Study of hard double-parton scattering in four-jet events in pp collisions at √s = 7 TeV with the ATLAS experiment

Journal of High Energy Physics 2016.11 (2016): 110 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)Artículo escrito por muchos autores, sólo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración y los autores que firman como pertenecientes a la UAMInclusive four-jet events produced in proton-proton collisions at a centre-ofmass energy of √ s = 7 TeV are analysed for the presence of hard double-parton scattering using data corresponding to an integrated luminosity of 37.3 pb−1 , collected with the ATLAS detector at the LHC. The contribution of hard double-parton scattering to the production of four-jet events is extracted using an artificial neural network, assuming that hard double-parton scattering can be approximated by an uncorrelated overlaying of dijet events. For events containing at least four jets with transverse momentum pT ≥ 20 GeV and pseudorapidity |η| ≤ 4.4, and at least one having pT ≥ 42.5 GeV, the contribution of hard double-parton scattering is estimated to be fDPS = 0.092 +0.005 −0.011 (stat.) +0.033 −0.037 (syst.). After combining this measurement with those of the inclusive dijet and four-jet cross-sections in the appropriate phase space regions, the effective cross-section, σeff, was determined to be σeff = 14.9 +1.2 −1.0 (stat.) +5.1 −3.8 (syst.) mb. This result is consistent within the quoted uncertainties with previous measurements of σeff, performed at centre-of-mass energies between 63 GeV and 8 TeV using various final states, and it corresponds to 21+7 −6% of the total inelastic cross-section measured at √ s = 7 TeV. The distributions of the observables sensitive to the contribution of hard double-parton scattering, corrected for detector effects, are also providedWe acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Sklodowska- Curie Actions, European Union; Investissements d’Avenir Labex and Idex, ANR, Région Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; Generalitat de Catalunya, Generalitat Valenciana, Spain; the Royal Society and Leverhulme Trust, United Kingdo

Process Of Reform. A View From The Teaching Personnel Of De University Of Nayarit.

The university, as an institution, takes a long time to change, since its change does not happen as it does with organisms that transform completely. Rather, what characterizes universities is their resistance to change, their adaptation, counterproposals and negotiations (Porter 2003, Ibarra 2005, 2006), which are expressed with unique characteristics in each particular case. The apparent contradictions, in a complex and hard to unravel context, are that motivate this study. We ask whether such changes will create a new university or will lead it into an undesirable road; whether the university is able to defend its original goals. Can it experience transformation with the same strength and creativity today as with that was found in the collective conscience forty years ago? Can it maintain its spirit of commitment with its social, cultural, and ecological environment? Can it conserve its “sense of self”? In order to understand how the essence of the university ethos is maintained or altered, “A university with sense of self” shows the ideas, attitudes, experiences and interpretations of the main actors at the Universidad Autónoma de Nayarit, the professors how they face these changes, and the “institutional reform” being proposed. We seek to explain how anticipated and desired change by the broader community in Nayarit, is in fact understood, assumed, lived, and carried out

