F. Hinterberger

Elastic scattering of 52 MeV deuterons

Abstract Strongly excited levels of the nuclei 12 C, 14 N, 20 Ne, 22 Ne, 27 Al, 28 Si, 32 S, 40 Ar, 48 Ti, 54 Fe, 58 Ni, 64 Ni, 208 Pb and 209 Bi have been investigated by means of inelastic scattering of 52 MeV deuterons. The angular distributions have been analysed in terms of the DWBA. The description of the excited states in the collective model yields good fits and values of the deformation parameter β L which agree with independent measurements. Satisfactory fits are obtained in an attempt to apply a microscopic theory of inelastic deuteron scattering. An effective nucleon-nucleon interaction of Wigner type V ( r ) = V N exp(− r 2 / γ 2 ) is assumed to induce the scattering. From target nuclei where shell-model functions for the ground and excited states are available, we deduce the parameters V N = 38±5 MeV and γ = 1.7 fm. For other target nuclei, information about the collective enhancement of the excited states is obtained which is more sensitive to the details of the nuclear structure than the β L values.

Parity violation in proton-proton scattering at 13.6 MeV

Abstract Parity nonconservation in proton-proton scattering has been studied by measuring the angle-integrated longitudinal analyzing power A z . We found A z (13.6 MeV)=(−1.5±0.5)×10 −7 . The error includes uncertainties due to statistics and corrections, as well as upper limits on systematic effects. The experimental result is discussed with respect to recent theoretical calculations.

High resolution study ofhyperon-nucleon interactions by associated strangeness production in pp collisions

Abstract The associated strangeness production in pp collisions was studied at bombarding energies of 2.3 and 2.7 GeV by detecting the outgoing K + particles with a high resolution magnetic spectrometer at forward angles up to 23.5° laboratory angle. The kaons were separated from an immense background of protons and pions by a highly resolving TOF electronics addition to vetoes from Cerenkov detectors utilizing either β differing Cerenkov light cones in lucite or different thresholds for light production in aerogel. The hyperon-nucleon missing mass spectra obtained show strong deviations from pure phase space which is ascribed to final state interactions of the pΛ and the Nσ systems. The structures found are discussed and compared with results from K − d → π − YN experiments, with theoretical calculations in the frame of OBE models, and with the prediction of sharp strange dibaryon resonances from several quark-bag models.

A Precision Measurement of pp Elastic Scattering Cross Sections at Intermediate Energies

Abstract.We have measured differential cross-sections for \ensuremath{\rm pp} elastic scattering with internal fiber targets in the recirculating beam of the proton synchrotron COSY. Measurements were made continuously during acceleration for projectile kinetic energies between 0.23 and 2.59 GeV in the angular range

Excitation functions of the analyzing power in elastic proton-proton scattering from 0.45 to 2.5 GeV

30^{\circ} \leq \theta_{\rm c.m.} \leq 90^{\circ}

The beam handling system at the bonn isochronous cyclotron

. Details of the apparatus and the data analysis are given and the resulting excitation functions and angular distributions presented. The precision of each data point is typically better than 4%, and a relative normalization uncertainty of only 2.5% within an excitation function has been reached. The impact on phase shift analysis as well as upper bounds on possible resonant contributions in lower partial waves are discussed.

Analysis of internal target effects in light ion storage rings

Abstract.Excitation functions AN(plab,Θc.m.) of the analyzing power in elastic proton-proton scattering have been measured in an internal target experiment at the Cooler Synchrotron COSY with an unpolarized proton beam and a polarized atomic hydrogen target. Data were taken continuously during the acceleration and deceleration for proton kinetic energies Tlab (momenta plab) between 0.45 and 2.5 GeV (1.0 and 3.3 GeV/c) and scattering angles 30 ° ⩽ Θc.m. ⩽ 90°. The results provide excitation functions and angular distributions of high precision and internal consistency. The data can be used as calibration standard between 0.45 and 2.5 GeV. They have significant impact on phase shift solutions, in particular on the spin triplet phase shifts between 1.0 and 1.8 GeV.

High resolution study of the Λp final state interaction in the reaction p+p→K++(Λp)

Abstract The lay-out and the ion-optical structure of the beam handling system at the Bonn Isochronous Cyclotron is described. The following beam preparation modes are possible with two double monochromator systems: (1) double dispersive with an extremely high momentum resolution of 30 000; (2) double dispersive with an adjustable dispersion matching with a magnetic spectrograph; (3) nondispersive, nearly isochronous, variable momentum resolution up to 8000, adjustable time of flight resolution below 0.5 ns; (4) achromatic with a transmission of 100%. The practical experiences in operating the system and achieving the design performances are discussed. The results of rigorous test measurements are given.

Measurement of spin correlation parameters A(NN), A(SS), and A(SL) at 2.1-GeV in proton proton elactic scattering

Abstract This paper considers the rate of beam phase space growth and beam losses caused by thin internal targets in light ion storage rings without beam cooling. The analysis of transverse emittance growth and beam losses by small angle Coulomb scattering is recapitulated. The formalism is extended to analyze the effects of transverse and longitudinal emittance growth by energy loss fluctuations. All target effects can be parametrized by two quantities, the mean square values θ rms 2 and δ rms 2 of the small angle scattering and relative momentum straggling per target traversal. This paper presents simple expressions for the transverse and longitudinal emittance growth, the beam survival probability and the quantities θ rms 2 and δ rms 2 .

Monte Carlo simulations of thin internal targets in intermediate energy proton storage rings

The reaction pp ! K + + (�p) was measured at Tp = 1.953 GeV and � = 0 ◦ with a high missing mass resolution in order to study thep final state interaction. The large final state enhancement near thep threshold can be described using the stan- dard Jost-function approach. The singlet and triplet scattering lengths and effective ranges are deduced by fitting simultaneously thep invariant mass spectrum and the total cross section data of the freep scattering.