Simulation of a Cross Section and Mass Measurement of a SM Higgs Boson in the H->WW->lvlv Channel at the LHC

The potential to discover a Standard-Model-like Higgs boson at the LHC in the mass range from 150-180 GeV, decaying into a pair of W bosons with subsequent leptonic decays, has been established during the last 10 years. Assuming that such a signal will eventually be observed, the analysis described in this paper investigates how accurate the signal cross section can be measured and how the observable lepton pt spectra can be used to constrain the mass of the Higgs boson. Combining the signal cross section with the analysis of the lepton pt spectra and assuming the SM Higgs cross section is known with an accuracy of +-5%, our study indicates that an integrated luminosity of about 10 fb-1 allows to measure the mass of a SM Higgs boson with an accuracy between 2 and 2.5 GeV.Comment: 19 pages, 11 Figure

NNLO QCD predictions for the H -> WW -> l l nu nu signal at the LHC

We present a first computation of the NNLO QCD cross section at the LHC for the production of four leptons from a Higgs boson decaying into W bosons. We study the cross section for a Higgs boson mass Mh = 165 GeV; around this value a Standard Model Higgs boson decays almost exclusively into W-pairs. We apply all nominal experimental cuts on the final state leptons and the associated jet activity and study the magnitude of higher-order effects up to NNLO on all kinematic variables which are constrained by experimental cuts. We find that the magnitude of the higher-order corrections varies significantly with the signal selection cuts. As a main result we give the value of the cross section at NNLO with all selection cuts envisaged for the search for the Higgs boson.Comment: typos corrected, version accepted in JHE

Suitability of high-pressure xenon as scintillator for gamma ray spectroscopy

In this paper we report the experimental study of high-pressure xenon used as a scintillator, in the context of developing a gamma ray detector. We measure a light yield near 2 photoelectrons per keV for xenon at 40 bar. Together with the light yield, we also measured an energy resolution of ~9% (FWHM) at 662 keV, dominated by the statistical fluctuations in the number of photoelectrons.Comment: 15 pages, 11 figure

Systematic uncertainties of the top background in the H->WW channel

The ttbar process is one of the main backgrounds for the H->WW->lnulnu signal search. The simulation of this background as well as an estimation of its contribution to the total systematic error for this Higgs search will be studied in detail. For this, the predictions of the PYTHIA, HERWIG, TopREX and MC@NLO Monte Carlos are compared in order to estimate the effect of different showering programs and of the spin correlations. Furthermore, the question of how to include NLO corrections will be addressed and the simulation of single top background at NLO discussed. In order to extrapolate the ttbar background to the Higgs signal region, once data is available, different normalization methods will be proposed and compared. The experimental uncertainties coming from different normalization processes will be estimated using a full CMS simulation

Combining Monte Carlo generators with next-to-next-to-leading order calculations: event reweighting for Higgs boson production at the LHC

We study a phenomenological ansatz for merging next-to-next-to-leading order (NNLO) calculations with Monte Carlo event generators. We reweight them to match bin-integrated NNLO differential distributions. To test this procedure, we study the Higgs boson production cross-section at the LHC, for which a fully differential partonic NNLO calculation is available. We normalize PYTHIA and MC@NLO Monte Carlo events for Higgs production in the gluon fusion channel to reproduce the bin integrated NNLO double differential distribution in the transverse momentum and rapidity of the Higgs boson. These events are used to compute differential distributions for the photons in the pp \to H \to \gamma \gamma decay channel, and are compared to predictions from fixed-order perturbation theory at NNLO. We find agreement between the reweighted generators and the NNLO result in kinematic regions where we expect a good description using fixed-order perturbation theory. Kinematic boundaries where resummation is required are also modeled correctly using this procedure. We then use these events to compute distributions in the pp \to H \to W^+W^- \to l^+l^- \nu\bar{\nu} channel, for which an accurate description is needed for measurements at the LHC. We find that the final state lepton distributions obtained from PYTHIA are not significantly changed by the reweighting procedure.Comment: 18 pages, 14 fig

Sexualité des adolescents et sida: processus et négociations autour des relations sexuelles et du choix de la contraception

