Author
D. M. Asner
Other affiliations: Carleton University, CERN
Bio: D. M. Asner is an academic researcher from Pacific Northwest National Laboratory. The author has contributed to research in topics: Physics & Large Hadron Collider. The author has an hindex of 40, co-authored 112 publications receiving 31378 citations. Previous affiliations of D. M. Asner include Carleton University & CERN.
Papers published on a yearly basis
Papers
More filters
TL;DR: The ATLAS Inner Detector as mentioned in this paper is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field, which was completed in 2008 and the detector took part in data-taking with single LHC beams and cosmic rays.
Abstract: The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.
181 citations
TL;DR: In this article, the anti-kt algorithm is used to identify jets, with two jet resolution parameters, R = 0.4 and 0.6, and the dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum.
Abstract: Jet cross sections have been measured for the first time in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb-1 recorded at the Large Hadron Collider. The anti-kt algorithm is used to identify jets, with two jet resolution parameters, R = 0.4 and 0.6. The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. Dijet cross sections are presented as functions of dijet mass and the angular variable $\chi$. The results are compared to expectations based on next-to-leading-order QCD, which agree with the data, providing a validation of the theory in a new kinematic regime.
177 citations
Southern Methodist University1, Syracuse University2, Vanderbilt University3, Wayne State University4, Carleton University5, Carnegie Mellon University6, University of Bonn7, University of Chicago8, Cornell University9, University of Florida10, George Mason University11, University of Illinois at Urbana–Champaign12, Indiana University13, University of Kansas14, Luther College15, University of Minnesota16, Northwestern University17, University at Albany, SUNY18, University of Oklahoma19, University of Pittsburgh20, University of Puerto Rico at Mayagüez21, Purdue University22, Rensselaer Polytechnic Institute23, University of Rochester24
TL;DR: In this paper, the CLEO detector operating at the CESR e+e- collider at 3.97-4.26 GeV was used to investigate 15 charmonium decay modes of the psi(4040), psi(4160), and Y(4260) resonances.
Abstract: Using data collected with the CLEO detector operating at the CESR e+e- collider at sqrt[s]=3.97-4.26 GeV, we investigate 15 charmonium decay modes of the psi(4040), psi(4160), and Y(4260) resonances. We confirm, at 11 sigma significance, the BABAR Y(4260)-->pi+pi- J/psi discovery, make the first observation of Y(4260)--> pi(0)pi(0) J/psi (5.1 sigma), and find the first evidence for Y(4260)-->K+K- J/psi(3.7 sigma). We measure e+e- cross sections at sqrt[s]=4.26 GeV as sigma(pi+pi- J/psi)=58(+12)(-10)+/-4 pb, sigma(pi(0)pi(0) J/psi)=23(+12)(-8)+/-1 pb, and sigma(K+K- J/psi)=9(+9)(-5)+/-1 pb, in which the uncertainties are statistical and systematic, respectively. Upper limits are placed on other decay rates from all three resonances.
166 citations
Carleton University1, Imperial College London2, Fermilab3, RWTH Aachen University4, Queen Mary University of London5, Max Planck Society6, CERN7, Budker Institute of Nuclear Physics8, Karlsruhe Institute of Technology9, Technische Universität München10, Sapienza University of Rome11, Los Alamos National Laboratory12, Stanford University13, University of Minnesota14, University of Glasgow15, Charles University in Prague16, University of Pisa17, Austrian Academy of Sciences18, University of Bergen19, University of Southampton20, Nara Women's University21, University of Florida22, University of Turin23, University of Edinburgh24, University of Warwick25, University of Massachusetts Amherst26, University of Bern27, University of Mainz28, Wayne State University29, Brookhaven National Laboratory30, Folkwang University of the Arts31, University of Victoria32, Washington University in St. Louis33, Indian Institute of Technology Madras34, University of Melbourne35, Princeton University36, Roma Tre University37, York University38, University of California, Irvine39, University of Valencia40, University of Padua41, University of Barcelona42, Tata Institute of Fundamental Research43, University of Vienna44, University of Paris-Sud45, University of Kentucky46, University of Oxford47, Iowa State University48, University of Bristol49, Rutherford Appleton Laboratory50, University of Texas at Austin51, École Polytechnique Fédérale de Lausanne52, University of California, Santa Cruz53, University of Cincinnati54, Purdue University55, ETH Zurich56, Queen's University57, Indiana University58, University of Cambridge59, University of Ljubljana60
TL;DR: In this time frame, measurements and the theoretical interpretation of their results have advanced tremendously as mentioned in this paper and a much broader understanding of flavor particles has been achieved, apart from their masses and quantum numbers, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions.
