Evidence for Observation of Virtual Radio Cherenkov Fields

TL;DR

This paper reports the first observation of virtual radio Cherenkov fields from ultra-relativistic protons and hadronic showers, demonstrating coherence and introducing advanced noise filtering techniques.

Contribution

It provides experimental evidence of virtual electromagnetic fields in the radio domain from high-energy protons and showers, with novel data processing methods for low signal-to-noise conditions.

Findings

Observation of virtual electromagnetic fields from 120 GeV protons.

Linear scaling of signal with number of particles indicates coherence.

First detection of fields from hadronic showers.

Abstract

We present evidence for observation of virtual electromagnetic fields in the radio domain from experiment T926 at the Fermilab Meson Test Beam Facility. Relativistic protons with 120 GeV energy traversed a sealed electromagnetic cavity and were observed in the radio regime of 200MHz-GHz. Closely related to ordinary Cherenkov radiation, which we also measured, the virtual fields require no acceleration for their existence. The experiment is also the first observation of fields from hadronic showers, an independent and new confirmation of coherent radio emission from ultra-relativistic particles. Conditions of very low signal to noise were overcome by a novel and unbiased filtering strategy that exploits exhaustive studies of correlations in the noise backgrounds. Linear scaling of the signal region with the number of beam particles provides evidence of coherence. Extrapolation to measurement of the field of a single relativistic proton charge is consistent within errors. Our study also illustrates new data processing methods that may be applied broadly in conditions of extremely low signal to noise.