NEUTRINOLESS DOUBLE BETA DECAY AS PROBE OF PHYSICS BEYOND THE STANDARD MODEL

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NEUTRINOLESS DOUBLE BETA DECAY AS PROBE OF
PHYSICS BEYOND THE STANDARD MODEL

• D. Zhuridov (MSU)
• Helmholtz Summer School
• Heavy Quark Physics
• Dubna, June 9, 2005

In collaboration with A. Ali and A.V. Borisov
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Leptonic number is not changed.
p
n
p
n
This process was observed for 10 nuclei.
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Leptonic number is changed by 2
units. Responsible for it could be

• Majorana neutrino
• scalar bilinear (leptoquark, doubly charged
  dilepton)
• SUSY particle

2001 Geidelberg-Moscow collaboration
Some experiments are planned to investigate an
electron angular distribution for the decay.
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Classes of mechanisms for the decay

• With long range operator
• With short range operator
• With middle range operator

u
d
u
d
d
u
u
d
First two classes are more expected.
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Long range mechanism
Most general effective Lagrangian
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For ultrarelativistic electrons and
nonrelativistic nucleus, for first nonzero terms
in expansion of electron plane waves the
differential width for -transitions is
R nuclear radius
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(No Transcript)
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Short range mechanism
It can be heavy Majorana neutrino, SUSY or LQ
mechanism.
Leptonic part of effective Lagrangian
gives the distribution proportional to
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To summarize