Unparticles are all the rage in physics at the moment. Yep, ya heard right: unparticles.

A few months back, Howard “Jumpin” Georgi at Harvard University stumbled across an entirely new type of stuff while foolin’ around with the field theories behind particle physics.

Ordinary particles pop out of these theories as solutions at certain scales. This gives particles a fixed measureable mass.

What Jumpin’ Georgi has found is an entirely new class of solutions that are scale free. That means this stuff has no average size but looks the same whatever scale you choose to examine it at.

This can’t be ordinary particle stuff cos mass is scale dependent–the further away you are from a particle, the smaller it looks, right? (Unless the particles have zero mass, in which case it don’t matter how far away you are, they always look the same. But Georgi ain’t interested in zero mass particles.)

He’s called this stuff unparticles cos it ain’t nothing like the particles we all know and lurv. Georgi’s work has created big excitement. A lot of people are a-scramblin and a-workin to better understand this stuff. You can almost hear that brainpower motorin through the gears.

How might we observe unparticles? Georgi reckons unparticles might interact weakly with ordinary matter and this might show up in particle accelerators as missing energy. But there’s only one accelerator powerful enough to spot em: the Large Hadron Collider at CERN which ain’t built yet, so we’ll have to wait a few years to observe direct evidence.

In the meantime, some astrotheorists are speculatin that unparticle stuff would have a significant effect on the physics of supernovas. So we might already have seen the effect of unparticles in our observations of explodin stars.

Steen “Ray” Hannestad and a few pals at the University of Aarhus in Denmark combed through the data on one famous event: SN1987a, the first supernova ever observed in action.

And the disappointing news is they ain’t seen nothing. Steen Ray reckons that supernova observations rule out the existence a large class of unparticle stuff.

The jury is still out, however. Supernova physics leaves open the possibility that unparticles might still rear their heads in other ways. But if Steen Ray is right, it ain’t quite as excitin’ as ya’ll had hoped.

Ref: arxiv.org/abs/0708.1404: Unparticle Constraints from SN1987A

This entry was posted on Friday, August 31st, 2007 at 2:29 am and is filed under Changin' the world. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.