The CLIC Physics Potential

The physics and detector studies for the Compact Linear Collider (CLIC) are introduced. A staged programme of e+e − collisions covering √ s = 380 GeV, 1.5 TeV, and 3 TeV would allow precise measurements of Higgs boson couplings, in many cases to the percent level. This corresponds to precision higher than that expected for the high-luminosity Large Hadron Collider. Such precise Higgs coupling measurements would allow sensitivity to a variety of new physics models and the ability to distinguish between them. In addition, new particles directly produced in pairs could be measured with great precision, and measurements in the top-quark sector would provide sensitivity to new physics effects at the scales of tens of TeV

Electroweak Cross-sections and Widths

The status of W and Z cross-section and width measurements from the CDF and D0 experiments is reviewed. Recent results that are discussed: the cross-section for Z production times the branching ratio to tau pairs, the rapidity and transverse momentum distributions of Z production in the electron channel, and the direct measurements of the W width and the Z invisible width; the latter from an analysis of events with large missing transverse energy and one or more energetic jets.Comment: Contribution to the Proceedings of the 34th International Conference on High Energy Physics; 4 pages, 2 figure

Diboson Physics at the Tevatron

Tevatron diboson measurements are reviewed, and new or recent results reported for Wgamma, Zgamma, and ZZ production in the leptonic decay modes, and for WW/WZ production in the lepton plus jets decay mode. The most stringent limits on anomalous triple gauge couplings are reported for each final state.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 5 pages, 13 figure

Microbial source tracking for the UK water industry

EngD ThesisThis thesis evaluates the suitability of two emerging microbial source tracking (MST) techniques, host-associated E. coli biomarkers and community-based MST. Previous human-associated E.coli markers (H8, H12, H14, H24) were evaluated for the first time in the UK; the sensitivity of H8 (10%) was lower than previously reported (50% (Gomi et al., 2014)) and if analysed through regulatory culture-based approaches alone, would have resulted in a high false negative rate (90%). In light of this, the Hu100 marker, with the highest abundance (2.64 x 106 gene copies/100 mL) across 14 wastewater treatment plants, was developed through interrogation of 263 E.coli genomes. The abundance of Hu100 was not significantly different to other markers, which, could be due to the large variability in the proportion of E.coli containing biomarkers. Due to this variation, it is recommend that the total marker abundance is used to compare different sites. Community-based MST uses high-throughput sequencing to compare bacterial communities of environmental samples, such as sea water, faecal taxon libraries (FTLs) which contain bacterial communities from known sources. Simulated microbial communities were used to evaluate how the composition of FTLs affected the accuracy and sensitivity of community-based MST. The inclusion of local samples appears to be more important than the size of the FTL to the accuracy of community-based MST. Furthermore, the inclusion of a river water sample as a ‘background sample’, improved method sensitivity from a 5% mixture of the sewage bacterial community in river waste to a 2% contribution of sewage. Two catchment studies highlighted the ubiquity of urban diffuse pollution, largely from septic tanks and misconnections, in rural and semi-rural catchments. Community-based MST showed a good correlation with human-associated markers and (rs >0.467, p <4.45x10-06), but only when human sources were dominant. Findings suggest that community-based MST is more useful than marker-based MST to survey catchments for a range of potential pollution sources. Investing ~£230k to perform MST in-house is the best option for Northumbrian Water, and other water companies, to incorporate qPCR and sequencing into their workflows. While >3000 samples need to be processed to achieve a return on investment, the business risk remains small, and other areas of the business will benefit from this investment.Northumbrian Water and EPSR

Measurement of σ(HVeVe) x BR(H→ ZZ*) and Higgs production in ZZ fusion at a 1.4 TeV CLIC collider

This paper presents the potential measurement at 1.4 TeV CLIC of the cross-section (times branching ratio) of the Higgs production via WW fusion with the Higgs subsequently decaying in ZZ⇤, s(Hnen¯e)⇥BR(H ! ZZ⇤), and of the Higgs production via ZZ fusion with the Higgs subsequently decaying in bb¯, s(He+e)⇥BR(H ! bb¯). For the H ! ZZ⇤ decay the hadronic final state, ZZ⇤ ! qqq¯ q¯, and the semi-leptonic final state, ZZ⇤ ! qql¯ +l , are considered. The results show that s(Hnen¯e)⇥BR(H ! ZZ⇤) can be measured with a precision of 18.3% and 6% for the hadronic and semi-leptonic channel, respectively. s(He+e)⇥BR(H ! bb¯) can be measured with a precision of 1.7%. This measurement also contributes to the determination of the Higgs coupling to the Z boson, gHZZInternational Workshop on Future Linear Colliders (LCWS14) : October 6-10, Belgrade, 2014

Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton–proton collisions at the LHC

This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of √s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about 30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than 20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Focus topics for the ECFA study on Higgs / Top / EW factories

In order to stimulate new engagement and trigger some concrete studies in areas where further work would be beneficial towards fully understanding the physics potential of an $e^+e^-$ Higgs / Top / Electroweak factory, we propose to define a set of focus topics. The general reasoning and the proposed topics are described in this document.Comment: v3: fixed spelling of two author