muon physics at the front end of a n -factory
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K. Long – U.C. Irvine - p. 1/
Muon Physics at the front end of a -Factory• At a -factory beams of 1013 - 1014 /s
could be developed. • Two types of experiments are especially
suited to such fluxes:– Search for a permanent electric dipole moment
d
– Search for lepton flavor violation in muon decay
• Such experiments would continue the long history that muon physics has with the development of the Standard Model, and searches for physics beyond it.
K. Long – U.C. Irvine - p. 2/
SM information/constraints from the muon:
• The strength of the weak interaction– i.e. the Fermi constant G from
• The fundamental nature of the weak interaction: V-A
• Lepton flavor conservation in -decay: → e , + → e+ e+ e-, N → e- N, are not yet seen
• VEV of the Higgs field:
• Induced form-factors in nuclear -capture• Limits on non-standard model physics from
the muon anomalous magentic moment a
K. Long – U.C. Irvine - p. 3/
• Muon Magnetic Dipole Momoment a chiral changing
• Muon EDM
P T CP
Three experiments that would most benefit from high flux:
K. Long – U.C. Irvine - p. 4/
Three experiments that would most benefit from high flux:• Muon Magnetic Dipole Momoment a chiral
changing
• Muon EDM
• Lepton Flavor Violation
P T
K. Long – U.C. Irvine - p. 5/
aμ, d LFV are sensitive to a wide range of new physics including SUSY. e.g. a is sensitive to:
• substructure
• SUSY (with large tanβ )
• many other things (extra dimensions, etc.)
K. Long – U.C. Irvine - p. 6/
The new theory value reported by S. Eidelman at ICHEP06 a difference with SM of 3.3
K. Long – U.C. Irvine - p. 7/
Left -Right
MSSM ~
Multi Higgs
MSSM
~ 1
10-24
10-22
10-26
10-28
10-30
10-32
10-34
10-36
e EDM (e.cm)
E. Hinds’ e-EDM experiment
at Imperial College with YbF molecules
is startingto explore this region
Standard Model
de < 1.6 x 10-27 e.cm
Commins (2002)
Excluded region (Tl atomic beam)
with thanks to Ed Hinds
n
199Hg
K. Long – U.C. Irvine - p. 8/
SUSY connection between a , Dμ , μ → e through the slepton mixing matrix → e MDM, EDM
~ ~
K. Long – U.C. Irvine - p. 9/
Past and Future of LFV Limits
+ e-→-
e+
Bra
nchi
ng R
atio
Lim
it
K. Long – U.C. Irvine - p. 10/
Experiments that can use the highest muon intensity:
• muon-electron conversion: to ~ 10-20
– Present Limit for - Ti: BR < 6 X 10-13
– PRISM/PRIME proposal •10-18 – 10-19 single event sensitivity
– -Fact front-end, 10-20
• muon EDM search– ~10-25 e cm needs NP2 of ~1018
– present limit d 10-19 e cm<~
K. Long – U.C. Irvine - p. 11/
Muon Summary and Outlook• The muon has provided us with much knowledge on
how nature works. New experiments on the horizion continue this tradition.
• Muon (g-2), with a precision of 0.5 ppm, has a 3.3 discrepancy with the standard model.
• If this discrepancy is from new physics, it would show up in an EDM and perhaps in LFV as well.
• MEG is set to turn on and collect data in the next year. • - → e- conversion holds the best experimental
prospect for going much further on LFV.
• There is an exciting program of muon physics that can be done at a -factory!
K. Long – U.C. Irvine - p. 12/
THE END
K. Long – U.C. Irvine - p. 13/
K. Long – U.C. Irvine - p. 14/
The SM Value for electron and muon anomalies
e vrs. : relative contribution of heavier things
e,
e*,
e,
e,
e,
e, e,
e,
e,
e,e,
K. Long – U.C. Irvine - p. 15/
Present EDM Limits
Particle Present EDM limit(e-cm)
SM value(e-cm)
n 3 x 10-26 (90%CL) 10-32 to 10-31
e- 1.6 x 10-27 (90%CL) < 10-41
< 10-38
199Hg 2.1 x 10-28 (95%CL)
*not yet final
K. Long – U.C. Irvine - p. 16/
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