Measuring properties of a Heavy Higgs boson in the $$ H\to t\overline{t}\to b{W}^{+}\overline{b}{W}^{-} $$ decay

• Published in: The journal of high energy physics Vol. 2018; no. 5
• Main Authors: Chang, Jung, Cheung, Kingman, Lee, Jae Sik, Lu, Chih-Ting, Park, Jubin
• Format: Journal Article
• Language: English
• Published: 01-05-2018
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP05(2018)162

Suppose a heavy neutral Higgs or scalar boson
H
is discovered at the LHC, it is important to investigate its couplings to the standard model particles as much as possible. Here in this work we attempt to probe the CP-even and CP-odd couplings of the heavy Higgs boson to a pair of top quarks, through the decay
$$ H\to t\overline{t}\to b{W}^{+}\overline{b}{W}^{-} $$
H
→
t
t
¯
→
b
W
+
b
¯
W
−
. We use the helicity-amplitude method to write down the most general form for the angular distributions of the final-state
b
quarks and
W
bosons. We figure out that there are 6 types of angular observables and, under
$$ \mathrm{C}\mathrm{P}\tilde{\mathrm{T}} $$
C
P
T
˜
conservation, one-dimensional angular distributions can only reveal two of them. Nevertheless, the
H
couplings to the
$$ t\overline{t} $$
t
t
¯
pair can be fully determined by exploiting the one-dimensional angular distributions. A Higgs-boson mass of 380 GeV not too far above the
$$ t\overline{t} $$
t
t
¯
threshold is illustrated with full details. With a total of 10
4
events of
$$ H\to t\overline{t}\to b{W}^{+}\overline{b}{W}^{+} $$
H
→
t
t
¯
→
b
W
+
b
¯
W
+
, one can determine the couplings up to 10-20% uncertainties.