Paul Jackson

Bio: Paul Jackson is an academic researcher from University of Adelaide. The author has contributed to research in topics: Large Hadron Collider & Higgs boson. The author has an hindex of 141, co-authored 1372 publications receiving 93464 citations. Previous affiliations of Paul Jackson include University of Rostock & Politehnica University of Bucharest.

Search for flavour-changing neutral current top-quark decays t → qZ in proton-proton collisions at √s=13 TeV with the ATLAS detector

Abstract: A search for flavour-changing neutral-current processes in top-quark decays is presented. Data collected with the ATLAS detector from proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of $ \sqrt{s}=13 $ TeV, corresponding to an integrated luminosity of 36.1 fb$^{−1}$, are analysed. The search is performed using top-quark pair events, with one top quark decaying through the t → qZ (q = u, c) flavour-changing neutral-current channel, and the other through the dominant Standard Model mode t → bW. Only Z boson decays into charged leptons and leptonic W boson decays are considered as signal. Consequently, the final-state topology is characterized by the presence of three isolated charged leptons (electrons or muons), at least two jets, one of the jets originating from a b-quark, and missing transverse momentum from the undetected neutrino. The data are consistent with Standard Model background contributions, and at 95% confidence level the search sets observed (expected) upper limits of 1.7 × 10$^{−4}$ (2.4 × 10$^{−4}$) on the t → uZ branching ratio and 2.4 × 10$^{−4}$ (3.2 × 10$^{−4}$) on the t → cZ branching ratio, constituting the most stringent limits to date.

Personal networks, support mobilization and unemployment.

Abstract: Measures were obtained of features of social network structure and the mobilization of instrumental and expressive support from a sample of 301 unemployed men. Findings showed dependence on a restricted number of family members and close friends, with high levels of expressive support (for example, 71 per cent of the sample reported that someone had ‘let you know that he or she is always around if you need help with something’). Follow-up interviews were obtained on two further occasions over a period of one year, and significant changes in network structure and support mobilization were found. A decrease in non-family network size suggested greater reliance on close family and friends and a withdrawal from weaker ties with members of the community. Finally, the findings of this study emphasize the importance of incorporating a time dimension into research on the mobilization of support following a stressful life event such as job loss.

Search for new phenomena using the invariant mass distribution of same-flavour opposite-sign dilepton pairs in events with missing transverse momentum in √s=13 TeV pp collisions with the ATLAS detector

Abstract: A search for new phenomena in final states containing an e(+)e(-) or m(+)m(-) pair, jets, and large missing transverse momentum is presented. This analysis makes use of proton-proton collision data ...

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Evaluating Goodness-of-Fit Indexes for Testing Measurement Invariance

Abstract: Measurement invariance is usually tested using Multigroup Confirmatory Factor Analysis, which examines the change in the goodness-of-fit index (GFI) when cross-group constraints are imposed on a measurement model. Although many studies have examined the properties of GFI as indicators of overall model fit for single-group data, there have been none to date that examine how GFIs change when between-group constraints are added to a measurement model. The lack of a consensus about what constitutes significant GFI differences places limits on measurement invariance testing. We examine 20 GFIs based on the minimum fit function. A simulation under the two-group situation was used to examine changes in the GFIs (ΔGFIs) when invariance constraints were added. Based on the results, we recommend using Δcomparative fit index, ΔGamma hat, and ΔMcDonald's Noncentrality Index to evaluate measurement invariance. These three ΔGFIs are independent of both model complexity and sample size, and are not correlated with the o...

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These