Search for acoustic signals from high energy cascades

High energy cosmic ray secondaries can be detected by means of the cascades they produce when they pass through matter. When the charged particles of these cascades ionize the matter they are traveling through, the heat produced and resulting thermal expansion causes a thermoacoustic wave. These sound waves travel at about one hundred-thousandth the speed of light, and should allow an array of acoustic transducers to resolve structure in the cascade to about 1 cm without high speed electronics or segmentation of the detector

Propagation and secondary production of low energy antiprotons in the atmosphere

Current theories, in which the observed antiproton component is attributed strictly to secondary production in high energy inelastic collisions of protons with the interstellar medium or the atmosphere, apparently fail to explain the relatively high p vertical intensities measured at mountain and balloon altitudes. Therefore, a more careful calculation of the theoretical secondary intensity spectra is required before more exotic sources for these excess p's can be explored. A one dimensional diffusion equation is used to calculate the expected vertical intensity of p's due only to secondary production in the atmosphere; any assumed primary p spectrum is also included. Two adjustable parameters, the inelasticity and charge exchange in nucleon-nucleus collisions, were included in the algorithm. In order to obtain an independent estimate of their values the proton vertical intensities in the atmosphere were calculated, adjusting the parameters until the curves fit the experimental proton data, and then assumed that these values were identical in antinucleon-nucleus collisions

Air fluorescence detection of large air showers below the horizon

In the interest of exploring the cosmic ray spectrum at energies greater than 10 to the 18th power eV, where flux rates at the Earth's surface drop below 100 yr(-1) km(-2) sr(-1), cosmic ray physicists have been forced to construct ever larger detectors in order to collect useful amounts of data in reasonable lengths of time. At present, the ultimate example of this trend is the Fly's Eye system in Utah, which uses the atmosphere around an array of skyward-looking photomultiplier tubes. The air acts as a scintillator to give detecting areas as large as 5000 square kilometers sr (for highest energy events). This experiment has revealed structure (and a possible cutoff) in the ultra-high energy region above 10 o the 19th power eV. The success of the Fly's Eye experiment provides impetus for continuing the development of larger detectors to make accessible even higher energies. However, due to the rapidly falling flux, a tenfold increase in observable energy would call for a hundredfold increase in the detecting area. But, the cost of expanding the Fly's Eye detecting area will approximately scale linearly with area. It is for these reasons that the authors have proposed a new approach to using the atmosphere as a scintillator; one which will require fewer photomultipliers, less hardware (thus being less extensive), yet will provide position and shower size information

Empirical Patterns in Google Scholar Citation Counts

Scholarly impact may be metricized using an author's total number of citations as a stand-in for real worth, but this measure varies in applicability between disciplines. The detail of the number of citations per publication is nowadays mapped in much more detail on the Web, exposing certain empirical patterns. This paper explores those patterns, using the citation data from Google Scholar for a number of authors.Comment: 6 pages, 8 figures, submitted to Cyberpatterns 201

On Dynamic Compromise

What prevents majorities from extracting surplus from minorities in a dynamic legislative process? In this paper we study an infinitely repeated game where legislators determine the division of a surplus each period. A division proposal is made at the beginning of the period by a randomly selected legislator and is then voted on. Proposals that are accepted by a simple majority are implemented, otherwise the status quo allocation prevails. We show existence of a symmetric Markov perfect equilibrium in which more than a minimum winning majority receive a positive allocation for an intermediate range of discount factors. However, the equilibrium outcome is sensitive to initial conditions: compromise is achieved when initial allocations are well distributed, otherwise the equilibrium spirals towards a complete absence of compromise. We find that, contrary to intuition, compromise becomes easier to sustain as the number of legislators increases. Classification-JEL Codes: C73, D74

Angular correlations in single-top-quark and Wjj production at next-to-leading order

I demonstrate that the correlated angular distributions of final-state particles in both single-top-quark production and the dominant Wjj backgrounds can be reliably predicted. Using these fully-correlated angular distributions, I propose a set of cuts that can improve the single-top-quark discovery significance by 25%, and the signal to background ratio by a factor of 3 with very little theoretical uncertainty. Up to a subtlety in t-channel single-top-quark production, leading-order matrix elements are shown to be sufficient to reproduce the next-to-leading order correlated distributions.Comment: 22 pages, 23 figs, RevTex4, fixed typos, to appear in Phys. Rev.

The antiproton component of the primary cosmic ray flux

Solution of Fokker-Planck diffusion equation in intensity prediction of antiproton component of primary cosmic ray flu