The exotic characteristics of Centauro-I: a model to describe Centauro-I

In our previous paper on Centauro-I (Ohsawa et al 2004 Phys. Rev. D 70 074028), we showed that the shower cluster, found in the block I12 of the lower chamber, is produced in the target layer by a number of hadrons with appreciable lateral spread. These hadrons are accompanied by no (or one at most) γ-ray(s) with energy above detection threshold, and produce no shower in the upper chamber but 28 visible C-jets (with the visible energy more than 2 TeV) in the target layer. These characteristics are quite exotic and unable to be described by a fluctuation of ordinary atmospheric families. In the present paper, we propose a model of strange quark matter (SQM) among the primary cosmic rays to describe the exotic features of the event. A large SQM droplet enters the atmosphere and fragments into a bundle of small strangelets in the atmosphere without emission of γ-rays, and these small strangelets explode into nucleons in the upper chamber. The number of collisions in the upper chamber is estimated to be as small as 3–4 in contrast to 20–30 collisions in the target layer. We discuss the intensity of Centauro-I together with the exotic events observed by the balloon and satellite experiments, which were also ascribed to strange quark matter.