Etudes des proprietes des neutrinos dans les contextes ...

tel-00450051, version 1 - 25 Jan 2010
νl
νl
W, Φ
l
W, Φ
l
γ, Z
f f
νl
νl
f = u,d,e
νl
νl
W, Φ W, Φ
νl
νl
γ, Z
f f
Z W W
f f f f
Figure 4.10: Feynman one-loop diagrams which give rise to νl-dependent radiative
corrections to the scattering νlf → νlf
in matter gives a huge potential for νe. For nντ − nνµ, only the correction for
ντ can give rise to a not so small radiative correction, since O(αm2 µ/m2 W ) ≃
1
100O(αm2τ /m2W ). These radiative corrections arise from the one-loop Feynman
diagrams in Fig.(4.10). These corrections are taken from [33]. They show that
even though the parameters λνℓf 2 are also modified by O(αmτ/m2 W ) corrections,
they are independent of f and therefore cancel out of νντ for a neutral medium.
Finally, the one-loop correction index is
pν∆nτµ = − √
2GF NfT3(fL)∆ρ f
with ∆ρ f ≡ ρ ντf − ρ νµf and the corrections associated to the diagrams give:
∆ρ e SM = ∆ρd SM
∆ρ u SM
= −αW
8π
= αW
8π
f
x(2 + x)
1 − x
x(4 − x)
1 − x
83
3x(2 − x)
+ lnx
(1 − x) 2
l
l
(4.49)
(4.50)
3x2
+
(1 − x) 2lnx
, (4.51)