Abstract
A search is presented for the pair production of new heavy resonances, each decaying into a top quark (t) or antiquark and a gluon (g). The analysis uses data recorded with the CMS detector from proton–proton collisions at a center-of-mass energy of 13
$$\,\text {Te}\hspace{-.08em}\text {V}$$
Te
V
at the LHC, corresponding to an integrated luminosity of 138
$$\,\text {fb}^{-1}$$
fb
-
1
. Events with one muon or electron, multiple jets, and missing transverse momentum are selected. After using a deep neural network to enrich the data sample with signal-like events, distributions in the scalar sum of the transverse momenta of all reconstructed objects are analyzed in the search for a signal. No significant deviations from the standard model prediction are found. Upper limits at 95% confidence level are set on the product of cross section and branching fraction squared for the pair production of excited top quarks in the
$$\text {t}^{*} \rightarrow {\text {t}} {\text {g}} $$
t
∗
→
tg
decay channel. The upper limits range from 120 to 0.8
$$\,\text {fb}$$
fb
for a
$$\text {t}^{*} $$
t
∗
with spin-1/2 and from 15 to 1.0
$$\,\text {fb}$$
fb
for a
$$\text {t}^{*} $$
t
∗
with spin-3/2. These correspond to mass exclusion limits up to 1050 and 1700
$$\,\text {Ge}\hspace{-.08em}\text {V}$$
Ge
V
for spin-1/2 and spin-3/2
$$\text {t}^{*} $$
t
∗
particles, respectively. These are the most stringent limits to date on the existence of
$$\text {t}^{*} \rightarrow {\text {t}} {\text {g}} $$
t
∗
→
tg
resonances.
