Interpretations of the ATLAS diboson resonances

The ATLAS Collaboration has reported excesses in searches for resonant diboson production decaying into hadronic final states. This deviation from the standard model prediction may be a signature of an extra bosonic particle having a mass of around 2 TeV with a fairly narrow width, which implies the presence of a new perturbative theory at the TeV scale. In this paper, we study interpretations of the signal and its implication to physics beyond the standard model. We find that the resonance could be regarded as a leptophobic vector particle, which could explain a part of the observed excesses without conflict with the present constraints from other direct searches for heavy vector bosons at the LHC as well as the electroweak precision measurements.

Figure 1

$\sigma (pp\to W^{\prime })\times \mathrm{BR}(W^{\prime }\to WZ)$ (black solid lines). Here we set $M_{W^{\prime }}=2\mathrm{TeV}$. The light-green shaded region is disfavored by the electroweak precision measurements. Dark-green and blue shaded regions are excluded by the limits from the $W^{\prime }\to Wh$ [6] and the dijet [18, 19] channels, respectively. The brown dashed line represents the case of the $\mathrm{SU}(2{)}_L\otimes \mathrm{SU}(2{)}_R\otimes \mathrm{U}(1{)}_{B-L}$ model with $\tan \beta =40$.

Figure 2

Branching ratios of dijet, top quarks, and $WW$ channels as functions of $Q_Q^{\prime }$ from top to bottom. Solid (dashed) lines represent the case of $\tan \beta =40$ (4). We set $M_{Z^{\prime }}=2\mathrm{TeV}$. The vertical gray line corresponds to the charge assignment in the ${\mathrm{E}}_6$ inspired leptophobic $Z^{\prime }$ model mentioned in the text.

Figure 3

Contour for the values of $\sigma (pp\to Z^{\prime })\times \mathrm{BR}(Z^{\prime }\to WW)$ in black solid lines. We also show the total decay width ${\mathrm{\Gamma }}_{\mathrm{tot}}$ in green dashed lines. Here we set $\tan \beta =40$ and $M_{Z^{\prime }}=2\mathrm{TeV}$. Blue and dark-blue shaded regions are excluded by the resonance searches in the dijet and $Z^{\prime }\to Zh$ channels, respectively. The dark (light) gray area is excluded by the $t\overline{t}$ resonance search if the $Z^{\prime }$ decay width is 200 (20) GeV. The vertical gray line corresponds to the charge assignment in the ${\mathrm{E}}_6$ inspired leptophobic $Z^{\prime }$ model mentioned in the text.