Leptophobic $Z′$ in models with multiple Higgs doublet fields
Journal
JHEP
Journal Volume
05
Pages
127
Date Issued
2015-02
Author(s)
Abstract
Abstract: We study the collider phenomenology of the leptophobic Z′ boson from an extra U(1)′ gauge symmetry in models with N -Higgs doublet fields. We assume that the Z′ boson at tree level has (i) no Z-Z′ mixing, (ii) no interaction with the charged leptons, and (iii) no flavour-changing neutral current. Under such a setup, it is shown that in the N = 1 case, all the U(1)′ charges of left-handed quark doublets and right-handed up- and down- type quarks are required to be the same, while in the N ≥ 3 case one can take different charges for the three types of quarks. The N = 2 case is not well-defined under the above three requirements. We study the pp→Z′V→bb¯V$$ pp\to Z^{\prime }V\to b\overline{b}V $$ processes (V = γ, Z and W±) with the leptonic decays of Z and W± at the LHC. The most promising discovery channel or the most stringent constraint on the U(1)′ gauge coupling constant comes from the Z′γ process below the tt¯$$ t\overline{t} $$ threshold and from the tt¯$$ t\overline{t} $$ process above the threshold. Assuming the collision energy of 8 TeV and integrated luminosity of 19.6 fb−1, we find that the constraint from the Z′γ search in the lower mass regime can be stronger than that from the UA2 experiment. In the N ≥ 3 case, we consider four benchmark points for the Z′ couplings with quarks. If such a Z′ is discovered, a careful comparison between the Z′γ and Z′W signals is crucial to reveal the nature of Z′ couplings with quarks. We also present the discovery reach of the Z′ boson at the 14-TeV LHC in both N = 1 and N ≥ 3 cases.
SDGs
Type
journal article