Transcript Leptonic Unitary Triangle

Combined analysis of EDMs and
Lepton Flavor Violating rare decays
YASAMAN FARZAN
IPM, Tehran
Manifestation of heavy states
Direct production at accelerators
Indirect effects in low energy phenomena
Historic example: Beta decay is the
indirect manifestation of W-boson.
Beta decay was discovered in the late
19th century.
Direct production of W boson took
place only in 1980’s.
Models predicting heavy states
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SUSY models
Extra dimensions
various Higgs models
…
All these models predict heavy particles to be directly
produced at LHC….
Indirect Effects in Low Energy
Experiments
Lepton Flavor Violating (LFV) processes:
Magnetic Dipole Moment:
Electric Dipole Moments (EDMs)
…..
In this talk, we shall focus on LFV and EDMs and their
Combined analysis.
In parallel to the progress in the high energy
frontier (via LHC and hopefully via ILC), in
upcoming years we expect breakthrough in the low
energy experiments, too.
Unlike the historic example of beta decay and
W-boson discovery, in the present era, progress
in both directions (low energy and high energy)
takes place simultaneously.
Complementary information can be derived
by combining the results.
Limitations of LHC
Suppose SUSY (or some other BSM) is discovered
at LHC. Little or none can be learned about the
the CP-violating phases in the lepton sector at LHC
(see however, Godbole Czech J Physc 55; Heinemeyer
and Velasco, hep-ph/0506267; Kittel, hep-ph/0504183 ).
ILC
Measuring CP-violation
Low energy experiments
Searches for EDMs can teach us about the CPviolating phases
EDM and MDM under CP
CP:
CP:
MDM conserves CP but EDM violates CP.
Present bound and prospects for
improvement
Present bound:
[PDG]
Near future:
DeMille et al
Foreseeable future:
Lamoreaux, nucl-ex/0109014
(employing solid state techniques; Shapiro’s old idea)
The phase of CKM:
The phases of PMNS:
de Gouvea, Gopalakrishna, PRD72
Positive signal
New Physics
Importance of CP-violation
Among all the parameters of a theory, CP-violating
phases hold a place of honor because CP-violation is
one of the three famous Sakharov’s conditions for
dynamically creating the Baryon asymmetry of the
universe.
The CP-violating phase that we would measure in the
labs might be in the heart of the fundamental
question why our body as well as the whole universe
around us (so far explored) is made of matter rather
than anti-matter.
Which phase is responsible for
baryogenesis?
In the framework of some models, the CP-violating
phase that is responsible for baryogenesis can also
show up in the EDM; e.g.,
(the phase of
bilinear Higgs term in the superpotential ) which
leads to both Electroweak baryogenesis and EDM.
Not all the CP-violating phases contributing to EDM
can lead to successful baryogenesis. To disentangle
the different contributions and to pinpoint the effect
of the mu-term, one has to work out all the phases.
Neutrino oscillation
The only evidence so far for physics BSM comes from
observation of neutrino oscillation.
Contribution of neutrino masses to LFV processes:
Petcov Sov J. NP25; Bilenky et al, PLB67; Altarelli et al, NPB125
PDG
Benerjee,
hepex/0702017
Positive signal in future
Physics BSM
LFV and CP-violation in MSSM
at one-loop
Strong bounds on
Effect of
on
NO LFV
No one loop contribution
Two-loop effect exists but the effect is suppressed.
LFV:
Ayazi
and
Farzan,
JHEP070
6
To have sizeable effect,
be both relatively large.
and
have to
Present bounds on
and
prospects for improvements
Banerjee, hep-ex/0702017
Super B-factory (physics/0512235)
Other effects of complex
Complex
does not contribute to Baryogenesis.
Phase of
can manifest itself in decay and
production of staus and can in principle be measured
at ILC.
Gajdosik, Godbole and Kraml, JHEP 0409; Bartl et al.,
PRD66
It will be exciting to derive complementary
information on this phase from low energy
experiments.
Condition for sizeable effect
If
or
the contribution of
to is suppressed even
if
is close to its present bound and
is large.
Contribution of the phase of
Left-right ratio
Suppose in future
is detected.
Q: Is there a way to extract
?
A: Yes, by studying the angular distribution of the final
particles:
is the angle between the spin of tau and the
momentum of the emitted
Measurement and interpretation
of
By studying the angular distributions of the final particles
at an
collider such as B-factory, it will be possible
to extract the value of
.
Kitano and Okada, PRD63 (2001) 113003
Interpretation of
or
:
Correlation of
and
Present bound
Near Future reach
The dots depicted by
the same color and
symbol in the two
panels correspond to
the same scatter point
All other phases=0
Correlation of
and
Present bound
Near Future reach
In the case of the
purple dots for which
regardless of
electron EDM is very
small and below
the reach of the current
experiments.
Correlation of
and
Present bound
Near Future reach
For
(to be tested by super B-factory)
regardless of the value of
,
is smaller than the
present bound.
Correlation of
and
Present bound
Near Future reach
If
and
,
there is a good
chance of detecting
in near future (blue
dots) provided that
is sizable .
Conclusions
By combining the information from
LFV and EDM
experiments, valuable information can be
derived on CP-violation
which can be considered complementary
to or a cross check of the CP study at ILC.