Cette étude a permis d'explorer, auprès d'adolescents de 16 à 20 ans, l'entrée dans la vie sexuelle et l'utilisation de contraception et de protection vis à vis des maladies sexuellement transmissibles en abordant les perceptions, les attitudes et les croyances qui y sont liées et en étudiant les interactions et les négociations entre les partenaires. Les résultats confirment un certain nombre d'informations déjà disponibles en Suisse et issues d'autres enquêtes auprès des adolescents. Mais ils apportent aussi des indications quelquefois inattendues sur des sujets non encore explorés par la recherche auprès des adolescents. [...] Par rapport à la plupart des enquêtes sur la sexualité des adolescents et la prévention du sida, elle s'attache à considérer les comportements sexuels dans une perspective biographique, à les situer dans leur contexte et à mettre en évidence les aspects relationnels des décisions prises en couple au cours des différentes relations. L'originalité de cette enquête tient d'une part au contenu du questionnaire qui apporte des informations non disponibles en Suisse jusqu'ici et d'autre part aux méthodes utilisées. [P. 5]]]> HIV Infections/prevention &amp; control ; Acquired Immunodeficiency Syndrome/prevention &amp; control; Sex Education ; Sexual Behavior ; Attitude to Health ; Adolescent ; Child ; Program Evaluation ; Condoms/utilization ; Health Knowledge, Attitudes, Practice ; Questionnaires ; Switzerland fre https://serval.unil.ch/resource/serval:BIB_1691.P001/REF.pdf http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_16916 info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_16916 info:eu-repo/semantics/submittedVersion info:eu-repo/semantics/openAccess Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_16918 2022-05-07T01:11:13Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_16918 Chemitry and Pharmacology of Asian Plants and Validation of Phytopharmaceuticals, Proceedings of the IOCD - International Symposium Chulabhorn, M Hostettmann, K info:eu-repo/semantics/book book 2000 oai:serval.unil.ch:BIB_16919 2022-05-07T01:11:13Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_16919 The Fugu rubripes tyrosinase gene promoter targets transgene expression to pigment cells in the mouse. Camacho-Hübner, A Rossier, A Beermann, F info:eu-repo/semantics/article article 2000 Genesis, vol. 28, pp. 99-105 oai:serval.unil.ch:BIB_1691E41DA533 2022-05-07T01:11:13Z ehelvetica openaire documents phdthesis urnserval <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_1691E41DA533 Methylation of GpG Island promoters in uveal melanoma Moulin, A.-P. Université de Lausanne, Faculté de biologie et médecine info:eu-repo/semantics/doctoralThesis phdthesis 2008 <![CDATA[ABSTRACT : Background: Inactivation of tumour-related genes by promoter hypermethylation is a common epigenetic event in the development of a variety of tumours. Aim: To investigate in primary uveal melanoma the status of promoter methylation of genes thought to be involved in tumour development: p16, TIMP3, RASSF1, RARB, FHIT, hTERT and APC. Methods: Gene promoter methylation was studied by methylation-sensitive single-strand conformation analysis and dot-blot assay in a series of 23 primary uveal melanomas. All DNA samples were obtained from paraffin-embedded formalin-fixed tissue blocks. Results: hTERT promoter methylation was found with a relatively high frequency (52%). Promoter methylation of p16, TIMP3, RASSF1, RARB, FHIT and APC was a rare event. For none of these genes did promoter methylation exceed 15% of tumour samples, and, for some genes (FHIT and APC), no methylation was found at all. Furthermore, promoter methylation was absent in 39% (9/ 23) of cases. In only 22% (5/23) of cases was hypermethylation of at least two promoters observed. Conclusions: Promoter methylation of hTERT is a regular event in uveal melanoma. Hypermethylation of the other genes studied does not seem to be an essential element in the development of this tumour. As promoter methylation of APC, RASSF1 and RARB is often observed in cutaneous melanoma, these results suggest that different epigenetic events occur in the development of cutaneous and uveal melanoma. RAPPORT DE SYNTHESE : L'inactivation de gènes par une hyperméthylation de leur promoteur apparaît être un événement épigénétique fréquent, se retrouvant dans de nombreuses tumeurs. Dans cette étude, nous avons investigué dans des mélanomes primaires de l'uvée l'état de méthylation du promoteur de gènes fréquemment impliqués dans le développent tumoral tels que p16, TIMP3, RASSFI, RARB, FHIT, hTERT et APC. La méthylation des promoteurs de gènes a été étudiée par methylationsensitive single-strand conformation analysis (MS-SSCA) et dot blot assay (MS-DBA) dans une série de 23 mélanomes primaires de l'uvée. Tous les échantillons tissulaires provenaient de matériel fixé dans le formol et conservé dans des blocs de parraffine. Nous avons identifié une fréquence relativement élevée (52%) pour la méthylation du promoteur de hTERT. En ce qui concerne le reste des gènes étudiés, nous avons retrouvé des fréquences de méthylation de promoteurs relativement basses avec 13% pour RASSF1, 13% pour RARB 13%, 9% pour TIMP3 et 4% pour p16. Nous n'avons pas retrouvé d'hyperméthylation des promoteurs des gènes APC et FRIT. La méthylation de hTERT apparaît être un événement important dans la biologie du mélanome de l'uvée. L'hyperméthylation des autres gènes évalués ne semble pas être cruciale dans le développent de cette tumeur. Comme la méthylation des promoteurs des gènes APC, RASSF1 et RARB a été fréquemment observée dans le mélanome de la peau, notre étude tend à démontrer que des mécanismes épigénétiques différents surviennent dans le développement respectif de ces tumeurs

Massive particle production to NNLO in QCD

We discuss the recent derivation of the one-loop squared virtual QCD corrections to the W boson pair production in the quark-anti-quark-annihilation channel in the limit where all kinematical invariants are large compared to the mass of the W boson. In particular, we elaborate on the combined use of the helicity matrix formalism with the Mellin-Barnes representations technique.Comment: Presented at "Loops and Legs in Quantum Field Theory", Sondershausen, 20-25 April 2008, 5 page

Next-to-leading order corrections to Wt production and decay

We present the results of a next-to-leading order calculation of Wt production, including the decays of both the top quark and the W boson. The effects of radiation in the decay of the top quark are also included. The separation of diagrams which appear in the real corrections, into singly- and doubly-resonant contributions, is performed using a b-jet veto which is motivated by the use of the bottom quark distribution function. We find that, for a choice of scale which is suitable for this approach, the QCD corrections are very mild and only change the cross section by up to 10% at the LHC, depending on the severity of the b-jet veto. When further cuts are applied, applicable for a Higgs boson search in the H->WW channel, we find that the radiative effects greatly decrease the number of background events expected from this process. In addition, the shapes of relevant distributions can be significantly changed at next-to-leading order.Comment: 31 pages, 12 figure

Silicon photomultiplier readout of a scintillating noble gas detector for homeland security

Detectors based on scintillation by high pressure 4He are a viable technology for instruments against the illicit trafficking of nuclear material. A design based on the use of solid state photodetectors is presented in this paper and the preliminary qualification discussed