Top quark anomalous couplings at the high-luminosity phase of the LHC

Abstract

The combination of the latest and most precise measurements of several top quark properties is presented in this paper in order to establish allowed regions on anomalous contributions to the Lorentz structure of the W tb vertex. These measurements include single top production cross sections, W boson helicity fractions and forward-backward asymmetries, both at Tevatron and at the Large Hadron Collider, up to a center-of-mass energy of 13 TeV. The results obtained at 95% Confidence Level for the top quark anomalous couplings are compared with the limits extracted from a combination that includes the expected measurements at the future High-Luminosity run of the Large Hadron Collider.

New physics with boosted single top production at the LHC and future colliders

“…At the HL-LHC the precision is expected to improve, assuming a reduction of modeling uncertainties and other systematic uncertainties associated to the Monte Carlo sample size. The expected limits at 95% CL are g L ∈ [−0.11, 0.08] from W helicity fractions and g L ∈ [−0.16, 0.19] from single top cross sections [40]. 3 Therefore, the sensitivity obtained with high-p T measurements is competitive with precision measurements performed in top production and decays.…”

BSM reach of single top-quark measurements

“…95% CL limits on anomalous couplings obtained by combining helicity fractions, single top production cross section and A FB asymmetries can be found in [14,15]. Those limits are summarized in Table 1 where ImV L is set to be 0.…”

“…The first two lines show 95% CL limits on anomalous couplings allowing all couplings to vary simultaneously, these limits are extracted from collected data at LHC and Tevatron [14]. The bottom two lines show limits where ReV L is kept fixed to 1 and include the extrapolated results from the HL-LHC (3000 fb −1 ) [15].…”