Phenomenology of a light gluon resonance in top-physics at Tevatron and LHC

E. ALVAREZ, L. DA ROLD, J. I. SANCHEZ VIETTO, A. SZYNKMAN

JOURNAL OF HIGH ENERGY PHYSICS - (Online)

Springer - SISA

Lugar: Trieste; Año: 2011 vol. 1109 p. 1 - 22

1029-8479

We present a phenomenological analysis of the recent Tevatron resultson the $tar t$ forward-backward asymmetry and invariant-massspectrum assuming a new contribution from an $s$-channel gluon resonance with a mass in the range from $700$ to $2500$ GeV.  In contrast to most of the previous works, this analysis shows that for masses below $sim 1$ TeV resonant New Physics could accommodate the experimental data.  In general, we find that axial-like couplings are preferred for light and top quark couplings, and that only top quark couples strongly to New Physics.  We find that composite model scenarios arise naturally from only phenomenological analyses of the experimental results. We show that our results are compatible with recent LHC limits in dijet and $tar t$ production, and find some tension for large resonance mass $sim 2.5$ TeV.  We indicate as best observables for discriminating a relatively light new gluon a better resolution in CDF forward-backward asymmetry, as well as the $tar t$ charge asymmetry and invariant-mass spectrum at the LHC.