# Presentation: 136107

## New Physics Searches Using Muons

- Preview of the Muon Working Group at
- the Proton Driver Workshop

- Muon g-2
- Muon EDM
- Muon lifetime			MuLan @ PSI
- Lepton Flavor Violation
- 	 e+MEG @ PSI
- 	 e+e+e-
- 	 e- conversion		MECO @ BNL
- 					PRIME @ JPARC

- R. Ray
- 9/24/04

## 		     MUON WORKING GROUP

- Preliminary Agenda

**Thursday 7 Oct: ****	****Working Group Session 2 ****	****	****	**Location: TBD
**10:30 - 11:15 ****	**Theory 					B. Marciano
**11:15 - 12:00 ****	**Muon EDM, g-2 and flavor violation from beyond the SM 	K. Babu
**12:00 - 12:30 ****	**g-2 					J. Miller
**14:00 - 14:30 ****	**Mu lifetime measurement - Mulan 			D. Hertzog
**14:30 - 15:00 ****	**Mu EDM 					J. Miller
**15:50 - 16:20 ****	**mu e Conversion - MECO 			TBD
**16:20 - 16:50 ****	**mu e Conversion - PRIME 			Y. Kuno
**16:50 - 17:20 ****	**Mu --> e gamma - MEG 				F. Cei

## Muon g-2

- A very precise test of the Standard Model
- sensitive to contributions from SUSY,
- WIMPs, extra dimensions, etc.

- Most recent result from the BNL experiment

**Theoretical prediction**

- Low-energy e+e- annihilation cross section data from CMD-2
- A new estimation of the light-by-light amplitude (K.Milnikov and A. Vainshtein)
- A new evaluation on 4  QED term (T.Kinoshita and M.Nio)

-  K.Hagiwara, A.D. Martin, D.Nomura, and T.Teubner.

- (e+e- data used)

-  K.Hagiwara’s  talk in W4

- Y. Okada
- NuFact 04

##               Muon EDM

- EDM of elementary particles violate both P and
- T, so CPT requires EDM to violate CP.  EDMs provide
- information on additional CP violating phases in SM.
- SM EDMs are only generated at the multi-loop level
- and are are extremely suppressed, so observation
- would be a definitive indication of new physics.
- Current bound on muon EDM is O(10-19) e cm

## SUSY and g-2, EDM

- Slepton-chargino (neutralino) loop diagrams contribute to g-2 and EDM
- at the one loop level.

**SUSY contribution to g-2****:** enhanced for a large value of the ratio of
- two Higgs VEVs (                                             ).

**SUSY contribution to EDM.**

- Naively muon EDM is expected as large as 0(10-22) e cm.

- In simple cases,

- We need source of the lepton-universality violation to enhance muon EDM.
- (Left-right symmetric seesaw model, K.S.Babu, B.Dutta, R.N.Mohapara 2000, etc)

- Y. Okada
- NuFact 04

## Muon Lifetime Measurement

- Muon lifetime is used to determine GF, the fundamental
- parameter that governs the strength of electroweak processes.

- q are higher order QED and QCD corrections

- The uncertainty of the theoretical corrections  (< 1 ppm) are an order of magnitude
- smaller than the error on the measured value of the muon lifetime.
- MuLan
- 1012 muon decays  1 ppm determination of  (> order of magnitude
- improvement over current PDG value)
- Determine GF to better than 1 ppm

## LFV and new physics

- Many models beyond the Standard Model contain sources of LFV.
- Although the simple seesaw or Dirac neutrino model predictions are small, other models of neutrino mass generation can induce observable effects.
-    Generalized Zee model  (K.Hasagawa, C.S.Lim, K.Ogure, 2003)
-    Neutrino mass from the warped extra dimension (R.Kitano,2000)
-    R-parity violating SUSY model (A.de Gouvea,S.Lola,K.Tobe,2001)
-    SUSY seesaw model

- Y. Okada
- NuFact 04

## Experimental bounds

- Mu-e conversion search at the level of 10-18 is proposed
- in the future muon facility at J-PARC (PRIME).

- (Ti)

- (Al)

- Belle new results

- Y. Okada
- NuFact 04

## Y. Okada

- NuFact 04

## SUSY GUT and SUSY Seesaw model

- The flavor off-diagonal terms in the slepton mass matrix are induced by  renormalization effects
- due to GUT and/or neutrino interactions.

- LFV

- L.J.Hall,V.Kostelecky,S.Raby,1986;A.Masiero, F.Borzumati, 1986

- Y. Okada
- NuFact 04

## -> e branching ratio

- -> e branching ratio

- SU(5) and SO(10) SUSY GUT

- SUSY seesaw model

- The branching ratio can be large
- in particular for SO(10) SUSY GUT model.

- J.Hisano and D.Nomura,2000

- K.Okumura

- SO(10)

- SU(5)

- Right-handed neutrino mass

- Right-handed selectron mass

- Y. Okada
- NuFact 04

## Z dependence of mu-e conversion branching ratio

- We have calculated the coherent mu-e conversion branching ratios in various nuclei for general LFV interactions to see:
- (1) which nucleus is the most sensitive to mu-e conversion searches,
- (2) whether we can distinguish various theoretical models by the Z dependence.

- Relevant quark level interactions

- Dipole

- Scalar

- Vector

- R.Kitano, M.Koike and Y.Okada. 2002

## The branching ratio is largest

- for the atomic number of Z=30 – 60.
- For light nuclei, Z dependences
- are similar for different operator forms.
- Sizable difference of Z dependences for dipole, scalar and vector interactions. This is due to a relativistic effect of the muon wave function.

- dipole

- scalar

- vector

- Another way to discriminate different models

- mu-e conversion rate normalized at Al.

## Higgs-mediated contribution to -e conversion in SUSY 

- The heavy Higgs-boson exchange provides
- a new contribution of a scalar type.

- Higgs-exchange contribution

- Photon-exchange contribution

**Higgs-mediated contribution to ********-e conversion in SUSY **
**seesaw model**

- R.Kitano,M.Koike,S.Komine, and Y.Okada, 2003

- SUSY loop diagrams can generate
- a LFV Higgs-boson coupling
- for large tan cases(K.Babu, C.Kolda,2002)

- Y. Okada
- NuFact 04

## Ratio of the branching ratios and Z-dependence of mu-e conversion rates

- mu-e conversion is enhanced.
- Z-dependence indicates the scalar exchange contribution.

- Y. Okada
- NuFact 04

## 			Summary

- Many opportunities available in muon physics to observe
- physics beyond the SM
- Observable effects are predicted by various models
- Comparison of g-2, EDM and various LFV processes along
- with significant theoretical input will be necessary to distinguish
- between different models.