The radiative decay Lambda(1520) -> Lambda gamma was recorded in the exclusive reaction p + N -> Lambda(1520)K+ + N at the SPHINX facility. The branching ratio for this decay and the corresponding partial width were found to be, respectively, Br[Lambda(1520) -> Lambda gamma] = (1.02 +/- 0.21) x 10(-2) and Gamma[Lambda(1520) -> Lambda gamma] = 159 +/- 35 keV (the quoted errors are purely statistical, the systematic errors being within 15%). (c) 2005 Pleiades Publishing, Inc.

The radiative decay Lambda(1520) --> Lambdagamma was measured directly in the study of the exclusive diffractive-like reaction p + N --> Lambda(1520)K+ + N, Lambda(1520) --> Lambdagamma with the SPHINX spectrometer. The values of the branching and partial width of this radiative decay were obtained: BR[Lambda(1520) --> Lambdagamma] = (1.02 +/- 0.21 (stat) +/- 0.15 (syst)) x 10(-2) and Gamma[Lambda(1520) --> Lambdagamma] 159 +/- 33 (stat) +/- 26 (syst) keV. (C) 2004 Elsevier B.V. All rights reserved.

The design of the drift tubes with flat and with wire field shaping electrodes is described. The physical characteristics of the tubes are studied in the beam of Serpukhov accelerator. The optical measurements of wires displacements are made for a long (7.4 m) drift tube with wire field shaping. The comparison of two drift tube options is presented.

The SIGMA-AYAKS setup was used to study the production of cumulative protons p(B), having kinetic energies in the range 0.1 < T(B) < 0.3 GeV and accompanied by fast rho0 mesons with the Feynman variable x(F) > 0.6 and squared transverse momentum p(t)2 < 1 (Ge V/v)2, in pion-nucleus interactions at the incident pi--meson momentum p(BM) = 40 GeV/c. In pi-Be interactions, the T(B)-dependence of the invariant cross section of cumulative. proton production is measured. The polarization properties and distributions of fast rho0 mesons over x(F) and p(l)2 are also studied. It is found that characteristics of rho0 mesons in the distinguished channel of the reaction are similar to those of rho0 mesons produced in the beam fragmentation range of pi-N interactions.

The inclusive cross sections of backward proton production in π−(K−, p)-Be, Al, Cu, Pb interactions at 40 GeV/c are presented. Protons have been detected in the angular range 150°–165° and kinetic energy region 0.1–0.3 GeV. The invariant cross-section ratios for various beam particles are independent of the values of kinetic energy and of the nuclear target type: 〈ƒK−/ƒπ−〉= 0.87 ± 0.03stat ± 0.03syst, 〈ƒp/ƒπ−〉 = 1.82 ± 0.10stat ± 0.05syst. The A-dependence of the cross-section slope parameter for A⩾27 is less than ∼2%.

The results of an experiment to search for dibaryon resonances in processes with cumulative protons in pi-Be interactions at 40 GeV/c are presented. For the mass range 2.5-4.1 GeV/c2 bounds of 10.7-20.3-mu-b are obtained on the cross section for production of dibaryon resonances decaying into a proton pair.

The results of an experimental search for dibaryon resonances in the target fragmentation region in the mass range 2.5-4.1 GeV/c2 in pi-Be interactions at the momentum 43 GeV/c are presented. Bounds of 0.5-12.6-mu-b are obtained on the cross section for production of dibaryon resonances which decay into a proton pair.

An iron-scintillation hodoscope hadron calorimeter made up of independent sections containing four total-absorption counters with a 20 x 20-cm cross-section is described. The energy resolution for hadrons in the range of 4-40 GeV is sigma-E/E = 0.02 + 0.52E-0.5, and the average space resolution is almost-equal-to 2 cm for E = 40 GeV.

The possibility is investigated of separate detection of hadrons and electrons (photons) by a combined hodoscope detector consisting of an Fe-scintillator hadron calorimeter (with a thickness of 5 nuclear-interaction lengths) and an electromagnetic calorimeter based on lead-glass counters (with a thickness of 4 radiation lengths) and a Pb converter. A separation level of almost-equal-to 10(-3) is obtained for electrons and negative pions with energies of 25 and 43 GeV, respectively, with a registration efficiency for one of the particles of 0.9.

