T2K experiment

T2K ("Tokai to Kamioka") is a particle physics experiment studying the oscillations of the accelerator neutrinos. The experiment is conducted in Japan by the international cooperation of about 500 physicists and engineers with over 60 research institutions from several countries from Europe, Asia and North America[1] and it is a recognized CERN experiment (RE13).[2][3] 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.[4]: 12, 20 

T2K was the first experiment which observed the appearance of electron neutrinos in a muon neutrino beam.[5] It also provided the world best measurement of oscillation parameter θ23[6] and a hint of a significant matter-antimatter asymmetry in neutrino oscillations.[7][8] The measurement of the neutrino-antineutrino oscillation asymmetry may bring us closer to the explanation of the existence of our matter-dominated Universe.[9][10]

The intense beam of muon neutrinos is produced in the J-PARC facility (Japan Proton Accelerator Research Complex) in Tokai on the east coast of Japan. The beam is directed towards the Super-Kamiokande far detector located 295 kilometres (183 mi) away in the city of Hida, Gifu prefecture. 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.[11]

  1. ^ "T2K experiment official page – T2K collaboration". Archived from the original on 2020-04-17. Retrieved 2020-03-31.
  2. ^ "Recognized Experiments at CERN". The CERN Experimental Programme. CERN. Archived from the original on 22 April 2019. Retrieved 9 March 2021.
  3. ^ "RE13/T2K : The long-baseline neutrino experiment". The CERN Experimental Programme. CERN. Archived from the original on 30 April 2020. Retrieved 20 January 2020.
  4. ^ Vilela, Cristovao (September 5–10, 2021). "The status of T2K and Hyper-Kamiokande experiments". PANIC 2021 Conference. Archived from the original on 2021-09-29. Retrieved 2021-09-29.
  5. ^ T2K Collaboration (2011). "Indication of Electron Neutrino Appearance from an Accelerator-produced Off-axis Muon Neutrino Beam". Physical Review Letters. 107 (4): 041801. arXiv:1106.2822. Bibcode:2011PhRvL.107d1801A. doi:10.1103/PhysRevLett.107.041801. PMID 21866992. S2CID 16654679.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  6. ^ T2K Collaboration (2014). "Precise Measurement of the Neutrino Mixing Parameter θ23 from Muon Neutrino Disappearance in an Off-Axis Beam". Phys. Rev. Lett. 112 (18): 181801. arXiv:1403.1532. Bibcode:2014PhRvL.112r1801A. doi:10.1103/PhysRevLett.112.181801. PMID 24856687. S2CID 11484010.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  7. ^ T2K Collaboration (2015). "Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6E20 protons on target". Phys. Rev. D91: 072010. arXiv:1502.01550. doi:10.1103/PhysRevD.91.072010. S2CID 34184232.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  8. ^ Abe, K.; et al. (15 April 2020). "Constraint on the matter–antimatter symmetry-violating phase in neutrino oscillations". Nature. 580 (7803): 339–344. arXiv:1910.03887. Bibcode:2020Natur.580..339T. doi:10.1038/s41586-020-2177-0. PMID 32296192. S2CID 203951445. Archived from the original on 16 April 2020. Retrieved 16 April 2020.
  9. ^ Fukugita, M.; Yanagida, T. (June 1986). "Barygenesis without grand unification". Physics Letters B. 174 (1): 45–47. Bibcode:1986PhLB..174...45F. doi:10.1016/0370-2693(86)91126-3.
  10. ^ Mohapatra, R N; et al. (1 November 2007). "Theory of neutrinos: a white paper". Reports on Progress in Physics. 70 (11): 1757–1867. arXiv:hep-ph/0510213. Bibcode:2007RPPh...70.1757M. doi:10.1088/0034-4885/70/11/R02. S2CID 119092531.
  11. ^ T2K Collaboration (2011). "The T2K Experiment". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 659 (1): 106–135. arXiv:1106.1238. Bibcode:2011NIMPA.659..106A. doi:10.1016/j.nima.2011.06.067. S2CID 55962579.{{cite journal}}: CS1 maint: numeric names: authors list (link)