# Tag Info

5

A pentaquark is a particle made of five quarks. "Penta" means 'five' in Greek. Technically it could be made of any combination of quarks/antiquarks, though subject to some restrictions - see below. Quarks are bound by the strong force. In the same way as the electromagnetic force sees the (electric) charge of particles and causes interactions only within ...

4

All processes involving neutrinos are weak mediated because neutrinos have zero electromagnetic and color charge. At tree level, all processes involving a $\nu + \bar\nu$ final state without other debris involve a time-like $Z^0$ (except neutrino NC scattering) which implies the annihilation of a particle/antiparticle pair (and will be suppressed relative ...

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In Scientific American, they said it was this specific grouping as illustrated, though with arbitrary coloring. It briefly stated how it must involve which quarks based on decay channels. I lost my hardcopy of the magazine so I can't easily look upmthe quotation now. I think it was not as you describe though... Yea, it's in Wikipedia now. In July ...

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I'm speculating here, basically looking at two considerations. Considering you used the term "radioactive decay" I'm going to look at this from a gross nuclear viewpoint rather than a particle/subnuclear viewpoint. If a nucleus is in it ground state, it would have no mode to lose energy without changing Z. So, in this case, no. If a nucleus is not in its ...

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Within the standard model alone, all these parameters are independent, and to those you can add the masses and mixing angles of the neutrinos. Possible additional symmetries beyond the standard model suggest some relations between the gauge couplings, since renormalization group analyses based on these symmetries lead to unification of these couplings at ...

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Inflation, separation of gravity from other forces, separation of strong from electroweak force, and electroweak symmetry breaking, are all different events. It's easiest to start by describing the different sorts of fields involved. Quantum fields get classified by their "spin", which describes the angular momentum states that field quanta (particles) can ...

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What you are looking for are explanations of effective field theory (for example see this review by Burgess http://arxiv.org/abs/hep-th/0701053) and chiral perturbation theory in particular (for example see this review by Scherer http://arxiv.org/abs/hep-ph/0210398, and here are some slides by Tiburzi that look good at first glance: ...

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Here we will for simplicity just consider an arbitrary finite-dimensional complex$^1$ semisimple Lie algebra $\mathfrak{g}$. I) One may show that the CSAs are precisely the maximal toral Lie subalgebras of $\mathfrak{g}$. In particular CSAs are abelian. Also the Killing form $\kappa:\mathfrak{g}\times \mathfrak{g}\to \mathbb{C}$ (which is ...

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I suggest you to read my answer here for a quick look into exotic hadrons. These particles mostly(at least so far) are very unstable appears for a short time and decay into another particles, hadrons and mesons. Hadrons made of 3 quarks and mesons one quark and its anti-matter. These unstable particles(resonances) have a quark content based on initial and ...

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