A search for narrow, high-mass resonances decaying to electron or muon pairs has been performed using pp collision data collected at s = 7 TeV by the CMS experiment in 2011. The data sample ...corresponds to an integrated luminosity of approximately 5 fba1. The event yields observed in the signal regions are consistent with predictions of the standard model backgrounds, and upper limits on the cross section times branching fraction for a resonance decaying to dileptons are extracted from a shape analysis of the dilepton invariant mass distribution. The resulting mass limits at 95% confidence level are 2330 GeV for the Z a2 in the Sequential Standard Model, 2000 GeV for the superstring-inspired Z I a2 resonance, 890 (540) GeV for the Stueckelberg extension Z St a2 with the mass parameter Im = 0.06 (0.04), and 2140 (1810) GeV for Kaluza-Klein gravitons with the coupling parameter k / M A= Pl of 0.10 (0.05). These limits are the most stringent to date.
A search for neutral Higgs bosons decaying to tau pairs at a center-of-mass energy of 7 TeV is performed using a dataset corresponding to an integrated luminosity of 4.6 fba1 recorded by the CMS ...experiment at the LHC. The search is sensitive to both the standard model Higgs boson and to the neutral Higgs bosons predicted by the minimal supersymmetric extension of the standard model (MSSM). No excess of events is observed in the tau-pair invariant-mass spectrum. For a standard model Higgs boson in the mass range of 110a145 GeV upper limits at 95% confidence level (CL) on the production cross section are determined. We exclude a Higgs boson with m H = 115 GeV with a production cross section 3.2 times of that predicted by the standard model. In the MSSM, upper limits on the neutral Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, m A , sets stringent new bounds in the parameter space, excluding at 95% CL values of tan I2 as low as 7.1 at m A = 160 GeV in the m h max benchmark scenario.
Dijet production in PbPb collisions at a nucleonanucleon center-of-mass energy of 2.76 TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 150 ...I14ba1 is analyzed. Jets are reconstructed using combined information from tracking and calorimetry, using the anti- k T algorithm with R = 0.3 . The dijet momentum balance and angular correlations are studied as a function of collision centrality and leading jet transverse momentum. For the most peripheral PbPb collisions, good agreement of the dijet momentum balance distributions with pp data and reference calculations at the same collision energy is found, while more central collisions show a strong imbalance of leading and subleading jet transverse momenta attributed to the jet-quenching effect. The dijets in central collisions are found to be more unbalanced than the reference, for leading jet transverse momenta up to the highest values studied.
Results are presented from a search for large, extra spatial dimensions in events with either two isolated muons or two isolated electrons. The data are from proton-proton interactions at s = 7 TeV ...collected with the CMS detector at the LHC. The size of the data sample corresponds to an integrated luminosity of approximately 2 fb - 1 . The observed dimuon and dielectron mass spectra are found to be consistent with standard-model expectations. Depending on the number of extra dimensions, the 95% confidence level limits from the combined mu mu and ee channels range from M s > 2.4 TeV to M s > 3.8 TeV , where M s characterizes the scale for the onset of quantum gravity.
A measurement of the t production cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV has been performed at the LHC with the CMS detector. The analysis uses a data sample ...corresponding to an integrated luminosity of 36 pb super(-1) and is based on the reconstruction of the final state with one isolated, high transverse-momentum electron or muon and three or more hadronic jets. The kinematic properties of the events are used to separate the t signal from W+jets and QCD multijet background events. The measured cross section is 173+39}_{-32} + consistent with standard model expectations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Recently many commercial and non-commercial Simulation Packages (SPs) have agreed to use the Functional Mockup Interface (FMI) as the medium of interoperability. FMI presents numerous opportunities ...to utilize highly specialized SPs for modeling, and simulating multidisciplinary applications with several components of various types. However there is one thing missing in the FMI; the master algorithm. The paper proposes to use, the High Level Architecture (HLA) compliant Run Time Infrastructure (RTI), as a master for the FMI compatible simulation components. The ultimate goal is to provide a completely generic and standalone master for the FMI, making FMI-based simulation components usable as plug and play components, on variety of distributed environments including grids and clouds. Towards this promising goal an initial methodology is outlined.
The gradual deployment of intelligent and coordinated devices in the electrical power system needs careful investigation of the interactions between the various domains involved. Especially due to ...the coupling between ICT and power systems a holistic approach for testing and validating is required. Taking existing (quasi-) standardised smart grid system and test specification methods as a starting point, we are developing a holistic testing and validation approach that allows a very flexible way of assessing the system level aspects by various types of experiments (including virtual, real, and mixed lab settings). This paper describes the formal holistic test case specification method and applies it to a particular co-simulation experimental setup. The various building blocks of such a simulation (i.e., FMI, mosaik, domain-specific simulation federates) are covered in more detail. The presented method addresses most modeling and specification challenges in cyber-physical energy systems and is extensible for future additions such as uncertainty quantification.
The simulation of cyber-physical systems involves modular heterogeneous systems. When embedding continuous subsystems in a discrete event system, in a classic approach the different subsystems use ...the same communication points and wait for each other. The approach presented in this paper uses predictions for every single continuous subsystem. That way the continuous subsystems can be used as discrete components in a discrete event system. This concept is implemented with FMUs (Functional Mock-up Units) generated with OpenModelica and the Discrete Event domain of Ptolemy II as a proof of concept. A model is implemented using this environment and compared to another implementation that uses only Ptolemy II. The results show the better scalability and shorter runtime of the presented approach compared to the pure Ptolemy II approach.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A search for supersymmetry in final states with jets and missing transverse energy is performed in pp collisions at a ...centre-of-mass energy of ... TeV. The data sample corresponds to an integrated luminosity of 4.98 fb super(-1) collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, alpha sub(T), is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. The search is performed in a signal region that is binned in the scalar sum of the transverse energy of jets and the number of jets identified as originating from a bottom quark. No excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of the constrained minimal supersymmetric extension of the standard model, and also in simplified models, with a special emphasis on compressed spectra and third-generation scenarios.Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A measurement is presented of the ZZ production cross section in the ZZ arrow right 22' decay mode with = e, mu and ' = e, ...mu , tau in proton-proton collisions at ... TeV with the CMS experiment at the LHC. Results are based on data corresponding to an integrated luminosity of 5.0 fb super(-1). The measured cross section ... is consistent with the standard model predictions. The following limits on ZZZ and ZZ gamma anomalous trilinear gauge couplings are set at 95% confidence level: ..., and ...Figure not available: see fulltext.
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