MASS DEPENDENCE OF SEARCHES FOR FRACTIONAL CHARGE IN MATTER USING ION BEAM TECHNIQUES
19859 pages
Published in:
- Phys.Rev.D 32 (1985) 1177-1185
Citations per year
Abstract: (APS)
If free quarks or other fractionally charged particles can exist, they should be present as a low primordial or cosmic-ray-produced concentration in terrestrial matter. The most sensitive searches have been dependent on the detection of anomalous ions by silicon-barrier or electron-multiplier detection systems, in which the dependence of energy transfer on ion velocity results in a decrease of detection efficiency with increasing mass, leading to a cutoff in observable particle mass for a given accelerating voltage. The factors governing this mass dependence are discussed, with illustrative calculations for a number of typical experiments. It is shown that the reported concentration limits are valid up to typically 10–100 proton masses for anomalous particles either in the free state or attached to low-Z atoms, but with lower sensitivity and reduced mass limits if bound to heavier atoms. The prospects for improving mass limits in future fractional charge searches are discussed. It is concluded that the detectable mass range could in principle be extended by several orders of magnitude in this type of experiment, and that in the case of positive ions of sufficiently high electron affinity the ‘‘potential mechanism’’ of electron ejection might provide a basis for fully mass-independent detection (although at the expense of a direct fractional-charge signature). The problem of pre-enrichment of the sample material is also considered, and a general method of estimating the mass dependence of electrical extraction techniques is given.- ION: SCATTERING
- SCATTERING: ION
- PARTICLE: FRACTIONALLY CHARGED
- SEARCH FOR: FRACTIONALLY CHARGED
- QUARK: SEARCH FOR
- DEPENDENCE: MASS
- mass dependence
- COUNTERS AND DETECTORS: EFFECT
- NUMERICAL CALCULATIONS
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