Abstract
AbstractWe study the time-honoured decay $$H^\pm \rightarrow A W^\pm $$
H
±
→
A
W
±
but for the first time, we do so for the case of both A and $$W^\pm $$
W
±
being off-shell, therefore computing a $$1\rightarrow 4$$
1
→
4
body decay. We show that the corresponding decay rate not only extends the reach of $$H^\pm $$
H
±
searches to small masses of the latter but also that the results of our implementation differ significantly from the yield of the $$1\rightarrow 3$$
1
→
3
body decay over the phase space region in which the latter is normally used. We show the phenomenological relevance of this implementation in the case of the so-called lepton-specific 2-Higgs Doublet Model (2HDM) over the mass region wherein the aforementioned $$1\rightarrow 4$$
1
→
4
body decay can dominate just beyond the top (anti)quark mass. This mass region is accessible in the lepton-specific 2HDM as the Yukawa couplings are such that limits from $$b \rightarrow s \gamma $$
b
→
s
γ
and $$\tau \rightarrow \mu \nu _{\tau } \bar{\nu _\mu }$$
τ
→
μ
ν
τ
ν
μ
¯
observables on $$M_{H^\pm }$$
M
H
±
are rather mild. However, we emphasize that similar effects may occur in other 2HDM types, as the $$W^\pm H^\mp A$$
W
±
H
∓
A
vertex is 2HDM type independent.
Funder
Science and Technology Facilities Council
Publisher
Springer Science and Business Media LLC