A. A. Semak

Measurement of the yields of positively charged particles at an angle of 35° in proton interactions with nuclear targets at an energy of 50 GeV

Momentum spectra of cumulative particles in the region of high transverse momenta (PT) in pA → h+ + X reactions were obtained for the first time. The experiment in which this was done was performed at the SPIN setup (Institute for High Energy Physics, Protvino) in a beam of 50-GeV protons interacting with C, Al, Cu, and W nuclei. Positively charged particles were detected at a laboratory angle of 35° and in the transverse-momentum range between 0.6 and 3.7 GeV/c. A strong dependence of the particle-production cross section on the atomic number was observed. A comparison with the results of calculations based on the HIJING and UrQMD models was performed in the subcumulative region.

Production of cumulative particles and light nuclear fragments at high p T values beyond the fragmentation region of nuclei in pA collisions at a proton energy of 50 GeV

The first data on the production of cumulative π+, p, and light nuclear fragments d and t emitted from a nucleus with a high transverse momentum at an angle of 35° in the laboratory system have been reported. The data have been obtained at the SPIN setup at the interaction of a 50-GeV proton beam extracted from the U-70 accelerator (IHEP, Protvino) with C, Al, Cu, and W nuclei.

Study of nuclear matter in hard proton-nuclei and nuclei-nuclei collisions at the U70 accelerator (FLUKTON project proposal)

A two-arm spectrometer FLUKTON for investigations in the field of relativistic nuclear physics at U70 energies is proposed to be constructed on base of the existing detector SPIN (IHEP, Protvino). The main objective is to obtain new data on clusters of cold superdense nuclear matter. Interaction of a high intensity proton beam with nuclear targets and an ion beam with liquid hydrogen and nuclear targets will be studied.

Knockout of deuterons and tritons with large transverse momenta in pA collisions involving 50-GeV protons

Formation of the d and t cumulative light nuclear fragments emitted from the nucleus with large transverse momenta at an angle of 35° in the laboratory frame is investigated. The data on collisions of 50-GeV protons with the C, Al, Cu, and W nuclei are collected using the extracted proton beam of the IHEP accelerator and the SPIN detector. The results indicate that the dominant contribution to formation of nuclear fragments comes from the local process of direct knockout from the nucleus.

Studying the counting rate capability of a glass multigap resistive plate chamber at an increased operating temperature

It is shown that a multigap resistive plate chamber made of commercial float glass is capable of sustaining high counting rates at an increased operating temperature. Two glass chambers were investigated on the test beamline of the U-70 accelerator at the Institute for High Energy Physics. The required radiation flux density at the detector was produced by means of radioactive sources. The time resolution of 80 ps or better was attained at a rate of ∼20 kHz/cm2 and an operating temperature of 45°C.