7,265 research outputs found
A large TPC prototype for an ILC detector
No full textA Time Projection Chamber (TPC) is a candidate for the central tracker of the future International Linear Collider (ILC) detectors. TPCs have already demonstrated very good performance in past collider experiments. In order to obtain one order of magnitude improvement in momentum resolution and the highest possible track recognition efficiency, the Linear Collider TPC (LCTPC) Collaboration is pursuing R&D activities to find the best state-of-the-art technology for the TPC. According to the ILD Letter of Intent, the TPC will have a diameter of 3.6 m and a length of 4.3 m. It should provide 200 space points with pad readout along a particle track, with a spatial resolution of 100 μm in the Rφ plane. To achieve these performances, a TPC equipped with Micro Pattern Gaseous Detectors (MPGD) instead of Multiwire Proportional Chambers (MWPC) is needed. Therefore the LCTPC Collaboration has built a large TPC prototype (LPTPC), with a diameter of 750 mm and a length of 600 mm, which can be equipped with Micromegas or GEMs as amplification structures. Since the end of 2008, the LPTPC has been exposed during several weeks to an electron beam of up to 6 GeV at DESY, in presence of a magnetic field of up to 1.0 Tesla. The LPTPC is not only a testing bed for several readout techniques based on MPGDs it is also a unique opportunity to understand the issues which arise when constructing such a large TPC. In this note we will report on the production and the commissioning of the LPTPC as well as the first results of the test beams. ©2009 IEEE.SCOPUS: cp.pSCOPUS: cp.pinfo:eu-repo/semantics/publishe
Performance of the CMS GE1/1 system at LHC Run-3 and prospects of the future ME0 system
No full textWe report on the operational performance and reliability of GE1/1, a new muon tracking and triggering station made of Triple-GEM detectors installed in the most forward region of the CMS muon spectrometer as part of the Phase-2 upgrades for LHC Run-3. The GE1/1 station, comprising 144 Triple-GEM detectors, has been collecting data since 2022. We detail its front-end electronics architecture, including VFAT3, GBTx, and VTRx components, and discuss issues encountered with VTRx transceiver outgassing and the mitigation strategies implemented. By optimizing the front-end electronics, we achieved significant improvements in time resolution, reaching 12 ns, and stabilized detector performance with 94% detection efficiency. Additionally, we provide insights into the planned ME0 station, focusing on the design advancements that will improve background rejection and timing capabilities in the forward region. These results contribute to the ongoing efforts to enhance the CMS muon detection and triggering system as the LHC luminosity increases
Search for the standard model Higgs boson produced in association with W and Z bosons in pp collisions at √s=7 TeV
No full textChatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Aguilo, E., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V.M., Hammer, J., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., Liko, D., Mikulec, I., Pernicka, M., Rahbaran, B., Rohringer, C., Rohringer, H., Schöfbeck, R., Strauss, J., Taurok, A., Waltenberger, W., Walzel, G., Widl, E., Wulz, C.-E., Mossolov, V., Shumeiko, N., Suarez Gonzalez, J., Bansal, S., Cornelis, T., De Wolf, E.A., Janssen, X., Luyckx, S., Mucibello, L., Ochesanu, S., Roland, B., Rougny, R., Selvaggi, M., Staykova, Z., Van Haevermaet, H., Van Mechelen, P., Van Remortel, N., Van Spilbeeck, A., Blekman, F., Blyweert, S., D'Hondt, J., Gonzalez Suarez, R., Kalogeropoulos, A., Maes, M., Olbrechts, A., Van Doninck, W., Van Mulders, P., Van Onsem, G.P., Villella, I., Clerbaux, B., De Lentdecker, G., Dero, V., Gay, A.P.R., Hreus, T., Léonard, A., Marage, P.E., Reis, T., Thomas, L., Vander Velde, C., Vanlaer, P., Wang, J., Adler, V., Beernaert, K., Cimmino, A., Costantini, S., Garcia, G., Grunewald, M., Klein, B., Lellouch, J., Marinov, A., McCartin, J., Ocampo Rios, A.A., Ryckbosch, D., Strobbe, N., Thyssen, F., Tytgat, M., Verwilligen, P., Walsh, S., Yazgan, E., Zaganidis, N., Basegmez, S., Bruno, G., Castello, R., Ceard, L., Delaere, C., Du Pree, T., Favart, D
High rate behavior and discharge limits in micro-pattern detectors
