Massive photons

[JulianO]

Here's an interesting theory. Do photons have rest mass? If they do it is very very small. ANd if so do they decay - which would change the light flux from distant galaxies.

http://physicsworld.com/cws/article/news/2013/jul/24/what-is-the-lifetime-of-a-photon

[George Jones]

How does the photon acquire mass without ruining gauge invariance? By a Higgs-like mechanism?

I am swamped with an overload at work, so I haven't read your link yet. Thanks for posting it; it looks interesting, and I hope to get a chance to look at it.

[JulianO]

No idea! How do neutrinos acquire mass? Not really my field!

[George Jones]

No idea! How do neutrinos acquire mass? Not really my field!

Neutrinos acquire mass through interaction with the standard Higgs fields. Photons are different than neutrinos, in that they are the force-carriyng particles (gauge bosons) of electromagnetism.

I have now scanned the Physics World article, and found the original research,

http://arxiv.org/abs/1304.2821

In the first paragraph, the author states that this isn't a problem. Don't know any of the details, though.

[JulianO]

I have now scanned the Physics World article, and found the original research,

http://arxiv.org/abs/1304.2821

In the first paragraph, the author states that this isn't a problem. Don't know any of the details, though.

Well he uses words I don't understand!

A nonzero photon mass is often dismissed on theoretical grounds, as the insertion of a mass term to the

Lagrangian of quantum electrodynamics (QED) breaks

gauge invariance and might therefore spoil renormalizability, i.e. the consistency of the theory at quantum level.

This is, however, not the case as the Proca Lagrangian can be viewed as a gauge-fixed version of the Stuckelberg

Lagrangian [3], which restores gauge invariance. For an exhaustive review we refer to [4]. To the point: gauge

bosons of abelian symmetries are permitted a mass by means of the Stuckelberg mechanism—retaining gauge

invariance, unitarity, and renormalizability. The question of a photon mass in QED is then purely

experimental, as there is no theoretical prejudice against a small m over m = 0.1

An interesting conclusion too

In conclusion, a massive photon sounds crazy and exotic, but it really is not. A massless photon is neither a

theoretical prediction nor a necessity, but rather a phenomenological curiosity

[JamesF]

Not really my field!

Very punny

James