SNO+

Abstract:

The algorithms used by the ATLAS Collaboration during Run 2 of the Large Hadron Collider to identify jets containing b-hadrons are presented. The performance of the algorithms is evaluated in the simulation and the efficiency with which these algorithms identify jets containing b-hadrons is measured in collision data. The measurement uses a likelihood-based method in a sample highly enriched in tt¯ events. The topology of the t→Wb decays is exploited to simultaneously measure both the jet flavour composition of the sample and the efficiency in a transverse momentum range from 20 to 600 GeV. The efficiency measurement is subsequently compared with that predicted by the simulation. The data used in this measurement, corresponding to a total integrated luminosity of 80.5 fb−1, were collected in proton–proton collisions during the years 2015–2017 at a centre-of-mass energy s√= 13 TeV. By simultaneously extracting both the efficiency and jet flavour composition, this measurement significantly improves the precision compared to previous results, with uncertainties ranging from 1 to 8% depending on the jet transverse momentum.

Abstract:

© 2019, The Author(s). One correction is made to the figure 4e of the paper.

Abstract:

In this document, technical details of the upgrade plan of the J-PARC neutrino beamline for the extension of the T2K experiment are described. T2K has proposed to accumulate data corresponding to $2\times{}10^{22}$ protons-on-target in the next decade, aiming at an initial observation of CP violation with $3\sigma$ or higher significance in the case of maximal CP violation. Methods to increase the neutrino beam intensity, which are necessary to achieve the proposed data increase, are described.

Abstract:

A search is conducted for the electroweak pair production of a chargino and a neutralino pp → χ˜ 1 χ˜ 0 2, where the chargino decays into the lightest neutralino and a W boson, χ˜ 1 → χ˜ 0 1W, while the neutralino decays into the lightest neutralino and a Standard Model-like 125 GeV Higgs boson, χ˜ 0 2 → χ˜ 0 1h. Fully hadronic, semileptonic, diphoton, and multilepton (electrons, muons) final states with missing transverse momentum are considered in this search. Higgs bosons in the final state are identified by either two jets originating from bottom quarks (h → bb¯), two photons (h → γγ), or leptons from the decay modes h → WW, h → ZZ or h → ττ. The analysis is based on 36.1 fb−1 of ffiffi s p ¼ 13 TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. Observations are consistent with the Standard Model expectations, and 95% confidence-level limits of up to 680 GeV in χ˜ 1 =χ˜ 0 2 mass are set in the context of a simplified supersymmetric model.