4,194 research outputs found
Low pT Hadronic Physics with CMS
The pixel detector of CMS can be used to reconstruct very low pT charged
particles down to about 0.1 GeV/c. This can be achieved with high efficiency,
good resolution and a negligible fake rate for elementary collisions. In the
case of central PbPb collisions the fake rate can be kept low for pT > 0.4
GeV/c. In addition, the detector can be employed for identification of neutral
hadrons (V0s) and converted photons.Comment: 6 pages. Presented at the Poster Session of Quark Matter 2006
Conference, Shanghai, 14-20 November 2006. Submitted to IJMP
Intrinsic volumes of random polytopes with vertices on the boundary of a convex body
Let be a convex body in , let , and let
be a positive and continuous probability density function with
respect to the -dimensional Hausdorff measure on the boundary of . Denote by the convex hull of points chosen randomly and
independently from according to the probability distribution
determined by . For the case when is a submanifold
of with everywhere positive Gauss curvature, M. Reitzner proved an
asymptotic formula for the expectation of the difference of the th intrinsic
volumes of and , as . In this article, we extend this
result to the case when the only condition on is that a ball rolls freely
in
Local load sharing fiber bundles with a lower cutoff of strength disorder
We study the failure properties of fiber bundles with a finite lower cutoff
of the strength disorder varying the range of interaction between the limiting
cases of completely global and completely local load sharing. Computer
simulations revealed that at any range of load redistribution there exists a
critical cutoff strength where the macroscopic response of the bundle becomes
perfectly brittle, i.e. linearly elastic behavior is obtained up to global
failure, which occurs catastrophically after the breaking of a small number of
fibers. As an extension of recent mean field studies [Phys. Rev. Lett. 95,
125501 (2005)], we demonstrate that approaching the critical cutoff, the size
distribution of bursts of breaking fibers shows a crossover to a universal
power law form with an exponent 3/2 independent of the range of interaction.Comment: 4 pages, 4 figure
Damage in Fiber Bundle Models
We introduce a continuous damage fiber bundle model that gives rise to
macroscopic plasticity and compare its behavior with that of dry fiber bundles.
Several interesting constitutive behaviors are found in this model depending on
the value of the damage parameter and on the form of the disorder distribution.
In addition, we compare the behavior of global load transfer models with local
load transfer models and study in detail the damage evolution before failure.
We emphasize the analogies between our results and spinodal nucleation in
first-order phase transitions.Comment: 9 pages, 13 figures (ps, eps
Creep rupture of viscoelastic fiber bundles
We study the creep rupture of bundles of viscoelastic fibers occurring under
uniaxial constant tensile loading. A novel fiber bundle model is introduced
which combines the viscoelastic constitutive behaviour and the strain
controlled breaking of fibers. Analytical and numerical calculations showed
that above a critical external load the deformation of the system monotonically
increases in time resulting in global failure at a finite time , while
below the critical load the deformation tends to a constant value giving rise
to an infinite lifetime. Our studies revealed that the nature of the transition
between the two regimes, i.e. the behaviour of at the critical load
, strongly depends on the range of load sharing: for global load
sharing has a power law divergence at with a universal
exponent of 0.5, however, for local load sharing the transition becomes abrupt:
at the critical load jumps to a finite value, analogous to second and
first order phase transitions, respectively. The acoustic response of the
bundle during creep is also studied.Comment: 4 pages, 4 figures, APS style, submitted for publicatio
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