Events of the α fragmentation of the 12C and 16O nuclei in nuclear track emulsion in inelastic interactions with 7 GeV/c positively charged hadrons has been studied in 4π geometry. The accumulated event statistics has allowed us to estimate the cross section for the 12C(h, h')3α and 16O(h, h')4α fragmentation reactions induced by a hadron beam.

A calibration procedure with 22Na radioactive sources for the counters of a gamma-nuclear transition spectrometer, which is fully integrated in the infrastructure of the Hyperon+ setup, including trigger and data acquisition systems, is proposed and implemented.

—The paper presents the upgrade project of the Hyperon-M experiment in the positive beam line of the U-70 accelerator complex in Protvino to study hadron-nuclear interaction mechanisms. It is proposed that the setup be upgraded to study the excited states of secondary nuclei formed by different types of primary hadron–nuclear interaction using precision nuclear gamma-ray spectroscopy. This could open a new direction of the nuclear physics at the junction with the physics of elementary particles at intermediate energies.

The analysis of amplitude spectra from a thin polystyrene-based scintillation counter on muon-enriched and hadron beams of channel 18 of the U-70 accelerator complex in Protvino has been presented. On the basis of statistics of 150 million events on the Hyperon-M setup, the contribution of the 3α -fragmentation processes are highlighted and the cross sections of these processes on hadron and pion beams with a momentum of 7 GeV/ c have been measured. In the future, the obtained result may be of interest for the method of analyzing the age of gas fields based on the concentration of helium in natural gas, the formation of which is possible in the reaction of 3α fragmentation of carbon nuclei in μ^12C interactions induced by high-energy cosmic muons.

Studies at the Nuclotron in JINR indicate the presence of a previously unknown resonance-like structure in the two-photon mass spectrum in the region of 300−400 MeV/c2, observed in nucleus-nucleus interactions. The goal of this work is to search for such structures in the two-photon mass spectrum in meson-nuclear interactions at a momentum of 7 GeV/c at the Hyperon-M experiment of the U-70 accelerator complex. An upper limit has been established on the ratio of the cross section for the formation of unknown resonance structures to the cross section for the production of η-meson ρ(R→2γ/η→2γ) < 3.2 × 10–3 at the 95

According to modern theories, the parameters of neutral mesons such as their mass and width are closely connected with the medium in which the mesons are present. Experimental data on the study of mesons in a nuclear medium are in demand for development of theoretical models describing processes in the field of nonperturbative quantum chromodynamics (QCD). Masses and widths of neutral mesons produced in meson-nucleus interactions on various nuclei are measured in the Hyperon-M experiment at the U70 accelerator. The paper describes a method for precision measurement of the parameters of neutral mesons, presents the results on measurement of the mass and width of the $$\omega (782)$$ meson and preliminary results on the measurement of the mass and width of the $${{f}_{2}}(1270)$$ meson. The measurements indicate the absence of dependence of the quantities under study on the nuclear environment.

The modification of the spectral function of vector mesons in nuclear matter is predicted in many theoretical models. However, the existing experimental results for testing these models are contradictory. Possible effects of the modification of the mass and width of ω mesons produced in the collisions of 7-GeV/c positively charged mesons with C, Be, Al, Cu, Sn, and Pb nuclear targets have been sought in the Hyperon-M experiment. The measured mass and width of ω mesons produced on the indicated nuclei are in agreement with each other with a high accuracy, which does not confirm the theoretical models predicting modification of the mass and/or width of the ω meson in nuclear matter.

