摘要:

The first experiment in which radio emission was detected from high energy particles is described. An array of dipoles was operated by a team of British and Irish physicists in 1964–5 at the Jodrell Bank Radio Observatory in conjunction with a simple air shower trigger. The array operated at 44 MHz with 2.75 MHz bandwidth. Out of 4,500 triggers a clear bandwidth-limited radio pulse was seen in 11 events. This corresponded to a cosmic ray trigger threshold of5×1016&hthinsp;eVand was of intensity close to that predicted. The early experiments which followed this discovery and their interpretation is described. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398155

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398156

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

In this lecture we conjecture that the Ultra-High Energy Cosmic Rays (UHECR) with energiesE>EGZK,whereEGZK∼5⋅1019&hthinsp;eVis the Greisen-Zatsepin-Kuzmin cut-off energy of cosmic ray spectrum, may originate from decays of superheavy long-livingX-particles populating the Universe thus providing a unique window into the very early epoch of the Universe, namely, that of preheating and reheating after inflation. These particles may constitute a considerable fraction of cold dark matter in the Universe. We argue that the unconventionally long lifetime of the superheavy particles, which should be in the range of1010–1022years, might require novel particle physics mechanisms of their decays, such as instantons. First of all I will describe a toy model illustrating the instanton scenario and then will describe the possible proper mechanism of creation of superheavy particles in the early Universe. It is my pleasure to emphasize that all I will talk about was done in collaboration with my friends V. A. Rubakov and I. I. Tkachev. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398157

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic processes in the Universe. Their existence triggered a flurry of theoretical explanations ranging from conventional shock acceleration to particle physics beyond the Standard Model and processes taking place at the earliest moments of our Universe. Furthermore, many new experimental activities promise a strong increase of statistics at the highest energies and a combination with &ggr;-ray and neutrino astrophysics will put strong constraints on these theoretical models. We give an overview of theoretical developments with a focus on neutrino fluxes and cross sections, an issue that may be of particular relevance for the radio detection method. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398158

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

This talk explores the possibility that the Universe may be populated with relic magnetic monopoles. Observations of galactic and extragalactic magnetic fields, lead to the conclusion that monopoles of mass≲1014&hthinsp;GeVare accelerated in these fields to relativistic velocities. The relativistic monopole signatures and features we derive are (i) the protracted shower development, (ii) the Cherenkov signals, (iii) the tomography of the Earth with monopoles, and (iv) a model for monopole airshowers above the GZK cutoff. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398159

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The temperature of the cosmic microwave background increases with redshift; at sufficiently high redshift it becomes possible for ultrahigh-energy photons and electrons to produce muons and pions through interactions with background photons. At the same time, energy losses due to interactions with radio background and intergalactic magnetic fields are negligible. The energetic muons and pions decay; yielding a flux of “signature” neutrinos with energiesE&ngr;∼1017&hthinsp;eV.Detection of these neutrinos can help understand the origin of ultrahigh-energy cosmic rays. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398160

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

The observation of twenty cosmic-ray air-showers at and above1020&hthinsp;eVposes fascinating problems for particle astrophysics: how the primary particles are accelerated to these energies, how the primaries get here through the 2.7K microwave background filling the Universe, and how the highest-energy events exhibit clustering on few-degree angular scales on the sky when charged particles are expected be bent by cosmic magnetic fields. An overview of the puzzles is presented, followed by a brief discussion of many of the models proposed to solve these puzzles. Emphasis is placed on (i) the signatures by which cosmic ray experiments in the near future will discriminate among the many proposed models, and (ii) the role neutrino primaries may play in resolving the observational issues. It is an exciting prospect that highest-energy cosmic rays may have already presented us with new physics not accessible in terrestrial accelerator searches. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398161

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

A prototype system for detecting radio pulses associated with extensive cosmic ray air showers is described. Sensitivity is compared with that in previous experiments, and lessons are noted for future studies. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398162

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Different characteristics of LF-MF-HF-VHF Radioemission (RE) from EAS have been studied theoretically as well as experimentally by the Gauhati University Cosmic Ray (GUCR) group since 1970. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398163

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Using the values of the dielectric constant, &Vegr;, determined with the help of various models the intensity of the coherent transition radiation (CTR) produced by extended air shower (EAS) particles is calculated in the meter wave length region. CTR produced at the inhomogeneities of Antarctic ice and mine salt dielectric constant is also considered. The possibilities of detection of such CTR and its influence on cosmic ray particle radio detection is discussed. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1398164

出版商:AIP    

年代:1901

数据来源: AIP