  The aim of this work was to determine the total width of the eta-prime meson.
The investigated meson was produced via the pp->ppeta-prime reaction in the
collisions of beam protons from COSY synchrotron with protons from a hydrogen
cluster target. The COSY-11 detector was used for the measurement of the
four-momentum vectors of outgoing protons. The mass of unregistered meson was
determined via the missing mass technique, while the total width was directly
derived from the mass distributions established at five different beam momenta.
Parallel monitoring of the crucial parameters (e.g. size and position of the
target stream) and the measurement close-to-threshold permitted to obtain mass
resolution of FWHM = 0.33 MeV/c^2.
  Based on the sample of more than 2300 reconstructed pp->ppeta-prime events
the determined total width of the eta-prime meson amounts to
0.226+-0.017(stat.)+-0.014(syst.) MeV, which is the most precise measurement
until now.
