Leptoquarks

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1/23 Contents Introduction, Motivation The Model - “colored Zee-Babu model” - Summary Lepton Number Violation at the LHC ed on ‘M. Kohda, HS, K. Tsumura, PLB718, 1436 (2013 Hiroaki SUGIYAMA (Maskawa Inst., Kyoto Sangyo Univ.)

description

Lepton number violation at the LHC. with. Leptoquarks. and. Diquarks. Hiroaki SUGIYAMA. (Maskawa Inst., Kyoto Sangyo Univ.). Contents. Introduction, Motivation. The Model - “colored Zee-Babu model” -. Lepton Number Violation at the LHC. Summary. - PowerPoint PPT Presentation

Transcript of Leptoquarks

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

Summary Lepton Number Violation at the LHC

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

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

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Introduction -Neutrino Oscillation-Introduction -Neutrino Oscillation-

Neutrino masses, mixings, and oscillations

Massive neutrinos can be mixed

Flavor transitions (oscillations) are possible

(quark sector : Cabibbo-Kobayashi-Maskawa matrix)

: Maki-Nakagawa-Sakata matrix (mixing)

: mass eigenstates (propagation): flavor eigenstates (weak interaction)

: distance: energy

: masses

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first oscillation maximum :

good set up (E, L) of experimentsto obtain and

P(t

ran

siti

on

)

accuracy for

accuracy for

Two Neutrino Case (good approximation)

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We have evidence of oscillations Neutrino masses are necessary

55 Japanese nuclear power reactors Kamioka mine

S. Abe et al., PRL100, 221803

apparently oscillating !

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or

?

?

atmospheric accelerator solar KamLAND

“normal” “inverted”

Current knowledge on neutrino masses and mixings

T2Kreactor

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Neutrino masses are extremely smaller than other fermion masses.

Introduction -Neutrino Mass-Introduction -Neutrino Mass-

Neutrino-specific mass term

Allowed only for neutrinos

Lepton number violation

Majorana :

for

neutrino-specific mechanism to generate their masses ?

c.f.

“Unnatural”

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e.g., Neutrinoless double beta decay

L#V processMajorana neutrino(tiny mass) (tiny rate)

Majorana mass & L#V processes

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MotivationMotivation

Input : Small Output : Small rate of L#V

Input : Unsuppressed L#V Output : Suppressed

Black box : TeV-scale particlesNo

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Two-Loop Neutrino MassTwo-Loop Neutrino Mass

Zee-Babu Model

colored version

A. Zee, NPB264, 99 (1986)K.S. Babu, PLB203, 132 (1988)

two colored loops

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

Summary Lepton Number Violation at the LHC

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

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

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Scalar Leptoquark

Scalar Diquark

Two-loop neutrino mass

The Model - Zee-Babu Model -The Model - Zee-Babu Model -

Briefly mentioned in ‘K.S. Babu and C.N. Leung, NPB619, 667 (2001)’

soft L#V term (no B#V)

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A Benchmark PointA Benchmark Point

LQ Yukawa :

DQ Yukawa :

Scale :

agree with neutrino oscillation data

satisfy constraints (couplings, masses)

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

Summary Lepton Number Violation at the LHC

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

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

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Large Hadron ColliderLarge Hadron Collider

4 Apr. 2008 4 Apr. 2008

collider at (cf. Tevatron: at )

26.7km ring (cf. 26.4km loop subway in Nagoya, Japan)(cf. 21.7km loop line in Osaka, Japan)

4 Jul. 2012 4 Jul. 2012

Higgs at CMS Higgs at ATLAS

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8.5 km

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L#V Process at the LHCL#V Process at the LHC

without missing

No missing energy No missing L#

Definite total L# of final states

Evidence for L#V

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without missing

L#V No SM process in principle

Hard

Clear evidence for L#V

No mimic event in SM

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forat

T. Han et al., JHEP 1012, 085 (2010)

(same for scalar)

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Large Good for Bad for

For fixed

Bad for Good for

is preferred

&

&

Benchmark point

Small

vs.

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w/ missing

w/o missing

w/o missing

@ Benchmark point

( )

is small

BUT is also small.

Sizable

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Benchmark point & LHC with

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SummarySummary

Zee-Babu Model with Leptoquark and Diquark

Unsuppressed L#V process at the LHC

without missing

Suppressed neutrino mass ( two-loop, , )

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BackupBackup

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L#V Process at the LHCL#V Process at the LHC

without missing

forat even for

for

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Production Cross SectionProduction Cross Section

T. Han, I. Lewis, and Z. Liu, JHEP 1012, 085 (2010)

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Bounds on MassesBounds on Masses

CMS : PRD86, 052013 (2012)

ATLAS : PLB709, 158 (2012)

EPJC72, 2151 (2012)

Leptoquark mass (for )

No analysis for

cf. CMS : arXiv:1302.4794

Diquark mass

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Bounds on MassesBounds on Masses

CMS : PRD86, 052013 (2012)

arXiv:1210.5629

JHEP1212, 055 (2012)

Leptoquark mass

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Bounds on MassesBounds on Masses

ATLAS : PLB709, 158 (2012)

EPJC72, 2151 (2012)

Leptoquark mass

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Bounds on MassesBounds on Masses

Diquark mass

No analysis for

cf. CMS : arXiv:1302.4794

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Constraints on New Yukawa CouplingsConstraints on New Yukawa Couplings

LQ Yukawa

Constraint : ( conversion )

Benchmark :

Constraint : ( meson decay )

Benchmark :

M. Carpenter and S. Davidson, EPJC70, 1071 (2010)

Constraint :

Benchmark :

MEG, PRL107, 171801 (2011)

MEG, arXiv:1303.0754

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32/23DQ Yukawa

mixing

mixingmixing

UTfit, JHEP0803, 049 (2008)

Benchmark point

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LFVLFV

Dangerous

We ignore .

Type-II or Type-X THDMs ( or are - odd)

or - triplet Leptoquark

No

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Neutrinoless Double Beta DecayNeutrinoless Double Beta Decay

@ Benchmark point