At the PAC meetings

High estimation of results, approval of new proposals

On 17 June, the 60th meeting of the Programme Advisory Committee for Particle Physics was held at the JINR International Conference Centre. Committee Chairman Itzhak Tserruya opened the meeting with a report on the implementation of the recommendations of the 59th meeting of the PAC. Information about the resolution of the 135th session of the Scientific Council and the decisions of the Committee of Plenipotentiaries of the Governments of the JINR Member States was presented by Vice-Director of the Institute Vladimir Kekelidze. The Scientific Council supported all recommendations of the PAC for the estimation of new projects and the extension of current projects in the field of particle physics within the proposed timeframes and ratings. The PAC members approved the plans of the Institute's Directorate to ensure full cooperation between scientists and specialists from the JINR Member States and CERN, as well as the efforts being made to establish new scientific ties with Mexico, Brazil and China.

Deputy Head of the Accelerator Department for Research at VBLHEP Anatoly Sidorin presented a report on the progress of the Nuclotron-NICA project in 2021-2024. In an interview with our newspaper, he explained why this particular period was chosen: "The Nuclotron-NICA project was launched after the Nuclotron upgrade was completed. It was extended several times, with new goals set each time. And the last time it was extended was in 2021. Unfortunately, this period coincided with the pandemic situation and then certain difficulties arose with the delivery of equipment, execution of orders…"

The Committee highly appreciated the successful completion of the first stage of the NICA project: the collider injection complex, including the KRION-6T heavy ion source, the HILAC, Booster, Nuclotron accelerators and beam transport lines, was put into operation and the ARIADNA fundamental and applied research programme was launched. The delay in the initial project schedule was mainly due to delays in the construction of the collider building and the delivery of equipment for the beam transport line from the Nuclotron to the collider. Currently, most of the collider equipment is ready for commissioning.

"This December, a technological session will start at the collider that will smoothly flow into a session with a beam," A. Sidorin commented on the new deadlines and work plans. "The technological session is a test of the cryostat system, the superconductivity breakdown protection system, the control system, the power supply systems. In general, all the technological systems. After it is successful, a session will start first at the Booster in order to increase the intensity. Afterwards, we will inject a beam from the Booster into the Nuclotron. And then we will hold a parallel session at BM@N and at the collider with a fixed target. In these experiments, there will be the same incident beam, the same target and geometry of the facility that will allow us to obtain essential information. This is the first stage that will begin next year. After that, we will move on to the collision of counter beams."

The PAC's recommendation is to extend the Nuclotron-NICA project until the end of 2027 with an A rating.

A report on the implementation of the MPD project was presented by Head of the Collaboration Viktor Ryabov (PNPI). Production of all detector components for the first phase of the MPD project is proceeding with minimal delays. The time-projection camera, time-of-flight system and 40 of the 50 half-sectors of the electromagnetic calorimeter are in operating mode, ready to begin data accumulation in 2025. Cooling of the solenoid to 70 K was successfully completed in early 2024. Cooling to liquid helium temperature should start in September. In October, magnetic field mapping will follow using a cartograph produced by the G.I.Budker Institute of Nuclear Physics (Novosibirsk). Installation of the carbon fiber support frame and detector subsystems is scheduled for early 2025. The detector should be ready to move into beam position in July 2025, according to the overall NICA project schedule.

The progress of the BM@N project was presented by the Leader of the Collaboration, Head of Sector at VBLHEP Mikhail Kapishin. The efforts of the BM@N experiment participants are focused on calibrating the time-of-flight system and developing techniques for analyzing Xe-CsI collisions with an energy of 3.8 GeV, registered during the session in 2023. The registered data were reprocessed on computers of the Multifunctional Information and Computing Complex of the Tier-1/Tier-2 level with improved software for reconstruction and calibration. The results of the analysis of the production of Λ-hyperons and K⁰_s mesons, as well as the direct proton flux in Xe-CsI collisions, were presented. The next session of the BM@N experiment is scheduled with a Xe beam at an energy of 2-3 A GeV.

A number of reports presented to the attention of the committee members below was dedicated to projects ending in 2024 and proposals for their prolongation.

