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Press Release
6 October 2015
The Royal Swedish Academy of
Sciences has
decided to award the Nobel Prize in Physics for
2015 to
Takaaki Kajita
Super-Kamiokande Collaboration
University of Tokyo, Kashiwa, Japan
and
Arthur B. McDonald
Sudbury Neutrino Observatory Collaboration
Queen's University, Kingston, Canada
"for the discovery of neutrino
oscillations, which shows that neutrinos have
mass"
Press Release
6 October 2015
The Royal Swedish Academy of
Sciences has
decided to award the Nobel Prize in Physics for
2015 to
Takaaki Kajita
Super-Kamiokande Collaboration
University of Tokyo, Kashiwa, Japan
and
Arthur B. McDonald
Sudbury Neutrino Observatory Collaboration
Queen's University, Kingston, Canada
"for the discovery of neutrino
oscillations, which shows that neutrinos have
mass"
Metamorphosis in the particle
world
The Nobel Prize in Physics 2015
recognises Takaaki
Kajita in
Japan andArthur
B. McDonald in
Canada, for their key contributions to the
experiments which demonstrated that neutrinos
change identities. This metamorphosis requires
that neutrinos have mass. The discovery has
changed our understanding of the innermost
workings of matter and can prove crucial to our
view of the universe.
Around the turn of the
millennium, Takaaki Kajita presented the
discovery that neutrinos from the atmosphere
switch between two identities on their way to
the Super-Kamiokande detector in Japan.
Meanwhile, the research group in
Canada led by
Arthur B. McDonald could demonstrate that the
neutrinos from the Sun were not disappearing on
their way to Earth. Instead they were captured
with a different identity when arriving to the
Sudbury Neutrino Observatory.
A neutrino puzzle that physicists
had wrestled with for decades had been resolved.
Compared to theoretical calculations of the
number of neutrinos, up to two thirds of the
neutrinos were missing in measurements performed
on Earth. Now, the two experiments discovered
that the neutrinos had changed identities.
The discovery led to the
far-reaching conclusion that neutrinos, which
for a long time were considered massless, must
have some mass, however small.
For particle physics this was a
historic discovery. Its Standard Model of the
innermost workings of matter had been incredibly
successful, having resisted all experimental
challenges for more than twenty years. However,
as it requires neutrinos to be massless, the new
observations had clearly showed that the
Standard Model cannot be the complete theory of
the fundamental constituents of the universe.
The discovery rewarded with this
year's Nobel Prize in Physics have yielded
crucial insights into the all but hidden world
of neutrinos. After photons, the particles of
light, neutrinos are the most numerous in the
entire cosmos. The Earth is constantly bombarded
by them.
Many neutrinos are created in
reactions between cosmic radiation and the
Earth's atmosphere. Others are produced in
nuclear reactions inside the Sun. Thousands of
billions of neutrinos are streaming through our
bodies each second. Hardly anything can stop
them passing; neutrinos are nature's most
elusive elementary particles.
Now the experiments continue and
intense activity is underway worldwide in order
to capture neutrinos and examine their
properties. New discoveries about their deepest
secrets are expected to change our current
understanding of the history, structure and
future fate of the universe.
Source:
Nobel Prizes Org
Contains: names, biographies and lectures
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