The minimum amount of charge possible is that of quarks. But it also has mass. Why is there no charge without mass? Or is it there?
10946
Are there any massless (zero invariant mass) particles carrying electric charge?  If not, why not? Do we expect to see any or are they a theoretical impossibility?
16163
Why can't photons have a mass? Could you explain this to me in a short and mathematical way?
19454
Or does it exist mathematically?  Is it really inconsistent with a common-sense, mathematics or known physical laws?   As far as I understand, if it exists, it must be far away from the "positive" matter because of repelling force, so it explains why there is no observations of such matter.   It would be also very consistent with the idea that the total energy of the Universe is zero. Doesn't it imply that the total mass of  the Universe is zero?   Can you please clarify the statements below that seem to contradict each other?  1)  -Max Tegmark.  2) Despite being completely inconsistent with a common-sense approach and the expected behavior of "normal" matter, negative mass is completely mathematically consistent and   3) Such matter would  and show some strange properties, stemming from the ambiguity as to whether attraction should refer to force or the oppositely oriented acceleration for negative mass.
119552
, I claimed that there was obviously an oscillating charge in a hydrogen atom when you took the superposition of a 1s and a 2p state. One of the respected members of this community (John Rennie) , saying:     Why do you say there is an oscillating charge distribution for a hydrogen atom in a superposition of 1s and 2p states? I don't see what is doing the oscillating.   Am I the only one that sees an oscillating charge? Or is John Rennie missing something here? I'd like to know what people think.
49782
Einstein equation  where $E$ is energy, $m$ mass, and $c$ the speed of light in vacuum. So does it mean objects without any mass does not posses energy for eg lights photons does not have mass but how can they posses energy
85870
Why massless particles have zero chemical potential?
115597
This question  , with very detailed answers.  After reading those answers, I am left with one more question: what is color charge?  It has nothing to do with colored light, it's a property possessed by quarks and gluons in analogy to electric charge, relates to mediation of strong force through gluon exchange, has to be confined, is necessary for quarks to satisfy Heisenberg principle, and one of the answers provided a great colored Feynman diagram of its interaction, clearly detailing how gluon-exchane leads to the inter-nucleon force.  But what is it?  To see where I'm coming from, in Newton's equation for gravity, the "charge" is mass, and is always positive, hence the interaction between masses is always attractive. In electric fields the "charge" is electric charge, and is positive or negative. (++)=+, (--)=+, so like charges repel (+-)=(-+)=-, so opposite charges attract. In dipole fields, the "charge" is the dipole moment, which is a vector.  It interacts with other dipole moments through dot and cross products, resulting in attraction, repulsion, and torque. In General Relativity, the "charge" is the stress-energy tensor that induces a curved metric field, in turn felt by objects with stress-energy through a more complicated process.  So what is color charge?  The closest that I've gotten is describing it through quaternions ($\mbox{red}\to i$, $\mbox{blue}\to j$, $\mbox{green}\to-k$, $\mbox{white}\to1$  , "anti"s negative), but that leads to weird results that don't entirely make sense (to me), being non-abelian.  Since $SU(3)$ is implicated, what part of $SU(3)$ corresponds to, for instance, "red" or "antigreen"?  (Like "positive charge" is $+e$, "negative charge" is $-e$).  What is the mathematical interaction of red and antired (like positive and negative is $(+e)(-e)=-e^2$), and what happens when you apply that interaction to red and antiblue?  (Like how electric charges interact with magnetic dipoles through their relative velocities).  If I had to point to a thing on paper and say "this here represents the red color charge", what would that thing be?  Does such a thing even exist?  In short, what is color charge?  I've had abstract algebra and group theory and some intro courses on field theory and QED, but I don't know a lot of jargon, or really a lot of algebra.  Sorry the question's so long.  Thanks for the future clarification!
72010
Why is the rest mass of the photon is taken to be zero?  If rest mass of the photon is non zero, then it leads to infinite energy of the photon (by $E=mc^2$ equation) and there is a violation of conservation of energy. Is this a reason?  Also, is there any thing called the relativistic mass of the photon?
72401
I am having hard time in understanding the concept of holes:   If there is no electron than how can it be a hole? For a moment lets assume absence of electron is termed as hole but how can this absent particle have mass? Under equilibrium  no electrons are present in conduction band. Why cant we termed this absence as holes in conduction band?
