Gluino hadronization, what do we know?

[arivero]

I was reading the wikipedia article on R-hadrons

http://en.wikipedia.org/wiki/R-hadron

If they are comoposed of a gluino, a quark and antiquark... They are still fermions, are they?

And if the "force field" joining the quark and antiquark is the gluino... should they be just point-sized particles, to avoid any paradoxes with the conservation of angular momentum?

If so, how are R-hadrons different from plain leptons?

 

[mathman]

Connections are gluons, not gluinos. Spin is integer, so they are bosons. Leptons are fundamental particles - no quarks or gluons.

 

[TumblingDice]

Connections are gluons, not gluinos. Spin is integer, so they are bosons. Leptons are fundamental particles - no quarks or gluons.

The article that the OP linked includes this:

One of such new fermions would be the gluino (spin 1/2, as dictated for the supersymmetric partner of a spin 1 boson, the gluon).

Perhaps someone can look deeper into this for arivero?

 

[lpetrich]

Supersymmetric particles interact just like their ordinary counterparts, to within spin and the like. A gluino thus interacts just like a gluon, complete with it having the same gauge quantum numbers: the adjoint rep of the QCD "color" symmetry group and being an electroweak scalar.

So a meson or a baryon can have a gluon added to it, or a gluon in a glueball can be replaced by a gluino, making a glueballino.

 

[arivero]

What I am fascinated for is, in which ways can a meson have a gluino added to it? Should the gluinos interact with the quarks in the meson, or not? Are there different models, perhaps with new interaction vertices? can we dispose of the gluon field (say, delete it from the lagrangian) and keep bound states only with gluino fields and quarks?

 

[mathman]

Supersymmetric particles are purely hypothetical. Any descriptions of combinations are speculative at best.

 

[arivero]

Supersymmetric particles are purely hypothetical. Any descriptions of combinations are speculative at best.

Yep, perhaps my question is if after some forty years of susy speculation, someone has speculated (and calculated, and wrote some paper) about the role of gluinos as binding particles, from the fact of being, as you say, in the adjoint rep of QCD.

As a minimum, without any extra vertex, we could have a bound state of quark and squark, where the exchange of a gluino changes the spin of the particles, the quark becomes squark, the squark becomes quark at each exchange. Or we could two quarks exchanging a gluino, becoming squarks, and then again exchange to become quarks again. Does such interaction has a bound state? will it be spin 1/2 or spin zero?

 

[Vanadium 50]

What I am fascinated for is, in which ways can a meson have a gluino added to it?

None. A meson is colorless, a gluino is colored, so a bound state must be colored, and there are no such states.

If you ask the question, is it possible for a system with the same quark content as a meson to be bound to a gluino, the answer is, yes, in exactly one way. Look at the SU(3) color representations. qqbar is either a singlet or an octet, and we know a singlet won't work. So we have 8x8 = 27 + 10 + 10bar + 8 + 8 + 1, so there is only one color singlet combination.

 

[arivero]

None.

To be clear, I am asking about using a gluino field instead of a gluon field. Mesons have a gluon field inside, and in the same sense I was hoping that a gluino field can be used to build some kind of particle binding a quark and an antiquark as if it were a meson.

 

[Vanadium 50]

Yes, I understand that. A gluino is colored, so does not bind to a color-neutral meson. If you want a g~+q+qbar bound state, there is exactly one way to do this to get the color indices to work out right.

 

[lpetrich]

[hep-ph/9908342] New Possibilities for a Light Gluino
From that article,

A light gluino would be expected to hadronize into a gluino-gluino state (gluinoball), a gluino-gluon state (glueballino, R0), a quark-antiquark-gluino state (mesino), or a three quark + gluino state (barino).

A glueballino is a glueball with a gluino instead of one of the gluons.

A mesino can have the quark and antiquark in a color-octet site instead of a color-singlet one. It can then combine with the gluino.

A barino can likewise have the three quarks in a color-octet state, though it would make the quarks' spins and flavors be mixed symmetry instead of symmetric.

 

[arivero]

Yes, I understand that. A gluino is colored, so does not bind to a color-neutral meson. If you want a g~+q+qbar bound state, there is exactly one way to do this to get the color indices to work out right.

By the same argument, there is no gluon field inside a meson?

 

[Vanadium 50]

No, by the same argument there is only one way to have a valence gluon in a meson. (These are called hybrids, and there are probable examples of them)