An analysis has been made of the world's data on very large extensive air showers with the object of deriving a `best-fit' primary energy spectrum.
It is reassuring that when the various, ...independently measured, spectra are standardised, using as a datum the well-known `dip' in the spectrum at about 3×10
18 eV, and a correction for inferred `noise', the measurements are all consistent.
The best-fit spectrum bears out the well-known problem with the lack of observation of a feature (a cut-off) due to interactions of the particles, commonly assumed to be extra-galactic protons, with the cosmic microwave background. However, we contend that a model involving extragalactic nuclei J. Phys. A 8 (1975) 1518; Astrophys. J. 205 (1976) 638; Astrophys. J. 512 (1999) 521 is satisfactory, although it is premature to be too prescriptive, due to the shortage of astronomical data.
We register events with large number of neutrons at the ground level as well as in the underground laboratory. These neutrons are produced in secondary cosmic ray interactions with matter surrounding ...the neutron detectors. We used the set of helium-3 filled gas proportional counters and plastic scintillators. We performed a series of measurements in different experimental setups to determine a role of particle cascades in generation of large neutron multiplicities. With GEANT4 simulation of experimental setup we estimated number of neutrons produced in a single event which is required to explain our measurements.
It is possible that violent processes resulting in Gamma Ray Bursts produce also high energy photons and cosmic rays. The possible correlations of very short GRB with, e.g., CMB, cosmic rays is ...briefly discussed. We have also begun preparation of the experiment correlating in real time data from Maze cosmic ray detector and Pi of the Sky robotic telescope.
A new extensive air shower (EAS) experiment has been installed at the laboratory site of the Forschungszentrum Karlsruhe. The main aim of the KASCADE 1 project is the determination of the chemical ...composition in the energy range around and above the knee of the primary cosmic ray spectrum. The main advantage of the new installation is the simultaneous measurement of a large number of observables for each individual event. This is achieved by the combination of various advanced detection techniques for the electromagnetic, the muonic, and the hadronic component of the extensive air showers. Data taking with a large part of the experiment has started at the end of 1995. The estimated accuracy of air shower data is discussed for the various detector components of KASCADE and first very preliminary results are presented.
The active galactic nucleus PG 1553+113 was observed by the MAGIC telescope in July 2006 during a multiwavelength campaign, in which telescopes in the optical, X-ray, and very high energies ...participated. Although the MAGIC data were affected by strong atmospheric absorption (calima), they were analyzed after applying a correction. In 8.5 h, a signal was detected with a significance of 5.0σ. The integral flux above 150 GeV was $(2.6\pm0.9)\times 10^{-7}~{\rm ph\,s^{-1}\,m^{-2}}$. By fitting the differential energy spectrum with a power law, a spectral index of $-4.1\pm0.3$ was obtained.
The search for correlations between secondary cosmic ray detection rates and seismic effects has long been a subject of investigation motivated by the hope of identifying a new precursor type that ...could feed a global early warning system against earthquakes. Here we show for the first time that the average variation of the cosmic ray detection rates correlates with the global seismic activity to be observed with a time lag of approximately two weeks, and that the significance of the effect varies with a periodicity resembling the undecenal solar cycle, with a shift in phase of around three years, exceeding 6 sigma at local maxima. The precursor characteristics of the observed correlations point to a pioneer perspective of an early warning system against earthquakes.
Propagation of ultra-high energy photons in the solar magnetosphere gives rise to cascades comprising thousands of photons. We study the cascade development using Monte Carlo simulations and find ...that the photons in the cascades are spatially extended over millions of kilometers on the plane distant from the Sun by 1 AU. We compare results from simulations which use two models of the solar magnetic field, and show that although signatures of such cascades are different for the models used, for practical detection purpose in the ground-based detectors, they are similar.
We describe the possible measurable difference in the Cherenkov light component of EAS induced by an electromagnetic particle (i.e., e
+, e
− or γ) and induced by a hadron (i.e., proton or heavier ...nuclei) in the TeV range. The method can be applied in experiments which use wave front sampling method of EAS Cherenkov light detection (e.g., THEMISTOCLE, ASGAT).
The last decade has brought about a profound transformation in multimessenger science. Ten years ago, facilities had been built or were under construction that would eventually discover the nature of ...objects in our universe could be detected through multiple messengers. Nonetheless, multimessenger science was hardly more than a dream. The rewards for our foresight were finally realized through IceCube's discovery of the diffuse astrophysical neutrino flux, the first observation of gravitational waves by LIGO, and the first joint detections in gravitational waves and photons and in neutrinos and photons. Today we live in the dawn of the multimessenger era. The successes of the multimessenger campaigns of the last decade have pushed multimessenger science to the forefront of priority science areas in both the particle physics and the astrophysics communities. Multimessenger science provides new methods of testing fundamental theories about the nature of matter and energy, particularly in conditions that are not reproducible on Earth. This white paper will present the science and facilities that will provide opportunities for the particle physics community renew its commitment and maintain its leadership in multimessenger science.
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