Eur. Phys. J. A (2008) 36: 7-16
https://doi.org/10.1140/epja/i2007-10543-x

Regular Article - Experimental Physics

Single production in np collisions for excess energies up to 90 MeV

¹ Institut für Kern- und Teilchenphysik, Technische Universität Dresden, D-01062, Dresden, Germany
² Physikalisches Institut, Universität Erlangen, D-91058, Erlangen, Germany
³ Physikalisches Institut, Universität Tübingen, D-72076, Tübingen, Germany
⁴ Institut für Kernphysik, Forschungszentrum Jülich, D-52425, Jülich, Germany
⁵ Institut für Strahlenphysik, Forschungszentrum Dresden-Rossendorf, D-01314, Dresden, Germany
⁶ Andrzej Soltan Institute for Nuclear Studies, PL-00681, Warsaw, Poland

^* e-mail: e.kuhlmann@physik.tu-dresden.de

Received: 15 August 2007
Accepted: 29 February 2008
Published online: 9 April 2008

Abstract

The quasifree reaction was studied in a kinematically complete experiment by bombarding a liquid-hydrogen target with a deuteron beam of momentum 1.85GeV/c and analyzing the data along the lines of the spectator model. In addition to the three charged ejectiles the spectator proton was also detected in the large-acceptance time-of-flight spectrometer COSY-TOF. It was identified by its momentum and flight direction thus yielding access to the Fermi motion of the bound neutron and to the effective neutron 4-momentum vector _n which differed from event to event. A range of almost 90MeV excess energy above threshold was covered. Energy-dependent angular distributions, invariant-mass spectra as well as fully covered Dalitz plots were deduced. Sizeable pp FSI effects were found as were contributions of p and d partial waves. In comparison with existing literature data the results provide a sensitive test of the spectator model. The behavior of the elementary cross-section σ₀₁ close to threshold is discussed in view of new cross-section data.