Widdekind Posted May 18, 2010 Posted May 18, 2010 If photons (zero rest mass) have no anti-particle, do Particle / Anti-Particle pairs necessarily have rest mass ? For example, that Anti-Neutrinos exist demands that Neutrinos have rest mass ??
ajb Posted May 19, 2010 Posted May 19, 2010 Showing that a particle is massive implies that the corresponding antiparticle is also massive and moreover the masses are identical.
Widdekind Posted May 24, 2010 Author Posted May 24, 2010 (edited) Thanks for the info. swansont said: Photons do have an antiparticle. It is the photon. What would a "photon / (anti-)photon" annihilation reaction look like ? Is such essentially, and simply, some sort of "scattering", wherein the wavelengths of the (incident) photons are affected ? ajb said: Showing that a particle is massive implies that the corresponding antiparticle is also massive and moreover the masses are identical. From something I saw on TV, could there possibly be some sort of "chiral analogy", between Anti-Matter & Matter, and Anti-Cyclones & Cyclones (in the weather of worlds, such as the storms of Gas Giants) ? Edited May 24, 2010 by Widdekind Consecutive posts merged.
ajb Posted May 24, 2010 Posted May 24, 2010 Widdekind said: What would a "photon / (anti-)photon" annihilation reaction look like ? Is such essentially, and simply, some sort of "scattering", wherein the wavelengths of the (incident) photons are affected ? You can have \gamma \rightarrow e^{+} + e^{-} in a background field, such as near a nucleus. Also one can have in free space \gamma + \gamma \rightarrow e^{+} + e^{-}. Widdekind said: From something I saw on TV, could there possibly be some sort of "chiral analogy", between Anti-Matter & Matter, and Anti-Cyclones & Cyclones (in the weather of worlds, such as the storms of Gas Giants) ? Maybe, both particles and antiparticles look the same up to "minus signs".
swansont Posted May 25, 2010 Posted May 25, 2010 Neutrinos and antineutrinos have opposite handedness, but that's because they violate parity.
Widdekind Posted June 10, 2010 Author Posted June 10, 2010 (edited) Photons are eigenstates of the Charge Conjugation © operator, with eigenvalue -1 (D.Griffiths. Intro. Elem. Part., pg. ~70). Might that mean, that turning a photon into an "anti-photon", involves a 180 degree phase shift (e^{i \pi} = -1) ?? After all, particles annihilate their anti-particles, and light wave-trains shifted by 180 degrees deconstructively interfere. Merged post follows: Consecutive posts merged ajb said: ...Also one can have in free space \gamma + \gamma \rightarrow e^{+} + e^{-}... Is it true, that photon "splitting", into pairs of particles/antiparticles, generally only happens near nuclei (and, presumably, there super-strong electromagnetic fields) ?? Cf. Vacuum Polarization*. * Gluons can "split", into quark-antiquark pairs, when stretched far enough (cf. link). But, the Color Force increases with distance, so that such "splitting" also occurs in extreme "Color Fields". Maybe Gauge Bosons "split" in extreme fields ?? (Wouldn't that be where they'd have the highest energies, anyway, for potential pair production??) Edited June 10, 2010 by Widdekind Consecutive posts merged.
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