O new physics, where art thou? A global search in the top sector

Abstract

We provide a comprehensive global analysis of Run II top measurements at the LHC in terms of dimension-6 operators. A distinctive feature of the top sector as compared to the Higgs-electroweak sector is the large number of four-quark operators. We discuss in detail how they can be tested and how quadratic terms lead to a stable limit on each individual Wilson coefficient. Predictions for all observables are computed at NLO in QCD. Our SFitter analysis framework features a detailed error treatment and shows that theoretical uncertainties are a limiting factor. * Notice that in Ref.[15] the top-gluon operator is defined as twice the OtG in Eq. (2.5).

Electroweak loops as a probe of new physics in $$ t\overline{t} $$ production at the LHC

“…Refs. [48,49] report comparatively loose bounds obtained from studying tZ production which also confirm that electroweak corrections to tt are apparently the strongest probe available at the LHC.…”

“…Global fits of New Physics contributions in terms of dimension-six operators relevant for the top quark sector have been carried out in refs. [48][49][50]. The resulting constraints on New Physics are substantial (see e.g.…”

New Physics Searches with Top Quarks

“…Each of these coefficients is constrained directly and also through correlations with other coefficients from LHC measurements of top observables. Several global analyses of top-pair production, single-top production and boson-associated top production have been performed [5,6,7,8]. In Figure 1 we show the results of the most recent global fit to LHC top data from Run I and Run II [8].…”

“…• identify the top's chirality in four-quark operators; Figure 1: Global analysis of LHC data for top observables in SMEFT [8]. Shown are 95% (light red/green/blue) and 68% (dark red/green/blue) CL bounds on top operators from global fits to LHJC data on top-pair production (blue), single top (green) and to the full data set of top-pair, single-top and bosonassociated top production (red).…”

Class imbalance techniques for high energy physics

“…Stronger bounds can be obtained indirectly, e.g. through global fits [56,57,58,59,60,61,62,63,64], among other methods. 2 However there are assumptions build into any indirect analysis.…”