Search for supermassive relics with a 2000-m2array of plastic track detectors

Abstract

A direct search has been made for supermassive relics (heavier than about 10 12 GeV/c 2 ) with a 2000-m 2 array of CR-39 track-etch detectors deployed underground for 2.1 yr. The nonobservation of penetrating tracks places a new upper limit for the velocity-dependent flux at 3.2x 10 ~1 6 cm ^s -1 sr _1 , for magnetic monopoles carrying various magnetic charges, for electrically charged relics, and for strange matter. This flux limit corresponds to a limit on the relic abundance of order n x /n r = \0 ~2 9 relative to the 3-K photons.PACS numbers: 96.40. De, 14.80.Hv, 14.80.Pb Recently the existence of various kinds of supermassive stable particles has been conjectured: Supermassive magnetic monopoles are generically predicted 1 by grand unified theories, Kaluza-Klein theories, and superstring theories. A large number of the grand unified theories and superstring theories predict 2 the existence of monopoles with multiple Dirac magnetic charges. Superstring theories 3 and composite theories of leptons and quarks 4 speculate on the existence of fractionally or integrally charged supermassive particles, which might not be totally confined. Higher-dimensional theories contain 5 supermassive (of the order of the Planck mass) stable particles named "pyrgon," which may be charged. If there exists a new conserved quantum number, the lightest particles carrying it must be stable. A quark matter which is absolutely stable (strange matter) has been proposed 6 as the ground state of nuclear matter. If such particles exist, they should have been created in the very early Universe and might have survived to today as the supermassive relics of the big bang. They might have participated in galaxy formation and may be trapped in the clusters of galaxies and in the galaxies with typical virial ft ( = v/c) of 3xlO -3 and 10~3, respectively. Such supermassive particles might constitute the dark mass of the galaxies and of the Universe. The existence of magnetic field in the galaxies can be used to deduce 7 an upper limit for the flux of magnetic monopoles of order 10 ~~1 5 cm~2s~1sr" 1 (Parker bound) at /?-10 ~3. However, possibilities of local enhancement have been considered 8 for the flux trapped in the solar system with an expected typical f3 of 10 ~4.With the aim of searching for an extremely low abundance of order n x /n y = 10 ~3 0 relative to the 3-K photons, we are conducting a search for penetrating tracks using a total of 3500 m 2 of CR-39 plastic track detectors. The results from an 80-m 2 array 9 in a mine and from a 160-m 2 array 10 at a mountain altitude have been reported elsewhere. In this paper, we report on an analysis of a 2000-m 2 array placed at underground sites.The principle {l of finding tracks in a plastic track-etch detector is as follows. The passing particle leaves a trail of localized damage (latent trail) in the form of broken chemical bonds. This trail is more vulnerable to a chemical attack than the bulk of the plastic. By chemically etching the plastic, visible etch cones are developed along the ...

Lake Baikal neutrino experiment: Selected results

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“…One can imagine a charged test particle moving in the neighbourhood of electrically, and magnetically charged massive bodies. According to (24), (25), and (35) the torsion vector V µ is created by magnetic charged bodies, while the Weyl vector w µ may be created by bodies having electric charge, as well by a self-inducing Proca term. Now, the structure of the field strength tensors is given by (31), and (32).…”

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