Neutron

[Qfwfq]

How does the standard model address this. http://physicsworld.com/cws/article/news/7064

In principle by QCD although not in practice, due to issues of computational tractability. Strong forces between nucleons are treated typically by meson exchange models or, more in general, reggeons. It is complicated stuff in any case.

[Farsight]

What's this, guys? The strong force is what keeps a proton together. The residual strong force is what keeps a nucleus together. Ever looked at elements and isotropes? It seems pretty obvious that the residual strong force is "neutron linkage". So while proton repulsion is a definite and people talk about neutron pressure or even repulsion, neutron-neutron linkage sounds plausible to me. But maybe it's best to start with a dineutron rather than a tetraneutron. Worth looking at I suppose, especially since a lot of the particles bandied around have very short lifetimes anyway. See: http://cdsweb.cern.ch/record/1237928?ln=no.

[Qfwfq]

It seems pretty obvious that the residual strong force is "neutron linkage".

While resort to intuitive ideas can be helpful in seeking models, even in the complicated realm of nuclear physics, it is by no means sufficient for a conclusive argument. Here is a telling sentence from the introduction of that article:

 

The neutron-neutron interaction is attractive in the [imath]^1 S[/imath] channel, and therefore, it is natural to expect that spin-zero [imath]nn[/imath] pair correlations may enhance in nuclear systems though the interaction is not so strong as to form a two-neutron bound state in a free space.

 

This kinda means that you don't just up and so easily expect to see dineutrons from a collision reaching your detectors. It seems like the real place to start is the following reference, which also points to the possibility that cluster states more complex than dineutrons may exist:

Migdal A. B., Yad. Fix., 16 (1972) 427; English translation Sov. J. Nucl. Phys., 16 (1973) 238.

[Little Bang]

I would think it difficult to build a detector for an object like the dineutron. The fact that they would be very rare and could fly through your detector without ever hitting a nucleus of the atoms that make up your detector would make the experiment difficult.

[Qfwfq]

Well I'm no expert on neutron calorimetry but I know they have methods, they've been handling the buggers ever since the days of Fermi and his boys in via Panisperna; from what I saw in those papers they simply aim to distinguish dineutrons or tetraneutrons from single ones by mass considerations. Try rummaging through:

 

http://www.google.com/#hl=en&source=hp&biw=1280&bih=609&q=neutron+calorimetry&btnG=Google+Search&aq=f&aqi=&aql=&oq=neutron+calorimetry&gs_rfai=&fp=df742e2542f01f0c

http://www.google.com/#hl=en&biw=1280&bih=609&q=neutron+calorimeter&aq=f&aqi=&aql=&oq=neutron+calorimeter&gs_rfai=&fp=e19d2cc95bec2408

Edited October 4, 2010 by Qfwfq
ghastly typo

[Little Bang]

Ty Q, it was somewhat helpful. They somehow generate a beam of protons and neutrons. Then separate the two with magnets and then detect the neutrons by the heat generated in their detector. I was unable to see how they could tell the difference between the neutron or dineutron.