On determination of the top quark mass at hadron colliders

A study has been made on a possibility to determine the top quark mass at hadron colliders by measuring the jets from its hadronic decay in a calorimeter. For this purpose 5000 events of the channel pp-bar → tt-bar+X → (W+b)(W-b-bar)+X → (qq-barb)(l-ν-barb-bar)+X (and charge conjugated to it) at √s=6 TeV has been produced with the ISAJET Monte Carlo program. Some features of top quark production and decay have been analyzed. The factors affecting the multijet invariant mass resolution have been analyzed in detail. It has been found that the bremsstrahlung that comes off the final state partons and background of overlapping gluon jets significantly reduces the precision of jet spectroscopy. A special algorithm of hard jet finding, optimized for top quark searching and measuring its mass in three jet invariant mass distributions, has been developed. As a result it has been shown that the systematic error of the mt measurement at hadron colliders can not be less than 3 GeV. 16 refs.; 17 figs.; 8 tabs