Discovery potential of the Standard Model Higgs in CMS at the LHC

This thesis presents the discovery potential of the Standard Model Higgs boson in the CMS experiment at the LHC. Detailed studies have been carried out to evaluate the detector performance in the difficult $\rm H\to\gamma\gamma$ channel. The electromagnetic crystal calorimeter is of main importance in this channel and it has been designed according stringent performance requirements. Test beam data of lead tungstate crystals have been analysed and it is shown that the performance of the crystals can meet the requirements. The Higgs decay into two photons has been studied with full detector simulation and the Higgs mass has been reconstructed. A potential danger for the photon measurement are the photon conversions in the detector material in front of the electromagnetic calorimeter. Different methods to recover these converted photons are developed and it is shown that, including the recovered conversions does not degrade the Higgs mass resolution. To complete the full Standard Model Higgs discovery range, studies of the other decay channels are reviewed and updated taking into account the next to leading order corrections to the cross-sections. A new study for the $\rm H\to ZZ\to2$l2$\nu$ channel shows that it can give an important contribution above m\sb{\rm H} = 400 GeV. An estimate of the integrated luminosity needed for an observable Higgs signal is derived. It is shown that a fast discovery (integrated luminosity less than 10 fb\sp{-1}) can be expected if the Higgs mass is in the range of 130-550 GeV. The most difficult regions are the low mass range (m\sb{\rm H}600 GeV). With 100 fb\sp{-1} of integrated luminosity the full mass range can be covered

Improving collaborative documentation in CMS

Complete and up-to-date documentation is essential for efficient data analysis in a large and complex collaboration like CMS. Good documentation reduces the time spent in problem solving for users and software developers. The scientists in our research environment do not necessarily have the interests or skills of professional technical writers. This results in inconsistencies in the documentation. To improve the quality, we have started a multidisciplinary project involving CMS user support and expertise in technical communication from the University of Turku, Finland. In this paper, we present possible approaches to study the usability of the documentation, for instance, usability tests conducted recently for the CMS software and computing user documentatio

Summary of the CMS Discovery Potential for the MSSM SUSY Higgses

This work summarises the present understanding of the expected MSSM SUSY Higgs reach for CMS. Many of the studies presented here result from detailed detector simulations incorporating final CMS detector design and response. With 30 fb-1 the h -> gamma,gamma and h -> bb channels allow to cover most of the MSSM parameter space. For the massive A,H,H+ MSSM Higgs states the channels A,H -> tau,tau and H+ -> tau,nu turn out to be the most profitable ones in terms of mass reach and parameter space coverage. Consequently CMS has made a big effort to trigger efficiently on taus. Provided neutralinos and sleptons are not too heavy, there is an interesting complementarity in the reaches for A,H -> tau,tau and A,H -> chi,chi.Comment: 19 pages, 27 figure

In Pursuit of Authenticity – CMS Open Data in Education

Publisher Copyright: © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).There are some universally acknowledged problems in school sciences. In developed countries worldwide, young people are not interested in studying STEM subjects. Whether that is because of perceived lack of personal relevance, disconnect from the actual fields of study, “sanitized” school practices or other factors is a matter of debate, but it is eminently clear that, as educators, we must do our best to combat this trend. In this paper, we discuss how open data from the CMS experiment has been used in education and present feedback from Finnish teachers who have received training in using these freely available programming resources to bring modern physics into their teaching. The main focus here is on the teachers' perception of authenticity in the use of “real world” research data, although there is an additional benefit of learning general scientific methods and cross-disciplinary data handling skills as well.Peer reviewe

An outlook of the user support model to educate the users community at the CMS Experiment

The CMS (Compact Muon Solenoid) experiment is one of the two large general-purpose particle physics detectors built at the LHC (Large Hadron Collider) at CERN in Geneva, Switzerland. The diverse collaboration combined with a highly distributed computing environment and Petabytes/year of data being collected makes CMS unlike any other High Energy Physics collaborations before. This presents new challenges to educate and bring users, coming from different cultural, linguistics and social backgrounds, up to speed to contribute to the physics analysis. CMS has been able to deal with this new paradigm by deploying a user support structure model that uses collaborative tools to educate about software, computing an physics tools specific to CMS. To carry out the user support mission worldwide, an LHC Physics Centre (LPC) was created few years back at Fermilab as a hub for US physicists. The LPC serves as a "brick and mortar" location for physics excellence for the CMS physicists where graduate and postgraduate scientists can find experts in all aspects of data analysis and learn via tutorials, workshops, conferences and gatherings. Following the huge success of LPC, a centre at CERN itself called LHC Physics Centre at CERN (LPCC) and Terascale Analysis Centre at DESY have been created with similar goals. The CMS user support model would also facilitate in making the non-CMS scientific community learn about CMS physics. A good example of this is the effort by HEP experiments, including CMS, to focus on data preservation efforts. In order to facilitate its use by the future scientific community, who may want to re-visit our data, and re-analyze it, CMS is evaluating the resources required. A detailed, good quality and well-maintained documentation by the user support group about the CMS computing and software may go a long way to help in this endeavour.Comment: 9 pages, 2 figure

Search for single production of vector-like quarks decaying to a Z boson and a top or a bottom quark in proton-proton collisions at root s=13 TeV

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Particle-flow reconstruction and global event description with the CMS detector

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Principal-component analysis of two-particle azimuthal correlations in PbPb and pPb collisions at CMS

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Search for dark matter and unparticles in events with a Z boson and missing transverse momentum in proton-proton collisions at root s=13 TeV

Erratum 1: DOI:10.1007/JHEP09(2017)106 Erratum 2: DOI:10.1007/JHEP01(2018)056Peer reviewe

Search for electroweak production of a vector-like quark decaying to a top quark and a Higgs boson using boosted topologies in fully hadronic final states

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