[News-releases] Canadians Help International Team Catch Neutrinos "In the Act"

[Tim Meyer]

News Release | Embargoed until July 19, 2013, 05:30am PDT

CANADIANS HELP INTERNATIONAL TEAM CATCH NEUTRINOS “IN THE ACT”

(Vancouver, BC) --- Today at the prestigious European Physical Society
meeting in Stockholm, Sweden, TRIUMF’s Michael Wilking announced a new
breakthrough in understanding neutrinos, nature’s most elusive particles.
Together with Canadian, Japanese, and other international colleagues as part
of the T2K collaboration, Dr. Wilking confirmed definitive observation of a
new type of neutrino oscillation, in which muon neutrinos transform to
electron neutrinos. It has been known that neutrinos transform from one kind
into another, but this particular transition had never before been
conclusively observed.  

Scott Oser, UBC professor of physics and astronomy and spokesperson for the
Canadian team known as T2K-Canada, commented, “Canada has been an
international leader in neutrino research since the success of the Sudbury
Neutrino Observatory (SNO). T2K was the logical next step after SNO in our
quest to understand neutrino oscillations, and Canada was in fact the first
international partner to join T2K. These new results are the culmination of
a decade of work, and open the door to future studies of how both neutrinos
and anti-neutrinos oscillate.”

In the T2K experiment in Japan, a beam of muon neutrinos is produced in the
Japan Proton Accelerator Research Complex, called J-PARC, located in Tokai,
Ibaraki prefecture, on Japan’s east coast. The neutrino beam is monitored by
a nearby detector complex (much of which was built in Canada) and aimed at
the gigantic Super-Kamiokande underground detector in Kamioka, near the west
coast of Japan, 295 km (185 miles) away. An analysis of data from
Super-Kamiokande associated with the neutrinos from J-PARC reveals that
there are more electron neutrinos (a total of 28 events) than would be
expected (4.6 events) without this new process.

In 2011, the collaboration announced the first hints of this process; now
with 4.5 times more data this transformation is firmly established. The
probability that random statistical fluctuations alone would produce the
observed excess of electron neutrinos is less than one in a trillion. This
T2K observation is the first of its kind to explicitly see a unique flavor
of neutrinos appear at the detection point from a beam initially consisting
of a different type of neutrino.

Neutrino oscillation is a manifestation of a long-range quantum mechanical
interference. Observation of this new type of neutrino oscillation leads the
way to new studies of charge-parity (CP) violation which provides a
distinction between matter and antimatter. This phenomenon has only been
observed in quarks (for which Nobel prizes were awarded in 1980 and 2008).
CP violation in neutrinos in the very early universe may be the reason that
the observable universe today is dominated by matter with no significant
antimatter, which is one of the most profound mysteries in science. Now with
T2K firmly establishing this form of neutrino oscillation that is sensitive
to CP violation, a search for CP violation in neutrinos becomes a major
scientific quest in the coming years, and T2K will lead the way. The T2K
experiment expects to collect 10 times more data in the near future,
including data with antineutrinos for studies of CP violation in neutrinos.

Mike Wilking said, “I chose to work on T2K because of the very important
role it had to play in the search for CP violation. Now that the transition
from muon neutrinos to electron neutrinos has been measured, and is quite
large, the search for CP violation in neutrinos becomes very compelling. We
are all now looking forward to the next phase of T2K, where we will begin to
probe the CP asymmetry between neutrinos and antineutrinos.”

For more information and media resources, please see http://triumf.ca/t2k.  


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**************************************************************
Timothy I. Meyer, Ph.D.
Head, Strategic Planning & Communications
TRIUMF -- Accelerating Science for Canada | 
    Un accélérateur de la démarche scientifique canadienne
4004 Wesbrook Mall | Vancouver, BC  V6T 2A3 | CANADA
Tel: 604.222.7674
Fax: 604.222.3791
Mobile (w/call fwd): 604.235.1925
E-mail: tmeyer at triumf.ca
WWW: http://www.triumf.ca
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