L.G. Landsberg

Elastic scattering of π−p, K−p and pp at 25 and 40 GeV/c

Elastic diffraction scattering of π−, K− and pon protons has been measured at 25 and 40 GeV/c at the Serpukhov Proton Accelerator. Differential elastic cross sections and diffraction slopes are presented in the momentum-transfer interval 0.07–0.80 (GeV/c)2 and compared with existing data at lower energies.

Elastic scattering of pi- p, K- p and anti-p p at 25-GeV/c and 40-GeV/c

Elastic diffraction scattering of π−, K− and pon protons has been measured at 25 and 40 GeV/c at the Serpukhov Proton Accelerator. Differential elastic cross sections and diffraction slopes are presented in the momentum-transfer interval 0.07–0.80 (GeV/c)2 and compared with existing data at lower energies.

Study of the electromagnetic transition form-factor in ω→π0μ+μ− decay

Abstract Sixty events of the rare eletromagnetic decay ω → π 0 μ + μ − have been detected. The branching ratio for this decay been obtained to be BR( ω → π 0 μ + μ − ) = (9.6 ± 2.3) × 10 −5 . The effective mass spectrum for muon pairs has been measured and the electromagnetic transition form-factor for the vertex ωπ 0 , F ω ( m μμ 2 ; m π 2 0) = (1 − m μμ 2 / Λ 2 ) −1 , has been determined, Λ = (0.65 ± 0.03) GeV/ c 2 . The results are compared with the vector-meson dominance model.

Investigation of the electromagnetic structure of the η meson in the decay η → μ+μ−γ

Abstract 600 events of the rare electromagnetic decay η → μ + μ − γ have been detected. The branching ratio has been measured as BR( η → μ + μ − γ ) = (3.1 ± 0.4) × 10 −4 . The electromagnetic form factor of the η meson, F ( m μμ 2 ;0 ) = (1 − m μμ 2 / Λ 2 ) −1 , has been determined. Λ = (0.72 ± 0.09) GeV/ c 2 is in good agreement with the vector meson dominance model.

Search for Theta(1540)^+ in exclusive proton-induced reaction p+C(N) \to Theta^+ \bar{K}^0 + C(N) at the energy of 70 GeV

A search for narrow Theta(1540)^+, a candidate for pentaquark baryon with positive strangeness, has been performed in an exclusive proton-induced reaction p+C(N) to Theta^+ bar{K}^0 + C(N) on carbon nuclei or quasifree nucleons at E_{beam}=70 GeV (sqrt{s} = 11.5 GeV) studying nK^+, pK_S and pK_L decay channels of Theta(1540)^+ in four different final states of the Theta^+ bar{K}^0 system. In order to assess the quality of the identification of the final states with neutron or K_L we reconstructed Lambda(1520)to nK_S and phito K_LK_S decays in the calibration reactions p+C(N)to Lambda(1520)K^+ + C(N) and p+C(N)to pphi + C(N). We found no evidence for narrow pentaquark peak in any of the studied final states and decay channels. Assuming that the production characteristics of the Theta^+ bar{K^0} system are not drastically different from those of the Lambda(1520)K^+ and pphi systems, we established upper limits on the cross section ratios sigma(Theta^+bar{K}^0)/sigma(Lambda(1520)K^+) < 0.02 and sigma(Theta^+bar{K}^0)/sigma(pphi) < 0.15 at 90% CL and a preliminary upper limit for the forward hemisphere cross section sigma(Theta^+bar{K}^0) < 30 nb/nucleon.Abstract.A search for narrow

Study of the radiative decayη′→π+π−γ

Theta(1540)^ +

SEARCH FOR THE PARTICLES WITH FRACTIONAL CHARGES (QUARKS) AT IHEP 70 GeV ACCELERATOR.

, a candidate for pentaquark baryon with positive strangeness, has been performed in an exclusive proton-induced reaction

Analysis of the reaction K−p → K− π−π+p at 40 GeV/c

p + mathrm{C}(N)to Theta^ + bar{K}^0 + mathrm{C}(N)

Production of low momentum negative particles by 70 GeV protons

on carbon nuclei or quasifree nucleons at Ebeam = 70 GeV (

Observation of antihelium-3

sqrt{s} = 11.5