Hi all,
I wanted a detailed explanation of why Rho meson is so very important in marking a Gamma gamma event.Or it would be great if someone could suggest me some papers related to this topic.
Since the electromagnetic interaction conserves spin, parity and charge conjugation quantum numbers (JPC), the Heisenberg uncertainty principle allows the photon to "fluctuate" into another uncharged particle with same JPC for a short time. The photon can thus fluctuate into the charge=0 rho, omega, phi and J/Psi vector mesons, since all have the same JPC=1--.
Since these vector mesons can interact via the strong interaction in addition to the electromagnetic, and the strong interaction is much stronger than the electromagnetic interaction, when the photon fluctuates into a vector meson its interaction strength is greatly enhanced. This leads to the model of "vector meson dominance" for photon energies in the 0.5
This is a technical topic-but one point may be that it's known that a massive vector meson cannot decay to two photons (the ``Landau-Yang theorem''). This could allow a selection of photons based on their correlations.
Since the electromagnetic interaction conserves spin, parity and charge conjugation quantum numbers (JPC), the Heisenberg uncertainty principle allows the photon to "fluctuate" into another uncharged particle with same JPC for a short time. The photon can thus fluctuate into the charge=0 rho, omega, phi and J/Psi vector mesons, since all have the same JPC=1--.
Since these vector mesons can interact via the strong interaction in addition to the electromagnetic, and the strong interaction is much stronger than the electromagnetic interaction, when the photon fluctuates into a vector meson its interaction strength is greatly enhanced. This leads to the model of "vector meson dominance" for photon energies in the 0.5
Garth's explanation is excellent. I would only add that if you want to read more about vector mesons, go through publications of HERA. We have measured rho, omega, phi, J/psi and even Upsilon exclusive production at high energies where perturbative QCD is applicable. Look into http://www-zeus.desy.de/zeus_papers/zeus_papers.html and search through paper titles.
Swathi, I did not notice you are actually affiliated at DESY, should you wish more detailed info on vector meson physics, please let me know, cheers
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Particle Physics
- Elementary Particle Physics