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How does protons has mass and not pions?

  1. Dec 17, 2015 #1
    hi, i've heard that protons has most of their mass from their electromagnetic and strong interactions between their quarks, but specifically, how does that make mass? and if so, what is intrinsic mass then?
    and pions has 2 quarks and strong and electro interactions, why doesn't it has mass? does it have to do with [only specific energy solutions can exist]? or am i off?

    i've heard that electrons has no mass when rest, because it only hass mass because it has a resistive force from the interaction between higgs and electromagnetic feild, but if so, what is "electron rest mass" then?

    sorry for the barrage of questions, but i tried to search it up, but i think i was using the wrong terms, therefore, you can just link me to the correct pages that explains what is mass of protons? and what is their intrinsic mass? mathematically or not is fine

  2. jcsd
  3. Dec 17, 2015 #2
    First, pions have mass, and so do electrons.

    Second, their masses come from their fields interacting with the higgs field. (With baryons, some of their mass may come from binding energy too.)

    I think you may be confused as to what is meant by "field" here, so let me try to clarify.
    The electron field and electromagnetic field are not the same thing. An electron *has* an electromagnetic field, but it itself is made from the electron field.
    The electron field interacts with the higgs field, giving it mass. However, the electromagnetic field does not interact with the higgs field. The electromagnetic field can also be thought of as the photon field. This is why photons are massless. (It is also worth noting that the electron field interacts with the electromagnetic field.)

    Think of individual particles as excitation of their fields. So an electron is an excitation of the electron field. A photon is an excitation of the electromagnetic field. A higgs boson is an excitation of the higgs field. Some fields interact with others.

    Hope this helps.
  4. Dec 17, 2015 #3


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    Where exactly did you look to get all this wrong info? Why did you not look at the PDG Handbook? It clearly stated the mass of pions and electrons.

    Knowing that now, do you want to reformulate your question?

  5. Dec 17, 2015 #4
    first, thankyou, that someone would spend time correcting me,
    so i thought that pions does have rest mass when they do, that's great news, i now know,
    but now i'd like to know what are electrons then? and do they have the same source of mass as from protons?

    and if so, how does proton have mass and how does electrons have mass
    cuz i'm now slightly confused, cuz photons are the "excitation" of the electron field, kinda like a boson?(but then why does higgs boson has mass?)
    and if photon is a boson of the electron field then what's an electron?

    i've heard that protons and neutrons though having intrinsic mass(higgs feild or not?) it only accounts to 10% of the mass, and most of the mass comes from the confined kinetic and binding energy of the quarks(that doesn't sound like higgs feild interaction, so how does that gets mass?)

    sorry for the barrage of questions, thankyou
  6. Dec 17, 2015 #5


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    How about simple google "proton mass" (1.6726219 × 10-27 kilograms), "electron mass" (9.10938356 × 10-31 kilograms), for a start?

    I grant you that pion mass is a bit more advanced, because there are 2 charged and one uncharged pion and you have to convert 139.57018(35) MeV/c2 using a factor ##\ \displaystyle 10^6\, {e\over c^2} = 1.783×10^{−30} ## for e.g. ##\pi^+##
  7. Dec 17, 2015 #6


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    Both particles share one source of mass (the Higgs mechanism), but most of the mass of the proton comes from its binding energy. It contributres to the energy a proton has at rest, and therefore contributes to its mass.
    What is "cuz"? All particles can be described as excitations of their corresponding fields. Including the Higgs boson, it is nothing special here.
    A different elementary particle.
    It would be shorter if you would use google and wikipedia first.

    field with ie, by the way.
  8. Dec 17, 2015 #7
    Not the electron field, the electromagnetic field.
    The electron field and electromagnetic field are not the same thing.

    Also, an electron is a fermion, and a photon is a boson. There are many fermions and bosons. Some bosons have mass, namely the higgs, the Z, and the W. Some don't have mass, namely the photon and gluons.
    Last edited: Dec 17, 2015
  9. Dec 17, 2015 #8


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    Slang shorthand for "because".
  10. Dec 17, 2015 #9


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    Pions were considered to carry the strong force responsible for the nuclei binding [not the nucleons=neutrons or protons]... The characteristic lenght of these type of strong interactions is approximately the size of the nuclei, and so you can figure out an intermediate boson mass approximately equal to the pion's. At the time this was studied the only close to that mass particle we knew of was the muon and that was why mistakenly they called the muon mu-meson in the past.

    electrons and protons are quiet different, because electrons are considered elementary particles while protons are not. The protons are a soup of particles: quarks (real or virtual) and gluons, that exist in a bound state. As a result they should gain some mass exactly due to their interactions+kinetic energy...and they do...

    The electron however gets its "mass" from the Higgs field acquiring a vacuum expectation value [vev]. The higgs boson also happens to be subject to interacting with the Higgs field's vev... In order to understand better those stuff it's good to take a theoretical particle physics course at a master's or advanced bachelor's level, where you will be able to see the Electroweak Theory and the spontaneous symmetry breaking.

    In the end of the day, the masses are still free parameters of the model and have to be determined experimentally.

    What is more massive? a free electron + a free proton, or a Hydrogen atom??? :)

    However in general, it's not so surprising if you read that the Pion is massless... Approximately it's true: if the quarks were massless + there is a chiral symmetry unbroken, and forgetting interactions between them, I am pretty sure that the pions would have been massless....
  11. Dec 17, 2015 #10
    thankyou, i think i've had enough info to go back into research now,
    because, my main problem is that internet doesn't always give you the right answers, that's why i do sometimes asks some weird questions before i go into deeper research, and i've had terrible experience correcting myself after reading several badly written article that misled me,

  12. Dec 17, 2015 #11


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    good things to trust after the basic ideas of wiki are anything in .edu (so belonging to some institute)
    personal blogs, public articles etc can be misleading!
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