FINAL STATE INTERACTIONS OF B→DKB\to DK DECAYS

We study the final state strong interactions of the $B\rightarrow DK$ decay processes, using the Regge model. We conclude that the final state interaction phases are very small, typically a few degrees. Neglecting final state interactions in obtaining the weak decay amplitudes is a good approximation.Comment: 10 pages, standard latex without figure

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 μcal/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 ∼8-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

What Is the Southern California Earthquake Center?

On February 11, Congressman George E. Brown, Jr., Chairman of the House Committee on Science, Space and Technology, together with the National Science Foundation, the U.S. Geological Survey, and state and local officials, helped inaugurate the Southern California Earthquake Center (SCEC) on the campus of the University of Southern California. SCEC is one of 14 new NSF Science and Technology Centers and includes a substantial commitment from the USGS for FY91. The center is a consortium of seven core academic institutions-USC (coordinating institution), Caltech, Columbia University's Lamont-Doherty Geological Observatory, University of California at Los Angeles, University of California at Santa Barbara, University of California at Santa Cruz, and University of California at San Diego's Scripps Institution of Oceanography-in partnership with the USGS's Office of Earthquakes, Volcanoes, and Engineering (OEVE). The center grew out of an April 3-5, 1989, workshop at Lake Arrowhead, Calif., convened by the USGS to discuss the need for an expanded effort in earthquake research in southern California

The extinction curve in the visible and the value of Rv

This article discusses the interstellar extinction curve in the visible and the value of Rv. It is concluded that the visible extinction curve is likely to be linear in the visible, and that indirect estimates of Rv from tentative determinations of Av, infrared, or UV observations are questionable. There is currently no evidence of any variation of Rv with direction. If Rv is close to 3, as it has been inferred from mid-infrared data, starlight in the visible is extinguished by a factor F/F_0=(2.5exp{-2micron/lambda})^{E(B-V)} in the visible. But if the visible wavelength range alone is considered, 4 appears as its most natural and probable value, and F/F_0= exp{-2E(B-V)/lambda}.Comment: 4 figures. Published in Astronomische Nachrichten. Label of Fig. 1 is corrected in the present version. Paper previously rejected by MNRAS (MJ Barlow editor, review is available

Results from a 1500 m deep, three-level downhole seismometer array: Site response, low Q values, and f_(max)

A three-level downhole array is being operated in a 1500-m-deep borehole within the seismically active Newport-Inglewood fault zone, Los Angeles basin. The array consists of three three-component 4.5 Hz seismometers deployed at the surface, and at 420 and 1500 m depth. An M = 2.8 earthquake that occurred 0.9 km away from the array at a depth of 5.3 km on 31 July 1986 generated rays traveling almost vertically up the downhole array. The P- and S-wave pulse shapes show increasing pulse rise time with decreasing depth, and the initial pulse slope is less steep at the surface than at 1500 m. The average value of t_s/t_p between 1500 and 420 m depth is 1.7 and between 420 and 0 m is 3.4. A near-surface site response results in amplification on the P wave by a factor of four and S waves by a factor of nine. These data indicate a near-surface Q_α of 44 ± 13 for rays traveling almost vertically. In the case of S waves, most of the high frequency content of the waveform beyond ∼ 10 Hz observed at 1500 m depth is lost through attenuation before the waveform reaches 420 m depth. The average Q_β is 25 ± 10 between 1500 and 420 m depth and 108 ± 36 between 420 and 0 m depth. The spectra of the S waves observed at 420 and 0 m of the downward reflected S phases may overestimate Q_β, because they are limited to a narrow band between 5 and 10 Hz and affected by the near-surface amplification. A Q_c of 160 ± 30 at 6 Hz was determined from the decay rate of the coda waves at all three depths. The corner frequency as determined from displacement spectra may be higher (f_c ∼ 10 Hz) at 1500 m depth than at (f_c ∼ 7 Hz) 420 and 0 m depth. Similarly, f_(max) significantly decreases as the waveforms travel toward the earth's surface, indicating that f_(max) is affected by near-surface attenuation. Beyond f_c, the average slopes of the spectra falloff of P-wave spectra is ∼f^(−2) at 1500 m depth and ∼ f^(−3) at the surface

Comments on "The long-period Galactic Cepheid RS Puppis. I. A geometric distance from its light echoes"

The luminous Galactic Cepheid RS Puppis is unique in being surrounded by a dust nebula illuminated by the variable light of the Cepheid. In a recent paper in this journal, Kervella et al. (2008) report a very precise geometric distance to RS Pup, based on measured phase lags of the light variations of individual knots in the reflection nebula. In this commentary, we examine the validity of the distance measurement, as well as the reality of the spatial structure of the nebula determined by Feast (2008) based upon the phase lags of the knots. {Kervella et al. assumed that the illuminated dust knots lie, on average, in the plane of the sky (otherwise it is not possible to derive a geometric distance from direct imaging of light echoes). We consider the biasing introduced by the high efficiency of forward scattering. We conclude that most of the knots are in fact likely to lie in front of the plane of the sky, thus invalidating the Kervella et al. result. We also show that the flat equatorial disk structure determined by Feast is unlikely; instead, the morphology of the nebula is more probably bipolar, with a significant tilt of its axis with respect to the plane of the sky. Although the Kervella et al. distance result is invalidated, we show that high-resolution polarimetric imaging has the potential to yield a valid geometric distance to this important Cepheid.Comment: 10 pages, 5 figures, 1 table; accepted by Astronomy & Astrophysic

A Hamiltonian Formulation for Long Internal Waves

A novel canonical Hamiltonian formalism is developed for long internal waves in a rotating environment. This includes the effects of background vorticity and shear on the waves. By restricting consideration to flows in hydrostatic balance, superimposed on a horizontally uniform background of vertical shear and vorticity, a particularly simple Hamiltonian structure arises, which can be thought of as describing a nonlinearly coupled infinite collection of shallow water systems. The kinetic equation describing the time evolution of the spectral energy of internal waves is subsequently derived, and a stationary Kolmogorov solution is found in the high frequency limit. This is surprisingly close to the Garrett--Munk spectrum of oceanic internal waves

Impact parameter description of multiparticle and elastic scattering

Impact parameter variables are defined for a multiparticle production process. The equation of unitarity for elastic scattering is written at high energy in terms of these variables. The overall impact parameter can be expressed in terms of the impact parameters of all the produced particles. The unitarity equation becomes an "optical theorem" at each impact parameter -- diffractive scattering is given by beam depletion. These features allow this technique to give a much clearer interpretation of unitarity in any model than has therefore been possible. This technique can be used to study existing models, and to suggest new ones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33832/1/0000089.pd