288
P. Jenni and T. S. Virdee
The H → γ γ mode provides good sensitivity to almost all Higgs boson
production processes. The interference between W-loop and top-loops provides
sensitivity to the relative sign of the fermion and boson couplings.
It is common to use a dedicated boosted decision tree discriminator to select
and categorize events; it is constrained using the diphoton kinematic variables,
photon isolation and identification variables, and per-event estimated diphoton mass
resolution for the pair of photons in the event.
ATLAS has measured the properties of the H → γ γ mode using 79.8 fb −1 of
collision data recorded at
√
s = 13 TeV [38]. The properties measured include
the signal strength, the cross section measurements for the production of a Higgs
boson through gluon–gluon fusion, vector boson fusion, and in association with
a vector boson or a top-quark pair. They are found to be compatible with the
predictions of the SM. The signal strength is measured to be μ = 1.06 ± 0.08
(stat), +0.08 –0.07 (exp), +0.07 –0.06 (theo), improving on the precision of the previous
ATLAS measurement at
√ s = 7 and 8 TeV by over a factor of three. The cross
section for the production of the Higgs boson decaying to two isolated photons in the
fiducial region of the selection of photons is measured to be 60.4 ± 6.1 (stat) ± 6.0
(exp) ± 60.3 (theo) fb, in good agreement with the SM value of 63.5 ± 3.3 fb. The
differential cross section, sensitive to higher order QCD corrections and properties
of the Higgs boson, such as its spin and CP quantum numbers, is illustrated in Fig.
6.9b and no significant deviation from a wide array of SM predictions is observed.
CMS has reported results from the H → γγ decay channel based on data
collected at
√
s = 13 TeV corresponding to an integrated luminosity of 35.6 fb −1
[39]. The diphoton invariant mass distribution, observed in CMS, is shown in
ATLAS
ATLAS Preliminary
Data, tot. unc.
gg H default MC + XH
NNLOJET SCET + XH
XH = VBF+VH+ttH+bbH
Syst. unc.
H
80
s = 13 TeV, 36.1 fb –1
s = 13 TeV, 79.8 fb –1
60
40
20
Stat. Unc.
Tot. Unc.
100
10 –1
1
10 –2
2
1
0
300
250
200
150
100
50
0
350
0
150
d
fid / dp
T
[fb/Gev]
p
T
[Gev]
Ratio to default
MC + XH
140
130
m [GeV]
j
jj
120
110
(a)
(b)
160
Fraction [%]
Fig. 6.9 (a) The data-driven determination of event fractions for γγ, γ-jet, and jet-jet events as a
function of m γγ after the final selection. (b) The fiducial differential cross section for pp. → γγ as
a function of p T (γγ) compared to the SM expectations
P. Jenni and T. S. Virdee
The H → γ γ mode provides good sensitivity to almost all Higgs boson
production processes. The interference between W-loop and top-loops provides
sensitivity to the relative sign of the fermion and boson couplings.
It is common to use a dedicated boosted decision tree discriminator to select
and categorize events; it is constrained using the diphoton kinematic variables,
photon isolation and identification variables, and per-event estimated diphoton mass
resolution for the pair of photons in the event.
ATLAS has measured the properties of the H → γ γ mode using 79.8 fb −1 of
collision data recorded at
√
s = 13 TeV [38]. The properties measured include
the signal strength, the cross section measurements for the production of a Higgs
boson through gluon–gluon fusion, vector boson fusion, and in association with
a vector boson or a top-quark pair. They are found to be compatible with the
predictions of the SM. The signal strength is measured to be μ = 1.06 ± 0.08
(stat), +0.08 –0.07 (exp), +0.07 –0.06 (theo), improving on the precision of the previous
ATLAS measurement at
√ s = 7 and 8 TeV by over a factor of three. The cross
section for the production of the Higgs boson decaying to two isolated photons in the
fiducial region of the selection of photons is measured to be 60.4 ± 6.1 (stat) ± 6.0
(exp) ± 60.3 (theo) fb, in good agreement with the SM value of 63.5 ± 3.3 fb. The
differential cross section, sensitive to higher order QCD corrections and properties
of the Higgs boson, such as its spin and CP quantum numbers, is illustrated in Fig.
6.9b and no significant deviation from a wide array of SM predictions is observed.
CMS has reported results from the H → γγ decay channel based on data
collected at
√
s = 13 TeV corresponding to an integrated luminosity of 35.6 fb −1
[39]. The diphoton invariant mass distribution, observed in CMS, is shown in
ATLAS
ATLAS Preliminary
Data, tot. unc.
gg H default MC + XH
NNLOJET SCET + XH
XH = VBF+VH+ttH+bbH
Syst. unc.
H
80
s = 13 TeV, 36.1 fb –1
s = 13 TeV, 79.8 fb –1
60
40
20
Stat. Unc.
Tot. Unc.
100
10 –1
1
10 –2
2
1
0
300
250
200
150
100
50
0
350
0
150
d
fid / dp
T
[fb/Gev]
p
T
[Gev]
Ratio to default
MC + XH
140
130
m [GeV]
j
jj
120
110
(a)
(b)
160
Fraction [%]
Fig. 6.9 (a) The data-driven determination of event fractions for γγ, γ-jet, and jet-jet events as a
function of m γγ after the final selection. (b) The fiducial differential cross section for pp. → γγ as
a function of p T (γγ) compared to the SM expectations