On the two-nucleon mass enhancement associated with the high momentum tail of the spectator in the deuteron break-up

The charge exchange reaction dp → (pp)n

“…In connection with the appreciable contribution of events with intermediate ∆-isobar [7,19], the main part of which comes from quasi-pp collisions (proceeding mainly via ∆ ++ and ∆ + -isobars) see diagrams a) and b) in the Fig. 4, it would be necessary to introduce a correction for this effect.…”

Enhancements observed in the two-proton invariant mass distribution in the pionless deuteron breakup at 3.3 GeV/c

“…In the effective masses of the pp-pair one of the peaks has been observed earlier [9]. The question arises whether the double structure exists in protonproton combinations of the dp--*ppn reaction.…”

“…# is the mass of the real u-meson, G1 (t) is the off-energy-shell u-meson formfactor, f~ is the amplitude of virtual pion absorption by the deuteron 9 To connect turn to the real u-meson in the nd~NN amplitude in expression (2), the results of [17,18] are used 9 By analogy with this, one can get: f2J f NN = G2 (qoff, qOn) fo2_ ~ NN, where "off" and "on" denote the off-energy shell and on-energy shell n-mesons, respectively; q is the pion momentum in the n-d CMS. Substituting this expression for f~ into expression (2) and IFd(1)l: into (1), one obtains the one-pion exchange contribution of Fig.…”

“…Let us try to select the class of inelastic scattering, e.g. with virtual 7~-meson production and absorption [9,10]. Due to kinematical constraints on re-meson absorption with a single nucleon, the majority of these events occurs on a nucleon pair.…”

The reactionpd ? ppn and the narrow dibaryon resonances

“…All these peaks, except for 2.08 GeV/c 2, were observed before in one or another experiment, here we see them together. One should note, that our procedure of the selection of the dibaryon peaks differs from that used in [4,5,10]. While in the present experiment only backward emitted pro-tons were selected, in the above mentioned works all the events were used.…”