Measurement of polarization angular coefficients in Z boson leptonic decays with ATLAS at the LHC

• Published in: Physics of particles and nuclei Vol. 48; no. 5; pp. 760 - 762
• Main Author: Fedin, O.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.09.2017
• Subjects: 2016; ANGULAR DISTRIBUTION; ATLAS DETECTOR; CERN LHC; Dubna; LEPTONIC DECAY; LEPTONS; Particle and Nuclear Physics; PERTURBATION THEORY; Physics; Physics and Astronomy; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; POLARIZATION; QUANTUM CHROMODYNAMICS; REST MASS; Russia; The International Session-Conference of SNP PSD RAS “Physics of Fundamental Interactions” April 12–15; W MINUS BOSONS; W PLUS BOSONS; WEINBERG ANGLE; WEINBERG-SALAM GAUGE MODEL; Z NEUTRAL BOSONS
• ISSN: 1063-7796; 1531-8559
• DOI: 10.1134/S1063779617050161

This paper presents the complete set of polarization angular coefficients A 0−7 describing lepton angular distributions in Z boson decay, which were measured at the ATLAS experiment in proton–proton collisions with the energy √ s = 8 TeV. Theoretical values for the difference A 0 − A 2 calculated in the fixed-order QCD perturbation theory O(α s 2 ), demonstrate significant deviation from the measured data, which indicates the necessity of taking into account higher order corrections. The evidence of nonzero coefficients A 5,6,7 was obtained for the first time, in accordance with theoretical calculations in O(α s 2 ) approximation. Measurement of the polarization angular coefficients A i is important for subsequent precision measurement of parameters of the electroweak model at the LHC, such as the sine of Weinberg electroweak mixing angle sin 2 θ W and the W boson mass.