Gluino Air Showers as a Signal of Split Supersymmetry

It has been proposed recently that, within the framework of split Supersymmetry, long lived gluinos generated in astrophysical sources could be detected using the signatures of the air showers they produce, thus providing a lower bound for their lifetime and for the scale of SUSY breaking. We present the longitudinal profile and lateral spread of $G$-hadron induced extensive air showers and consider the possibility of measuring them with a detector with the characteristics of the Pierre Auger Observatory.Comment: 4 pages, 3 eps figure

On the cross correlation between the arrival direction of ultra-high energy cosmic rays, BL Lacertae, and EGRET detections: A new way to identify EGRET sources?

With the aim of testing recent claims for a particularly strong correlation between ultra-high energy cosmic rays (UHECRs), observed with the AGASA and the Yakutsk experiments, and a sample of BL Lacertae (BL Lacs), we here conduct a blind statistical assessment. We search for associations between the same set of BL Lac objects and the arrival directions of 33 relevant UHECRs observed with the Haverah Park and the Volcano Ranch experiments. Within the accuracy of angle determination, there are no positional coincidences. The probability that this null result arises as a statistical fluctuation from the strongly correlated case is less than 5%. This implies that the possible correlation between the arrival directions of UHECRs and BL Lacs is not statistically sustained. We discuss the impact of our findings on the propose additional connection among UHECRs, BL Lacs, and EGRET gamma-ray blazars. Recently, such an association was used as classification technique for EGRET sources. Here we show that its main underlying hypothesis, i.e., the EGRET angular uncertainty is twice that quoted in the Third EGRET Catalog, underestimates the goodness of existing gamma-ray data.Comment: References added. Accepted for publication in Astrophys. J. Let

A pot of gold at the end of the cosmic “raynbow”?

We critically review the common belief that ultrahigh energy cosmic rays are protons or atomic nuclei with masses not exceeding that of iron. We find that heavier nuclei are indeed possible, and discuss possible sources and acceleration mechanisms for such primaries. We also show detailed simulations of extensive air showers produced by “superheavy” nuclei, and discuss prospects for their detection in future experiments.Facultad de Ciencias Exacta

A pot of gold at the end of the cosmic “raynbow”?

We critically review the common belief that ultrahigh energy cosmic rays are protons or atomic nuclei with masses not exceeding that of iron. We find that heavier nuclei are indeed possible, and discuss possible sources and acceleration mechanisms for such primaries. We also show detailed simulations of extensive air showers produced by “superheavy” nuclei, and discuss prospects for their detection in future experiments.Facultad de Ciencias Exacta

SCROD: School Cosmic Ray Outreach Detector

We report progress on applying technologies developed for LHC-era experiments to cosmic ray detection, using scintillating tiles with embedded wavelength-shifting fibers and avalanche photodiode readouts as parts of a robust, inexpensive cosmic air shower detector. We are planning to deploy such detectors in high schools as part of an outreach effort able to search for long-distance correlations between airshowers.Comment: To be published in the Proceedings of the 28th International Cosmic Ray Conference http://www.icrr.u-tokyo.ac.jp/icrc2003

High energy physics in the atmosphere: phenomenology of cosmic ray air showers

The properties of cosmic rays with energies above 106 GeV have to be deduced from the spacetime structure and particle content of the air showers which they initiate. In this review we summarize the phenomenology of these giant air showers. We describe the hadronic interaction models used to extrapolate results from collider data to ultra high energies, and discuss the prospects for insights into forward physics at the LHC. We also describe the main electromagnetic processes that govern the longitudinal shower evolution, as well as the lateral spread of particles. Armed with these two principal shower ingredients and motivation from the underlying physics, we provide an overview of some of the different methods proposed to distinguish primary species. The properties of neutrino interactions and the potential of forthcoming experiments to isolate deeply penetrating showers from baryonic cascades are also discussed. We finally venture into a terra incognita endowed with TeV-scale gravity and explore anomalous neutrino-induced showers.Facultad de Ciencias Exacta

Unmasking the tail of the cosmic ray spectrum

A re-examination of the energy cosmic ray spectrum above 1020 eV is presented. The overall data-base provides evidence, albeit still statistically limited, that non-nucleon primaries could be present at the end of the spectrum. In particular, the possible appearance of superheavy nuclei (seldom discussed in the literature) is analysed in detail.Facultad de Ciencias Exacta