No full textWe present and discuss a set of systematic measurements, carried out with gaseous proportional micro-pattern detectors, in order to assess their maximum gain when irradiated with high-rate soft X-rays and heavily ionizing alpha particles. The inventory of detectors tested includes: micro-strips, micromegas, micro-dot, gas electron multiplier, CAT (compteur a trous), trench (or groove), micro-CAT (or WELL) detectors, as well as systems with two elements of gaseous amplification in cascade. We confirm the general trend of all single-stage detectors to follow Raether's criterion, i.e. a spontaneous transition from avalanche to streamer, followed by a discharge, when the avalanche size reaches a value of a few 107; a noticeable exception is the micro-clot counter holding more than 108. In multiple structures, where the gain is shared between two devices in cascade, the maximum overall gain under irradiation is increased by at least one order of magnitude; we speculate this to be a consequence of a voltage dependence of Raether's limit, larger for low operating potentials. Our conclusion is that only multiple devices can guarantee a sufficient margin of reliability for operation in harsh LHC running conditions.F.I. 1,0910Elsevier, Amsterdaminfo:eu-repo/semantics/publishe
Search for new heavy particles decaying to Z0Z0→eeee in pp̄ collisions at s=1.96TeV
No full textWe report the results of a search for the anomalous production of a massive particle decaying to four electrons via two Z0 bosons in 1.1fb-1 of pp̄ collisions at s=1.96TeV collected by the CDF II detector at Fermilab. We employ optimized electron identification criteria to maximize acceptance and efficiency. We estimate the backgrounds in the invariant mass range 500-1000GeV/c2 to be 0.028±0.009(stat)±0.011(syst) events. We observe zero events in this search region. Assuming a Randall-Sundrum graviton production model, we set 95% C.L. limits on σ×BF(G→Z0Z0)<4- 6pb, depending on the graviton mass. © 2008 The American Physical Society.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Study of Triple-GEM detector for the upgrade of the CMS muon spectrometer at LHC
No full textThis doctoral thesis is part of the upgrade of the CMS experiment at the Large HadronCollider of CERN, the LHC. CMS, together with the ATLAS experiment, led to thediscovery of the Brout-Englert-Higgs boson in 2012. But the LHC research program isnot over yet. Indeed, the LHC is intended to operate even at least 20 more years. Duringthis period, the luminosity will grow gradually up to five times its nominal value of 10 34cm −2 s −1 initially foreseen. This increase in luminosity requires the LHC experiments,like CMS, to upgrade their detectors as well as their data acquisition system. One of thenext major CMS upgrade is the addition of a new detector layer in the forward muonspectrometer of CMS. The technology that has been chosen by the CMS collaborationfor this upgrade is the Triple Gas Electron Multiplier (Triple-GEM) technology. Thisupgrade aims to maintain the trigger performance despite the increasing rate of particles(> 1 kHz/cm 2 ) and will also improve the reconstruction of muons tracks, thanks to aexcellent spatial resolution (∼ 250 μm). It is the study and characterization of thistechnology that is the subject of this thesis.This characterization of the Triple-GEM detectors starts with a detailed study of thetime resolution. This study has been performed using different Monte Carlo simulationslike GARFIELD, and has demonstrated that the Triple-GEM detectors equipped withthe new VFAT3 electronics (developed for this upgrade) fulfill the requirements for theCMS upgrade.Then we have studied different detector prototypes. First, we have built two small 10×10cm 2 prototypes and developed a test bench at the ULB laboratory. This test bench hasallowed us to study another important parameter of the Triple-GEM detectors: the gain.Later, we also had the opportunity to take part in the data taking and analysis of a testbeam campaign at CERN. The analysis of the data of this test beam is also presentedin detail.The last part of this work concerns the study of the spatial resolution. We have estimatedthe spatial resolution of the Triple-GEM detector equipped with a binary electronics byMonte Carlo simulations as well as analytically. This study has been extended to otherdetector technologies like the Micromegas and the silicon sensors.Cette th`ese de doctorat s’inscrit dans le cadre de la mise `a niveau de l’exp ́erience CMSaupr`es du grand collisionneur de protons du CERN, le LHC. CMS, avec l’exp ́erienceATLAS, a permis la d ́ecouverte du boson de Brout-Englert-Higgs en 2012. Mais leprogramme de recherche du LHC n’est