Comet (experiment)

{{Short description|Nuclear physics project in J-PARC, Japan}}

COMET (Coherent Muon to Electron Transition) is a nuclear physics experiment in J-PARC, Tokai, Japan.{{cite web|url=https://comet.kek.jp/intro.html|title=μ-e conversion search|work=COMET Experiment at J-PARC|publisher=COMET Collaboration|access-date=2021-12-05}}{{cite journal|title=COMET Phase-I technical design report|year=2020|doi=10.1093/ptep/ptz125|last1=Zuber|first1=K.|last2=Zhang|first2=Y.|last3=Zhang|first3=J.|last4=Zdorovets|first4=M. V.|last5=Yudin|first5=Yu V.|last6=Yuan|first6=Y.|last7=Yoshioka|first7=T.|last8=Yoshida|first8=M.|last9=Yoshida|first9=H.|last10=Yeo|first10=B.|last11=Yao|first11=W. C.|last12=Yano|first12=T.|last13=Yang|first13=Y.|last14=Yamane|first14=T.|last15=Yamanaka|first15=M.|last16=Yamamoto|first16=A.|last17=Yamaguchi|first17=H.|last18=Xing|first18=T. Y.|last19=Wu|first19=C.|last20=Wong|first20=T. S.|last21=Wong|first21=M. L.|last22=Warin-Charpentier|first22=P.|last23=Abdullah|first23=W A T Wan|last24=Vrba|first24=V.|last25=Volkov|first25=A.|last26=Velicheva|first26=E.|last27=Ueno|first27=K.|last28=Uchida|first28=Y.|last29=Uchida|first29=T.|last30=Tsverava|first30=N.|journal=Progress of Theoretical and Experimental Physics|volume=2020|issue=3|s2cid=119208126|display-authors=29|doi-access=free|hdl=10044/1/75733|hdl-access=free}} In contrast to the usual muon decay to an electron and neutrino, COMET seeks to look for neutrinoless muon to electron conversion, where the electron flies away with an energy of 104.8 MeV. Muon to electron conversion is not forbidden in the Standard Model but the branching ratio is about $\backslash mathcal\{O\}(10^\{-54\})$ considering neutrino oscillations. In beyond the Standard Model approaches the muon to electron conversion process can be as high as $\backslash mathcal\{O\}(10^\{-15\})$ e.g. via the supersymmetric $\backslash tilde\{\backslash chi\_\{0\}\; \}$.

COMET will be{{when|date=December 2021|reason=Should include a date, and since this is phrased as a future event, it should be described in terms of when they plan to do this}} using a new beamline connecting the J-PARC main ring and the J-PARC Nuclear and particle Physics Experimental Hall (NP hall).

The current{{when|date=December 2021}} spokesperson is Kuno Yoshitaka alongside project manager Mihara Satoshi.{{citation needed|date=December 2021}} The collaboration consists of universities coming from 15 countries.{{cite web|url=https://comet.kek.jp/collabo.html|title=The COMET Collaboration|work=COMET Experiment at J-PARC|publisher=COMET Collaboration|date=November 2021|access-date=2021-12-05}}