E. Hagberg

Measurement of the neutron and the proton F2 structure function ratio

The ratio of the structure function F2n/F2p (x) has been measured in deep inelastic scattering of 274 GeV muons on hydrogen and deuterium targets exposed simultaneously to the beam. The results were obtained from 0.3 (0.6) million events from hydrogen (deuterium) in the range 0.004 <x< 0.8 and 1 <Q2< 190 GeV2. At x < 0.25 both the statistical and the systematic error is below 2%. Implications for parton distributions and for the σw/σz production cross section ratio in pp collisions are discussed. When compared to other results obtained at lower energies, the data indicate a Q2 dependence of the ratio.

Soft π−p and pp elastic scattering in the energy range 30 to 345 GeV

Abstract Differential cross sections for π − p and pp elastic scattering have been measured at incident momenta ranging from 30 to 345 GeV and in the t range 0.002 (GeV/ c ) 2 ⩽ | t | ⩽ 0.04 (GeV/ c ) 2 . From the analysis of the data, the ratio ϱ ( t = 0) of the real to the imaginary parts of the forward scattering amplitude was determined together with the logarithmic slope b of the diffraction cone. The results on the real parts confirm the validity of the forward dispersion relations at high energies. Using the dispersion relations, it was shown that the experimental data on ϱ π −p( t = 0) require a continuous rise of the total πp cross sections, at least up to the energy of 2000 GeV, thus revealing a close similarity in high-energy behaviour of πp and pp interactions. The results on the slope parameters from this experiment together with the analysis of the available world data demonstrate that the existing experimental data are consistent with the hypothesis of a universal shrinkage of the hadronic diffraction cone at high energies. The value of the asymptotic shrinkage parameter α p ′ was found to be independent of the kind of the incident hadron and of the momentum transfer in the t range | t | ⩽ 0.2 (GeV/ c ) 2 : 2 α p ′ = ± 3 (GeV/ c ) −2 .

Measurements of the total π-He and p-He cross sections and the slopes of the forward diffraction peak at energies from 50 to 300 GeV

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.

Experimental results on pp forward elastic scattering and the possibility of universal shrinkage of the hadronic diffraction cone

Abstract The differential cross section of pp scattering has been measured in the energy region 100–300 GeV and in the t -range 0.002 t | c ) 2 . The results on the real part of the scattering amplitude agrees with dispersion relation calculations. We also report on our determination of the slope parameter b together with an analysis of the world data of b for different hadrons and different t -values. It is shown that the data are consistent with the hypothesis of a universal shrinkage of the hadronic diffraction cone at high energies.

Measurements of

Abstract The differential cross section has been measured at 30, 50, 80, 100, 120 and 140 GeV/ c for 0.002 t | GeV / c ) 2 . The results show that the π − p real part goes from negative to positive values below 80 GeV/ c . The slope parameter in the t -region measured is significantly higher than what has been found − t = 0.2 (GeV/ c ) 2 .

\pi

Abstract The differential cross section ofπ−p scattering has been measured in the energy region 100–345 GeV and in thet-range 0.002

-p elastic scattering in the coulomb interference region at high energies

Abstract 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.

Measurements ofπ−p forward elastic scattering at high energies

Abstract A small angle interaction trigger processor (SAIT) used in a muon scattering experiment (NA28) at CERN is described. It comprises 10 FASTBUS modules and employs ECL 100K and 10K type circuits. The processor can select events with scattering angles larger than ∼1 mrad and can be used at a beam intensity of up to 10 7 particles per second without appreciable deadtime losses.

Determination of the absolute momentum of a high-energy hadron beam using elastic scattering of hadrons from a helium target

Abstract A system for measurement and selection of small-angle scattering was developed for the study of high-energy muon interactions with nuclei. The trigger decision was obtained by using the information from more than 500 individual scintillation counters placed in and around the beam. They were distributed in 8 successive planes upstream and 4 planes downstream of the target. In the trigger logic, each beam particle in the 5 cm wide beam was identified and, a fast trigger signal was produced, only if the track was consistent with a scattering process. The beam rate was ∼ 107 s−1 and the decision time of the trigger processor, built in the FASTBUS standard, was typically 80 ns. The reaction between 280 GeV muons and different target nuclei could be studied down to scattering angles of 1.6 mrad. The trigger rate with these conditions was of the order of 10−5 per incident beam particle.

A fast trigger processor, for a scattering experiment, implemented in fastbus

Abstract 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.