56706
Quark doesn't constitutes more fundamental particle and proton and neutron consist of quarks. Now come to beta decay.      $n \rightarrow p + e^{-} + \bar{\nu}_e $    How can  an electron  emit from an neutron whereas electron is a fundamental particle? Is the electron created from gluon?
26661
I know this isn't the right place for asking this question, but in other places the answers are so awfull.. I'm studying eletricity, so, I start seeing things like "charges", "electrons has negative charges",etc. But I didn't quite understand what charge is. I search a little bit on the internet and found it related to electromagnetic fields, then I thought "negative and positive may be associeted with the behaviour of the particle in the field, great!", but the articles about e.m. fields already presuppose "negative" and "positive" charges. In other places, I see answers relating charges to the amount of electrons/protons in an atom, but if that's right, the "negative" electron is an atom without any protons? What about the neutron? So, my questions are (1) What are charges; and (2) How a particle can "be" electrically charged. What does that really mean? Thanks for your time.
73863
What constitutes protons? When I see pictures, I can't understand. Protons are made of quarks, but some say that they are made of 99% empty space. Also, in this illustration from Wikipedia, what's between the quarks?
23484
It is well known that the most of the proton (or any other hadron with light quarks) mass is not made up from quark masses, but it is dynamically generated by QCD mess inside. I've also heard that, even if quarks would be massless, protons (and other hadrons) would still have a nonzero mass.  However, if proton mass does not (in most part) arise from the quark masses, from which dimensionful constants does it arise?  I've heard that proton mass arises from spontaneous symmetry breaking of scale invariance. However, this is a troublesome explanation, or non-explanation at best, because it opens more questions:  If a theory is scale invariant, how can it pick a scale when breaking this symmetry? The proton mass is a constant, so how can the scale invariance be broken across entire universe the same way? Is there a field, very resistant to change, that permeates entire space to ensure the constancy of proton mass?
27056
I simply know that a single free quark does not exist. What is the reason that we can not get a free quark?  If we can't get a free quark then what is single-top-quark?
45644
I understand that assuming light is quantized implies that if a lower energy interacts with  metal, it is possible that that quanta will not have enough energy to eject the electron. What prevents two quanta from interacting with the electron at the same time, though, and summing to have enough energy to release the particle. Indeed, what if two separate light rays of the same frequency impact the electron, why can't that free it?
73016
Suppose you reset the parameters of the standard model so that the Higgs field average value is zero in the vacuum, what would happen to standard matter?  If the fundamental fermions go from a finite to a zero rest mass, I'm pretty sure that the electrons would fly away from nuclei at the speed of light, leaving positively charged nuclei trying to get away from each other.  Looking at the solution for the Hydrogen atom, I don't see how it would be possible to have atoms with zero rest mass electrons.  What happens to protons and neutrons?  Since only a very small part of the mass of protons and neutrons is the rest mass of the quarks, and since they're flying around in there at relativistic speeds already, and since the nuclear force is so much stronger than the electrical force with an incredible aversion to naked color, would protons and neutrons remain bound assemblages of quarks and virtual gluons?  Would they get a little larger?  A little less massive?  What would happen to nuclei?  Would they stay together?  If the protons and neutrons hold together and their properties change only some, then I might expect the same of nuclei.  Different stable isotopes, different sizes, and different masses, but I would expect there would still be nuclei.  Also the W and Z particles go to zero rest mass.  What does that do to the electroweak interactions?  Does that affect normal stable matter (outside of nuclear decay modes)?  Is the weak force no longer weak?  What happens to the forces overall?
106610
My question is loaded with assumptions so to minimize them, I would like to ask it with respect to an electron and anti-electron annihilating.  When I think of annihilation, I think of electron and positron turning into energy where the total energy represents the combined masses plus kinetic energy each particle had prior to the collision and annihilation (Assumption 1).  But, doesn't the field of each charged particle also have an energy content and does this energy content of the charged particle field show up in the final energy?  I have never seen this though, only the sum of the mass energy. (Assumption 2 possibly).  Also, how is it that the masses annihilate if they are not ANTI to each other.  Mass has no opposite like charge does (or other things).  Does the annihilation of the charges also somehow annihilate the masses and if this is the case, that would require energy so this energy should show up somewhere.  Or is there some other opposite "thing" that results in annihilation of mass?  Physicists used to think that electron mass was actually the inertia of moving charge in a field (or something like that).  Is there some kind of connection between mass and charge such that charge annihilation is also mass annihilation?