# SU(3) and dark U(1) coupling to dark matter

1. Jul 6, 2013

### pdxautodidact

Is anyone familiar with a
$$SU\left( 3 \right) \otimes U \left( 1 \right){}_d$$ or $$SU \left( 3 \right) \otimes SU\left( 2 \right) \otimes U \left( 1 \right)_d$$ model? Kind of what I'm currently interesting in working with, but I don't have access to anything other than the arxiv.

cheers.

Last edited: Jul 6, 2013
2. Jul 7, 2013

### fzero

More generally one would just add a $U(1)_d$ to the full Standard Model and study the implications. Langacker might be a useful resource. From the inspire link you can browse through the numerous articles that cite this review. If you have something more specific in mind, it would help to narrow down more useful references.

3. Jul 7, 2013

### pdxautodidact

Well, coupling a dark radiation component has been done: "http://arxiv.org/abs/0810.5126. [Broken] Can one make an SU(3) coupling to dark matter, intead of the standard SU(2) isospin route. The arguments I hear for WIMPS are that they interact only via the weak nuclear force, thus they happen extremely rarely since distance scales are so small. What rules out a coupling to the strong nuclear force since it operates on similar scales? Could dark matter not be hadronic and not not reveal itself until deconfinement? Most of the universe is dark matter, I mean, it's probably got stuff going on too, just like our 4%, unless we go to an anthropic explanation.

Last edited by a moderator: May 6, 2017
4. Jul 7, 2013

### mitchell porter

I'm not entirely clear on whether your SU(3) is that of the standard model, or whether it's a new "dark SU(3)" mediated by dark gluons... The latter is more straightforward - you have dark baryons, a dark strong force that SM particles don't feel, and it can probably be made consistent with the data.

The first option is more challenging and interesting. If you have "dark quarks" that couple to SM gluons, they could mess up ordinary nuclear physics, because an SM gluon could turn into a dark quark and its antiparticle. So let's suppose they're so heavy that this is unlikely... My next concern would be, what happens when an astrophysical dark baryon collides with an ordinary nucleus? It seems like something pretty spectacular might happen, e.g. formation of dark-light hybrid hadrons, containing a mix of SM quarks and dark quarks.

5. Jul 8, 2013

### fzero

There is a collection of references on strongly interacting dark matter candidates at http://en.wikipedia.org/wiki/Strongly_interacting_massive_particle, SIMPs. In these works, it is not necessarily the case that the self-interaction is the strong interaction of QCD, but some references, in particular Wandelt et al also consider that possibility.

An important result is contained in the paper by Mack et al. Previously exclusion limits on SIMPs had been derived from astrophysical limits and underground detector non-observation, leaving a window in the space of cross-section vs. mass plot (see in particular fig. 2 of Zaharijas and Farrar.) Mack et al consider the case where the SIMP is its own antiparticle and find that annihilation processes would lead to excessive heating of the Earth.

A further constraint, coming from gamma ray production via cosmic ray proton-dark matter interactions, is considered by Mack and Manohar, where it is argued that a huge window is closed. This analysis does not seem to rely on assuming any properties of DM particle and antiparticle, and would presumably apply even in the case where there was a large matter-antimatter asymmetry in the dark matter sector.

In any case, this seems to be an interesting topic that would be worthwhile to understand even if the end result is negative.

6. Jul 8, 2013

### pdxautodidact

hi both & thanks,

i don't meen a new gauge groupn (except the dark U(1)), merely to look at strongly interacting particles in addition to weakly interacting particles. i'm not in graduate school or academia, and it's been a few years since i've been reading papers, so i'm a little out of the loop and tryign to ease back into it. fzero: thanks for the second set of links, and mitchel, thanks for the advice of things to take into consideration. hoping to put something out before grad school applications, even if it's just to the arXiv.

cheers