pas pour autant termin ́e. En effet, le LHC estdestin ́e `a fonctionner encore au moins 20 ans. Pendant cette p ́eriode, la luminosit ́e vacroˆıtre progressivement jusqu’`a atteindre environ cinq fois la valeur nominale de 10 34cm −2 s −1 initialement pr ́evue et ce d’ici 2025. Cette augmentation de luminosit ́e pousseles exp ́eriences du LHC, comme CMS, `a mettre `a jour les d ́etecteurs ainsi que leurssyst`emes d’acquisition de donn ́ees. Une des prochaines mises `a niveau majeures deCMS est l’addition d’une nouvelle couche de d ́etection dans le spectrom`etre `a muonvers l’avant. La technologie de d ́etection qui a ́et ́e choisie par la collaboration CMS estla technologie des Triple Gas Electron Multiplier (Triple-GEM). Cette mise `a niveaua pour but de maintenir les performances du syst`eme de d ́eclenchement et ce malgr ́el’augmentation de taux de particules (> 1 kHz/cm 2 ) et de permettre ́egalement, grˆacea la tr`es bonne r ́esolution spatiale des Triple-GEM (∼ 250 μm), l’am ́elioration de la re-construction des traces de muons. C’est l’ ́etude des caract ́eristiques de cette technologiequi est le sujet de cette th`ese.Cette caract ́erisation des d ́etecteurs Triple-GEM commence par une ́etude d ́etaill ́ee de lar ́esolution temporelle. Cette ́etude a ́et ́e r ́ealis ́ee `a l’aide de diff ́erentes simulations MonteCarlo telles que GARFIELD et a permis de montrer que les Triple-GEMs ́equip ́es de lanouvelle ́electronique VFAT3 (sp ́ecifiquement d ́evelop ́ee pour les Triple-GEMs) remplis-sent les conditions pour la mise `a niveau de CMS.Nous avons ensuite ́etudi ́e diff ́erents prototypes. Tout d’abord nous avons construit deuxpetits (10 × 10 cm 2 ) prototypes de Triple-GEM et d ́evelop ́e un banc de test au sein dulaboratoire de l’ULB. Ce banc de test nous a permis d’ ́etudier un autre param`etre impor-tant des d ́etecteurs Triple-GEM: le gain. Au cours de cette th`ese nous avons ́egalementparticip ́e `a la prise de donn ́ees et `a l’installation de diff ́erents tests en faisceau au CERN.L’analyse des donn ́ees du test en faisceaux d’octobre 2014 est aussi pr ́esent ́ee en d ́etail.La derni`ere partie de ce travail concerne l’ ́etude de la r ́esolution spatiale. Nous avonsestim ́e la r ́esolution spatiale par simulation de Monte Carlo ainsi que de mani`ere an-alytique pour des d ́etecteurs GEM munis d’une ́electronique binaire. Cette ́etude a ́egalement ́et ́e g ́en ́eralis ́ee `a d’autres d ́etecteurs tels que les Micromegas ou encore lescapteurs au silicium.Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe
Measurement of associated W plus charm production in pp collisions at √s=7 TeV
No full textIndividuals have received support from the Marie-Curie programme and the Euro- pean Research Council and EPLANET (European Union); the Leventis Foundation; the A.P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of Czech Republic; the Council of Science and Industrial Research, India; the Compagnia di San Paolo (Torino); the HOMING PLUS programme of Foundation for Polish Science, cofinanced by EU, Regional Development Fund; and the Thalis and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF.Chatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V.M., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., Krätschmer, I., Liko, D., Mikulec, I., Rabady, D., Rahbaran, B., Rohringer, C., Rohringer, H., Schöfbeck, R., Strauss, J., Taurok, A., Treberer-Treberspurg, W., Waltenberger, W., Wulz, C.-E., Mossolov, V., Shumeiko, N., Suarez Gonzalez, J., Alderweireldt, S., Bansal, M., Bansal, S., Cornelis, T., De Wolf, E.A., Janssen, X., Knutsson, A., Luyckx, S., Mucibello, L., Ochesanu, S., Roland, B., Rougny, R., Staykova, Z., Van Haevermaet, H., Van Mechelen, P., Van Remortel, N., Van Spilbeeck, A., Blekman, F., Blyweert, S., D'Hondt, J., Kalogeropoulos, A., Keaveney, J., Maes, M., Olbrechts, A., Tavernier, S., Van Doninck, W., Van Mulders, P., Van Onsem, G.P., Villella, I., Caillol, C., Clerbaux, B., De Lentdecker, G., Favart, L., Gay, A.P.R., Hreus, T., Léonard, A., Marage, P.E., Mohammadi, A., Perniè, L., Reis, T., Seva, T., Thomas, L., Vander Velde, C., Vanlaer, P., Wang, J., Adler, V., Beernaert, K., Benucci, L., Cimmino, A., Costantini, S., Dildick, S., Garcia, G., Klein, B., Lellouch, J., Marinov, A., McCartin, J., Ocampo Rios, A.A., Ryckbosch, D., Sigamani, M., Strobbe, N., Thyssen, F., Tytgat, M., Walsh, S., Yazgan, E., Zaganidis, N
Measurement of the muon charge asymmetry in inclusive pp →W + X production at s=7 TeV and an improved determination of light parton distribution functions
