Physics Letters B 763 (2016) 341–346
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Determination of the top-quark mass from hadro-production of single
top-quarks
S. Alekhin
a,b
, S. Moch
a,∗
, S. Thier
a
a
II. Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany
b
Institute for High Energy Physics, 142281 Protvino, Moscow region, Russia
a r t i c l e i n f o a b s t r a c t
Article history:
Received
30 August 2016
Received
in revised form 15 October 2016
Accepted
20 October 2016
Available
online 28 October 2016
Editor:
A. Ringwald
We present a new determination of the top-quark mass m
t
based on the experimental data from the
Tevatron and the LHC for single-top hadro-production. We use the inclusive cross sections of s-and
t-channel top-quark production to extract m
t
and to minimize the dependence on the strong coupling
constant and the gluon distribution in the proton compared to the hadro-production of top-quark pairs.
As part of our analysis we compute the next-to-next-to-leading order approximation for the s-channel
cross
section in perturbative QCD based on the known soft-gluon corrections and implement it in the
program HatHor for the numerical evaluation of the hadronic cross section. Results for the top-quark
mass are reported in the MS and in the on-shell renormalization scheme.
© 2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP
3
.
Since the discovery of the top-quark in 1995 [1,2], the precise
value of its mass has always been of great interest as a funda-
mental
parameter of the Standard Model (SM). In the course of
time several approaches have been used to extract the top-quark
mass m
t
as summarized for instance in [3]. While kinematic fits to
the top-quark decay products allow for a very precise determina-
tion
of parameters in Monte Carlo (MC) programs that are used to
describe the measured distributions, the relation of these MC pa-
rameters
to the fundamental SM parameters needs to be calibrated
and related uncertainties need to be taken into account [4]. The
determination of the top-quark mass from inclusive cross sections
measured at the hadron colliders Tevatron and the Large Hadron
Collider (LHC) provides an alternative way. This allows to relate
the experimental cross section measurements directly to theoreti-
cal
calculations which use a top-quark mass parameter in a well-
defined
renormalization scheme.
In
this regard, the pair production of top-quarks has been of
primary interest. It is dominantly mediated by the strong inter-
actions.
In consequence, theoretical predictions for top-quark pair
production are highly sensitive to the value of the strong coupling
constant α
s
as well as to the parton luminosity parameterized
through the parton distribution functions (PDFs) of the colliding
hadrons. In fact, the uncertainty in the value of α
s
and the depen-
dence
on the gluon PDF are the dominant sources which limit the
*
Corresponding author.
E-mail
address: sven-olaf.moch@desy.de (S. Moch).
precision of current theory predictions at the LHC [5]. Future mea-
surements
in particular at the LHC in Run 2 can potentially provide
improved determinations of α
s
and the PDFs, yet it is worth to in-
vestigate
other methods to access m
t
that do not rely on these
controversial quantities.
In this letter we determine the top-quark mass based on single-
top
production cross section measurements as a complementary
way to arrive at a well-defined value for m
t
that is largely indepen-
dent
of α
s
and the gluon PDFs. Single-top production generates the
top-quark in an electroweak interaction, predominantly in a ver-
tex
with a bottom-quark and a W -boson. The orientation of this
vertex assigns single-top production diagrams to different chan-
nels
as illustrated in Fig. 1. As our focus is on the minimization
of the correlation between m
t
, α
s
and the gluon luminosity, we
consider only the so-called s-channel and t-channel production of
single top-quarks in the following. The cross sections for those pro-
cesses
are directly proportional to the light quark PDFs, which are
nowadays well constrained by data on the measured charged lep-
ton
asymmetries from W
±
gauge-boson production at the LHC. We
use the inclusive single-top cross section measurements for those
channels to determine m
t
and compare the results to the ones ob-
tained
from t
¯
t production. Our study is based on data from the
Tevatron at center-of-mass energy
√
S = 1.96 TeV as well as from
the LHC at
√
S = 7, 8 and the most recent one at 13 TeV.
The theoretical description of both top-quark pair production
and single-top production has reached a very high level of accu-
racy.
The total cross section of t
¯
t hadro-production has been calcu-
lated
up to the next-to-next-to-leading order (NNLO) corrections
http://dx.doi.org/10.1016/j.physletb.2016.10.062
0370-2693/
© 2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP
3
.