Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Vocal quality description of senile characters from Hollywood movies

PURPOSE: to describe the vocal quality of Hollywood movies characters playing elderly people roles. METHODS: a total of 50 aged character voice samples were used, 11 female and 39 male, from 38 Hollywood movies from the period between 1993 and 2001. Twenty speech therapists performed a perceptual auditory analysis. The listener's task required classifying each character either as elderly or as adult by their speech features, and also assessing their voices following the parameters that are most frequently addressed in the literature as being disordered at an old age. The parameters were hoarseness, vocal fry, breathiness, strain, roughness, vocal weakness, nasal resonance, tremor, vocal modulation, pitch and fundamental frequency stability. RESULTS: after the perceptual auditory analysis we noted that a great number of actors (82%) used senile voices indicating old age, even though not all of them were elderly. The most salient voice set altered was vocal quality (92%), demonstrated by vocal fry (80%), breathiness (54%), strain (38%), hoarseness (30%), and weak voice (28%). The second vocal set most used by the actors for their roles was extensive vocal modulation (44%). It was also observed that vocal instability (64%) was used by the actors. CONCLUSION: it can be concluded from the results that Hollywood movies characterize the elderly characters through evident deviations in vocal quality and modulation, using disordered types of voices and vocal unstable and extensive modulation.OBJETIVO: descrever a qualidade vocal de personagens idosos dos filmes de Hollywood. MÉTODOS: foram colhidas 50 amostras de fala de personagens idosos, 11 do sexo feminino e 39 do masculino, de 38 filmes hollywoodianos dos anos de 1993 a 2001. Através da análise perceptivo-auditiva das amostras de fala, 20 fonoaudiólogos treinados classificaram cada personagem em idoso e não idoso, além de avaliarem as vozes quanto aos seguintes parâmetros citados pela literatura como mais alterados: rouquidão, crepitação, soprosidade, tensão, aspereza, astenia, nasalidade, tremor, modulação, pitch e estabilidade da frequência fundamental. RESULTADOS: após a análise perceptivo-auditiva, foi observado que a grande maioria dos atores (82%) utilizou voz de idoso para representar seus papéis. O marcador mais evidente nas vozes foi alteração na qualidade vocal (92%), demonstrada por crepitação (80%), soprosidade (54%), tensão (38%), rouquidão (30%) e astenia (28%). O segundo marcador mais utilizado pelos atores nas suas representações foi a modulação vocal ampla e variada (44%). Também foram observadas alterações no controle da voz (36%) e instabilidade da frequência fundamental (38%). CONCLUSÃO: a partir dos resultados obtidos pode-se concluir que os filmes de Hollywood caracterizam o idoso através de desvios evidentes na qualidade e modulação da voz, utilizando tipos de vozes alteradas e modulação vocal ampla e instável.Universidade Federal de São Paulo (UNIFESP) Centro de Estudos da VozUNIFESP, Centro de Estudos da VozSciEL

A Quantitative Theory of Laser-Generated Ultrasound

The basic work of R. M. White [1] on the generation of elastic waves by transient surface heating was followed by numerous theoretical and experimental investigations, to understand the nature of the strange elastic waveforms obtained and to make this technique available for practical applications [2]. The theoretical considerations of L. R. F. Rose [3] about a point of dilation just below the surface of an elastic halfspace leads to a reasonable qualitative agreement with experiments, but do not relate all relevant material and laser beam parameters to the displacement field. This contributions outlines the application of an extended theory to a complete system of nondestructive evaluation, taking into account the structure of different laser modes, the optical, thermal and elastic material properties as well as the finite area of a capacitance transducer

Search for R-parity-violating supersymmetry in events with four or more leptons in sqrt(s) =7 TeV pp collisions with the ATLAS detector

A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb−1 of $\sqrt{s}=7\;\mathrm{TeV}$ proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m 1/2 up to 820 GeV are excluded for 10 < tan β < 40

Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at √s = 7 TeV with the ATLAS detector

This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of √s = 7 TeV;{\rm Te}{\rm V}$and correspond to an integrated luminosity of$4.6\;{\rm f}{{{\rm b}}^{-1}}$. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum${{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}$and pseudorapidity$|\eta |\lt 1.9$, is measured to be${{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques

Charged-particle distributions at low transverse momentum in √s=13 13 TeV pp interactions measured with the ATLAS detector at the LHC

Measurements of distributions of charged particles produced in proton–proton collisions with a centre-of-mass energy of 13 TeV are presented. The data were recorded by the ATLAS detector at the LHC and correspond to an integrated luminosity of 151 μb −1 μb−1 . The particles are required to have a transverse momentum greater than 100 MeV and an absolute pseudorapidity less than 2.5. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on multiplicity are measured in events containing at least two charged particles satisfying the above kinematic criteria. The results are corrected for detector effects and compared to the predictions from several Monte Carlo event generators

Measurement of the inelastic proton-proton cross section at √s=13 TeV with the ATLAS detector at the LHC

This Letter presents a measurement of the inelastic proton-proton cross section using 60  μb −1 of pp collisions at a center-of-mass energy √s of 13 TeV with the ATLAS detector at the LHC. Inelastic interactions are selected using rings of plastic scintillators in the forward region (2.0710 −6 , where M X is the larger invariant mass of the two hadronic systems separated by the largest rapidity gap in the event. In this ξ range the scintillators are highly efficient. For diffractive events this corresponds to cases where at least one proton dissociates to a system with M X >13  GeV . The measured cross section is compared with a range of theoretical predictions. When extrapolated to the full phase space, a cross section of 78.1±2.9  mb is measured, consistent with the inelastic cross section increasing with center-of-mass energy