Comparison of inclusive K+ production in proton-proton and proton-neutron collisions

TL;DR

This study measures K+ production in proton-proton and proton-neutron collisions at various energies, revealing differences near threshold that are largely explained by unobserved K0 production in pn reactions.

Contribution

It provides new experimental data on K+ spectra in pp and pn collisions at multiple energies, with corrections for Fermi motion and shadowing.

Findings

K+ production is stronger in pp than pn near threshold

Most of the difference is due to unobserved K0 production in pn reactions

Data covers four beam energies from 1.826 to 2.650 GeV

Abstract

The momentum spectra of K+ produced at small angles in proton-proton and proton-deuteron collisions have been measured at four beam energies, 1.826, 1.920, 2.020, and 2.650 GeV, using the ANKE spectrometer at COSY-Juelich. After making corrections for Fermi motion and shadowing, the data indicate that K+ production near threshold is stronger in pp- than in pn-induced reactions. However, most of this difference could be made up by the unobserved K0 production in the pn case.