Structures in the Nucleon-Nucleon System

Abstract

The status of dibaryon resonances in I = 0 and I = I states is discussed together with new data.

Single Spin Asymmetries in Inclusive High Energy Hadron–hadron Collision Processes

“…It has also been found that there exist many simple relations between the A N 's for hadron production in reactions using different projectile-target combinations. E.g., comparingp(↑)+p(0) with p(↑)+p(0), we predicted [16] that there should be change of sign for π + and π − productions, which is confirmed by the E704 data [5,7]. Predictions for processes using polarized neutron or deutron targets have also been made [18].…”

“…Data on A N for hadron production at high energies is now available for p(↑) + [5,7], and π + p(↑) → π (or η) + X [8]. These data show the following characteristics:…”

“…Single spin hadron-hadron collision experiments, in which one of the colliding hadrons is transversely polarized, are of particular interests for the following reasons: A large amount of data is now available [1][2][3][4][5][6][7][8]. Besides the well known analyzing power in pp-elastic scattering [1], we have now data [2][3][4][5][6][7][8] on left-right asymmetry A N in single-spin inclusive processes for the production of different kinds of mesons, Λ hyperon or direct photon in collisions using transversely polarized proton as well as antiproton beams.…”

“…Besides the well known analyzing power in pp-elastic scattering [1], we have now data [2][3][4][5][6][7][8] on left-right asymmetry A N in single-spin inclusive processes for the production of different kinds of mesons, Λ hyperon or direct photon in collisions using transversely polarized proton as well as antiproton beams. It has been observed that A N is up to 40% in the beam fragmentation region, whereas the theoretical expectation [9] were A N ≈ 0.…”

Tracing the origin of left-right asymmetries in inclusive single-spin reactions

“…Striking left-right asymmetries (A N ) for hadron production in single-spin high-energy hadron-hadron collisions have been observed [1][2][3][4][5][6][7][8][9]. Significant effects have been seen in the projectile fragmentation region in experiments with transversely polarized proton beams [3][4][5][6][7][8][9] as well as in those with transversely polarized anti-proton beams [5,9]. Data are now available not only for pions [3][4][5][6]9] but also for η meson [8], for kaons [9] and for hyperon [7].…”