The results of measurement of the inclusive cross sections for production of cumulative protons in pi- (K -,pBAR) Be, Al, Cu, Pb interactions at 40 GeV/c are presented. Protons were detected in the angular range 150-165-degrees and in the kinetic-energy range 0.1-0.3 GeV. The ratios of the invariant cross sections for various types of beam particles do not depend on the kinetic energy or on the type of nucleus: = 0.87 +/- 0.03stat +/- 0.03syst, and = 1.82 +/- 0.10stat +/- 0.05syst. No dependence on A was observed for the slope parameter of the cross sections at a level of about 2% for A greater-than-or-equal-to 27. An increase of the ratios of the cross sections, f(A) (A)/f(A) (Be), at values of the cumulative number x(K) > 2 can be considered as an indication that the probabilities of production in light and heavy nuclei of objects with a mass exceeding two-nucleon masses are different.

The results of a study of drift-tube modules filled with pure methane are presented. Each module contains eight drift tubes 46 mm in diameter with an anode wire with a diameter of 40 or 60-mu-m. The efficiency plateau for minimally ionizing particles is 1.2 kV for an electronic-recording-system threshold of 1.5-mu-A. Measured time-coordinate curves are given. The maximum electron drift time for the tubes with a 40-mu-m anode is 0.30-mu-sec, and the average coordinate resolution is 0.23 mm. The background count of the modules is chiefly due to cosmic particles. The characteristics of the modules are independent of the type of aluminum alloy from which they are made. The modules are suitable for elementary-particle coordinate detectors with areas of thousands of square meters.

A Fe-scintillator hodoscopic hadron calorimeter is described. It consists of independent sections, each containing four total absorption counters 20×20 cm2 in cross section. The energy resolution for hadrons in the energy range E = 4–40 GeV is σE/E = 0.02 + 0.52/√E and the mean space resolution is ∼ 2 cm at 40 GeV.

The construction and manufacturing procedure of 6000 drift tubes for the SAMUS muon spectrometer of the D0 detector are described in detail. The diameter of the stainless steel tubes is 30 mm, their length varies within the range of 0.2–3.8 m. A testing procedure of the main parameters of the tubes is proposed and the results of testing all the tubes after manufacturing are given. With a pure methane filling the maximum drift time for electrons is 0.16 μs, the plateau of effective detection of minimum ionizing particles is equal to 1.0 kv and the coordinate resolution is σx = 0.3 mm.

The performances of the TOF scintillation counters used in the SIGMA-AIAKS spectrometer are presented. The counters, made of NE110, are 150, 65 and 10 cm long, 10 cm wide and 1.5 cm thick. The time resolutions for minimum ionizing particles have been measured to be σt = 0.18 ns, 0.14 ns and 0.11 ns respectively. The main contribution to the resolution is given by the photoe collection statistics determined by the decay time of the scintillator and the difference of the optical paths in the counter. The scintillation counters, assembled into hodoscopes of 1.5 × 3.2 m2 and 0.65 × 0.8 m2 are used for identification of particles through the TOF. The algorithms of off-line data processing are also presented.

We report measurements of inclusive cross sections for production of cumulative protons in ..pi../sup -/, K/sup -/, and p-bar interactions in Be at 40 GeV/c. The data demonstrate an exponential drop of the cross sections in the kinetic-energy region 0.1--0.3 GeV with a slope 44--48 MeV. The total numbers of cumulative protons recorded in the kinetic-energy range studied are 1314 from ..pi../sup -/, 603 from K/sup -/, and 163 from p-bar. Ratios of cross sections are obtained for the different types of incident particles, average values of which in the energy interval studied are = 0.95 +- 0.05 +- 0.03 and = 2.23 +- 0.19 +- 0.13.

In the reaction of π- dissociation into a μ+μ-π- system on a Cu nucleus, a clear enhancement in the ρ0π- effective-mass distribution has been observed in the π2(1680) region. Partial-wave analysis shows that this enhancement is due to the P-wave and has a resonant nature. Coherent and incoherent cross-sections for this enhancement have been measured.