## anonymous one year ago How massive is photons?

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1. anonymous

How are photons often drawn?

2. IrishBoy123

$$\gamma$$ inside the customary little ball

3. anonymous

@IrishBoy123 thank you

4. Michele_Laino

photon is a massless particle, even if the current theory doesn't deny the hypothesis for a not massless photon. Current researches give this limit for photon mass: $\Large {m_\gamma } \leqslant {10^{ - 48}}{\text{grams}}$

5. rvc

thanks @Michele_Laino

6. Michele_Laino

:) @rvc

7. Astrophysics

@Michele_Laino Hey, how would you even measure that, or is that one of the results from the relativity equations?

8. IrishBoy123

i reckon this is a great answer - there's some physics wordplay going on here https://www.physicsforums.com/threads/do-photons-have-mass.511175/

9. Michele_Laino

no, many experiments are made in order to establish the mass of the photon

10. Michele_Laino

here is a reference about an experiment on the photon mass: P.A. Franken and G.W. Ampulski, Phys. Rev. Letters 26, 115 (1971)

11. Michele_Laino

subsequently many others experiments are made starting from the Proca equations, which substitute the Maxwell equations, if the photon is not massless. Those equations can be derived by the Proca Lagrangian: $\Large {L_{{\text{Proca}}}} = - \frac{1}{{16\pi }}{F_{\alpha \beta }}{F^{\alpha \beta }} + \frac{{{\mu ^2}}}{{8\pi }}{A_\alpha }{A^\alpha } - \frac{1}{c}{J_\alpha }{A^\alpha }$

12. Michele_Laino

where: $\Large {F_{\alpha \beta }},\;{A_\alpha },\;{J_\alpha }$ are the electromagnetic tensor, quadrivector potential, and quadrivector density current respectively, furthermore: $\Large \mu = \frac{{{m_{ph}}c}}{\hbar }$ m_ph is the photon mass

13. Michele_Laino

I have written a scientific paper on the photon mass, and I have showed that if the photon has a mass, then another quantum action has to exist. nevertheless my article is unpublished

14. Astrophysics

Awesome, thanks for the information guys! I also read the link you gave @IrishBoy123 thank you. @Michele_Laino Is it possible I could get a copy, I would like to give it a read, sounds very interesting. Thanks again :)

15. Michele_Laino

yes! I can attach my paper as PDF file here

16. IrishBoy123

@Michele_Laino you're an awesome resource in these parts!

17. Michele_Laino

thanks! :) @IrishBoy123

18. Astrophysics

That would be great! Haha yes Michele is!

19. Michele_Laino

ok! please wait a moment, since I have to retrieve my article @Astrophysics

20. Astrophysics

No problem! Take your time :)

21. Michele_Laino

ok!

22. Michele_Laino

here is my article:

23. Astrophysics

Awesome, thank you! I will read over it and if I have questions I will message you!

24. Michele_Laino

ok! :)

25. Astrophysics

Thanks again

26. Michele_Laino

:)