AIP Conf.Proc.

Data from antiproton interactions in neon is discussed. The possibility of quark degrees of freedom within the reaction is discussed.

Nucl. Instrum. Meth. A

The measurement of angles and momenta, as well as the identification of the masses of the products of p 4 He annihilation events detected in a self-shunted streamer chamber are described.

Phys. Rev. D

The vertex γ→3π has been investigated in the reaction of pion pair production by pions in the nuclear Coulomb field, π−+(Z,A)→π−+π0+(Z,A), in the region of low-invariant-mass π−π0 pairs. The experiment has been carried out in the 40-GeV pion beam of the IHEP accelerator (Serpukhov) with the SIGMA spectrometer. We have measured for the first time the cross section of the reaction in the region of momentum transfer squared q2<2×10−3 (GeV/c)2, σ/Z2=1.63±0.23±0.13 nb, and the γ→3π coupling constant F3π=12.9±0.9±0.5 GeV−3, where the first (second) error is statistical (systematic). The obtained result agrees with the calculations based on the Wess-Zumino-Witten effective Lagrangian. The hypothesis of chiral anomalies and the color-SU(3) quark symmetry are confirmed.

Nucl.Instrum.Meth.A

The storage ring Siberia-1 was put into operation as a dedicated source of synchrotron radiation at the Kurchatov Institute (Moscow) in 1983. It was designed and built at the Institute of Nuclear Physics (Novosibirsk) [1].

Phys.Lett.B

A new value of the upper limit for the branching ratio of the decay of K 0 S into e + e − has been experimentally obtained using a lead glass detector. The value is BR (K 0 S → e + e − ) < 1.1 × 10 −4 (90% CL).

Phys. Lett. B

Evidence is presented for the anomalously shorter mean free path of Z = 2 secondary nuclei from 4 He-p interactions at 8.6 and 13.5 GeV/ c incident momenta. About 43000 Z = 2 nuclei leading to 8000 secondary interactions have been studied. An admixture of 0.8% of anomalons was found with a mfp of 6 cm as compared to 230 cm for “normal” fragments. Our result is compared, by using the reduced mfp, with other existing data on doubly-charged secondary nuclei.

Yad.Fiz.

The mechanism of the reaction 3 He + p → p + p + d is studied by making use of the ITEP 80 cm liquid-hydrogen bubble chamber exposed to a beam of 5 GeV/ c 3 He nuclei. The reaction cross section is equal to 20.6 ± 0.3 mb. The phase-space regions associated with quasifree scattering (QFS) and final-state interactions (FSI) are selected. Angular, mass and momentum distributions of the reaction products are obtained in the entire kinematically allowed range. The experimental data in the QFS region are compared with theoretical calculations based on the simplest pole-diagram approximation. The 3 He and deuteron wave functions (WF) correspond to the realistic RSC potential. The D-wave components of these WF are taken into account. The absolute value of the cross section and shape of the distributions are described as a whole reasonably well within the frame of the model considered in the kinematical region where FSI may be neglected. But at large spectator momenta there is an essential disagreement. The possible reasons for this are discussed.

Sov. Phys. J.

We have studied the effect that the discreteness of atomic planes has on electron motion in crystals. The characteristic orientation angles found for a crystal correspond to the maximum probability of transitions in the energy spectrum of associated electron motion.

Z.Phys.C

The multiplicity distributions of charged particles produced from π−,K− and$\bar p$ interactions with the nuclei Li, C, S, Cu, CsI, Pb at 40 GeV/c were studied. It was found that the linear relationD=a〈n〉+b is satisfied for the distributions of different kinds of secondary particles including knocked out protons. Consequently, the use of the scaling variablez′=(an+b)/(a〈n〉+b) ensures the scaling of the distributions with respect to the mass numberA at least up to the second moment.

Phys.Rev.Lett.

We present the results of an experimental investigation of the production in the nuclear Coulomb field of low-invariant-mass pions pairs by the reaction π−Z→π−π0Z at 40 GeV. We have obtained for the first time the experimental value of the γ→3π coupling constant F3π(0)=13.0±0.9±1.3 GeV−3, where the first (second) error is statistical (systematic). This result is in agreement with calculations based on the theory of chiral anomalies.

Nucl. Instrum. Meth. B

The experimental setup and methods to search for double beta decay of 150 Nd and other isotopes are described. The applied method of multidimensional analysis allows the two-neutrino mode of ββ-decay, neutrinoless mode (neutrino mass and right-handed mechanisms separately) and the mode with Majoron emission to be observed directly. The results of measurements of 50.5 g of 150 Nd for 2000 h are discussed. Multidimensional spectra calculated for the proposed experiment to search for double positron decay and a crossing process are given.

Nucl. Instrum. Meth. B

A description of a cylindrical magnetic spectrometer intended for a wide program of investigations on the meson beam of the JINR phasotron at Dubna is given. The spectrometer includes cylindrical proportional chambers, cylindrical scintillation hodoscopes, electronics, a fast processor for data discrimination and a system of feeding data into a computer and the electrical supply. The first investigations will include measurements of rare decays of muons and pions.

Nucl. Instrum. Meth. B

The construction, technology and characteristics of cylindrical multiwire proportional chambers with a low amount of matter in the working volume and described. The chamber have been built at JINR, Dubna, and are intended for the use as coordinate detectors of charged particles in the multipurpose ARES spectrometer. They may be used also in experiments in which detectors with large solid angle and axial symetry are needed.

Nuovo Cim.A

Total and differential cross sections for the π+4He→π+p3H, π+4He → π+2p2n and π+4He → 3pn reactions have been measured atEπ=68, 120, 135 and 156 MeV. Total and differential cross-sections for the π−4He → π−p3H and π−4He → π−2p2n reactions have also been measured atEπ=120,135, 156, 174 and 208 MeV. The measurements have been performed using high-pressure helium-filled streamer chamber, exposed to the synchrocyclotron of the JINR of Dubna. The analysis of the (πp3H) reactions shows that the proton knock-out process is mainly a quasi-free (πp) scattering involving the Δ(1232)-resonance excitation. The same resonance also seems to be produced in the (π2p2n) reaction. The π+ absorption reaction takes place on a nucleon pair and the cross-section values turn out to be close to those of the π+d → pp reaction.

Nucl. Phys. A

By means of a streamer chamber exposed to the LEAR antiproton beams, the total reaction cross sections, the charged-prong multiplicity distributions and lower limits for the production of negative pions and K s 0 in the p̄-Ne interaction were measured at 19.6, 48.7 and 179.6 MeV. Annihilation was found to be dominant over all other non-elastic p̄-Ne processes. An analysis of Ne and other nuclei data in the frame of the Glauber theory allowed us to determine the ratio between the p̄-n and the p̄-p cross sections. An analysis in the light of INC model predictions allowed us to show up events which can be interpreted as annihilations having occurred deeply inside the nuclei.