Colored Scalars And The CDF $W+$dijet Excess

The recent data on $W+$dijet excess reported by CDF may be interpreted as the associated production of a $W$ and a new particle of mass about 150 GeV which subsequently decays into two hadron jets. We study the possibility of explaining the $W+$dijet excess by colored scalar bosons. There are several colored scalars which can have tree level renormalizable Yukawa couplings with two quarks, $({\bf 8}, {\bf 2},1/2)$, $(\bar{\bf 6}({\bf 3}), {\bf 3}({\bf 1}), -1/3)$, $(\bar {\bf 6}({\bf 3}), {\bf 1}, -4/3(2/3))$. If one of these scalars has a mass about 150 GeV, being colored it can naturally explain why the excess only shows up in the form of two hadron jets. Although the required production cross section and mass put constraints on model parameters and rule out some possible scenarios when confronted with other existing data, in particular FCNC data, we find that there are strong constraints on the Yukawa couplings of these scalars. Without forcing the couplings to be some special texture forms most of the scalars, except the $({\bf 3}, {\bf 3}, -1/3)$, are in trouble with FCNC data. We also study some features for search of these new particles at the RHIC and the LHC and find that related information can help further to distinguish different models.
Comment: RevTex, 17 pages and 4 figures. Some minor corrections