Search for lepton-number violation of muon

From 1 to 5 October 2018, the 26th regular COMET collaboration meeting was held in the Georgian Technical University in Tbilisi.

The COMET experiment (COherent Muon to Electron Transition) conducted at the J-PARC accelerator complex in Japan is aimed at search for possible violation of the fundamental principle, i.e. the lepton number conservation law in the charged lepton sector of the Standard Model of elementary particles. In the prepared COMET experiment, scientists suggest possible observation of the process, which is prohibited by the Standard Model, of neutrino-free transition of a muon into an electron as a result of the interaction of a muon beam of the record intensity with aluminum nuclei.

The collaboration holds workshops three times a year, two of which are held at the J-PARC accelerator complex where the experiment is conducted, and one of them is held offsite, in one of the 17 member states. The 26th collaboration meeting was organized in the Georgian Technical University with the support of the Shota Rustaveli National Science Foundation of Georgia and JINR.

Prime Minister of Georgia Mamuka Bakhtadze and Minister of Education, Science, Culture and Sports Mikhail Batiashvili took part in the opening of the meeting. Ambassador of Japan in Georgia Mr. Tadaharu Uehara also participated in the opening ceremony. In his welcoming speech, the Prime Minister noted that the interest in such events is in line with the priorities of the government of Georgia in development of high-tech projects jointly with recognized leaders of the world scientific and technical community. Adoption of high technologies was chosen by the government of Georgia as one of the main vectors of the state development. It was noted that in the frames of the COMET project a close and fruitful cooperation of Georgian scientists and scientists from the JINR Member States exists and contributes to strengthening of traditional contacts between JINR and scientific groups of Georgia. Rector of the Georgian Technical University Academician Archil Prangishvili expressed his special interest in cooperation of the University with JINR in the frames of the COMET project.

The scientific programme of the meeting was opened by a review report presented by Head of the Project Professor Yoshitaka Kuno from the Osaka University. The programme of all days of the meeting was rich and included reports on the latest developments for every field of the project, and covered all ranges of preparation to experiments in the frames of the project.

JINR staff members presented reports on all the fields in which Dubna takes part. They included reports on a detailed study of properties of the LYSO scintillator as a structural element of the electromagnetic calorimeter, the results of studying the changes in time of the mechanical properties of the straw tubes, which make up the straw tracker, and modeling of the electron drift lines in the tube for mutual configuration of electric and magnetic fields typical for COMET. It was reported on the state of work of the DLNP JINR on creation of a site (the “clean room”) for production in automated mode of new generation straw tubes of 5 mm in diameter, which are necessary for the second stage of the experiment. The reports that were presented by Georgian scientists concerned developments on creation of the protection system from the cosmic background noise that is a very important component of the COMET project.

In addition to the scientific programme, participants of the meeting watched a wonderful concert of students of the Georgian Technical University with amazing dances and unique polyphonic singing, and also made a guided tour to the sacred and historical places – Jvari Monastery and Svetitskhoveli Cathedral in the city of Mtskheta. A special joy to all participants was a trip to the wine region of Georgia – Kakheti – where they tasted famous brands of Georgian wines saperavi, mukuzani, kindzmarauli, khvanchkara and others.

Closing the meeting, professor Kuno noted the perfect organization of the event and on behalf of all the participants expressed a deep gratitude and appreciation to the organizers and Georgian colleagues.

Following information of the organizing committee of the 26th COMET Collaboration Meeting.