mollwollfumble said:
An up to date review of particle physics: mesons and baryons. 60 pages long.
eg. all types of mesons have been found, but so far there aren’t any baryons containing even two charmed quarks.
https://arxiv.org/pdf/1609.08928.pdf
I realise that this paper will be daunting to those, like me, who have never studied quantum mechanics in university. So here is a brief introduction.
There are six quarks, the light quarks up and down (u & d), the strange quark s, the charmed quark c, the bottom quark b, and the top quark t. The top quark doesn’t appear here, it decays too quickly to form mesons and hadrons.
Mesons are formed from two quarks, or to be more precise from a quark and an antiquark. An antiquark is written with an overbar. The pi is an example of a meson. Hadrons are formed from three quarks. Protons and neutrons are hadrons.
You may remember SPDF from electron orbitals around atoms. S is the ground state and P, D and F are excited states. Excited states have more energy (mass) than ground states. This energy (mass) is measured in MeV. “Potential” is the potential energy of these excited states. Excited states are marked with a superscript *.
J is the angular momentum, with values 0, 1, -1, 2, -2, 3, etc. +, -, 0 are the signs for positive charge, negative charge and no charge.
That’s almost all you need to know. A ‘D’ is a meson with a charmed quark. So a ‘Ds’ is a meson with a charmed and strange quark. A ‘B’ is a meson with a bottom quark. A ‘Bs’ is a meson with a bottom and strange quark. A ‘Lambda c’, a ‘Sigma c’, a ‘Xi c’ and an ‘Omega c’ are all hadrons with a charmed quark, distinguished by having different values for angular momentum J. A ‘Lambda b’, a ‘Sigma b’, a ‘Xi b’ and an ‘Omega b’ are all hadrons with a bottom quark, distinguished by having different values for angular momentum J.
That’s all that’s needed for an introduction. Tables 2 to 8 summarise all known mesons and hadrons with charmed and bottom quarks. The Status star rating from one star to four stars indicates how well each observed subatomic particle is understood. Four stars means that we know everything about the subatomic particle, one star means that it’s quite possible that the particle doesn’t even exist.
The pictures in the article are pretty pictures. Detailed discussions mentioning differences between theory and observation can be omitted on first reading.
