• Energy Research

High transverse momentum jets produced in pp collisions at a centre of mass energy of 7 TeV are used to measure the transverse energy-energy correlation function and its associated azimuthal asymmetry. The data were recorded with the ATLAS detector at the LHC in the year 2011 and correspond to an integrated luminosity of 158 $\mathrm{pb}^{-1}$. The selection criteria demand the average transverse momentum of the two leading jets in an event to be larger than 250 GeV. The data at detector level are well described by Monte Carlo event generators. They are unfolded to the particle level and compared with theoretical calculations at next-to-leading-order accuracy. The agreement between data and theory is good and provides a precision test of perturbative Quantum Chromodynamics at large momentum transfers. From this comparison, the strong coupling constant given at the $Z$ boson mass is determined to be $��_{\mathrm{s}}(m_Z) = 0.1173 \pm 0.0010 \mbox{ (exp.) }^{+0.0065}_{-0.0026} \mbox{ (theo.)}$. 19 pages plus author list (35 pages total), 4 figures, 4 tables, submitted to Phys. Lett. B, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2014-03/

Abstract The production of Z bosons in association with a high-energy photon (Zγ production) is studied in the neutrino decay channel of the Z boson using pp collisions at $$ \sqrt{s}=13 $$ s = 13 TeV. The analysis uses a data sample with an integrated luminosity of 36.1fb−1 collected by the ATLAS detector at the LHC in 2015 and 2016. Candidate Zγ events with invisible decays of the Z boson are selected by requiring significant transverse momentum (p T) of the dineutrino system in conjunction with a single isolated photon with large transverse energy (E T). The rate of Zγ production is measured as a function of photon E T, dineutrino system p T and jet multiplicity. Evidence of anomalous triple gauge-boson couplings is sought in Zγ production with photon E T greater than 600 GeV. No excess is observed relative to the Standard Model expectation, and upper limits are set on the strength of ZZγ and Zγγ couplings.