Definition of "hypercharge" []

• A quantum number equal to twice the average electric charge of a particle multiplet or, equivalently, to the sum of the strangeness and the baryon number. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Gell-Mann's proposed the new rule: Elementary particles can be transformed in others by the strong and the electromagnetic interactions only if the total hypercharge is conserved."
• "You might think that you could just have a single SU (2) L or U (1) hypercharge gauge boson connect that loop to the Standard Model fermion ψ, but that vanishes by gauge invariance; you need two gauge bosons, and thus two loops."
• "In the original version of this post (and in the original version of our paper), I claimed that you would need a three loop diagram in the case where the dark matter had zero hypercharge (so you had to use SU (2) L gauge bosons, which couple only to the left-handed fermions)."