Filtering Deterministic Layer Effects in Imaging

Sensor array imaging arises in applications such as nondestructive evaluation of materials with ultrasonic waves, seismic exploration, and radar. The sensors probe a medium with signals and record the resulting echoes, which are then processed to determine the location and reflectivity of remote reflectors. These could be defects in materials such as voids, fault lines or salt bodies in the earth, and cars, buildings, or aircraft in radar applications. Imaging is relatively well understood when the medium through which the signals propagate is smooth, and therefore nonscattering. But in many problems the medium is heterogeneous, with numerous small inhomogeneities that scatter the waves. We refer to the collection of inhomogeneities as clutter, which introduces an uncertainty in imaging because it is unknown and impossible to estimate in detail. We model the clutter as a random process. The array data is measured in one realization of the random medium, and the challenge is to mitigate cumulative clutter scattering so as to obtain robust images that are statistically stable with respect to different realizations of the inhomogeneities. Scatterers that are not buried too deep in clutter can be imaged reliably with the coherent interferometric (CINT) approach. But in heavy clutter the signal-to-noise ratio (SNR) is low and CINT alone does not work. The “signal,” the echoes from the scatterers to be imaged, is overwhelmed by the “noise,” the strong clutter reverberations. There are two existing approaches for imaging at low SNR: The first operates under the premise that data are incoherent so that only the intensity of the scattered field can be used. The unknown coherent scatterers that we want to image are modeled as changes in the coefficients of diffusion or radiative transport equations satisfied by the intensities, and the problem becomes one of parameter estimation. Because the estimation is severely ill-posed, the results have poor resolution, unless very good prior information is available and large arrays are used. The second approach recognizes that if there is some residual coherence in the data, that is, some reliable phase information is available, it is worth trying to extract it and use it with well-posed coherent imaging methods to obtain images with better resolution. This paper takes the latter approach and presents a first attempt at enhancing the SNR of the array data by suppressing medium reverberations. It introduces filters, or annihilators of layer backscatter, that are designed to remove primary echoes from strong, isolated layers in a medium with additional random layering at small, subwavelength scales. These strong layers are called deterministic because they can be imaged from the data. However, our goal is not to image the layers, but to suppress them and thus enhance the echoes from compact scatterers buried deep in the medium. Surprisingly, the layer annihilators work better than intended, in the sense that they suppress not only the echoes from the deterministic layers, but also multiply scattered ones in the randomly layered structure. Following the layer annihilators presented here, other filters of general, nonlayered heavy clutter have been developed. We review these more recent developments and the challenges of imaging in heavy clutter in the introduction in order to place the research presented here in context. We then present in detail the layer annihilators and show with analysis and numerical simulations how they work

Enigmatic HCl + Au(111) reaction: a puzzle for theory and experiment

Theoretical Chemistr

Understanding the rotational excitation in scattering of D2 from CH3-Si(111)

We have studied the origin of the striking rotational excitation probability, found experimentally, for D2 upon scattering from a organic-terminated Si(111) surfac

Stability of CIS/CIGS Modules at the Outdoor Test Facility over Two Decades: Preprint

This paper discusses examining the status and question of long-term stability of copper indium diselenide (CIS) photovoltaic (PV) module performance for numerous modules that are deployed in the array field, or on the roof of, the outdoor test facility (OTF) at NREL, acquired from two manufacturers

Validation of a Photovoltaic Module Energy Ratings Procedure at NREL

The procedure determines the energy production of a PV module for five reference days. The reference days represent possible operating environments and are qualitatively described as Hot Sunny, Cold Sunny, Hot Cloudy, Cold Cloudy, and Nice. Based on statistical weather criteria, these days were selected from the National Solar Radiation Database (NSRDB). Besides the hourly solar radiation and meteorological data from the NSRDB, the reference days include air mass, angle of incidence, plane of array, and spectral irradiance for a south-facing PV module at latitude tilt, battery-charging voltage, and parameters f1 and f2 for determining PV module temperature. Indoor I-V curve measurements over a range of temperatures and irradiances characterize the electrical performance of a PV module and are used to determine factors to correct for non-linear performance when irradiance and temperature vary. They also serve as a matrix of reference I-V curves for translating to reference-day condition s. The sensitivity of a PV module to variations in the spectral distribution of the incident radiation is accounted for by using an incident irradiance. Differences in PV module thermal characteristics are accounted for by using a PV module's installed nominal operating cell temperature (INOCT) for input to the Fuentes temperature model. The procedure does not consider radiation and transmittance losses at large incident angles. These losses were judged too small, and not sufficiently different, for various PV modules to justify the complexity of their measurement and inclusion in the procedure. PV performance measurements from NREL's Outdoor Test Facility during calendar-year 1998 were used to validate the procedure by comparing modeled and measured maximum power values for seven flat-plate PV modules representing different technologies. On an annual basis, modeled values compared within 5% of measured values. Taking into account reproducibility errors from ratings being performed by different facilities and the modeling errors, the following statement applies to the ability of this procedure to show relative differences in the energy production of two PV modules: ''Because of errors in measurements and energy rating methodology, differences of 8% or less in the energy ratings of two PV modules are not significant. If one of the PV modules is amorphous silicon, differences of 13% or less in the energy ratings of two PV modules are not significant.'' This work was performed to develop and validate a PV module energy rating procedure for incorporation into IEEE PAR1479, ''Recommended Practice for the Evaluation of Photovoltaic Module Energy Production.'

Role of van der Waals forces in the diffraction of noble gases from metal surfaces

Theoretical Chemistr

Role of van der Waals forces in the diffraction of noble gases from metal surfaces

International audienc