Observation of the diphoton decay of the Higgs boson and measurement of its properties

Peer reviewe

Study of Vector Boson Scattering and Search for New Physics in Events with Two Same-Sign Leptons and Two Jets

A study of vector boson scattering in pp collisions at a center-of-mass energy of 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.4 fb(-1) collected with the CMS detector. Candidate events are selected with exactly two leptons of the same charge, two jets with large rapidity separation and high dijet mass, and moderate missing transverse energy. The signal region is expected to be dominated by electroweak same-sign W-boson pair production. The observation agrees with the standard model prediction. The observed significance is 2.0 standard deviations, where a significance of 3.1 standard deviations is expected based on the standard model. Cross section measurements for (WW +/-)-W-+/- and WZ processes in the fiducial region are reported. Bounds on the structure of quartic vector-boson interactions are given in the framework of dimension-eight effective field theory operators, as well as limits on the production of doubly charged Higgs bosons

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Search for a W or Techni-rho Decaying into WZ in pp Collisions at root s=7 TeV

A search is performed in pp collisions at root s 7 TeV for exotic particles decaying via WZ to final states with electrons and muons. The data sample corresponds to an integrated luminosity of approximately 5 fb(-1). No significant excess is observed in the data above the expected standard model background. Upper bounds at 95% confidence level are set on the production cross section of the W boson described by the sequential standard model and on the W WZ coupling. W bosons with masses below 1143 GeV are excluded. Limits are also set in the context of low-scale technicolor models, under a range of assumptions concerning the model parameters

Impact of simian immunodeficiency virus (SIV) infection on lymphocyte numbers and T-cell turnover in different organs of rhesus monkeys

HIV infection leads to reduced numbers and increased turnover of CD4+ T cells in blood. However, blood represents only 2% of the total lymphocyte pool, and information about other organs is lacking, leading to controversy about the effects of HIV infection on T-cell homeostasis. Therefore, we have determined phenotype and turnover of lymphocyte subsets in various tissues of macaques. Infection with simian immunodeficiency virus (SIV) resulted in increased proliferation rates of T cells in all organs. Despite reduced CD4 counts in blood, absolute numbers of CD4+ T cells were increased in spleen and lymph nodes and remained stable in nonlymphoid organs such as liver, lung, bone marrow, and brain during the asymptomatic phase, indicative for an altered tissue distribution. In animals killed with first signs of AIDS, total body CD4 counts and proliferation rates had returned to control levels, whereas thymocytes were almost completely absent. Our data show that a drastically increased turnover in the early stages of HIV infection, driven by a generalized immune activation rather than a homeostatic response to CD4+ T-cell destruction, is followed by exhaustion of the regenerative capacity of the immune system

Search for a light charged Higgs boson decaying to c-sbar in pp collisions at sqrt(s) = 8 TeV

see paper for full list of authorsInternational audienceA search for a light charged Higgs boson, originating from the decay of a top quark and subsequently decaying into a charm quark and a strange antiquark, is presented. The data used in the analysis correspond to an integrated luminosity of 19.7 inverse-femtobarns recorded in proton-proton collisions at sqrt(s) = 8 TeV by the CMS experiment at the LHC. The search is performed in the process t tbar to W+/- b H-/+ bbar, where the W boson decays to a lepton (electron or muon) and a neutrino. The decays lead to a final state comprising an isolated lepton, at least four jets and large missing transverse energy. No significant deviation is observed in the data with respect to the standard model predictions, and model-independent upper limits are set on the branching fraction BF( t to H+ b ), ranging from 1.2 to 6.5% for a charged Higgs boson with mass between 90 and 160 GeV, under the assumption that BF( H+ to c sbar ) = 100%

