Using ATLAS to investigate the associated production of a Higgs Boson with a pair of top quarks

This thesis describes the study of the channel t \overline{t} H^{0}(H^{0}\rightarrowb\overline{b} with the ATLAS detector with 30fb^-1 of data and a center of mass energy of 10 TeV. Chapter 1 provides a description of the ATLAS detector, followed by a theoretical background in Chapter 2 and a discussion of phenomenology and event generation in Chapter 3. Issues associated with leptons and missing energy are presented in Chapter 4, with focus on optimising the preselection cuts to reduce the rate of background processes, including those previously unconsidered for this channel but found to be important as a consequence of this study. In addition, the reconstruction of the leptonically decaying W Boson from lepton and missing energy is described. The treatment of jets is introduced in Chapter 5, with the focus being again on the optimisation of preselection cuts. Studies presented here are on corrections for energy lost via both muons and neutrinos in semi-leptonic bdecays and preselection cuts based on the transverse momenta and b-weights of individual jets. The issues associated with combinatorial background and the use of jet charge to reduce it is also introduced here. The choice of jet algorithm is considered of great importance for this channel, thus is presented in detail in Chapter 6. Chapter 7 explores the reconstruction of the Higgs Boson from jet pairs, focusing on the segregation of jets by b-weight. The reconstruction of the t \overline{t} H^{0} system is studied with various techniques; an investigation of the use of jet charge to discriminate between b and \overline{b} jets is presented as a novel likelihood variable.Chapter 8 summarises the results obtained using the optimised preselection, jet algorithm and jet charge method. Systematic uncertainties are discussed throughout the thesis where relevant and also summarised

Unexceptional Violence in Exceptional Times: Disablist and Ableist Violence During the COVID-19 Pandemic

It is well established that violence and oppression towards vulnerable and marginalised communities are intensified and compounded during times of social upheaval, and the COVID-19 pandemic has exacerbated disablist and ableist violence against disabled people. During the first year of the pandemic, we have been confronted with instances of violence meted out to disabled subjects. In this article, we provide a theorisation of such violence. Based on an assemblage of our collective readings of Butler, Campbell and Young, as well as our own observations and experiences, we suggest that added anxieties currently confronting people’s fragile corporeal embodiment are licensing abled subjects to violate disabled subjects to put them back in their place. Through an excavation of ‘Norms, Binaries, and Anxieties’, ‘Abjection, Substitutability, and Disavowal’, and ‘Ableism and (Un)grievability’, we trace the social contours of disablist and ableist violence, both within and beyond the context of the COVID-19 pandemic, and provide a way of imagining otherwise to resist this violence.

The extraordinary intricacies of policing vulnerability

Vulnerable people have become a key focus of policy over the past few decades. As a result, police organisations have had to adapt to ongoing requests for specialised attention and protocol development to mediate the interactions between frontline officers and members of a variety of vulnerable groups. This article examines the various socio-political developments that have led to contemporary policing practices in relation to vulnerable people, untangles a series of problems in our current approach to vulnerability. Additionally, we propose an alternative operationalisation of vulnerability, which shifts the focus from siloed cultural competency to integrated critical diversity, and in doing so, attempts to relieve some of the institutional, political and operational pressure faced by policing services

The role of verbal-textual hostility in hate crime regulation : final report

Verbal-textual hostility (VTH) plays a significant role in victims’ subjective perceptions of hatred and police officers’ assessment of a prejudice-related violence. Yet, to date, the role of VTH in ‘hate’ crime has been under-researched. The aim of this research has been to assess and evaluate the forensic possibilities contained in a closer reading of the words used in these crimes. Through a content analysis of incident characteristics and officers’ narratives of incidents, this report maps out how key speech-text indicators may assist to better evaluate the force and effects of prejudice-related violence. It is expected that this type of contextual analysis will lead to the development of more sophisticated risk assessment tools for use in frontline policing, and more targeted service enhancements for victims

Honour, Violence and Heteronormativity

Popular representations of Honour Based Violence (HBV) and honour killings construct this violence as an artefact of an uncivilised code of morality. Here ird, sharaf or izzat and shame are adhered to particular moral codes that are more likely to be found in the Quran. This clichéd version of HBV frames Muslim women’s sexual autonomy as exceptionally regulated, most commonly by male family members with the complicity of female relatives. In its most extreme (and publicly known) form, HBV is epitomised by the ‘honour’ killings that come to the attention of the criminal justice system and, as a consequence, the media. Yet emerging research shows that HBV unfolds through increasingly punitive systems of social punishment, which is neither unique to Islam, nor religious communities more generally. In this paper, it is argued that the construction of HBV as a matter of deviant and antiquated Muslim honour codes is Islamophobic and that a more productive lens through which to understand collective familial violence may lie in the conceptual framework of heteronormativity

Rapid turnover of T cells in acute infectious mononucleosis.

