Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

3 Search Results

Sorted by Relevance
Save Results
...

  1. Description and Performance of Track and Primary-Vertex Reconstruction with the CMS Tracker

    Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; ... - JINST
    A description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For tbar t events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of p(T) > 0.9GeV is 94% for pseudorapidities of |η| < 0.9 and 85% for 0.9 < |η| < 2.5. The inefficiency is caused mainly by hadrons that undergomore » nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of p(T) = 100GeV emitted at |η| < 1.4, the resolutions are approximately 2.8% in p(T), and respectively, 10μm and 30μm in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10–12μm in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung.« less

  2. Exact Screened Calculations of Atomic-Field Bremsstrahlung

    Tseng, H. K. ; Pratt, R. H. - Physical Review, A (General Physics)
    A discussion of relativistic bremsstrahlung cross sections is given for incident-electron kinetic energies in the range 5 keV-1 MeV, based on an exact numerical calculation using screened potentials. Comparisons are made with previous authors' results, extending the discussion of a preliminary note. Exact point-Coulomb and Born-approximation results are contrasted. The present results show that the Born approximation significantly underestimates the bremsstrahlung cross sections in the energy region considered. Finally, screening effects are somewhat larger than expected, and when large are not well described by a form factor.

  3. Proton Bremsstrahlung at 140 Mev

    Wilson, Richard - Physical Review
    The high energy gamma-rays arising from 140-Mev proton bombardment of several elements has been studied using a scintillation counter telescope to detect secondary electrons. The angular distribution is consistent with an approximately isotropic distribution in the center-of-mass system if we assume the bremsstrahlung to come from $p-n$ collisions inside the nucleus. This is in disagreement with a phenomenological potential treatment of the $p-n$ force or the scalar-meson theory. The form of the spectrum is found to be consistent with the $$\frac{dv}{v}$$ shape and the dependence on $$Z$$ much as would be expected from an opaque nucleus with only the neutronmore » contributing to the bremsstrahlung.« less
...
Search for:
All Records
Subject
BREMSSTRAHLUNG
Refine by:
Article Type
Availability
Journal
Creator / Author
more less
Publication Date
Research Organization
more less