V. N. Roinishvili

Measurement of π−-meson polarizability in pion compton effect

Abstract About 7 × 10 3 events of Compton effect on pion in the reaction π − A → A π − γ st 40 GeV/ c were detected and for the first time the charged pion polarizability was obtained α π = (6.8 ± 1.4) × 10 −43 cm 3 .

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.

A1, A2 and A3 production in π−p→π−π−π+p at 25 and 40 GeV/c

A sample of ∼ 70 000 fitted events of the reaction of π−p→π−π−π+p at 25 and 40 GeV/c has been obtained with the CERN-IHEP boson spectrometer at the Serpukhov accelerator. A partial-wave analysis shows that (i) A1 and A3 cannot be described by a Breit-Wigner amplitude, (ii) the A2 can be well described by a Breit-Wigner amplitude, (iii) although A1, A3 and A2 have different properties, the energy dependence of their production cross section is similar.

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.

The reaction π−p → π−π−π+p at 25 and 40 GeV/c

The reaction pp→pπ−π+p has been studied at 25 and 40 GeV/c at the Serpukhov proton synchroton using the CERN-IHEP spectrometer. The differential cross section has been determined as a function of four-momentum transfer to the proton (0.05–0.30 (GeV/c)2) and pππ mass (up to 2.2 and 2.6 GeV/c2). At both energies there is a broad low-mass maximum with an enhancement at 1.6–1.8 GeV/c2. The cross section in a given mass band falls rapidly with |t|, with an exponential slope that decreases with increasing mass. In both the background and the 1.7 GeV/c2 peak there is a strong Δ−−π+ component. Possible spin-parity (JP) contributions to it are discussed. Throughout the range 1.5–2.2 GeV there is at least one state of J ⩾ 32 and there is interference between states of opposite P, |ΔJ| ⩽ 1. At the peak there is a J ⩾ 52 component. There are striking parallels between this reaction and the boson reactions π−p→π−π−π+p and K− → K−π−π+p.

Experimental estimation of the sum of pion electrical and magnetic polarizabilities

The pion radiative scattering πZ→πZγ at 40 GeV was investigated. Coulomb scattering-i.e. pion Compton-effect-dominates for small fourmomentum transfers in this reaction. In our previous paper we found the pion polarizability to beβπ=(−6.8±1.4)·10−43, cm3, where we assume following the theory that the sum of electrical and magnetic polarizabilities (απ+βπ)≃0. More complete analysis of our data is done in order to test this assumption. The result for (απ+βπ) is in agreement with theoretical predictions.

J/ψ particle production by 70 GeV/c protons

Abstract Invariant mass spectrum of μ + μ − pairs produced by 70 GeV/ c protons in Be target are presented. Distinct enhancements in the mass regions of ϱ, ω mesons, φ meson and J/ψ particle are observed. For J/ψ production x and p ⊥ 2 distributions are given. The total cross section for the reaction p + Be → ( J ψ → μ + μ − ) + … is equal to 9.5 ± 2.5 nb/nucleus .

The A-dependence of J/ψ-particle inclusive distributions

Abstract The differential cross sections d σ d x and d σ d p t 2 of inclusive J/ψ production by 43 GeV/ c π − off Be, Cu and W nuclei have been measured. Fitting d σ d p t 2 ∼ A α (p t 2 ) we observed the increase of α with p t 2 .

J/ψ production off Be, Cu and W by 43 GeV/c negative pions

Abstract The A -dependence of J/ψ inclusive production by 43 GeV/ c π − -mesons was measured to be σ = (18 ± 6) A (0.92±0.06) nb/nucleus for x > 0.

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

Abstract The reaction K − p → K − π − π + p has been measured at 25 and 40 GeV/ c at the Serpukhov Proton Accelerator. The production cross section at 25 and 40 GeV/ c as a function of momentum transfer and K ππ mass is presented, and results of the partial-wave analysis of the K ππ system yielding information about Q(1300), K ∗ (1400) and L(1770) mesons are discussed.