hypercharge

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.

Nobel Prize in Physics 1969 - Presentation Speech 1972

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.

Dark Matter and Fifth Forces Sean 2008

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).

Dark Matter and Fifth Forces Sean 2008

The only thing about this which is slightly complicated is the U (1) hypercharge assignments.

Guest Post: Joe Polchinski on Science or Sociology? Sean 2007

This one, the creation of Sheldon Glashow, Abdus Salam, and Stephen Weinberg, combines SU (2) xU (1) with the then-little-known Higgs mechanism to produce a theory that conserves “weak hypercharge”, and accounts for both the weak interactions and the photon (electromagnetism).

Higgs 101 John 2007

He introduced a new fundamental characteristic of a multiplet called its hypercharge.

Nobel Prize in Physics 1969 - Presentation Speech 1972

It should be remarked that Gell-Mann initially used instead of the hypercharge a closely related number called the strangeness.

Nobel Prize in Physics 1969 - Presentation Speech 1972

However, we only include the fundamental coupling, including the hypercharge U (1) group.

The Reference Frame 2010

U (1) generator "Y" (hypercharge) and the third, z-rotation generator of the "isospin" SU (2):

The Reference Frame 2010

At extremely high energies, well behind the right end of the graphs above, the hypercharge

The Reference Frame 2010