The MONUMENT project is aimed at experimentally measuring muon capture on several daughter nuclei (in relation to candidates for the neutrinoless double beta decay). These measurements are of significance to verify the accuracy of theoretical calculations of nuclear matrix elements.

The group of DLNP scientists, along with their European colleagues, submitted an application for measuring muon capture on several isotopes at the Meson Factory of the Paul Scherrer Institute (PSI) in Switzerland. The application was considered and approved by the PSI Program Committee. The beam time was provided for the research in 2021 with a further programme at least for three years.

The project is a follow-up and extension of the previous programme of muon capture measurements proposed and implemented under the leadership of JINR researchers in 1998−2006. The DLNP group has rich experience in precision nuclear spectroscopy and in conducting experiments to study rare processes and muon capture.

At present, the MONUMENT collaboration comprises 27 members from 11 international institutions. JINR plays a leading role in the experiment. Our partners are in charge of the experimental infrastructure of the accelerator complex. We are responsible for the main part of the project. The collaboration members from JINR are great engineers, real experts, and they are V. V. Belov, K. N. Gusev, I. V. Zhitnikov, D. R. Zinatulina (head of the project), S. V. Kazartsev, N. S. Rumyantseva, E. A. Shevchik, M. V. Shirchenko, Yu. A. Shitov, and M. V. Fomina.

In October-November 2021, ordinary muon capture on enriched isotopes 136Ba and 76Se was measured in cooperation with other collaboration members. As the next stage, the measurements scheduled for June 2022 will be performed with isotopically enriched targets 100Mo and 96Mo. The results of upcoming measurements are of significance for studying the double beta decay and can also be helpful for investigations in astrophysics.

The video was filmed by Vyacheslav Belov. It shows the key moments of the first experimental stage of the MONUMENT project in 2021. These are the assembly of the measuring setup, adjustment of the equipment, measurements themselves, etc. The setting is the Meson Factory of the Paul Scherrer Institute.

The JINR team was divided into groups and came to the run using the time provided as efficiently as possible to fulfill their tasks. The researchers had to work in three shifts, eight hours each. It is quite difficult to keep such a schedule, but the guys did it! Thanks to all team members for their high-quality and productive work! Already now we are preparing for the next project stage!


Daniya Zinatulina