PROBING THE ANOMALOUS COUPLINGS OF THE TOP QUARK WITH GLUON AT THE LHC AND TEVATRON

In this paper, we study the sensitivity of the fraction of t (t) over bar events arising from gluon gluon fusion to the chromoelectric and chromomagnetic dipole moments (CEDM and CMDM) as well as the total and differential t (t) over bar cross-sections at the LHC and Tevatron. The sensitivity of measured charged asymmetry at the LHC to CEDM and CMDM is also studied. We find that at the Tevatron and the LHC. nonzero values of CMDM could suppress the t (t) over bar production rate. It is shown that the ratio of sigma(gg -> t (t) over bar)/sigma(p (p) over bar -> t (t) over bar) at the Tevatron is more sensitive to CEDM and CMDM than the LHC case. The presence of CEDM always increases the contribution of gluon-gluon fusion process in top pair rate at the Tevatron and LHC. Except for a small range of CMDM, the presence of CEDM and CMDM can increase the fraction of gluon gluon fusion at the Tevatron and LHC. The measured ratio of sigma(gg -> t (t) over bar)/sigma(pp -> t (t) over bar) at the Tevatron is used to derive bounds on the chromoelectric and chromomagnetic dipole moments as well as the total and differential (d sigma/dm(t (t) over bar)) cross-sections at the LHC and Tevatrom and t he measured charged asymmetry at the LHC. The combination of d sigma(TeV)/dm(t (t) over bar) and sigma(LHC) provides stringent limits on CMDM and CEDM.