Combinations of single-top-quark production cross-section measurements and |f_LV V_tb| determinations at √s = 7 and 8 TeV with the ATLAS and CMS experiments

Abstract

This paper presents the combinations of single-top-quark production cross-section measurements by the ATLAS and CMS Collaborations, using data from LHC proton-proton collisions at (\sqrt{s}) = 7 and 8 TeV corresponding to integrated luminosities of 1.17 to 5.1 fb⁻¹ at (\sqrt{s}) = 7 TeV and 12.2 to 20.3 fb⁻¹ at (\sqrt{s})=8TeV. These combinations are performed per centre-of-mass energy and for each production mode: (t)-channel, (tW), and (s)-channel. The combined (t)-channel cross-sections are 67.5 ± 5.7 pb and 87.7 ± 5.8 pb at (\sqrt{s}) = 7 and 8 TeV respectively. The combined (tW) cross-sections are 16.3 ± 4.1 pb and 23.1 ± 3.6 pb at (\sqrt{s}) = 7 and 8 TeV respectively. For the (s)-channel cross-section, the combination yields 4.9 ± 1.4 pb at (\sqrt{s})=8TeV. The square of the magnitude of the CKM matrix element (V_{tb}) multiplied by a form factor f LV is determined for each production mode and centre-of-mass energy, using the ratio of the measured cross-section to its theoretical prediction. It is assumed that the top-quark-related CKM matrix elements obey the relation (|V_{td}|,|V_{ts}| ≪ |V_{tb}|). All the (|f_{LV}V_{tb}|^2) determinations, extracted from individual ratios at (\sqrt{s}) = 7 and 8 TeV, are combined, resulting in (|f_{LV}V_{tb}|) = 1.02 ± 0.04 (meas.) ± 0.02 (theo.). All combined measurements are consistent with their corresponding Standard Model predictions.

Description
Keywords
High Energy Physics - Experiment, Hadron-Hadron scattering (experiments)
Citation
Aaboud, M., Aad, G., Abbott, B., Abbott, D. C., Abdinov, O., Abed Abud, A., Abhayasinghe, D. K., Abidi, S. H., AbouZeid, O. S., Abraham, N. L., Abramowicz, H., Abreu, H., Abulaiti, Y., Acharya, B. S., Adachi, S., Adam, L., Adamczyk, L., … Adamek, L. (2019). Combinations of single-top-quark production cross-section measurements and |fLVVtb| determinations at $\sqrt{s}$ = 7 and 8 TeV with the ATLAS and CMS experiments. In Journal of High Energy Physics (Vol. 2019, Issue 5). Springer Science and Business Media LLC. https://doi.org/10.1007/jhep05(2019)088