Can the neutrino speed anomaly be defended?

TL;DR

This paper critically examines the claim of superluminal neutrino speeds by analyzing potential systematic errors in the OPERA experiment, questioning the assumption that proton timing directly reflects neutrino emission timing.

Contribution

It identifies two main sources of systematic errors—filter-induced group delay and beam movement—that could explain the neutrino speed anomaly without requiring superluminal velocities.

Findings

Systematic effects can account for the observed early neutrino arrival.

Filter group delay may introduce timing shifts in the measurement.

Beam movement during spill could affect the timing analysis.

Abstract

The OPERA collaboration reported [1] a measurement of the neutrino velocity exceeding the speed of light by 0.025%. For the 730 km distance from CERN in Geneva to the OPERA experiment an early arrival of the neutrinos of 60.7 ns is measured with an accuracy of \pm6.9 ns (stat.) and \pm7.4 ns (sys.). A basic assumption in the analysis is that the proton time structure represents exactly the time structure of the neutrino flux. In this manuscript, we challenge this assumption. We identify two main origins of systematic effects: a group delay due to low pass filters acting on the particular shape of the proton time distribution and a movement of the proton beam at the target during the leading and trailing slopes of the spill.