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aditya ver.2.0
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Do really is the presence of an antiparticle of photon possible in the cosmos? Does it have one?
Sir,Nugatory said:The photon is its own antiparticle.
aditya ver.2.0 said:Sir,
How can a photon be its own antiparticle, as a particle and anti particle annihilate each other?
Sir,M Quack said:When a particle/antiparticle pair annihilates the energy and momentum have to go somewhere. Usually a pair of two photons is created that take them up.
If you wanted to annihilate a pair of photons you would also have to create a pair of different particles. This could in principle be a different pair of photons, but such an process is very unlikely.
For any other pair of particles the photons have to have enough energy to create the particles in the first place, i.e. the energy equivalent to their rest mass. The lightest massive particle is the electron, with a rest mass of 511 keV. You need to create an electron and a positron, so you need at least 2*511 keV. This process is exactly the inverse of the annihilation of a electron-positron pair that creates two photons.
An effect that is often observed is called "pair creation" when a photon with energy higher than 2*511 keV annihilates with a (virtual) photon from
the electric field near a heavy nucleus to create an electron and a positron.
The lightest massive charged particle.M Quack said:The lightest massive particle is the electron
Not always. And the photon is one of those exceptions.aditya ver.2.0 said:a particle and anti particle annihilate each other
I wouldn't call it an exception. When two antiparticles interact they do always annihilate each other. The result of annihilation can be any combination of particles that conserve energy, momentum, charge, spin, etc. So an electron and a positron can annihilate and produce a pair of photons. Run that same reaction backwards and you have a pair of photons annihilating to produce an electron and a positron. So I would say that it is not an exception, it is just rare since photons are not pulled to each other in the same way that positrons and electrons are.mfb said:Not always. And the photon is one of those exceptions
Yes but it requires a minimal photon energy, whereas the first reaction does not require special conditions for particle energies.DaleSpam said:Run that same reaction backwards and you have a pair of photons annihilating to produce an electron and a positron.
Hmm, good point. I had not considered scattering, which obviously I should have.mfb said:I would not call t-channel scattering of electron+positron an annihilation, but it is certainly an interaction.
A.T. said:Maybe it helps to consider matter and antimatter as the same thing just advancing in opposite directions in time. Since photons do not advance in time (don't age), they are neither matter nor antimatter, but a state between the two.
No. Why do you think so? I don't get why charges, and in particular the electric charge are/is often considered as special.Simon Bridge said:Since QFT does not impose any other restriction that would imply that uncharged particles would be their own antiparticle
Why? In the same way two particles don't annihilate, the antiparticles don't do that. Annihilations are special reactions of particles with antiparticles.Simon Bridge said:But we also popularly expect two antiparticles to annihilate.
How can a photon and anti-photon annihilate each other and produce heavier body than themselves?DaleSpam said:I wouldn't call it an exception. When two antiparticles interact they do always annihilate each other. The result of annihilation can be any combination of particles that conserve energy, momentum, charge, spin, etc. So an electron and a positron can annihilate and produce a pair of photons. Run that same reaction backwards and you have a pair of photons annihilating to produce an electron and a positron. So I would say that it is not an exception, it is just rare since photons are not pulled to each other in the same way that positrons and electrons are.
The only thing required is that energy and momentum are conserved. In particular, in a two-photon system, you can go to the CoM frame (as long as the photons are not going in the same direction) where the total momentum is zero. If the total energy in this frame is larger than the total mass of the particle-antiparticle pair, this is possible.aditya ver.2.0 said:How can a photon and anti-photon annihilate each other and produce heavier body than themselves?
They don't. The mass of a system is always greater than the sum of the masses of the constituent particles. In this case the system of two photons has the same mass as the system of an electron and a positron.aditya ver.2.0 said:How can a photon and anti-photon annihilate each other and produce heavier body than themselves?
An antiparticle of photon is a theoretical particle that has the same mass and spin as a photon, but with opposite charge. It is also known as an "anti-photon" or "pair-photon".
The existence of antiparticle of photon is explored through experiments and observations in high-energy particle physics. Scientists use particle accelerators to create and study the behavior of particles, including antiparticles. They also look for signs of antiparticles in cosmic rays and other phenomena in the universe.
Finding an antiparticle of photon would have significant implications for our understanding of the laws of physics and the structure of the universe. It would also provide further evidence for the existence of antimatter, which has been a topic of interest and research in physics for decades.
While there is currently no direct evidence for the existence of antiparticle of photon, some theories, such as supersymmetry, predict its existence. Additionally, experiments at the Large Hadron Collider have observed the behavior of particles that could potentially be antiparticles of photons.
One of the main challenges in exploring the existence of antiparticle of photon is the difficulty in detecting and studying them. Antiparticles are highly unstable and often quickly annihilate when they come into contact with particles of the same type. This makes it challenging for scientists to observe and study them in detail. Additionally, creating and controlling antiparticles in a laboratory setting is a complex and expensive process.