A report on the SPD detector project status was presented by Head of the Colliding Beams Department at DLNP Alexey Guskov. The collaboration currently includes over 400 scientists from over 30 research centres worldwide. As part of the technical design preparation, R&D was carried out on the basic subsystems of the experimental facility and prototypes of the basic detector units were manufactured. Currently, the first phase subsystems that include the muon system, the superconducting solenoid and the associated cryogenic system, various detectors for event registration, data acquisition, control, gas distribution systems, as well as support structures and the corresponding IT infrastructure will be developed. Chairman of the SPD Advisory Committee Professor Ivan Logashenko presented an expert report on the project. The PAC highly appreciated the achievements of the SPD collaboration participants in updating the physics programme of the experiment and implementing numerous tests to prepare the conceptual and technical designs. It was recommended to extend the SPD project until the end of 2029 with an A rating.

A report on the NA61/SHINE experiment at CERN was presented by Alexander Dmitriev. The PAC meeting highlighted new results in the processing of the experiment data and the contribution of JINR to the modernization of the detector, its further maintenance and software development. It was recommended to extend the project until the end of 2026 with a B rating. Dmitry Madigozhin presented a report on JINR's participation in the NA62 experiment at CERN. The JINR group made a significant contribution to the development, production and maintenance of the NA62 magnetic spectrometer, software, development of the scientific programme, data accumulation and analysis. The PAC highly appreciated these achievements. It was noted that the completion of the NA62 data set is expected in 2025, while the analysis and preparation of publications will take several more years. Therefore, the JINR group's further participation in the NA62 experiment was recommended until the end of 2027 with an A rating.

The results obtained by the JINR group in the STAR experiment at the RHIC collider were presented by Alexey Aparin. The Programme Advisory Committee highly appreciated the reports presented by young scientists and students at international conferences. The experience they gained from the STAR experiment will be useful when carrying out experiments at the NICA accelerator complex. It is recommended to extend JINR's participation in the STAR experiment until the end of 2026 with a B rating.

The report by Zviad Tsamalaidze on the participation of the JINR group in the COMET project at J-PARC was taken into account. In 2023-2024, the Institute's staff made a significant contribution to the development and production of several subdetectors. In particular, progress was achieved in the development of a technology for producing straw tubes with parameters superior to those available so far. In addition, the JINR collaboration staff took part in the assembly and testing of the first straw tracker station at J-PARC. The PAC highlighted with satisfaction the significant role that the JINR group plays in the development and construction of the basic subsystems of the COMET facility, as well as its participation in the governance structure of the collaboration. JINR's further participation in COMET was recommended until the end of 2029 with an A rating.

Yury Davydov presented a proposal to open a new project "Development of a technique for registering particles in future experiments with the participation of JINR" aimed at developing new detectors and new techniques to process and analyze experimental data taking into account current trends in achieving maximum energies and intensities of particle beams. The project is focused on servicing future colliding beam experiments at the NICA accelerator complex, the Super Charm-Tau Factory - an electron-positron collider at the Budker Institute of Nuclear Physics and the Circular Electron-Positron Collider (CEPC) in China, as well as fixed-target experiments at accelerators with average and high beam energies. The PAC supports the proposal to open this project and encourages the participants to prepare and submit in one year a more detailed programme outlining the specific goals and objectives of the project. Accordingly, it is recommended to open the project for a period of one year with an A rating.

Later, reports on the scientific results obtained by JINR groups in LHC experiments were given: Boris Batyunya spoke about his research in the ALICE collaboration, Ivan Eletskikh - in the ATLAS experiment, Vladimir Karzhavin - in the CMS experiment.

Five reports by young scientists from DLNP and VBLHEP were heard with interest at the poster session. Ksenia Alishina's report "Investigation of Λ-hyperons in carbon collisions with solid targets in the BM@N experiment" was selected for presentation at the session of the Scientific Council in September.

The next meeting of the PAC for Elementary Particle Physics is scheduled for 20-21 January, 2025.

Galina MYALKOVSKAYA,
photos by Igor LAPENKO and Elena PUZYNINA