2,059 research outputs found

    Observation of a new particle in the search for the Standard Model Higgs boson at the CMS detector

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    The discovery of the Standard Model (SM) Higgs boson is one of the primary physics objectives of the Large Hadron Collider at CERN. This thesis describes a search carried out for the SM Higgs boson on data collected during the 2011 and 2012 proton-proton (pp) collision runs with the CMS detector corresponding to integrated luminosities of 5:1fb-1 and 5:3fb-1 respectively. A detailed description of the search for the SM Higgs boson decaying to two photons from the full dataset collected at CMS during the 2011 pp collision run is provided. In particular, the development of signal and background modelling techniques used for statistical interpretations of the data are highlighted. Results of the search using these techniques from the 2011 dataset are presented. In addition, an update to the analysis including data taken during 2012 is described and the results from the combined 2011 and 2012 analyses given. Results from the combination of several Higgs decay channels at CMS are reported, including those presented in the International Conference on High Energy Physics in July 2012 at which the announcement of discovery was made. Ongoing studies to ascertain the properties of the new particle are discussed and preliminary results from the combined 7 and 8 TeV datasets (corresponding to 5:1fb-1 and 12:2fb-1 respectively) are presented.Open Acces

    “The People Who Leave Here Are Not the People Who Arrived.”: A Qualitative Analysis of the Therapeutic Process and Identity Transition in the Offender Personality Disorder Pathway

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    Individuals with personality disorder are often construed as difficult to treat, and sometimes even “untreatable.” In this study, 24 men who had completed treatment on the offender personality disorder treatment pathway participated in focus groups at a high-security prison in the United Kingdom. The results of the data analysis revealed three superordinate themes that captured the impact and experience of the therapeutic process. The three themes were “A self-reconstructed,” which focused on the reconstruing and reconstructions of participants’ identity and how intervention assisted with a coherent narrative of self. The second superordinate theme, “Relational resilience and dealing with abandonment,” relates to the attachment to therapists and the negotiation of relational boundaries and resilience. The third theme, “Reimagining and re-experiencing trauma,” focuses on participants’ exploration and reliving of trauma, and how group processes allowed for shared understanding and a reconstruing of their trauma. Implications for policy and practice are discussed

    3 to 12 millimetre studies of dense gas towards the western rim of supernova remnant RX J1713.7-3946

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    The young X-ray and gamma-ray-bright supernova remnant RXJ1713.7-3946 (SNR G347.3-0.5) is believed to be associated with molecular cores that lie within regions of the most intense TeV emission. Using the Mopra telescope, four of the densest cores were observed using high-critical density tracers such as CS(J=1-0,J=2-1) and its isotopologue counterparts, NH3(1,1) and (2,2) inversion transitions and N2H+(J=1-0) emission, confirming the presence of dense gas >10^4cm^-3 in the region. The mass estimates for Core C range from 40M_{\odot} (from CS(J=1-0)) to 80M_{\odot} (from NH3 and N2H+), an order of magnitude smaller than published mass estimates from CO(J=1-0) observations. We also modelled the energy-dependent diffusion of cosmic-ray protons accelerated by RXJ1713.7-3946 into Core C, approximating the core with average density and magnetic field values. We find that for considerably suppressed diffusion coefficients (factors \chi=10^{-3} down to 10^{-5} the galactic average), low energy cosmic-rays can be prevented from entering the inner core region. Such an effect could lead to characteristic spectral behaviour in the GeV to TeV gamma-ray and multi-keV X-ray fluxes across the core. These features may be measurable with future gamma-ray and multi-keV telescopes offering arcminute or better angular resolution, and can be a novel way to understand the level of cosmic-ray acceleration in RXJ1713.7-3946 and the transport properties of cosmic-rays in the dense molecular cores.Comment: 17 pages, 13 figures and 5 tables. Accepted for publication in MNRAS 2012 February 1

    Boreal forest floor greenhouse gas emissions across a Pleurozium schreberi-dominated, wildfire-disturbed chronosequence

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    The boreal forest is a globally critical biome for carbon cycling. Its forests are shaped by wildfire events that affect ecosystem properties and climate feedbacks including greenhouse gas (GHG) emissions. Improved understanding of boreal forest floor processes is needed to predict the impacts of anticipated increases in fire frequency, severity, and extent. In this study, we examined relationships between time since last wildfire (TSF), forest floor soil properties, and GHG emissions (CO2, CH4, N2O) along a Pleurozium schreberi-dominated chronosequence in mid- to late succession located in northern Sweden. Over three growing seasons in 2012–2014, GHG flux measurements were made in situ and samples were collected for laboratory analyses. We predicted that P. schreberi-covered forest floor GHG fluxes would be related to distinct trends in the soil properties and microbial community along the wildfire chronosequence. Although we found no overall effect of TSF on GHG emissions, there was evidence that soil C/N, one of the few properties to show a trend with time, was inversely linked to ecosystem respiration. We also found that local microclimatic conditions and site-dependent properties were better predictors of GHG fluxes than TSF. This shows that site-dependent co-variables (that is, forest floor climate and plant-soil properties) need to be considered as well as TSF to predict GHG emissions as wildfires become more frequent, extensive and severe

    Pushing the precision frontier at the LHC with V+jets

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    This documents the proceedings from a workshop titled `Illuminating Standard candles at the LHC: V+jets' held at Imperial College London on 25th-26th April 2017. It summarises the numerous contributions to the workshop, from the experimental overview of V+jets measurements at CMS and ATLAS and their role in searching for physics beyond the Standard Model to the status of higher order perturbative calculations to these processes and their inclusion in state of the art Monte Carlo simulations. An executive summary of the ensuing discussions including a list of outcomes and wishlist for future consideration is also presented

    Operation Moonshot: rapid translation of a SARS-CoV-2 targeted peptide immunoaffinity liquid chromatography-tandem mass spectrometry test from research into routine clinical use

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    OBJECTIVES: During 2020, the UK's Department of Health and Social Care (DHSC) established the Moonshot programme to fund various diagnostic approaches for the detection of SARS-CoV-2, the pathogen behind the COVID-19 pandemic. Mass spectrometry was one of the technologies proposed to increase testing capacity. METHODS: Moonshot funded a multi-phase development programme, bringing together experts from academia, industry and the NHS to develop a state-of-the-art targeted protein assay utilising enrichment and liquid chromatography tandem mass spectrometry (LC-MS/MS) to capture and detect low levels of tryptic peptides derived from SARS-CoV-2 virus. The assay relies on detection of target peptides, ADETQALPQRK (ADE) and AYNVTQAFGR (AYN), derived from the nucleocapsid protein of SARS-CoV-2, measurement of which allowed the specific, sensitive, and robust detection of the virus from nasopharyngeal (NP) swabs. The diagnostic sensitivity and specificity of LC-MS/MS was compared with reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) via a prospective study. RESULTS: Analysis of NP swabs (n=361) with a median RT-qPCR quantification cycle (Cq) of 27 (range 16.7-39.1) demonstrated diagnostic sensitivity of 92.4% (87.4-95.5), specificity of 97.4% (94.0-98.9) and near total concordance with RT-qPCR (Cohen's Kappa 0.90). Excluding Cq>32 samples, sensitivity was 97.9% (94.1-99.3), specificity 97.4% (94.0-98.9) and Cohen's Kappa 0.95. CONCLUSIONS: This unique collaboration between academia, industry and the NHS enabled development, translation, and validation of a SARS-CoV-2 method in NP swabs to be achieved in 5 months. This pilot provides a model and pipeline for future accelerated development and implementation of LC-MS/MS protein/peptide assays into the routine clinical laboratory
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