T2K experiment

T2K ("<a href="/facts/T%25C5%258Dkai%2c_Ibaraki/ce9Q36Yk">Tokai</a> to <a href="/facts/Kamioka%2c_Gifu/kz5klrI4">Kamioka</a>") is a <a href="/facts/Particle_physics/YgIuyj2t">particle physics</a> experiment studying the <a href="/facts/Neutrino_oscillations/c1cc5noc">oscillations</a> of the <a href="/facts/Accelerator_neutrinos/6JvA3Rm1">accelerator neutrinos</a>. The experiment is conducted in <a href="/facts/Japan/U5mz0SRT">Japan</a> by the international cooperation of about 500 physicists and engineers with over 60 research institutions from several countries from Europe, Asia and North America and it is a recognized <a href="/facts/CERN/y1gwRchm">CERN</a> experiment (RE13). T2K collected data within its first phase of operation from 2010 till 2021. The second phase of data taking (T2K-II) is expected to start in 2023 and last until commencement of the successor of T2K – the Hyper-Kamiokande experiment in 2027.: 12, 20 
T2K was the first experiment which observed the appearance of <a href="/facts/Electron_neutrino/e5hQPWIQ">electron neutrinos</a> in a <a href="/facts/Muon_neutrino/A8kPHDKd">muon neutrino</a> <a href="/facts/Particle_beam/mg5EIlWb">beam</a>. It also provided the world best measurement of oscillation parameter θ23 and a hint of a significant <a href="/facts/CP_violation/Nu5lCsPI">matter-antimatter asymmetry</a> in neutrino oscillations. The measurement of the neutrino-antineutrino oscillation asymmetry may bring us closer to the explanation of the existence of our <a href="/facts/Baryon_asymmetry/kfUEYG4F">matter-dominated</a> Universe.
The intense beam of muon neutrinos is produced in the <a href="/facts/J-PARC/PpzQDCEw">J-PARC</a> facility (Japan Proton Accelerator Research Complex) in Tokai on the east coast of Japan. The beam is directed towards the <a href="/facts/Super-Kamiokande/pvvQ3ogI">Super-Kamiokande</a> far detector located 295 kilometres (183 mi) away in the city of <a href="/facts/Hida%2c_Gifu/kz5klrI4">Hida</a>, <a href="/facts/Gifu_prefecture/3IRVpFjh">Gifu prefecture</a>. The properties and composition of the neutrino flux are first measured by a system of near detectors located 280 metres (920 ft) from the beam production place at the J-PARC site, and then again in the Super-Kamiokande detector. Comparison of the content of different neutrino flavours in these two locations allows measurement of the oscillations probability on the way between near and far detectors. Super-Kamiokande is able to detect interactions of both, muon and electron neutrinos, and thus measure the disappearance of muon neutrino flux, as well as electron neutrino appearance in the beam.

T2K experiment open-in-new

T2K experiment