Measurement of the Higgs boson production rate in association with top quarks in final states with electrons, muons, and hadronically decaying tau leptons at $$\sqrt{s} = 13\,\text {TeV} $$ s = 13 TeV
The European Physical Journal C(2021)
摘要
The rate for Higgs (
$${\mathrm{H}} $$
) bosons production in association with either one (
$${\mathrm{t}} {\mathrm{H}} $$
) or two (
$${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$
) top quarks is measured in final states containing multiple electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton–proton collisions recorded at a center-of-mass energy of
$$13\,\text {TeV} $$
by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137
$$\,\text {fb}^{-1}$$
. The analysis is aimed at events that contain
$${\mathrm{H}} \rightarrow {\mathrm{W}} {\mathrm{W}} $$
,
$${\mathrm{H}} \rightarrow {\uptau } {\uptau } $$
, or
$${\mathrm{H}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} $$
decays and each of the top quark(s) decays either to lepton+jets or all-jet channels. Sensitivity to signal is maximized by including ten signatures in the analysis, depending on the lepton multiplicity. The separation among
$${\mathrm{t}} {\mathrm{H}} $$
,
$${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$
, and the backgrounds is enhanced through machine-learning techniques and matrix-element methods. The measured production rates for the
$${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$
and
$${\mathrm{t}} {\mathrm{H}} $$
signals correspond to
$$0.92 \pm 0.19\,\text {(stat)} ^{+0.17}_{-0.13}\,\text {(syst)} $$
and
$$5.7 \pm 2.7\,\text {(stat)} \pm 3.0\,\text {(syst)} $$
of their respective standard model (SM) expectations. The corresponding observed (expected) significance amounts to 4.7 (5.2) standard deviations for
$${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$
, and to 1.4 (0.3) for
$${\mathrm{t}} {\mathrm{H}} $$
production. Assuming that the Higgs boson coupling to the tau lepton is equal in strength to its expectation in the SM, the coupling
$$y_{{\mathrm{t}}}$$
of the Higgs boson to the top quark divided by its SM expectation,
$$\kappa _{{\mathrm{t}}}=y_{{\mathrm{t}}}/y_{{\mathrm{t}}}^{\mathrm {SM}}$$
, is constrained to be within
$$-0.9< \kappa _{{\mathrm{t}}}< -0.7$$
or
$$0.7< \kappa _{{\mathrm{t}}}< 1.1$$
, at 95% confidence level. This result is the most sensitive measurement of the
$${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$
production rate to date.
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