Measurement of ϕ meson production in p + p interactions at 40, 80 and 158 GeV/c with the NA61/SHINE spectrometer at the CERN SPS

Abstract

Results on ϕ meson production in inelastic p+p collisions at CERN SPS energies are presented. They are derived from data collected by the NA61/SHINE fixed target experiment, by means of invariant mass spectra fits in the ϕ→K + K − decay channel. They include the first ever measured double differential spectra of ϕ mesons as a function of rapidity y and transverse momentum p T for proton beam momenta of 80GeV/c 80GeV/c and 158GeV/c 158GeV/c , as well as single differential spectra of y or p T for beam momentum of40GeV/c. The corresponding total ϕ yields per inelastic p+p event are obtained. These results are compared with existing data on ϕ meson production in p+p collisions. The comparison shows consistency but superior accuracy of the present measurements. The emission of ϕ mesons in p+p reactions is confronted with that occurring in Pb+Pb collisions, and the experimental results are compared with model predictions. It appears that none of the considered models can properly describe all the experimental observations.