165 citations
[...]
Ludwig Maximilian University of Munich1, Graduate University for Advanced Studies2, University of Edinburgh3, Sapienza University of Rome4, Syracuse University5, Carleton University6, Durham University7, Karlsruhe Institute of Technology8, RWTH Aachen University9, Fermilab10, Queen Mary University of London11, University of Notre Dame12, Max Planck Society13, Technische Universität München14, Technical University of Dortmund15, University of Savoy16, International Centre for Theoretical Physics17, National Central University18, University of Hawaii at Manoa19, University of Bergen20, CERN21, University of Liverpool22, Cornell University23, University of Florida24, University of Calabria25, University of Paris26, University of Cambridge27, Charles University in Prague28, Imperial College London29, ETH Zurich30, Jožef Stefan Institute31, Folkwang University of the Arts32, University of Turin33, University of Warwick34, University of Pisa35, University of Oxford36, University of Ljubljana37, Institute on Taxation and Economic Policy38, Technion – Israel Institute of Technology39, University of Zurich40, California Institute of Technology41, Nagoya University42, Saga University43, University of Regensburg44, Moscow State University45, University of Warsaw46, Rensselaer Polytechnic Institute47, University of Genoa48, Wayne State University49, École Polytechnique50, University of Pavia51, University of Clermont-Ferrand52, University of Chicago53, École Polytechnique Fédérale de Lausanne54, Autonomous University of Barcelona55, University of Bern56, Lancaster University57, Brookhaven National Laboratory58, Heidelberg University59, University of Bologna60, University of Hamburg61
TL;DR: In this article, the authors provide a coherent, up-to-date picture of the status of flavour physics before the start of the LHC and initiate activities on the path towards integrating information on NP from high-pT and flavour data.
Abstract: With the advent of the LHC, we will be able to probe New Physics (NP) up to energy scales almost one order of magnitude larger than it has been possible with present accelerator facilities. While direct detection of new particles will be the main avenue to establish the presence of NP at the LHC, indirect searches will provide precious complementary information, since most probably it will not be possible to measure the full spectrum of new particles and their couplings through direct production. In particular, precision measurements and computations in the realm of flavour physics are expected to play a key role in constraining the unknown parameters of the Lagrangian of any NP model emerging from direct searches at the LHC. The aim of Working Group 2 was twofold: on one hand, to provide a coherent, up-to-date picture of the status of flavour physics before the start of the LHC; on the other hand, to initiate activities on the path towards integrating information on NP from high-pT and flavour data.
149 citations
Cited by
More filters
Journal Article•
28,685 citations
TL;DR: In this article, the authors present a cosmological analysis based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation.
Abstract: This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted “base ΛCDM” in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H0 = (67.8 ± 0.9) km s-1Mpc-1, a matter density parameter Ωm = 0.308 ± 0.012, and a tilted scalar spectral index with ns = 0.968 ± 0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68% confidence limits on measured parameters and 95% upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of τ = 0.066 ± 0.016, corresponding to a reionization redshift of . These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base ΛCDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find Neff = 3.15 ± 0.23 for the effective number of relativistic degrees of freedom, consistent with the value Neff = 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to ∑ mν < 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with | ΩK | < 0.005. Adding a tensor component as a single-parameter extension to base ΛCDM we find an upper limit on the tensor-to-scalar ratio of r0.002< 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r0.002 < 0.09 and disfavours inflationarymodels with a V(φ) ∝ φ2 potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w = −1.006 ± 0.045, consistent with the expected value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundances for the best-fit Planck base ΛCDM cosmology are in excellent agreement with observations. We also constraints on annihilating dark matter and on possible deviations from the standard recombination history. In neither case do we find no evidence for new physics. The Planck results for base ΛCDM are in good agreement with baryon acoustic oscillation data and with the JLA sample of Type Ia supernovae. However, as in the 2013 analysis, the amplitude of the fluctuation spectrum is found to be higher than inferred from some analyses of rich cluster counts and weak gravitational lensing. We show that these tensions cannot easily be resolved with simple modifications of the base ΛCDM cosmology. Apart from these tensions, the base ΛCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.
10,728 citations
[...]
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These
9,929 citations
TL;DR: In this article, a search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10−9.
9,282 citations
TL;DR: The Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) at CERN as mentioned in this paper was designed to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10(34)cm(-2)s(-1)
Abstract: The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10(34)cm(-2)s(-1) (10(27)cm(-2)s(-1)). At the core of the CMS detector sits a high-magnetic-field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4 pi solid angle. Forward sampling calorimeters extend the pseudo-rapidity coverage to high values (vertical bar eta vertical bar <= 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t.
5,193 citations