Rivet analyses
Differential cross-sections of t-channel single-top production
Experiment: ATLAS (LHC)
Inspire ID: 3098996
Status: VALIDATED
Authors: - Maren Stratmann
References: - JHEP 05 (2026) 174 - DOI:10.1007/JHEP05(2026)174 - arXiv: 2601.04938 - Expt page: ATLAS-TOPQ-2023-44
Beams: p+ p+
Beam energies: (6500.0, 6500.0)GeV
Run details: - Parton-level pp -> tq, no fiducial selection
The production of single top quarks and top antiquarks via thei t-channel exchange of a virtual W boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider. The full Run 2 data sample recorded with the ATLAS detector in the years 2015-2018 is used, corresponding to an integrated luminosity of 140 fb−1 The absolute and normalised production cross-sections are measured differentially as a function of the transverse momentum and absolute rapidity of the top quark and top antiquark. In addition, the ratio of top quark to top antiquark production cross-sections is measured. The measured distributions are compared with next-to-leading-order quantum chromodynamics predictions obtained with different combinations of matrix-element generators, parton-shower programs and proton parton distribution functions, as well as to next-to-next-to-leading-order calculations. Overall, good agreement is observed between the measurements and the theoretical predictions. For most measured distributions, the sensitivity to differences between the predictions is limited by the systematic uncertainties in the measurement. The measured differential distributions are also interpreted in an effective field theory approach to constrain the Wilson-Coefficient CQq3, 1 associated with a four-quark operator. The interpretation accounts for the effect of the selection efficiency, which is altered significantly by non-zero contributions from CQq3, 1.
Source
code:ATLAS_2026_I3098996.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/PartonicTops.hh"
namespace Rivet {
/// @brief Differential cross-sections of t-channel single-top production
class ATLAS_2026_I3098996 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2026_I3098996);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(PartonicTops(TopDecay::ALL), "LastTop");
// Book histograms
book(_h_t_pt, 18 ,1 ,1);
book(_h_t_y, 20 ,1 ,1);
book(_h_tbar_pt, 19 ,1 ,1);
book(_h_tbar_y, 21 ,1 ,1);
book(_h_t_pt_norm, 22 ,1 ,1);
book(_h_t_y_norm, 24 ,1 ,1);
book(_h_tbar_pt_norm, 23 ,1 ,1);
book(_h_tbar_y_norm, 25 ,1 ,1);
book(_h_ratio_pt, 26 ,1 ,1);
book(_h_ratio_y, 27 ,1 ,1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Last tops (standard)
const Particles& lasttop = apply<PartonicTops>(event, "LastTop").particlesByPt();
if (lasttop.size() != 1) vetoEvent;
const Particle& t = lasttop[0];
if (t.charge() > 0) {
_h_t_pt_norm->fill(t.pT()/GeV);
_h_t_pt->fill(t.pT()/GeV);
_h_t_y_norm->fill(t.absrap());
_h_t_y->fill(t.absrap());
} else {
_h_tbar_pt_norm->fill(t.pT()/GeV);
_h_tbar_pt->fill(t.pT()/GeV);
_h_tbar_y_norm->fill(t.absrap());
_h_tbar_y->fill(t.absrap());
}
}
/// Normalise histograms etc., after the run
void finalize() {
const double sf = crossSection() / picobarn / sumOfWeights();
normalize(_h_t_pt_norm);
normalize(_h_t_y_norm);
scale(_h_t_pt, sf);
scale(_h_t_y, sf);
normalize(_h_tbar_pt_norm);
normalize(_h_tbar_y_norm);
scale(_h_tbar_pt_norm, sf);
scale(_h_tbar_y_norm, sf);
divide(_h_t_pt, _h_tbar_pt, _h_ratio_pt);
divide(_h_t_y, _h_tbar_y, _h_ratio_y);
}
/// @name Histograms
/// @{
Histo1DPtr _h_t_pt_norm, _h_t_y_norm, _h_tbar_pt_norm, _h_tbar_y_norm;
Histo1DPtr _h_t_pt, _h_t_y, _h_tbar_pt, _h_tbar_y;
Estimate1DPtr _h_ratio_pt,_h_ratio_y;
/// @}
};
RIVET_DECLARE_PLUGIN(ATLAS_2026_I3098996);
}