NASA Goddard Space Flight Center | IceCube | 2015 Oct 21
[img3="An apparent cutoff (purple box) in the highest-energy neutrinos detected by the IceCube Neutrino Observatory (red error bars and box) could be a result of energy losses incurred by faster-than-light neutrinos. If so, the neutrinos are exceeding the speed of light by only 5 parts in a billion trillion. Detections at higher energies will provide even tighter limits. (Credits: NASA Goddard Space Flight Center)"]http://www.nasa.gov/sites/default/files ... _chart.jpg[/img3][hr][/hr]Studying the highest-energy particles in the cosmos provides scientists with a way to test how well they understand the cutting edge of physics. Recently, scientists using a giant particle detector at the South Pole have set records for the highest-energy observations of mysterious subatomic entities called neutrinos. If neutrinos happen to be traveling faster than light, a feat that violates Einstein's relativity theory but is allowed by some newer rival theories, these measurements provide a way to determine how far they're pushing the speed limit.
"A foundational tenet of relativity is what physicists call Lorentz invariance," explained Floyd Stecker, a theorist in the Astrophysics Science Division at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "This includes the notion that light traveling in a vacuum sets a cosmic speed limit that cannot be exceeded by any matter or information."
But some versions of theories designed to replace general relativity, such as string theory and loop quantum gravity, predict possible exceptions. The highest-energy neutrinos offer a way to determine how big any faster-than-light loophole may be. ...
Searching for Traces of Planck-Scale Physics with High Energy Neutrinos - Floyd W. Stecker et al
- Physical Review D 91(4):045009 (15 Feb 2015) DOI: 10.1103/PhysRevD.91.045009
arXiv.org > hep-ph > arXiv:1411.5889 > 21 Nov 2014 (v1), 09 Feb 2015 (v3)
http://asterisk.apod.com/viewtopic.php?t=35087