68,861 research outputs found
A Study for a Tracking Trigger at First Level for CMS at SLHC
It is expected that the LHC accelerator and experiments will undergo a
luminosity upgrade which will commence after several years of running. This
part of the LHC operations is referred to as Super-LHC (SLHC) and is expected
to provide beams of an order of magnitude larger luminosity (1035cm-2sec-1)
than the current design. Preliminary results are presented from a feasibility
study for a First Level Tracking Trigger for CMS at the SLHC using the data of
the inner tracking detector. As a model for these studies the current CMS pixel
detector with the same pixel size and radial distances from the beam has been
used. Monte Carlo studies have been performed using the full CMS simulation
package (OSCAR) and the occupancy of such a detector at SLHC beam conditions
has been calculated. The design of an electron trigger which uses both the
calorimeter energy depositions and the pixel data to identify isolated
electrons and photons has been investigated. Results on the tracker occupancy
and the electron trigger performance are presentedComment: Presented at LECC, Heidelberg 200
Fork-decompositions of matroids
For the abstract of this paper, please see the PDF file
On matroids of branch-width three
For the abstract of this paper, please see the PDF file
Self-similar static solutions admitting a two-space of constant curvature
A recent result by Haggag and Hajj-Boutros is reviewed within the framework
of self-similar space-times, extending, in some sense, their results and
presenting a family of metrics consisting of all the static spherically
symmetric perfect fluid solutions admitting a homothety.Comment: 6 page
The western blue groper (Achoerodus gouldii), a protogynous hermaphroditic labrid with exceptional longevity, late maturity, slow growth, and both late maturation and sex change
The western blue groper (Achoerodus gouldii) is shown to be
a temperate protogynous hermaphrodite, which spawns between early winter and mid-spring. Because A. gouldii changes body color at about the time of sex change, its color can be
used as a proxy for sex for estimating the size and age at sex change and for estimating growth when it is not possible to use gonads for determining the sex of this fish. The following characteristics make A. gouldii highly susceptible to overfishing: 1) exceptional longevity, with a maximum age (70 years) that is by far the greatest yet estimated for a labrid; 2) slow growth for the first 15 years and little subsequent growth by females; and 3) late maturation at a large total length (TL50 = 653 mm) and old age (~17 years) and 4) late sex change at an even greater total length (TL50 = 821 mm) and age (~35 years). The TL50 at maturity and particularly at sex change exceeded the minimum legal total length (500 mm) of A. gouldii and the lengths of many recreationally and commercially caught fish. Many of these characteristics are found in certain deep-water fishes that are likewise considered susceptible to overfishing. Indeed, although fishing effort for A. gouldii in Western Australia is not particularly high, per-recruit analyses indicate that this species is already
close to or fully exploited
High powered arc electrodes
Nonconsumable metal electric arc electrodes are described capable of being operated in a variety of gases at various pressures, current, and powers. The cathode has a circular annulus tip to spread the emission area for improved cooling
The Woolsack and the Winding Stair
Lives of the Lord Chancellors 1940-1970 R.F.V.Heuston Oxford: Clarendon Press, 1987. 253pp. Hardback £25.0
Coherent states for compact Lie groups and their large-N limits
The first two parts of this article surveys results related to the
heat-kernel coherent states for a compact Lie group K. I begin by reviewing the
definition of the coherent states, their resolution of the identity, and the
associated Segal-Bargmann transform. I then describe related results including
connections to geometric quantization and (1+1)-dimensional Yang--Mills theory,
the associated coherent states on spheres, and applications to quantum gravity.
The third part of this article summarizes recent work of mine with Driver and
Kemp on the large-N limit of the Segal--Bargmann transform for the unitary
group U(N). A key result is the identification of the leading-order large-N
behavior of the Laplacian on "trace polynomials."Comment: Submitted to the proceeding of the CIRM conference, "Coherent states
and their applications: A contemporary panorama.
Asymptotic iteration method for eigenvalue problems
An asymptotic interation method for solving second-order homogeneous linear
differential equations of the form y'' = lambda(x) y' + s(x) y is introduced,
where lambda(x) \neq 0 and s(x) are C-infinity functions. Applications to
Schroedinger type problems, including some with highly singular potentials, are
presented.Comment: 14 page
Perturbation expansions for a class of singular potentials
Harrell's modified perturbation theory [Ann. Phys. 105, 379-406 (1977)] is
applied and extended to obtain non-power perturbation expansions for a class of
singular Hamiltonians H = -D^2 + x^2 + A/x^2 + lambda/x^alpha, (A\geq 0, alpha
> 2), known as generalized spiked harmonic oscillators. The perturbation
expansions developed here are valid for small values of the coupling lambda >
0, and they extend the results which Harrell obtained for the spiked harmonic
oscillator A = 0. Formulas for the the excited-states are also developed.Comment: 23 page
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