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binbots
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I was recenlty watching a lecture by Feynman where is talks about particles, and how all particles have anti particles. A photon is a particle but I can't find any discussion about a anti photon. Reason?
PipBoy said:I forget, is it because the Photons travel back in time, so to speak, that we observe them to be their own anti-particles or am I getting this horribly confused with Electrons?
binbots said:I was recenlty watching a lecture by Feynman where is talks about particles, and how all particles have anti particles. A photon is a particle but I can't find any discussion about a anti photon. Reason?
PipBoy said:I forget, is it because the Photons travel back in time, so to speak, that we observe them to be their own anti-particles or am I getting this horribly confused with Electrons?
Bararontok said:The polarity of the photon’s electric charge is positive
Bararontok said:The Fermion elementary particles that have no electromagnetic fields which are the electron, muon, and tau neutrinos have no anti-particles because they have electric charges of 0e.
Bararontok said:Here is the PDF showing the maximum amount of mass and charge that a photon can carry when traveling in a vacuum:
daschaich said:Please note that the maximum photon mass and charge are incredibly tiny. They are, in fact, zero as best we can measure them. No photon mass or charge has ever been measured, but experiments are not yet perfect, and never will be.
piareround said:I think you might be getting confused on something...
Perhaps with http://en.wikipedia.org/wiki/Nonlinear_optics#Optical_phase_conjugation"?
bcrowell said:This is a general thing in quantum field theory. Any particle traveling backward in time can be interpreted as its antiparticle. For a photon, the version traveling backward in time is the same as the version traveling forward in time.
Bararontok said:But because there is no measurable electromagnetic field emanating from these neutrino particle groups, whether they are classified as Majorana or Dirac Fermions does not change the fact that they are uncharged particles.
The mass and charge in this case are only a scaling of the energy content of the photon because mass and charge is only applicable to the fermions that carry force fields and use them for action at a distance interactions. An individual gauge boson can only truly be measured by the energy it carries because it is incapable of this type of interaction and can only exert influence if it directly comes in contact with other photons or a force field.
Parlyne said:The fact that neutrinos carry no electric charge does not tell you whether or not they are their own anti-particle. Neutrinos carry both weak isospin and hypercharge. These change under charge conjugation. The only way that neutrinos can be their own antiparticles is if some additional new physics causes a certain type of mixing between the fundamental neutrino and anti-neutrino states, which can't occur in the standard model alone (and, in fact, must be related to the mechanism by which neutrino masses are generated).
Parlyne said:The W bosons, which are two of the three carriers of the weak force, have both mass and electric charge. In fact, the W bosons have the same magnitude of charge as the electron and the mass of about 86 protons. The photon, by contrast, has never been measured to have any mass or charge. The limits in the PDG file you linked simply state the smallest values of each that would be detectable by experiments that have been performed to date. It is not, in any sense, a statement that these value are not zero. It is simply a statement that we could not, at this point, know if their values were different from zero but didn't violate those limits.
Bararontok said:Interestingly enough, when I check the data sheets for both the neutrinos and anti-neutrinos, the pages link only to the neutrinos which makes the properties of both particles exactly identical. What then would differentiate the neutrinos from their anti-particle counterparts?
I was referring to mass and charge in terms of energy and I did not say that other bosons did not have any fixed mass and charge values. I was referring to the photon's mass and charge as simply another way of denoting the energy that it carries but that when the photon is incorporated into the electromagnetic field of a charged fermion, that energy is used to thermally excite the charged fermion.
Parlyne said:If neutrinos and anti-neutrinos are distinct, they can be differentiated by the processes they can be involved in. For example, in a standard beta decay, a neutron decays to a proton, an electron and an electron anti-neutrino. If the anti-neutrino subsequently scatters off of a nucleus, there is a (small, but non-zero) chance that it could be transmuted into a charged lepton. If the neutrino is its own anti-particle, this could produce either an electron or a positron; but, if the neutrino is not its own anti-particle, this could only lead to a positron.
In practice, this is a difficult experiment to perform because the neutrino interacts so weakly.
Bararontok said:So this means that having an electromagnetic field has nothing to do with whether a particle will have an anti-particle or not because even the uncharged neutrino group has anti-particles. What then causes a particle to be an anti-particle if it does not have a charge opposite to its identical particle? Because when I looked at data sheets and compared the charged particles to their charged anti-particles the anti-particles were the same in every respect except for the polarity of their electromagnetic fields which are opposite to their counterparts.
Read this definition for antiparticle and you will see that having an opposite electric charge is a prerequisite to being an anti-particle:
http://en.wikipedia.org/wiki/Antiparticle
Additionally, you previously mentioned that weak iso-spin and weak hyper-charge can be used to tell the particle and anti-particle pairs apart and I saw the values RH and LH for the weak iso-spin and weak hyper-charge of the neutrinos so does this mean that RH and LH are used to differentiate the particles and anti-particles as opposed to only using the polarity of the electric charge to make the differentiation?
Bararontok said:In conclusion, there are three states that determine whether a particle will be matter or anti-matter and that would be the electric charge, isospin and hypercharge. The LH values apply to the neutrinos while the RH values apply to the anti-neutrinos.
I have summarized your data in this table to differentiate the LH and RH values:
Neutrino LH Isospin Up = 1/2 || Anti-Neutrino RH Isospin Down = -1/2
Neutrino LH Hypercharge = -1/2 || Anti-Neutrino RH Hypercharge = -1
But I was wondering if these values apply to all three neutrinos. Could you give me a data table for this because wikipedia does not have one?
daschaich said:It is actually still an open question whether or not neutrinos and anti-neutrinos are identical. If they are identical, then neutrinos and anti-neutrinos would be "Majorana fermions". If they are distinct, then neutrinos and anti-neutrinos would be "Dirac fermions".
Xia Ligang said:Neutrinos have no charge. What happen if C operates neutrinos? I think it deserves thinking over. Maybe we should extend the perception of anti-pariticles.
Particles and antiparticles are subatomic particles that make up the building blocks of matter. They have opposite charges and spin, but are otherwise identical in mass and properties.
Particles and antiparticles can interact through annihilation, where they collide and are converted into energy, or through creation, where energy is converted into particles and antiparticles.
Photons are particles of light and are their own antiparticles. They are the smallest units of light and have no mass, but carry energy and momentum.
Particles and antiparticles can be created in high-energy collisions, such as in particle accelerators, or through natural processes, such as radioactive decay.
Particles and antiparticles play a crucial role in the formation and evolution of the universe. The Big Bang theory suggests that equal amounts of particles and antiparticles were created, but due to asymmetry in the laws of physics, particles outnumbered antiparticles, leading to the formation of matter as we know it.