Leptons and their corresponding neutrinos have a lepton number of 1, while antileptons and lepton antineutrinos have a lepton number of -1. A quantum number can only take integer values.Īll quarks have a baryon number of \dfrac\right). This means that in a particle interaction, both sides of the equation must have the same baryon number. See also: Electron capture Positron Quantum mechanics. 1 All other conserved quantum numbers ( angular momentum, electric charge, lepton number) of the produced particles must sum to zero thus the created particles shall have opposite values of each other. Before the beta decay there are no leptons, that is, the lepton number is zero. 22 : E - p 0 (off mass shell) In all calculations we integrate over the virtual particles 4-momentum (4D integral). Conservation of energy and momentum are the principal constraints on the process. Virtual particles are internal to diagram(s). The baryon number is a quantum number and is conserved for all particle interactions. electric charge, lepton number Virtual particles do not conserve E and p. Baryons have a baryon number of B = 1, antibaryons have a baryon number of B = -1, with all other particles having a baryon number of B = 0. I SYMBOL I MASS I CHARGE I SPIN I LEPTON NUMBER I MU-NESS I BARYON NUMBER. There are other types of baryons, including sigmas \left(\Sigma\right) and lambdas \left(\Lambda\right), but these have very short half-lives and you don’t need to know them.Īll particles have a baryon number \left(B\right). Energetic collisions between electrons and positrons give rise. But it is not really an electron or a positron. The virtual electron-positron can be off shell, which means different frames might even disagree about whether it is a virtual electron or a virtual positron. The incoming electron and positron are real, so they must be on shell. The quarks are all the same type of quark either 3 normal quarks (baryon) or 3 antiquarks (antibaryon). Any particle can be a virtual particle, even an electron.
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