Monday, October 12, 2020

The Latest Standard Model Constant Estimates

A new analysis of LHC Run-1 data produces estimates for the strong force coupling constant and the top quark mass that are consistent with the global averages with intermediate sized margins of error (which isn't entirely independent of these measurements, as there is some data overlap).

The top quark mass measurement in this study is 1.2 sigma on the high side of the global average (the PDG direct measurement global average is 172.76±0.30 GeV). The strong force coupling constant measurement in this study is 1.2 sigma on the low side of the global average, which is 0.1179±0.0010. 

Submitted on 8 Oct 2020]

Simultaneous extraction of αs and mt from LHC tt¯ differential distributions

We present a joint extraction of the strong coupling αs and the top-quark pole mass mt from measurements of top-quark pair production performed by the ATLAS and CMS experiments at the 8 TeV LHC. For the first time, differential NNLO theory predictions for different values of the top-quark mass are utilised for four kinematic distributions: the average transverse momentum of the top-quark, its average rapidity and the pair invariant mass and rapidity. The use of fastNLO tables for these distributions allows rapid evaluation of the differential theory predictions for different PDF sets. We consider the single differential distributions from the experiments both separately and in combination in order to obtain the best fit to theory. Our final values are αs=0.1159+0.00130.0014 and mt=173.8+0.80.8 GeV which are compatible with previous extractions using top-quark measurements. In the case of mt, our value is also compatible with the world average value collated by the Particle Data Group.
Comments:35 pages. Supplementary results available at this http URL
Subjects:High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex)
Report number:CAVENDISH-HEP-20/12, TTK-20-31, P3H-20-051
Cite as:arXiv:2010.04171 [hep-ph]

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