Kam-Biu Luk
University
of
California, Berkeley
and
Lawrence
Berkeley
National Laboratory
Neutrinos
are
supposed to be massless in the Standard Model of particle
physics for several
decades. However, a series of experiments has recently
provided compelling
evidences for a new phenomenon, neutrino oscillation, that
implies the three
types of neutrinos observed in laboratories do have mass after
all. Neutrino
oscillation can be described with a set of three
neutrino-mixing angles, of which
the smallest one called θ
13 was
unknown until
recently. One approach for determining θ13
is to utilize
a running nuclear reactor which is
a copious source of low-energy electron
antineutrinos. In this talk, the recent discovery of a new
kind of neutrino
oscillation due to a non-zero value of θ13
observed in
reactor-based experiments will
be presented. The implications of this surprising observation
will also be
highlighted.