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Hiroaki SUGIYAMA (Maskawa Inst., Kyoto Sangyo Univ.)

Contents     Introduction, Motivation The Model “colored Zee-Babu model” Lepton Number Violation at the LHC Summary based on ‘M. Kohda, HS, K. Tsumura, PLB718, 1436 (2013) ’

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Introduction -Neutrino Oscillation Neutrino masses, mixings, and oscillations Massive neutrinos can be mixed : flavor eigenstates (weak interaction) : mass eigenstates (propagation) : Maki-Nakagawa-Sakata matrix ( mixing ) (quark sector : Cabibbo-Kobayashi-Maskawa matrix) Flavor transitions (oscillations) are possible : masses : distance : energy

Two Neutrino Case (good approximation)

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accuracy for accuracy for first oscillation maximum : good set up (E, L) of experiments to obtain and

e.g., Measurement in KamLAND experiment 55 Japanese nuclear power reactors Kamioka mine

4/23

apparently oscillating !

We have evidence of oscillations

S. Abe

et al

., PRL

100

, 221803

Neutrino masses are necessary

Current knowledge on neutrino masses and mixings

?

5/23 atmospheric accelerator reactor T2K solar KamLAND or “normal” “inverted” ?

Introduction -Neutrino Mass Neutrino masses

are extremely smaller than other fermion masses.

6/23 neutrino-specific mechanism to generate their masses ?

c.f.

“Unnatural” for Neutrino-specific mass term Majorana : Allowed only for neutrinos Lepton number violation

Majorana mass & L#V processes Majorana neutrino (tiny mass) L#V process (tiny rate) e.g., Neutrinoless double beta decay

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Input : Small Motivation Output : Small rate of L#V

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Input : Unsuppressed L#V Output : Suppressed Black box : TeV-scale particles No

Two-Loop Neutrino Mass Zee-Babu Model

A. Zee, NPB

264

, 99 (1986) K.S. Babu, PLB

203

, 132 (1988) 9/23

colored version two colored loops

10/23

Hiroaki SUGIYAMA (Maskawa Inst., Kyoto Sangyo Univ.)

Contents     Introduction, Motivation

The Model “colored Zee-Babu model” -

Lepton Number Violation at the LHC Summary based on ‘M. Kohda, HS, K. Tsumura, PLB718, 1436 (2013) ’

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The Model Zee-Babu Model -

Briefly mentioned in ‘K.S. Babu and C.N. Leung, NPB

619

, 667 (2001)’

Scalar Leptoquark Scalar Diquark Two-loop neutrino mass soft L#V term (no B#V)

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A Benchmark Point LQ Yukawa : DQ Yukawa : Scale : satisfy constraints (couplings, masses) agree with neutrino oscillation data

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Hiroaki SUGIYAMA (Maskawa Inst., Kyoto Sangyo Univ.)

Contents     Introduction, Motivation The Model “colored Zee-Babu model” -

Lepton Number Violation at the LHC

Summary based on ‘M. Kohda, HS, K. Tsumura, PLB718, 1436 (2013) ’

Higgs at CMS Large Hadron Collider Higgs at ATLAS

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4 Apr. 2008 4 Apr. 2008 4 Jul. 2012 4 Jul. 2012 collider at (cf. Tevatron: at ) 26.7km ring (cf. 26.4km loop subway in Nagoya, Japan) (cf. 21.7km loop line in Osaka, Japan)

8.5 km

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L#V Process at the LHC without missing

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No missing energy No missing L# Definite total L# of final states Evidence for L#V

without missing Hard L#V No SM process in principle No mimic event in SM

Clear

evidence for L#V

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18/23

(same for scalar)

19/23 T. Han

et al.

, JHEP

1012

, 085 (2010)

at for

vs.

For fixed Large Small Good for Bad for Benchmark point & & Bad for Good for is preferred

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is small BUT is also small.

Sizable @ Benchmark point w/o missing ( ) w/o missing w/ missing

Benchmark point & LHC with

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Summary Zee-Babu Model with Leptoquark and Diquark Suppressed neutrino mass ( two-loop, , )

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Unsuppressed L#V process at the LHC without missing

Backup

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L#V Process at the LHC without missing

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at for for even for

Production Cross Section

26/23 T. Han, I. Lewis, and Z. Liu, JHEP

1012

, 085 (2010)

Bounds on Masses Leptoquark mass (for ) CMS :

PRD

86

, 052013 (2012) 27/23

ATLAS :

PLB

709

, 158 (2012) EPJC

72

, 2151 (2012)

Diquark mass No analysis for cf. CMS :

arXiv:1302.4794

Leptoquark mass CMS : Bounds on Masses

PRD

86

, 052013 (2012) 28/23 JHEP

1212

, 055 (2012) arXiv:1210.5629

Leptoquark mass ATLAS : Bounds on Masses

PLB

709

, 158 (2012) EPJC

72

, 2151 (2012) 29/23

Diquark mass No analysis for cf. CMS : Bounds on Masses

arXiv:1302.4794

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Constraints on New Yukawa Couplings LQ Yukawa

M. Carpenter and S. Davidson, EPJC

70

, 1071 (2010) 31/23

Constraint : Benchmark : ( conversion ) Constraint : Benchmark : ( meson decay ) Constraint : Benchmark :

MEG, PRL

107

, 171801 (2011) MEG, arXiv:1303.0754

DQ Yukawa mixing

UTfit, JHEP

0803

, 049 (2008)

Benchmark point

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mixing mixing

LFV We ignore . No Type-II or Type-X THDMs ( or are - odd) or - triplet Leptoquark

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Dangerous

Neutrinoless Double Beta Decay @ Benchmark point

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