Nucl.Instrum.Meth.

In a small-angle elastic scattering experiment (NA8) in the H8 beam of the CERN Super Proton Synchrotron, the absolute momentum of the incident beam particles has been determined from data on hadron— 4 He elastic scattering. Measurements were performed at beam momenta ranging from 100 GeV/ c to 300 GeV/ c , and the average absolute momentum was determined with a precision of 0.15%. This method can be applied also at higher energies.

Nucl.Instrum.Meth.

We have measured the ionization loss of highly relativistic protons and pions passing through an ionization chamber filled with hydrogen at 10 atm pressure. The Lorentz factor of the particles ranged from γ = 100 to γ = 1800. The ionization loss was found our results disagree with the theoretical predictions of Tsytovich, according to which radiative corrections lead to a decrease in the ionization loss at higher energies.

Nucl.Phys.B

Differential cross sections for elastic scattering of pions and protons on helium have been measured at incident momenta ranging from 50 to 300 GeV/ c in the t -range 0.008 < | < | < 0.05 (GeV/ c ) 2 . Both recoil α-particles and forward particles were detected in this experiment. The experimental method provided an absolute normalization of the cross sections with an estimated precision of 1%. From the analysis of the data, the diffraction slope parameters and total cross sections have been obtained. The results are compared with Glauber model calculations.

Czech. J. Phys. B

The calculations of magnetic field in the NA4 spectrometer provided the magnetic field map for the reconstruction program. The field in iron is toroidal and decreases approximately logarithmically fro

Nucl. Phys. A

We have observed 150 double charge exchange events, π − + 7 Li → π + + anything , at an incident π − lab kinetic energy of 102 MeV. The π + were recorded in an emulsion stack at 30° to the incident π − beam. No significant peak due to the hypothetical reaction π − + 7 Li → π + + 7 H(g.s.) was observed in the part of the π + energy spectrum corresponding to a 7 H binding energy between −5 MeV and +25 MeV. Our new upper limit for the corresponding differential cross section is 1.0 × 10 −31 cm 2 sr (90% C.L.). The π + spectrum was recorded down to low energies (20 MeV < E π + < 100 MeV); its shape implies a strong final-state interaction among the π + , the proton and the six neutrons. The differential double charge exchange cross section integrated over all π + energies was determined as ( dσ dΩ ) tot = (4.2 ± 1.7) × 10 −30 cm 2 sr .

J.Phys.G

The differential cross sections d sigma /dt of the reactions 3H+p to 3He+n and 3H+p to 3H+p at a triton momentum of 2.5 GeV/c (equivalent to a proton kinetic energy Tp=318 MeV) have been measured. The ITEP 80 cm hydrogen bubble chamber was exposed to a 2.5 GeV/c separated triton beam. 2350 events of the reaction 3H(p,n)3He and 2574 events of the reaction 3H(p,p)3H were selected and analysed. Calculations performed in the framework of the multiple scattering theory taking the spin-isospin structure of the NN amplitude into account fit the data very well and show the high sensitivity of the charge-exchange cross section to the double spin-flip NN amplitudes.

Nuovo Cim. A

Differential cross-sections ofπ-3He elastic scattering have been measured at 145, 180 and 195 MeV and compared with the optical-model predictions. In constructing the optical potential, the strong-interaction nuclear form factors are extracted from the electric and magnetic form factors, taking into account the mesonic-exchange effects in the electron-nucleus scattering. A possibility of determining the nuclear magnetic radius fromπ-3He elastic-scattering data is discussed.