Study of the dijet mass spectrum in W+2 jets events

The invariant mass spectrum of the two jets with the highest transverse momenta in events with two or three jets, produced in association with a W boson, is presented. The analyzed data sample corresponds to an integrated luminosity of 4.7~fb${}^{-1}$ collected with the CMS detector at $\sqrt{s} = 7$ TeV. The observed dijet mass distribution is modeled empirically with a set of templates obtained from simulated event samples. We set an upper limit of 1.3~pb at 95\% confidence level on the production cross section times W$\to\ell\nu$ branching fraction for a generic Gaussian signal peaked at 150~GeV. %%which corresponds to a cross %%section of 1.5~pb at the Tevatron. Several theoretical models that predict a resonant enhancement near 150 GeV are excluded.