No full textPublished by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.Measurements of the muon charge asymmetry in inclusive pp → W + X production at root s= 7 TeV are
presented. The data sample corresponds to an integrated luminosity of 4.7 fb−1 recorded with the CMS
detector at the LHC. With a sample of more than 20 million W → μν events, the statistical precision is
greatly improved in comparison to previous measurements. These new results provide additional
constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable
x from 10−3 to 10−1. These measurements and the recent CMS measurement of associated W þ charm
production are used together with the cross sections for inclusive deep inelastic e p scattering at HERA in
a next-to-leading-order QCD analysis. The determination of the valence quark distributions is improved,
and the strange-quark distribution is probed directly through the leading-order process g þ s → W þ c in
proton-proton collisions at the LHC.the Austrian Federal Ministry of Science and Research and the Austrian Science Fund; the Belgian Fonds de la Recherche Scientifique, and Fonds voor Wetenschappelijk Onderzoek; the Brazilian Funding Agencies (CNPq, CAPES, FAPERJ, and FAPESP); the Bulgarian Ministry of Education and Science; CERN; the Chinese Academy of Sciences, Ministry of Science and Technology, and National Natural Science Foundation of China; the Colombian Funding Agency (COLCIENCIAS); the Croatian Ministry of Science, Education and Sport, and the Croatian Science Foundation; the Research Promotion Foundation, Cyprus; the Ministry of Education and Research, Recurrent financing contract SF0690030s09 and European Regional Development Fund, Estonia; the Academy of Finland, Finnish Ministry of Education and Culture, and Helsinki Institute of Physics; the Institut National de Physique Nucléaire et de Physique des Particules/CNRS, and Commissariat à l’Énergie Atomique et aux Énergies Alternatives/CEA, France; the Bundesministerium für Bildung und Forschung, Deutsche Forschungsgemeinschaft, and Helmholtz-Gemeinschaft Deutscher Forschungszentren, Germany; the General Secretariat for Research and Technology, Greece; the National Scientific Research Foundation, and National Innovation Office, Hungary; the Department of Atomic Energy and the Department of Science and Technology, India; the Institute for Studies in Theoretical Physics and Mathematics, Iran; the Science Foundation, Ireland; the Istituto Nazionale di Fisica Nucleare, Italy; the Korean Ministry of Education, Science and Technology and the World Class University program of NRF, Republic of Korea; the Lithuanian Academy of Sciences; the Mexican Funding Agencies (CINVESTAV, CONACYT, SEP, and UASLP-FAI); the Ministry of Business, Innovation and Employment, New Zealand; the Pakistan Atomic Energy Commission; the Ministry of Science and Higher Education and the National Science Centre, Poland; the Fundação para a Ciência e a Tecnologia, Portugal; JINR, Dubna; the Ministry of Education and Science of the Russian Federation, the Federal Agency of Atomic Energy of the Russian Federation, Russian Academy of Sciences, and the Russian Foundation for Basic Research; the Ministry of Education, Science and Technological Development of Serbia; the Secretaría de Estado de Investigación, Desarrollo e Innovación and Programa Consolider-Ingenio 2010, Spain; the Swiss Funding Agencies (ETH Board, ETH Zurich, PSI, SNF, UniZH, Canton Zurich, and SER); the National Science Council, Taipei; the Thailand Center of Excellence in Physics, the Institute for the Promotion of Teaching Science and Technology of Thailand, Special Task Force for Activating Research and the National Science and Technology Development Agency of Thailand; the Scientific and Technical Research Council of Turkey, and Turkish Atomic Energy Authority; the Science and Technology Facilities Council, UK; the U.S. Department of Energy, and the U.S. National Science Foundation. Individuals have received support from the Marie-Curie programme and the European Research Council and EPLANET (European Union); the Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of Czech Republic; the Council of Science and Industrial Research, India; the Compagnia di San Paolo (Torino); the HOMING PLUS programme of Foundation for Polish Science, cofinanced by EU, Regional Development Fund; and the Thalis and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF
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