Some observations on transverse momentum of charged pions emitted in π--nucleon collisions at 4.4 gev

The distribution of transverse momentum pt of charged pions produced in pion-nucleon collisions at 4.4 GeV has been obtained. The distribution has a relatively broad maximum, centred at pt ≈ 200 MeV/c with <pt> = 300 ±23 MeV/c. It is found that <pt> for charged pions increases with the angle of emission up to about 10°–15°, beyond which it has a constant value. Further, the transverse momentum seems to be independent of multiplicity. It is pointed out that while in proton-nucleon collisions,<pt> for charged pions decreases gradually from 350 MeV/c at 24 GeV to as low as 142 MeV/c at 4.2 GeV, in pion-nucleon collisions it shows much less variation, viz., it decreases from 360 MeV/c at 16 GeV to only 300 MeV/c at 4.4 GeV. These features can be understood reasonably well on the hypothesis that a majority of the pions at these energies result from resonance states