Search results
Results From The WOW.Com Content Network
Three antiquarks of different anticolors, giving an antibaryon with baryon number −1. The baryon number was defined long before the quark model was established, so rather than changing the definitions, particle physicists simply gave quarks one third the baryon number. Nowadays it might be more accurate to speak of the conservation of quark ...
Baryon number violation is a necessary condition to produce an excess of baryons over anti-baryons. But C-symmetry violation is also needed so that the interactions which produce more baryons than anti-baryons will not be counterbalanced by interactions which produce more anti-baryons than baryons.
These lists detail all known and predicted baryons in total angular momentum J = 1 / 2 and J = 3 / 2 configurations with positive parity. [5]Baryons composed of one type of quark (uuu, ddd, ...) can exist in J = 3 / 2 configuration, but J = 1 / 2 is forbidden by the Pauli exclusion principle.
Baryon number violation is a necessary condition to produce an excess of baryons over anti-baryons. But C-symmetry violation is also needed so that the interactions which produce more baryons than anti-baryons will not be counterbalanced by interactions which produce more anti-baryons than baryons.
This quantum number is the charge of a global/gauge U(1) symmetry in some Grand Unified Theory models, called U(1) B−L.Unlike baryon number alone or lepton number alone, this hypothetical symmetry would not be broken by chiral anomalies or gravitational anomalies, as long as this symmetry is global, which is why this symmetry is often invoked.
For a strange quark, with electric charge − + 1 / 3 , a baryon number of + + 1 / 3 , and strangeness −1, we get a hypercharge Y = − + 2 / 3 , so we deduce that I 3 = 0 . That means that a strange quark makes an isospin singlet of its own (the same happens with charm , bottom and top quarks), while up and down constitute ...
As quarks have a baryon number of + + 1 / 3 , and antiquarks of − + 1 / 3 , the pentaquark would have a total baryon number of 1, and thus would be a baryon. Further, because it has five quarks instead of the usual three found in regular baryons (a.k.a. "triquarks"), it is classified as an exotic baryon.
Some beyond-the-Standard-Model grand unified theories (GUTs) explicitly break the baryon number symmetry, allowing protons to decay via the Higgs particle, magnetic monopoles, or new X bosons with a half-life of 10 31 to 10 36 years. For comparison, the universe is roughly 1.38 × 10 10 years old. [3]