# Can Left Handed Up Quarks Transform Into Right Handed Ones?

• talanum52
In summary, the conversation discusses the need for additional bosons for transforming isospin and the inclusion of a left-handed and right-handed quark in the standard model Lagrangian. The possibility of a new particle in the Higgs sector that could change a left-handed quark into a right-handed one is also mentioned, similar to how the Higgs interacts with the W and B particles in the unbroken electroweak field.
talanum52
Homework Statement
Can Left Handed Up Quarks Transform Into Right Handed Ones?
Relevant Equations
u(i) = 1/2
Isospin must be transformable if it is the case. In which case there must be additional Bosons for doing the transformation.

Can you write down a term in the standard model lagrangian where you have ##\bar u_R## and ##u_L##?

vanhees71 and topsquark
It's uR and uL.

No, but I can write down a formula containing a new particle, with the particle's properties (for the case of an electron, not u-quark).

talanum52 said:
It's uR and uL.

No, but I can write down a formula containing a new particle, with the particle's properties (for the case of an electron, not u-quark).
Hint: Look at the Higgs sector.

-Dan

topsquark said:
Hint: Look at the Higgs sector.

-Dan
Doesn't, for example, a left-handed electron change into a right-handed one by coupling to the Higgs field? Which is why the neutrino has no Higgs-induced mass?

So, a left-handed quark can change into a right-handed one indeed?

topsquark and vanhees71
talanum52 said:
It's uR and uL.
You need a bar above one of them to preserve gauge symmetries...

BoraxZ and topsquark
malawi_glenn said:
You need a bar above one of them to preserve gauge symmetries...
I thought the same. Loosely speaking, before the SU(2)LxU(1)Y symmetry is broken, Higgs couples the ##\phi _l## and ##\bar{\phi} _r##: ##\bar{\phi} _l h {\phi} _r##. When the symmetry is broken this becomes ##m\bar{\phi} \phi##, where the ##\phi##'s are superpositions of l and r.

It's comparable to the Higgs interacting with the three W's and B of the unbroken electroweak field. After this interaction, the interaction vertex term becomes a mass term, the Z0 and W+/- being superpositions of the three W's and B (like the l and r in the previous paragraph).

Last edited:
malawi_glenn

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