Elastic proton-deuteron scattering at intermediate energies

Abstract

Observables in elastic proton-deuteron scattering are sensitive probes of the nucleon-nucleon interaction and three-nucleon force effects. The present experimental data base for this reaction is large, but contains a large discrepancy between data sets for the differential cross section taken at 135 MeV/nucleon by two experimental research groups. This paper reviews the background of this problem and presents new data taken at KVI. The nucleon-nucleon potential (NNP) has been studied extensively by investigating the properties of bound nuclear systems, and, in more detail, via a comparison of high-precision two-nucleon scattering data with modern potentials based on the exchange of bosons [1,2,3]. A few of the modern NNPs were facilitated by a partialwave analysis (PWA), that provides a nearly modelindependent analysis of the available scattering data [4]. The modern NNPs reproduce the world data base with a reduced chi-square close to one and have, therefore, been accepted as high-quality benchmark potentials. The precision of modern NNPs has given confidence to study in detail the three-nucleon potential (3NP) which was already predicted in 1939 by Primakoff and Wilson [5]. Compelling evidence of 3NP effects came from various recent theoretical and experimental studies. For example, for light nuclei, Green's function Monte-Carlo calculations employing the high-quality NNPs clearly underestimate the experimental binding energies [2], and, therefore, show that NNPs are not sufficient to describe the three-nucleon and heavier systems accurately. In the last decade, high-precision data at intermediate energies in elastic Nd and dN scattering [6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23] for a large energy range together with rigorous Faddeev calculations [24] * Electronic address: ramazani@kvi.nl † Electronic address: messchendorp@kvi.nl for the three-nucleon system have proven to be a sensitive tool to study the 3NP. In particular, a large sensitivity to 3NP effects exists in the minimum of the differential cross section [25,26]. Precision data for a large energy interval for the differential cross section and analyzing power came from recent experimental studies at KVI [7,8,9], RIKEN [10] and RCNP [12]. All these experiments had one common energy of 135 MeV/nucleon. Strikingly, the cross sections obtained at KVI were found to be significantly larger than those measured at RIKEN and at RCNP. The KVI data show significant deviation from predictions of state-of-the-art Faddeev calculations incorporating modern NNPs and 3NPs at this energy, whereas the results obtained at RIKEN and RCNP imply that the cross section can be described reasonably well exploiting the same potentials.This paper presents the results of a new measurement of the differential cross sections of the reaction 2 H( p, d)p at a proton-beam energy of 135 MeV, taken to provide additional data at 135 MeV/nucleon. These results are compared with the previously published data taken at intermediate energies. The data are obtained at KVI using a ne...

Dynamics of Three-Nucleon System Studied in Deuteron–Proton Breakup Experiments

“…At beam energies above 100 MeV per nucleon certain discrepancies between data and calculations still persist, though significantly reduced as compared to predictions based on purely 2N potentials (cf. [12] and references therein). On the other hand, the precise experimental data demonstrate both the successes and the difficulties of the current models in describing analyzing powers, spin-transfer and spin-correlation coefficients for N d elastic scattering.…”

“…Such an approach was applied in a series of experiments carried out at KVI, which comprised the studies of the 1 H(d,pp)n and 2 H(p,pp)n reactions with deuteron beams of energies 100, 130 and 160 MeV (50, 65, 80 MeV/nucleon) and proton beams with energies of 135 and 190 MeV. The detection systems of large angular acceptance, SALAD and BINA [11][12][13], were employed. Regarding differential cross sections, an experiment using the 4π WASA detector and deuteron beams of energies from 170 to 200 MeV/nucleon has recently been performed at the COSY ring of FZ-Jülich, while the investigations at lower (proton) beam energies between 108 and 160 MeV are currenly being carried out with the use of the BINA detector at the newly opened Cyclotron Center Bronowice (Cracow, Poland).…”

Recent results on deuteron–proton scattering from RIKEN

“…∼ 180 • at a higher energy 250 MeV/nucleon. Since these features are clearly seen as going to higher energies [31,32], the relativistic effects have been estimated by using the Lorentz boosted NN potentials with the TM99 [33]. However the relativistic effects have turned out to be small and only slightly alter the cross sections (see Fig.…”

Invariant Coordinates in Breakup Reactions

“…Experimental studies of the 1 H (d, pp)n reactions with deuteron beams of energies 130 and 160 MeV were performed at KVI in Groningen, using SALAD and BINA detectors [12][13][14]. The SALAD detector consisted of a three-plane MWPC and a scintilator hodoscopes: 24 horizontal detectors (ΔE) and 24 vertical stopping detectors (E), arranged perpendicularly to one another.…”