7

Charged current anomalies: RD and RD∗

=

Using ~ SM like after taking into account the constraints from flavour changing process Belle Collaboration:

If this signal is confirmed then this minimal model needs to be extended!

Include additional leptoquark R2 = (3, 2, 7/6) / S1= (3, 1, 1/3) ?

8

See for example: Becirevic et al. 18 Crivellin et al. 17

A “peek” into the flavour structure of scalar triplet LQ

To select a benchmark ε we parametrise RK(∗) data best fit value as (mh1 ∼ 1.5 TeV)

=> ∼ 0.215

How to implement a flavour structure for y?

Textures consistent with all the constraints from flavour violation:

! ∼

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Can be inspired by Froggatt-Nielsen/flavor symmetry/… amongst the most stringent constraints

Prospects for flavour violating processes

⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ↓ ↓ ↓ ↓ ↓ ↓ ⇑

▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■

★ ★ ★

μ->e γ τ->μ γ τ->e γ μ-> eee τ-> μμμ Cr(μ->e,N) K+→π +νν KL→π 0νν RK(*

νν /1010

KL→μ e Bs→μ e 10-18 10-16 10-14 10-12 10-10 10-8 μ->e γ τ->μ γ τ->e γ μ-> eee τ-> μμμ Cr(μ->e,N) K+→π +νν KL→π 0νν RK(*

νν /1010

KL→μ e Bs→μ e Branching ratio

⇓ Current upper bound ↓ Future sensitivity ⇑ Current lower bound

▲

Texture I

▼

Texture II

■

Texture III

★ SM prediction

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Exciting possibilities to probe leptoquark coupling textures at experiments!

Connection between LFUV and charged LFV

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[μ→ γ] [μ→] [μ-] [ +→π +νν]

2000 4000 6000 8000 10000 10-15 10-13 10-11 10-9

mh1 (GeV)

The textures give a direct correlation between LFUV data with charged LFV The current upper limits on Charged LFV processes translates into an upper bound on leptoquark masses within collider reach

What about neutrino oscillation data?

Three generations mΣ : 2.5, 3.5, 4.5 TeV Global best fit values for

• ther oscillation parameters

Scan for a complex consistent with the perturbativity limits

Lightest neutrino mass 0.001 eV

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Recall:

Ruled out ! 3 TeV

Concluding Remarks

We considered a simple scalar leptoquark extension [SM + 2 Scalar LQ + Triplet Majorana fermion (3 gen)] allowing to 


• 1. Accommodate the latest data on neutrino oscillation parameters
• 2. Explain the RK(∗) anomalies
• 3. Account for a correct relic abundance for dark matter
• 4. Consistent with the bounds on the leptoquark couplings from the relevant leptonic and semi-leptonic

meson decays, neutral meson anti-meson oscillations, and CLFV processes 


• 5. Exciting prospects for probing the model in future CLFV experiments:

μ − e conversion in nuclei and radiative decays μ → eγ, τ → μγ, eγ, μ → 3e and τ → 3μ



 A consistent UV completion

Implementing a mechanism for baryogenesis Computation of EDMs (two-loop)

Some open issues

Thanks a lot for your attention!

Source: Symmetry

Backup I: Full Lagrangian

Backup II: Relevant Lagrangian for neutrino masses

U is the PMNS mixing matrix

is a complex orthogonal matrix

νL νC

L

h−1/3

1

h−1/3

2

h−1/3

1

h−1/3

2

dC

L

dL dC

R

dR Σ0

Backup III: Dark matter co-annihilation channels

t-channel s-channel

Backup IV:Some important constraints from the mesonic observables

10

Backup V: LFV: current limits and future sensitivities

Conversion

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