Few-Body Systems 0, 1–3 (2007)
c ? by Springer-Verlag 2007
Printed in Austria
Proton-deuteron elastic scattering at
135 MeV with BINA
A. Ramazani-Moghaddam-Arani1,2∗, H.R. Amir-Ahmadi1, A. Biegun1,
M. Eslami-Kalantari1, I. Gaˇ spari´ c3, L. Joulaeizadeh1,
N. Kalantar-Nayestanaki1, St. Kistryn4, A. Kozela5, H. Mardanpour1,
J.G. Messchendorp1∗∗, H. Moeini1, S.V. Shende1, E. Stephan6, R. Sworst4
1KVI, University of Groningen, Groningen, The Netherlands
2University of Kashan, Kashan, Iran
3Rudjer Boˇ skovi´ c Institute, Zagreb, Croatia
4Institute of Physics, Jagiellonian University, Cracow, Poland
5Institute of Nuclear Physics, Cracow, Poland
6Institute of Physics, University of Silesia, Katowice, Poland
Abstract. Differential cross sections and vector analyzing powers for the
p + d → p + d reaction have been measured using a new experimental setup
(BINA) at KVI. The data are compared with published results and are found
to be significantly different.
The nucleon-nucleon potential (NNP) has been studied extensively by in-
vestigating 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 are based
on a partial-wave analysis (PWA), which provides a nearly model-independent
analysis of the available scattering data . The modern NNPs fit with a χ2≈ 1
the world data base and have, therefore, been accepted as a high-quality bench-
mark. The precision of modern NNPs has given confidence to study in detail the
three-nucleon potential (3NP) which was already predicted in 1939 by Pimakoff
and Wilson .
In the last decade, high-precision data at intermediate energies in Nd elastic
scattering [6, 7, 8, 9, 10, 11] for a large energy interval together with rigorous Fad-
deev calculation  for the three-nucleon system have proved 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 . Precision data in a large energy
interval for the differential cross section and analyzing power came from recent
experimental studies at KVI [6, 7, 8], RIKEN  and RCNP . 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 mea-
sured at RIKEN and at RCNP. The KVI data suggest a significant contribution
2 Proton-deuteron elastic scattering at 135 MeV with BINA
of the 3NP at this energy, whereas the results obtained at RIKEN and at RCNP
imply a much smaller contribution of the 3NP. This paper presents preliminary
differential cross sections and vector-analyzing powers of the2H(p,d)p reaction
at 135 MeV/nucleon. The data are obtained at KVI using a new experimen-
tal equipment, Big Instrument for Nuclear-polarization Analysis, abbreviated as
BINA is composed of two parts. The forward part consists of a Multi-Wire
Proportional Chamber (MWPC) and a segmented hodoscope of thin scintilla-
tors with a thickness of 2 mm followed by thicker scintillators with a thickness
of 12 cm. This combination of detectors provides a measurement of the scat-
tering angles, particle identification, and an energy determination for protons
and deuteron. The backward part has 149 phoswich scintillator elements, cover-
ing polar angles between 40◦to 165◦and are glued together to operate as the
scattering chamber. A beam of polarized protons from the AGOR accelerator
impinged a liquid-deuterium target with a thickness of 3.85 mm with an uncer-
tainty of 5% which was mounted in the center of the backward part of BINA.
The beam current was typically 15 pA and monitored during the experiment via
a Faraday cup at the end of the beam line. The current meter was calibrated
using a precision current source with an uncertainty of 2%.
For this experiment, events were selected in which deuterons were detected in
the forward part in coincidence with a scattered proton in the backward part of
BINA. The efficiency of the coincidence hardware trigger was determined from
a data sample obtained from a minimum-bias trigger and found to be 98±1%.
In the analysis, a large part of the background, pre-dominantly from break-
up reaction, was reduced by verifying the kinematical correlation between the
scattering angle of the deuterons with that of the corresponding proton. Part
of the background stems from elastically scattered deuterons which undergo a
hadronic interaction inside the scintillators. The amount of hadronic interaction
has been estimated and corrected for by analyzing a part of the data for which the
break-up background is negligible and by conducting Monte-Carlo simulations
using the GEANT3 framework incorporating the GHEISHA hadronic model. The
contribution of the hadronic interaction obtained with the simulation framework
were in good agreement with the estimates using the experimental data and were
found to be typically 16% with an uncertainty of 2%. Similarly, the detection
efficiency of the MWPC was obtained by using a nearly background free data
sample and was found to be typically 97% with an uncertainty of 1%.
Figure 1 shows the preliminary results (filled circles) for the vector analyzing
power (left panel) and the differential cross section (right panel) as a function of
the center-of-mass angle. For the analyzing power measurements, the beam po-
larization was determined using the In-Beam Polarimeter, IBP . The results
are compared with the older KVI data [6, 7, 8] (open squares) and data taken at
RIKEN  (open triangles). The error bars for all symbols represent statistical
uncertainties. In most cases the error bar is smaller than the symbol size. The
shaded bands in the right panel of Fig. 1 represent the systematic uncertainties.
The solid lines represent a Faddeev calculation by the Bochum-Cracow theory
group including the CD-Bonn NNP and the revised Tucson Melbourne (TM’)
130 140 150
KVI 2003 [6,7,8]
130 140 150
d /d [mb/sr]
Figure 1. Preliminary results (filled circles) for the vector analyzing power (left panel) and the
differential cross section (right panel) as a function of the center-of-mass angle. For a description
see the text.
3NP. Note that the analyzing power data are in a very good agreement with the
previous measurement taken at KVI. Furthermore, note the striking discrepancy
between the published KVI and RIKEN data for the differential cross section in
the right panel of Fig. 1. The preliminary cross section data fall between the two
published data sets and differ significantly from the previous measurements.
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