DOI: 10.1140/epjc/s2003-01138-0
Analytical calculations of four-neutrino oscillations in matter
Y. Kamo, Y. Higasida, J.-I. Ichihara, S.-I. Kubota, S. Tokuo and S. YajimaDepartment of Physics, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
(Received: 9 October 2002 / Revised version: 27 December 2002 / Published online: 14 March 2003)
Abstract
We analytically derive the transition probabilities
for four-neutrino oscillations in matter.
The time-evolution operator giving the neutrino oscillations
is expressed by
a finite sum of terms up to the third power of the Hamiltonian
in a matrix form, using the Cayley-Hamilton theorem.
The result of the computation for the probabilities
in some mass patterns tells us that
it is actually difficult to observe
the resonance between one of the three active neutrinos and
the fourth (sterile) neutrino near the earth,
even if the fourth neutrino exists.
© Società Italiana di Fisica, Springer-Verlag 2003
