The study of the proton-proton collisions at the beam momentum 1581 MeV/c K. N. Ermakov, V. I. Medvedev, V. A. Nikonov, O. V. Rogachevsky, A. V. Sarantsev, V. V. Sarantsev and S. G. Sherman Eur. Phys. J. A, 50 6 (2014) 98 Published online: 13 June 2014 DOI: 10.1140/epja/i2014-14098-5