Measurement of the ratio B(t›Wb)/B(t›Wq) in pp collisions at s=8 TeV

The ratio of the top-quark branching fractions R=B(t›Wb)/B(t›Wq), where the denominator includes the sum over all down-type quarks (q=b,s,d), is measured in the tt¯ dilepton final state with proton–proton collision data at s=8 TeV from an integrated luminosity of 19.7 fb-1, collected with the CMS detector. In order to quantify the purity of the signal sample, the cross section is measured by fitting the observed jet multiplicity, thereby constraining the signal and background contributions. By counting the number of b jets per event, an unconstrained value of R=1.014±0.003(stat.)±0.032(syst.) is measured, in a good agreement with current precision measurements in electroweak and flavour sectors. A lower limit R>0.955 at the 95% confidence level is obtained after requiring R?1, and a lower limit on the Cabibbo–Kobayashi–Maskawa matrix element |Vtb|>0.975 is set at 95% confidence level. The result is combined with a previous CMS measurement of the t-channel single-top-quark cross section to determine the top-quark total decay width, ?t=1.36±0.02(stat.)-0.11 +0.14(syst.) GeV. © 2014 The Author

Search for heavy neutrinos and W bosons with right-handed couplings in proton-proton collisions at sqrt(s) = 8 TeV

Submitted to Eur. Phys. J. C. arXiv admin note: text overlap with arXiv:1405.7225 ; see paper for full list of authorsA search for heavy, right-handed neutrinos, N[l] (l = e, mu), and right-handed WR bosons, which arise in the left-right symmetric extensions of the standard model, has been performed by the CMS experiment. The search was based on a sample of two lepton plus two jet events collected in proton-proton collisions at a center-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 inverse femtobarns. No significant excess of events over the standard model expectation is observed. For models with strict left-right symmetry, and assuming only one N[l] flavor contributes significantly to the WR decay width, the region in the two-dimensional (M[WR], M[N]) mass plane excluded at a 95% confidence level extends to approximately M[WR] = 3.0 TeV and covers a large range of neutrino masses below the WR boson mass, depending on the value of M[WR]. This search significantly extends the (M[WR], M[N]) exclusion region beyond previous results

Search for supersymmetry in hadronic final states with missing transverse energy using the variables αT and b-quark multiplicity in pp collisions at √s = 8 TeV

Submitted by Vitor Silverio Rodrigues ([email protected]) on 2014-05-27T11:30:34Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:48:49Z : No. of bitstreams: 1 2-s2.0-84883824987.pdf: 1540579 bytes, checksum: be6bbff5192436d9fcdbc367ffd1650e (MD5) Made available in DSpace on 2014-05-27T11:30:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-09-01 An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb-1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, αT, is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks. © 2013 CERN for the benefit of the CMS collaboration. CERN, Geneva Yerevan Physics Institute, Yerevan Institut für Hochenergiephysik der OeAW, Wien National Centre for Particle and High Energy Physics, Minsk Universiteit Antwerpen, Antwerpen Vrije Universiteit Brussel, Brussel Université Libre de Bruxelles, Bruxelles Ghent University, Ghent Université Catholique de Louvain, Louvain-la-Neuve Université de Mons, Mons Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro Universidade do Estado do Rio de Janeiro, Rio de Janeiro Universidade Estadual Paulista, São Paulo Universidade Federal do ABC, São Paulo Institute for Nuclear Research and Nuclear Energy, Sofia University of Sofia, Sofia Institute of High Energy Physics, Beijing State Key Laboratory of Nuclear Physics and Technology Peking University, Beijing Universidad de Los Andes, Bogota Technical University of Split, Split University of Split, Split Institute Rudjer Boskovic, Zagreb University of Cyprus, Nicosia Charles University, Prague Academy of Scientific Research and Technology of the Arab Republic of Egypt Egyptian Network of High Energy Physics, Cairo National Institute of Chemical Physics and Biophysics, Tallinn Department of Physics University of Helsinki, Helsinki Helsinki Institute of Physics, Helsinki Lappeenranta University of Technology, Lappeenranta DSM/IRFU CEA/Saclay, Gif-sur-Yvette Laboratoire Leprince-Ringuet, Ecole Polytechnique IN2P3-CNRS, Palaiseau Institut Pluridisciplinaire Hubert Curien, Universite de Strasbourg, Universite de Haute Alsace Mulh CNRS/IN2P3, Strasbourg CNRS-IN2P3, Institut de Physique Nucléaire de Lyon Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne Institute of High Energy Physics and Informatization Tbilisi State University, Tbilisi I. Physikalisches Institut RWTH Aachen University, Aachen III. Physikalisches Institut A RWTH Aachen University, Aachen III. 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