Theoretical and Experimental Topics on Ultra High Energy Cosmic Rays

Since their first observation in 1962, the existence of Ultra High Energy Cosmic Rays (UHECR) remains a mystery in modern astrophysics. Those cosmic rays, with energies well above 50 EeV ($50\times 10^{18}$eV), can hardly be accelerated, even in the most active parts of our universe such as FR-II radio galaxies or AGNs, nor can they travel on distances larger than 100 Mpc. In the following some of the production and acceleration models for UHECR are reviewed and some of the transport issues are exposed. Finally the detection and identification on Earth of those ``cosmic bullets'' are presented.Comment: 46 pages, 16 figures. Lecture given at the XXVIII International Meeting on Fundamental Physics, Sanlucar de Barameda, Cadiz Spain, 14-18 February 200

A procedure to produce excess, probability and significance maps and to compute point-sources flux upper limits

A short note to propose a procedure to construct excess maps, probability maps and to calculate point source flux upper limits.Comment: 7 pages, 3 figure

A model for the time uncertainty measurements in the Auger surface detector array

The precise determination of the arrival direction of cosmic rays is a fundamental prerequisite for the search for sources or the study of their anisotropies on the sky. One of the most important aspects to achieve an optimal measurement of these directions is to properly take into account the measurement uncertainties in the estimation procedure. In this article we present a model for the uncertainties associated with the time measurements in the Auger surface detector array. We show that this model represents well the measurement uncertainties and therefore provides the basis for an optimal determination of the arrival direction. With this model and a description of the shower front geometry it is possible to estimate, on an event by event basis, the uncertainty associated with the determination of the arrival directions of the cosmic rays

An Estimate of the Spectral Intensity Expected from the Molecular Bremsstrahlung Radiation in Extensive Air Showers

A detection technique of ultra-high energy cosmic rays, complementary to the fluorescence technique, would be the use of the molecular Bremsstrahlung radiation emitted by low-energy electrons left after the passage of the showers in the atmosphere. The emission mechanism is expected from quasi-elastic collisions of electrons produced in the shower by the ionisation of the molecules in the atmosphere. In this article, a detailed calculation of the spectral intensity of photons at ground level originating from the transitions between unquantised energy states of free ionisation electrons is presented. In the absence of absorption of the emitted photons in the plasma, the obtained spectral intensity is shown to be 5 10^{-26} W m^{-2}Hz^{-1} at 10 km from the shower core for a vertical shower induced by a proton of 10^{17.5} eV.Comment: 16 pages, 6 figures, accepted in Astroparticle Physics. Compared to v1 version: 1. Inclusion of ro-vibrational processes. 2. Use of more accurate ionization potential values and energy distribution of the secondary electron

Molecular Bremsstrahlung Radiation at GHz Frequencies in Air

A detection technique for ultra-high energy cosmic rays, complementary to the fluorescence technique, would be the use of the molecular Bremsstrahlung radiation emitted by low-energy ionization electrons left after the passage of the showers in the atmosphere. In this article, a detailed estimate of the spectral intensity of photons at ground level originating from this radiation is presented. The spectral intensity expected from the passage of the high-energy electrons of the cascade is also estimated. The absorption of the photons in the plasma of electrons/neutral molecules is shown to be negligible. The obtained spectral intensity is shown to be $2\times10^{-21}$W cm$^{-2}$ GHz$^{-1}$ at 10 km from the shower core for a vertical shower induced by a proton of $10^{17.5}$ eV. In addition, a recent measurement of Bremsstrahlung radiation in air at gigahertz frequencies from a beam of electrons produced at 95 keV by an electron gun is also discussed and reasonably reproduced by the model.Comment: 20 pages, 9 figures, figures (2,4,7) improved in v2, accepted by Phys. Rev.

The Technique Research on Account Information Signing in the Commercial Bank Channel Trade System

摘要 在经济全球化发展的大背景下，开放和竞争已经成为世界金融发展的主流，银行业的全球竞争将日益激烈。商业银行要想在激烈的市场竞争中立于不败之地并持续发展，就需要加快金融创新、科技创新，提高核心竞争力。随着金融信息化建设的不断深入，商业银行信息系统集中化程度越来越高。正在建立的“账户信息签约系统”将不同的各个孤岛中的账户进行签约处理，使其提供客户的账户信息、银行的交易渠道链接共享，拓展多交易渠道互动及增强交易渠道个性化服务能力，实现跨交易渠道识别客户并通过签约服务应用系统为客户提供方便、快捷的账户信息。 本文分析了商业银行信息资源的特征和服役的各个系统的特点，论证了建立“账户信息签约系统”的...Abstract Under the development of economic globalization, the opening and competition has become the mainstream of financial development in twenty-one century, and the competition between international banks tends to be fiercer. If commercial banks want to succeed in this process and keep developing, they need speed up their financial and technological innovations to improve the core comp...学位：工程硕士院系专业：软件学院_工程硕士(软件工程)学号：X200523001

UHE tau neutrino flux regeneration while skimming the Earth

The detection of Earth-skimming tau neutrinos has turned into a very promising strategy for the observation of ultra-high energy cosmic neutrinos. The sensitivity of this channel crucially depends on the parameters of the propagation of the tau neutrinos through the terrestrial crust, which governs the flux of emerging tau leptons that can be detected. One of the characteristics of this propagation is the possibility of regeneration through multiple $\nu_\tau \leftrightarrow \tau$ conversions, which are often neglected in the standard picture. In this paper, we solve the transport equations governing the $\nu_\tau$ propagation and compare the flux of emerging tau leptons obtained allowing regeneration or not. We discuss the validity of the approximation of neglecting the $\nu_\tau$ regeneration using different scenarios for the neutrino-nucleon cross-sections and the tau energy losses.Comment: 8 pages, 8 figure

Angular Power Spectrum Estimation of Cosmic Ray Anisotropies with Full or Partial Sky Coverage

We study the angular power spectrum estimate in order to search for large scale anisotropies in the arrival directions distribution of the highest-energy cosmic rays. We show that this estimate can be performed even in the case of partial sky coverage and validated over the full sky under the assumption that the observed fluctuations are statistically spatial stationary. If this hypothesis - which can be tested directly on the data - is not satisfied, it would prove, of course, that the cosmic ray sky is non isotropic but also that the power spectrum is not an appropriate tool to represent its anisotropies, whatever the sky coverage available. We apply the method to simulations of the Pierre Auger Observatory, reconstructing an input power spectrum with the Southern site only and with both Northern and Southern ones. Finally, we show the improvement that a full-sky observatory brings to test an isotropic distribution, and we discuss the sensitivity of the Pierre Auger Observatory to large scale anisotropies.Comment: 16 pages, 6 figures, version accepted for publication by JCA

Kalman Filter Track Fits and Track Breakpoint Analysis

We give an overview of track fitting using the Kalman filter method in the NOMAD detector at CERN, and emphasize how the wealth of by-product information can be used to analyze track breakpoints (discontinuities in track parameters caused by scattering, decay, etc.). After reviewing how this information has been previously exploited by others, we describe extensions which add power to breakpoint detection and characterization. We show how complete fits to the entire track, with breakpoint parameters added, can be easily obtained from the information from unbroken fits. Tests inspired by the Fisher F-test can then be used to judge breakpoints. Signed quantities (such as change in momentum at the breakpoint) can supplement unsigned quantities such as the various chisquares. We illustrate the method with electrons from real data, and with Monte Carlo simulations of pion decays.Comment: 27 pages including 10 figures. To appear in NI