Eur. Phys. J. A (2020) 56: 249
https://doi.org/10.1140/epja/s10050-020-00255-0

Regular Article - Experimental Physics

A comprehensive study of analyzing powers in the proton–deuteron break-up channel at 135 MeV

¹ KVI-CART, University of Groningen, Groningen, The Netherlands
² Department of Physics, School of Science, Yazd University, Yazd, Iran
³ Institute of Theoretical Physics and Astronomy, Vilnius University, Saulėtekio al. 3, 10222, Vilnius, Lithuania
⁴ M. Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
⁵ Institute of Physics, Jagiellonian University, Kraków, Poland
⁶ Institute of Nuclear Physics, PAS, Kraków, Poland
⁷ Department of Physics, University of Sistan and Baluchestan, Zahedan, Iran
⁸ Department of Physics, Faculty of Science, University of Kashan, Kashan, Iran
⁹ Department of Physics, University of Tehran, Tehran, Iran
¹⁰ Institute of Physics, University of Silesia, Chorzow, Poland

^* e-mail: m.t.bayat@rug.nl

Received: 3 June 2020
Accepted: 18 September 2020
Published online: 6 October 2020

Abstract

A measurement of the analyzing powers for the $$^2\hbox {H}(\vec {p},pp)n$$ break-up reaction was carried out at KVI exploiting a polarized-proton beam at an energy of $$135\,\hbox {MeV}$$. The scattering angles and energies of the final-state protons were measured using the Big Instrument for Nuclear-polarization Analysis (BINA) with a nearly $$4\pi $$ geometrical acceptance. In this work, we analyzed a large number of kinematical geometries including forward–forward configurations in which both the final-state particles scatter to small polar angles and backward–forward configurations in which one of the final-state particles scatters to large polar angles. The results are compared with Faddeev calculations based on modern nucleon–nucleon (NN) and three-nucleon (3N) potentials. Discrepancies between polarization data and theoretical predictions are observed for configurations corresponding to small relative azimuthal angles between the two final-state protons. These configurations show a large sensitivity to 3N force effects.