148 research outputs found
Heat flow near major strike-slip faults in California
Seventeen heat-flow measurements were made in crystalline rock near the San Andreas, San Jacinto, and Garlock faults, California, in regions representative of several levels of seismic activity. Data from these measurements, together with other heat-flow determinations in California and offshore along the continental borderland, do not clearly demonstrate the existence of a heat-flow anomaly in the vicinity of these major faults, although regularities in the data are present. The mean value of the seventeen determinations is 1.65 ÎŒcal/cm^2/sec, ±0.28 s.d. It is concluded that any or all of the following are the case: (a) the amount of energy converted to heat near a fault is no larger than that appearing as seismic waves; (b) the presently inferred rates of slip on the faults studied have been going on for only the last few million years or less; (c) the high density of fault systems in central and southern California contributes to a regionally high heat flow but prevents the resolution of energy from any single member; (d) the frictional heat generation varies from place to place along the faults. In the region between Lake Hughes and San Bernardino, now seismically inactive, but in the zone of rupture from the âŒ8-magnitude Fort Tejon earthquake, six measurements show no correlation with distance from the San Andreas fault. Near the San Jacinto fault in the Peninsular Ranges, a region characterized by frequent intermediate- and low-magnitude earthquakes, determinations at 1 and 4 km from the fault are the same; they are 20% higher than a measurement 13 km to the west but are not appreciably different from a probable regional average 25 km to the east in the Imperial Valley. Near Hollister, where the San Andreas fault is creeping at a rate of several centimeters per year, a measurement 3 km west of the fault gives a value similar to those found elsewhere along the fault, yet significantly higher than values to the east on the western flank of the Sierra Nevada. Finally, measurements across the historically inactive Garlock fault exhibit high fluxes near the fault in comparison with a determination 8 km to the north, but these measurements are only slightly higher than values characteristic of the Mojave block to the south
Unitarity, duality and absorption; A general discussion and a definite model
We study the problem of incorporating unitarity effects into dual scattering amplitudes. Possible forms and interpretations for amplitudes which have dual properties consistent with experimental data (including the fixed-t zero structure, the dominance of peripheral resonances, etc.) are discussed. A detailed physical interpretation, in terms of absorption effects, is provided at all energies. A specific model is presented which demonstrates that amplitudes of the desired kind do exist and that one can work with them.The model is studied in detail for spinless particles (e.g. [pi][pi] scattering). Apart from a few technical difficulties the resulting amplitude can be studied at all energies and angles and behaves in all aspects essentially as we expect realistic scattering amplitudes (and data) to behave.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34053/1/0000331.pd
A study of the zero modes of the Faddeev-Popov operator in Euclidean Yang-Mills theories in the Landau gauge in d=2,3,4 dimensions
Examples of normalizable zero modes of the Faddeev-Popov operator in SU(2)
Euclidean Yang-Mills theories in the Landau gauge are constructed in d=2,3,4
dimensions.Comment: 18 pages. Text modifications. References added. Version accepted for
publication in the EPJ
Quark initiated coherent diffractive production of muon pair and W boson at hadron colliders
The large transverse momentum muon pair and W boson productions in the quark
initiated coherent diffractive processes at hadron colliders are discussed
under the framework of the two-gluon exchange parametrization of the Pomeron
model. In this approach, the production cross sections are related to the
small-x off-diagonal gluon distribution and the large-x quark distribution in
the proton (antiproton). By approximating the off-diagonal gluon distribution
by the usual gluon distribution function, we estimate the production rates of
these processes at the Fermilab Tevatron.Comment: 11pages, 6 PS figures, to appear in PR
Diffractive light quark jet production at hadron colliders in the two-gluon exchange model
Massless quark and antiquark jet production at large transverse momentum in
the coherent diffractive processes at hadron colliders is calculated in the
two-gluon exchange parametrization of the Pomeron model. We use the helicity
amplitude method to calculate the cross section formula. We find that for the
light quark jet production the diffractive process is related to the
differential off-diagonal gluon distribution function in the proton. We
estimate the production rate for this process at the Fermilab Tevatron by
approximating the off-diagonal gluon distribution function by the usual
diagonal gluon distribution in the proton. And we find that the cross sections
for the diffractive light quark jet production and the charm quark jet
production are in the same order of magnitude. We also use the helicity
amplitude method to calculate the diffractive charm jet production at hadron
colliders, by which we reproduce the leading logarithmic approximation result
of this process we previously calculated.Comment: 15 pages, 4 PS figures, Revte
Atmospheric aerosols at the Pierre Auger Observatory and environmental implications
The Pierre Auger Observatory detects the highest energy cosmic rays.
Calorimetric measurements of extensive air showers induced by cosmic rays are
performed with a fluorescence detector. Thus, one of the main challenges is the
atmospheric monitoring, especially for aerosols in suspension in the
atmosphere. Several methods are described which have been developed to measure
the aerosol optical depth profile and aerosol phase function, using lasers and
other light sources as recorded by the fluorescence detector. The origin of
atmospheric aerosols traveling through the Auger site is also presented,
highlighting the effect of surrounding areas to atmospheric properties. In the
aim to extend the Pierre Auger Observatory to an atmospheric research platform,
a discussion about a collaborative project is presented.Comment: Regular Article, 16 pages, 12 figure
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