Deuteron breakuppd→{pp}snwith forward emission of a fast

Abstract

The deuteron breakup reaction pd → {pp} s n, where {pp} s is a fast proton pair emitted in forward direction with small excitation energy E pp < 3 MeV, has been studied at proton beam energies of 0.5-2.0 GeV using the ANKE spectrometer at COSY-Jülich. The differential c.m. cross sections are measured in complete kinematics and provide angular distributions of the neutron emission angle in the range θ n = 168 •-180 • , the dependence on beam energy at θ n = 180 • , angular distributions of the direction of the proton in the pp rest frame, and distributions of the excitation energy E pp of the proton pair. The obtained data are analyzed on the basis of theoretical models previously developed for the pd → dp process in a similar kinematics and properly modified for the diproton channel in pd → {pp} s n. It is shown that the measured observables are highly sensitive to the short-range part of the nucleon-nucleon interaction.

Resonance-like coherent production of a pion pair in the reaction $pd \rightarrow pd \pi\pi$pd→pdππ in the GeV region

“…4 ≈ 7% via simultaneous recording of single protons from small-angle elastic and quasi-elastic scattering off the deuterons. The data taking, track reconstruction, particle momentum determination and the cross section normalization procedures are described in detail elsewhere [29,[31][32][33].…”

“…[27,28]) did not satisfy the above-stated requirements and were not aimed at studying the ABC effect. Fortunately, the data obtained at the ANKE@COSY setup in the deuteron break-up study at the beam energies of 0.8-2.0 GeV [29] contained a significant array of events with a final pd pair emitted forward with a high momentum of the both particles. These events well satisfy the kinematical conditions for the coherent meson production in the reaction…”

The legacy of the experimental hadron physics programme at COSY

“…The kinematics are then very similar to those of proton-deuteron backward elastic scattering. The unpolarized differential cross section for hard proton-deuteron breakup was measured at ANKE at ten proton beam energies from 0.5 GeV to 2.0 GeV with the standard E pp < 3 MeV cut [96,97] and the results are shown in Fig. 32.…”

“…[96] (open circles) and Ref. [97] (closed circles). The predictions of one nucleon exchange are shown by the dashed line and those of the ∆ mechanism by the thin solid line.…”

“…The predictions of one nucleon exchange are shown by the dashed line and those of the ∆ mechanism by the thin solid line. The total predictions of the model, including small single-scattering contributions, are shown by the thick solid line [97]. The upper scale shows the internal momentum q of the nucleons in the deuteron (or diproton) for the one nucleon exchange.…”