2007/08/29 by TOF collaboration, M. Abdel-Bary, K.-Th. Brinkmann +35
Physics and Astronomy · #Nuclear physics research studies #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #nucl-ex
paper · pdf · doi:10.1140/epja/i2007-10543-x
published as Eur.Phys.J.A36:7-16,2008 · 21 pages, 9 figures, 4 tables, submitted to EPJA
arxiv created 2007/08/29 · openalex publication_date 2008/04/01 · arxiv updated 2012/08/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/29
The quasifree reaction np→ pp\pim was studied in a kinematically complete experiment by bombarding a liquid hydrogen target with a deuteron beam of momentum 1.85 GeV/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 ℙn which differed from event to event. A range of almost 90 MeV 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. The behavior of the elementary cross section σ01 close to threshold is discussed in view of new cross section data. In comparison with existing literature data the results provide a sensitive test of the spectator model.