Dip or nothingness of a Higgs resonance from the interference with a complex phase

Abstract

We show that new resonance shapes---a pure dip, nothingness, and an enhanced pure peak---can be produced from the interference between the resonance and continuum with a relative phase. Production conditions of those new shapes are derived based on a general parametrization of the interference. The narrow width approximation is modified to work with the nonzero imaginary part of interference, and the correction factor can characterize the resonance shape. We demonstrate that the new resonance shapes of heavy Higgs bosons, ${H}^{0}$ and ${A}^{0}$ in the type-II aligned two Higgs doublet model, generally show up in $gg\ensuremath{\rightarrow}{H}^{0}/{A}^{0}\ensuremath{\rightarrow}t\overline{t}$ as well as $b\overline{b}$ and $\ensuremath{\gamma}\ensuremath{\gamma}$ channels. The pure ${A}^{0}$ resonance dip in the $t\overline{t}$ channel is a particularly interesting signal as it can be probed by the current search techniques that do not even take into account interferences; the high-luminosity LHC 14 TeV can perhaps probe a large part of its parameter space.