An alternative view: Electric charge is the relative direction of imaginary lines of force in an electric field. Electric field is circular in nature. As charge is a relative entity, type of charge depends on reference used and all electric fields have both positive and negative electric charges. Electric charge is a functional entity.

Mas is another functional entity that shows mathematical relation between external force on a body and body's acceleration in the direction of force. Mass is often considered to represent equivalent of quantity of three-dimensional matter in a body.

With sufficient deliberations, any type of relation can be established between functional entities.

See: http://viXra.org/abs/1409.0062 , 'MATTER (Re-examined)' www.matterdoc.info

Let me try to answer the question this way:

Electrically charged particles cannot be massless because of their self-energy. The field that is constituted by the charge contains some energy and contributes to the mass of the charged particle because of the equivalence of mass and energy (“E=mc2”). Thus, the mass of an electrically charged particle cannot be exactly zero. I.e., there is no electrical charge without mass.

For the color-charged gluons the situation is different due to their much more complicated self-interacting terms. They underlie a manifest gauge symmetry, which is not spontaneously broken (as it is in the electroweak sector). This “forbids” massive gluons.

Thus, to my current knowledge, I have no reason to doubt the masslessness of gluons, even if every electrically charged particle must have a (rest) mass.

If there is any reason for gluons to have mass (e.g. by experiment), there would be a need to revise QCD. (However, as already stated, currently I do not know any evidence for that.)

Dear Lorns-Olaf Stahlberg

What do you mean by field energy of charge and how it can be treated as mass. What is the difference between mass and this field energy. /

When it is applied to gluon, quantum mechanics and classical will have their own separate definitions of mass and energy.

The science has started from 'classical' but when we reach quantum level we are changing the definitions. How far it is reasonable ?

Dear Siva Prasad Kodukula,

A nice explanation of this topic can be found here, for instance:

http://www.desy.de/~geiser/Lehre/SS09/Masse092.pdf

Unfortunately, this is not in English but in German.

You may also find information (in English) on the wikipedia page on "electromagnetic mass".

https://en.wikipedia.org/wiki/Electromagnetic_mass

(However, I do not guarantee for the correctness of these explanations, since I am not the author.)

I am not sure whether I really understand your question about the difference between mass and energy. At least there is no difference, because mass and energy are equivalent.

Furthermore, I do not see the very difference between the definitions of mass and energy within classical physics (including relativity) and quantum physics. However, there is - in fact - a difference between classical and quantum physics concerning the concept of self-energy.

Regards

Lorns

Dear Lorns,

Thank you.

The main difference between mass and energy is 'Inertia'. Of course Now I don't want to get in to that discussion. Thank you. I will go through your explanations.