The π 0, η, K 0, ω, and f 2(1270) masses were measured at the HYPERON-Msetup in meson-nucleus interactions at a momentum of 7 GeV/c by using six nuclear targets: Be, C, Al, Cu, Sn, and Pb. The experiment in question proved to be insensitive to the expected effects of a modification to the omega-meson mass in nuclear matter. As for the f 2(1270) meson, its mass and width values averaged over all experimental data, \(m_{f_2 }\) = 1275.8 ± 1.0(stat.) ± 0.4(syst.) MeV/c 2 and \(\Gamma _{f_2 }\) = 190.3 ± 1.9(stat.) ± 1.8(syst.) MeV/c 2, agree well with the world-average values. At the same time, our experimental data do not rule out the possible effect of an in-medium modification to the f 2(1270)-meson mass for heavy nuclei at a level better than 0.4%.

A light-emitting diode (LED) monitoring system of the PHOS photon spectrometer in the ALICE experiment on the CERN large hadron collider is described. The spectrometer includes three modules in the form of 64 × 56 matrices consisting of plumbum tungstate (PWO) crystals. As test light signal sources, Kingbright L934SCC superbright green light-emitting diodes with an individual instrumental regulation of light flash intensities in each channel of the spectrometer are used. The system ensures adjustment and monitoring of the electronics at the stage of preparing for the physical trigger of the PHOS modules and is intended to perform special test measurements with the spectrometer without using high-energy particles. In addition, in the course of the experiment, it allows one to promptly monitor each channel of the spectrometer and keep track of temperature variations of the light yield of the PWO crystals. In this case, the long-term relative channel monitoring stability is ensured at a 1.2 × 10−3 level.

A method for correcting the nonlinearity of the electromagnetic calorimeter response is described. This method is based on minimizing the deviation of the measured mass of a neutral π0 meson decaying into two photons, depending on their energy. This method has been developed for the LGD2 electromagnetic calorimeter and used in the Hyperon-M experiment at the U-70 accelerator of the Institute for High Energy Physics. The proposed correction technique has made it possible to substantially reduce variations of the reconstructed π0 and η meson masses in accordance with their minimum energies.

A structure of the multicomputer data acquisition complex for the Hyperon-M experiment at the U-70 accelerator (Protvino, Russia) is described. This complex has been designed to collect and merge data from several particle detectors, the electronic systems of which are made either to the MISS or SUMMA standard. The MISS system is autonomously operated under control of a special ЛЭ-74 controller that collects information in its internal buffer storage during a beam spill. The data acquired are combined with the information from the SUMMA electronics and are copied to an external storage device (a hard disk of a computer) in intervals between spills. On the contrary, software control is needed for the SUMMA electronics to read data on each event. Software-and hardware-based methods are used to provide joint operation of the electronic systems made to diverse standards and guarantee that the streams of incoming data are correctly merged. The problems of net interactions between different parts of the multicomputer system and monitoring of this system are analyzed.

A large-scale prototype of the PHOS electromagnetic spectrometer, which is part of the ALICE detector, has been built and tested. This prototype has 256 detector channels and is operated at −25°C. Each detector channel is a lead-tungstate crystal coupled to an Avalanche Photo-Diode with a low-noise preamplifier. The prototype includes a 16×16 crystal matrix, photo-detectors, analog and digital electronics, a thermo-stabilized cooling system, a light-emitting diode monitoring system, and a charged-particle detector acting as veto counter. Results of measurements using electron and hadron beams of the CERN PS and SPS accelerators are discussed, and the performance of the prototype is evaluated.

The Ring Imaging Cherenkov Detector (RICH) for the CBM experiment is designed to provide electron identification in the momentum range of electrons from low-mass vector meson decays, p . 10− 12 GeV/c. In addition, the RICH detector will be used for K/π separation at above 56 GeV/c, where the TOF capabilities quickly deteriorate. In the following, the overall design of the RICH detector, its main components and first simulation studies will be presented. The overall design of the RICH detector is shown in Fig. 1. The detector will be positioned behind the dipole magnet about 1.5 m downstream of the target. It will consist of a 2.2 m long gas radiator with a beam pipe in the center, two arrays of spherical hexagonal Berylliumglass mirrors, two photodetector planes and corresponding support structures. The total volume of the RICH detector will be about 60 m.