Search for in muonic atom at COMET experiment
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Transcript of Search for in muonic atom at COMET experiment
Search for in muonic atom at COMET experiment
Masato Yamanaka (ICRR, Univ. of Tokyo)
Collaborators
Masafumi Koike (Saitama Univ.)Yoshitaka Kuno (Osaka Univ.)Joe Sato (Saitama Univ. )
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Introduction
Introduction
In Standard Model (SM)
Lepton Flavour Violation (LFV) through the neutrino oscillation
But … Forever invisible
Discovery of the LFV signalOne of the evidence for beyond
the SM
Introduction
Prove for structure of new physics
Comparing LFV signals in each process type Discrimination of new physics
models
Desire for detectable new LFV process
Supersymetric model
Extra dimension model
Introduction
New idea for LFV search in muonic
atomme ee
What is sensitive to ?
Flavor violation between and e
m
Where is the stage ?
MUSIC, COMET, and PRISM
What is advantage ?
Clean signal, and simultaneous search with other LFV processes
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nucleus muon electron
Muonic atom
electron 1S orbitmuon 1S
orbit
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in muonic atom
electron 1S orbitmuon 1S
orbit
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LFV vertex
Interaction rate
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electron 1S orbitmuon 1S
orbit
Interaction rate
Cross section for elemental interaction
in muonic atom
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LFV vertex
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Lagrangian
LFV source
Model dependent parmeters
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Lagrangian
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Lagrangian
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For A g (i = 1, 2, …, 6)
L(R) =~ i
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electron 1S orbitmuon 1S
orbit
Interaction rate
Overlap of wave function of and
m e
in muonic atom
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LFV vertex
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Muonic atom
Overlap of wave functions ∴Muon localizing
at nucleus positon
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Branching ratio
Lifetime of free muon (2.197 10 s)
-6×
Lifetime of bound muon
2.19 10 s for H
-6× 1
(7 - 8) 10 s for U
-8×238
Discovery reach
Discovery reach
Branching ratio ( )
m e g
Ratio between BR( ) and BR( )
m e g me e e
Discovery reach
Ratio between BR( ) and BR( )
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Discovery reach
Discovery reach
For run-time 1 year 3 10 s
× 7~
10
18
10
19
- muon at COMET experiment
Discovery reach
can be first signal of LFV !?
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Summary
Summary
New LFV process
in muonic atom
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Clean signal (back to back electron with E m /2)
Interaction rate
Advantage : Large nucleus
~=e m
Detectable in on-going or future experiments
We wish to observe LFV in the process
Appendix
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nucleus muon electron
Muonic atomelectron 1S orbit
muon 1S orbit
One of the candidates for beyond the SM Supersymmetric (SUSY)
modelSupersymmetry
Lepton SleptonGauge boson
Gaugino
Symmetry between boson and fermion
Stability of Higgs mass, dark matter, gauge coupling unification, hierarchy problem, and so on
Why SUSY models ??