Third road to the OPERA: a tunnel after all?

Abstract

The debate on OPERA focused on two extremes: either "OPERA is wrong" or our formulation of the laws of physics needs a major overhaul. I here argue that some effort should be directed toward manifestations of laws that are already known, but whose implications are poorly understood in OPERA-type contexts. My preferred example of this sort is that the OPERA result might be the first observation of a previously unnoticed effect, belonging to a family of effects which includes those responsible for the well-known peculiar properties of the "tunneling time". Tentative support for this specific hypothesis comes from the presence of evanescence and "postselection", and the observation that the fraction of neutrinos absorbed in rock on the way from CERN to LNGS is of a few parts in $10^5$, i.e. comparable to the fraction of the overall travel time by which OPERA neutrinos are found to reach LNGS earlier than expected. This leads me to stress that the OPERA result is still consistent with subluminality of a suitably "postselection-corrected" velocity. Adopting the popular (but here disfavored) interpretation of the OPERA result as a "signal velocity" one could obtain superluminal values of the postselection-corrected velocity in some technologically feasible OPERA-like setups, a prediction which I propose to test. I also propose a semi-heuristic formula for the "rock dwell time" and find that it gives a result in rough agreement with the OPERA travel-time measurements. This suggests that effects similar to the ones found for OPERA's muon neutrinos should also be found, but with tangibly different magnitude, for muon anti-neutrinos under similar experimental conditions. And I argue that, whether or not they end up being relevant for the OPERA anomaly, the effects here considered should be significant in the Planck-scale realm.