During acute infectious mononucleosis (AIM), large clones of Epstein-Barr virus-specific T lymphocytes are produced. To investigate the dynamics of clonal expansion, we measured cell proliferation during AIM using deuterated glucose to label DNA of dividing cells in vivo, analyzing cells according to CD4, CD8 and CD45 phenotype. The proportion of labeled CD8(+)CD45R0(+) T lymphocytes was dramatically increased in AIM subjects compared to controls (mean 17.5 versus 2.8%/day; p<0.005), indicating very rapid proliferation. Labeling was also increased in CD4(+)CD45R0(+) cells (7.1 versus 2.1%/day; p<0.01), but less so in CD45RA(+) cells. Mathematical modeling, accounting for death of labeled cells and changing pool sizes, gave estimated proliferation rates in CD8(+)CD45R0(+) cells of 11-130% of cells proliferating per day (mean 47%/day), equivalent to a doubling time of 1.5 days and an appearance rate in blood of about 5 x 10(9) cells/day (versus 7 x 10(7) cells/day in controls). Very rapid death rates were also observed amongst labeled cells (range 28-124, mean 57%/day),indicating very short survival times in the circulation. Thus, we have shown direct evidence for massive proliferation of CD8(+)CD45R0(+) T lymphocytes in AIM and demonstrated that rapid cell division continues concurrently with greatly accelerated rates of cell disappearance

The effectiveness of Payments for Ecosystem Services at delivering improvements in water quality: lessons for experiments at the landscape scale

Background Randomised Control Trials (RCTs) are used in impact evaluation in a range of fields. However, despite calls for their greater use in environmental management, their use to evaluate landscape scale interventions remains rare. Payments for Ecosystem Services (PES) incentivise land users to manage land to provide environmental benefits. We present the first RCT evaluation of a PES program aiming to improve water quality. Watershared is a program which incentivises landowners to avoid deforestation and exclude cattle from riparian forests. Using this unusual landscape-scale experiment we explore the efficacy of Watershared at improving water quality, and draw lessons for future RCT evaluations of landscape-scale environmental management interventions. Methods One hundred and twenty-nine communities in the Bolivian Andes were randomly allocated to treatment (offered Watershared agreements) or control (not offered agreements) following baseline data collection (including Escherichia coli contamination in most communities) in 2010. We collected end-line data in 2015. Using our end-line data, we explored the extent to which variables associated with the intervention (e.g. cattle exclusion, absence of faeces) predict water quality locally. We then investigated the efficacy of the intervention at improving water quality at the landscape scale using the RCT. This analysis was done in two ways; for the subset of communities for which we have both baseline and end-line data from identical locations we used difference-in-differences (matching on baseline water quality), for all sites we compared control and treatment at end-line controlling for selected predictors of water quality. Results The presence of cattle faeces in water adversely affected water quality suggesting excluding cattle has a positive impact on water quality locally. However, both the matched difference-in-differences analysis and the comparison between treatment and control communities at end-line suggested Watershared was not effective at reducing E. coli contamination at the landscape scale. Uptake of Watershared agreements was very low and the most important land from a water quality perspective (land around water intakes) was seldom enrolled. Discussion Although excluding cattle may have a positive local impact on water quality, higher uptake and better targeting would be required to achieve a significant impact on the quality of water consumed in the communities. Although RCTs potentially have an important role to play in building the evidence base for approaches such as PES, they are far from straightforward to implement. In this case, the randomised trial was not central to concluding that Watershared had not produced a landscape scale impact. We suggest that this RCT provides valuable lessons for future use of randomised experiments to evaluate landscape-scale environmental management interventions

The Market for Borrowing Corporate Bonds

This paper describes the market for borrowing corporate bonds using a comprehensive data set from a major lender. The cost of borrowing corporate bonds is comparable to the cost of borrowing stock, between 10 and 20 basis points, and both have fallen over time. Factors that influence borrowing costs are loan size, percentage of inventory lent, rating, and borrower identity. There is no evidence that bond short sellers have private information. Bonds with Credit Default Swaps (CDS) contracts are more actively lent than those without. Finally, the 2007 Credit Crunch does not affect average borrowing costs or loan volume, but does increase borrowing cost variance

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry