Measurement of phi meson production in p plus p interactions at 40, 80 and 158 mml:mspace width='0.166667em' mml:mspace>GeV/c with the NA61/SHINE spectrometer at the CERN SPS: NA61/SHINE Collaboration

摘要

Results on phi 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 phi -> K+K- decay channel. They include the first ever measured double differential spectra of phi mesons as a function of rapidity y and transverse momentum pT for proton beam momenta of 80 mml:mspace width="0.166667em"/mml:mspace GeV/c and 158 mml:mspace width="0.166667em" /mml:mspace GeV/c, as well as single differential spectra of y or pT for beam momentum of 40 Mml:mspace width="0.166667em"mml:mspace GeV/c. The corresponding total phi yields per inelastic p+p event are obtained. These results are compared with existing data on phi meson production in p+p collisions. The comparison shows consistency but superior accuracy of the present measurements. The emission of phi 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.