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A Comment on the article by Anchordoqui et al. 'Hunting long-lived gluinos at the Pierre Auger Observatory' [L. A. Anchordoqui, A. Delgado, C. A. Garcia Canal, and S. J. Sciutto, Phys. Rev. D 77, 023009 (2008)].

We argue that too much exotic scene setting is not necessary for the explanation of the Centauro events observed by the mountain based emulsion chambers. We show that a proper understanding of the detector helps to find a mundane solution to the 'decades old cosmic ray mystery'. We conclude that the exotic events observed so far are not inconsistent with the incorrect evaluation of the detector response and misinterpretation of the experimental signal.

We wish to put forward an explanation for a peculiar cosmic ray event with energy {sigma}E{sub {gamma}}{>=}2x10{sup 15} eV detected in 1975 by the balloon borne emulsion chamber experiment performed in the stratosphere, at the altitude {>=}30 km above sea level. For almost 30 years the event has been described as unusual, invoking new exotic mechanisms or models. In our opinion there is no need for an extraordinary explanation. Contrary to the widespread belief, the event gives us an example of 'unrecognized standard physics'. At the same time this event revealed a variety of features which are of considerable interest for cosmic rays, nuclear physics, and astrophysics. Here we show that the observed family is most likely to be a result of a heavy nucleus interaction with an air nucleus. In this case a primary particle would originally have been in the energy region above 'the knee' of the cosmic ray spectrum.

An unusual Centauro phenomenon in which cosmic rays enter the atmosphere producing tens of charged hadrons, but virtually no neutral pions, has been a mystery for more than 30 years. Since the discovery of Centauro I in 1972 by the Brazil-Japan Collaboration operating x-ray emulsion chambers at 5200 m on Mt. Chacaltaya in the Bolivian Andes, a variety of models have been proposed (including new types of interaction or the creation of new types of matter). Here we show that the solution to a long-standing scientific puzzle lies with the details of the Chacaltaya detector. The new analysis of the original Centauro I event reveals that there is a difference in the angle between the upper block and lower block events, so the two are not products of the same interaction. That leaves only the lower chamber data connected to the Centauro I event. It is shown that, with the revised understanding of the event, new physics is no longer required for the explanation.

A new analysis of mountain-top x-ray emulsion chamber data is presented. We utilize a refined experimental apparatus and a standardized analysis approach, including the simulated data. The results indicate that most of the phenomena reported previously can be explained as fluctuations within standard hadronic interaction physics. In the wide energy region we see no indication of a large change in the primary composition.

The inelasticity distribution of hadron-lead collisions in the energy region exceeding ${10}^{14}$ eV is estimated on the basis of 66 events, induced by cosmic ray hadrons and detected at high mountain altitudes at Pamir (4300 m, 595 ${\mathrm{g}/\mathrm{c}\mathrm{m}}^{2}).$ The distribution of the best fitting is approximated as $g(K)dK=[\ensuremath{\alpha}(1\ensuremath{-}{K)}^{{m}_{1}\ensuremath{-}1}+\ensuremath{\beta}{K}^{{m}_{2}\ensuremath{-}1}]dK,$ where ${m}_{1}=0.5,$ ${m}_{2}=1.125,$ $\ensuremath{\alpha}=0.26,$ $\ensuremath{\beta}=0.55,$ giving $〈K〉=0.60.$ The errors of the parameters are discussed in the text. The distribution is compared with those which are based on theoretical models.