Lower and upper bounds on CSL parameters from latent image formation and IGM heating

We study lower and upper bounds on the parameters for stochastic state vector reduction, focusing on the mass-proportional continuous spontaneous localization (CSL) model. We show that the assumption that the state vector is reduced whan a latent image is formed, in photography or etched track detection, requires a CSL rate parameter \λ that is larger than conventionally assumed by a factor of roughly 2 \× 109\± 2, for a correlation length rC of 10⁻⁵\ cm. We reanalyze existing upper bounds on the reduction rate and conclude that all are compatible with such an increase in \λ. The best bound that we have obtained comes from a consideration of heating of the intergalactic medium (IGM), which shows that \λ can be at most 3 \× 109\± 1 times as large as the standard CSL value, again for rC=10⁻⁵ \ cm. (For both the lower and upper bounds, quoted errors are not statistical errors, but rather reflect estimates based on modeling uncertainties.) We discuss modifications in our analysis corresponding to a larger value of rC. With a substantially enlarged rate parameter, CSL effects may be within range of experimental detection (or refutation) with current technologies.