Single-Pion Production in pp Collisions at 0.95 GeV/c (II)

Abstract

The single-pion production reactions $pp\to d{\pi }^{+}$, $pp\to np{\pi }^{+}$ and $pp\to pp{\pi }^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p\approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. Main emphasis is put on the presentation and discussion of the $np{\pi }^{+}$ channel, since the results on the other channels have already been published previously. The total and differential cross sections obtained are compared to theoretical calculations. In contrast to the $pp{\pi }^0$ channel we find in the $np{\pi }^{+}$ channel a strong influence of the $\Delta$ excitation already at this energy close to threshold. In particular we find a $(3co{s}^2\Theta +1)$ dependence in the pion angular distribution, typical for a pure s-channel $\Delta$ excitation and identical to that observed in the $d{\pi }^{+}$ channel. Since the latter is understood by a s-channel resonance in the ${}^1{D}_2$ $pn$ partial wave, we discuss an analogous scenario for the $pn{\pi }^{+}$ channel.

References in corpus (11)

• Meson production in nucleon--nucleon collisions close to the threshold
• Nucleon-nucleon elastic scattering to 3 GeV
• Towards a field theoretic understanding of NN->NNpi
• Two-Pion Production in Proton-Proton Collisions with Polarized Beam
• Polarization phenomena in the reaction NN to NNpi near threshold
• Production of the 1S0 diproton in the pp -> pp pi0 reaction at 0.8 GeV
• Single-Pion Production in pp Collisions at =.95 GeV/c (I)
• Spin correlations in $\vec{p}\vec{p}\to pn{\pi }^{+}$ pion production near threshold
• Partial-wave analysis of $\vec{p}\vec{p}\to pp{\pi }^{\circ }$ data
• Single- and Double-Pion Production in Nucleon Collisions on the Nucleon and on Nuclei -- the ABC Effect and its Possible Origin in a Dibaryonic Resonance
• Observation of strong final-state effects in pi+ production in pp collisions at 400 MeV

Cited by in corpus (4)

• Two-Pion Production in Proton-Proton Collisions with Polarized Beam
• Study of exclusive one-pion and one-eta production using hadron and dielectron channels in pp reactions at kinetic beam energies of 1.25 GeV and 2.2 GeV with HADES
• On the Production of ${\pi }^{+}{\pi }^{+}$ Pairs in pp Collisions at 0.8 GeV
• Search for an Isospin I =3 Dibaryon