http://www.universetoday.com/2008/01/23/large-hadron-collider-could-detect-unparticles/
Large Hadron Collider Could Detect "Unparticles"
Written by Ian O'Neill
Unparticles may have fractal properties.
Understanding the mysterious dark matter in our universe is paramount to
cosmologists. Dark matter and dark energy makes up the vast majority of
mass in the observable universe. It influences galaxy rotation, galactic
clusters and even holds the answer to our universe's fate. So, it is
unsurprising to hear about some outlandish physics behind the possible
structure of this concealed mass. A Harvard scientist has now stepped up
the plate, publishing his understanding about dark matter, believing the
answer may lie in a type of material that has a mass, but doesn't behave
like a particle. "Unparticles" may also be detected by the high energy
particle accelerator, the Large Hadron Detector (LHD) at CERN going
online in a few weeks time. High energy physics is about to get stranger
than it already is…
Dark matter is theorized to take on many forms, including: neutron
stars, weakly interacting massive particles (WIMPs), neutrinos, black
holes and massive compact halo objects (MACHOs). It is hard, however, to
understand where the majority of mass comes from if you can't observe
it, so much of what we "know" about this dark source of matter and
energy will remain theory until we can actually find a way of observing
it. Now, we have a chance, not only to observe a form of dark matter,
but also to generate it.
A simulation of a LHC collision (credit:CERN)
Professor Howard Georgi, a Harvard University physicist, wants to share
his idea that the "missing mass" of the universe may be held in a type
of matter that cannot be explained by the current understanding of
physics. The revelation came to him when he was researching what can be
expected from the future results of LHC experiments. Beginning with
quantum mechanics (as one would expect), he focused on the interactions
between sub-atomic particles. Using the "Standard Model", which
describes everything we know and understand about matter in our universe
(interactions, symmetry, leptons, bosons etc.), Georgi soon came to a
dead end. He then side stepped a basic premise of the standard model:
the forces that govern particle interactions act differently at
different length scales.
"I did think I was crazy," Prof. Georgi on the moment he stumbled on the
"unparticle theory".
This is one of the major failings of the standard model - the
unification of the four universal forces: weak force, strong force,
electromagnetic force and gravitational force. The standard model unites
the first three, but neglects gravity. Gravity simply does not fit. So
Georgi took the bold step and calculated what could be generated by the
LHC without the help of standard sub-atomic thinking and scale length
restrictions.
The unparticle would therefore be "scale invariant", a property of
fractals. Unparticles can interact over any scale lengths without
restriction. When viewed, the unparticle will act as a fractal and will
look similar over any scale (a characteristic known as self-similarity).
Unparticles will also take on any mass, some or all the mass, depending
on the scale you are viewing at. Now the implication of mass suddenly
becomes interesting to the dark matter hunters out there. Unparticles
could be a huge source of dark matter.
As they have mass, unparticles would also possess an "ungravity".
Ungravity should have a strong, short-distance effect on matter in the
observable world, and so, may be observed by sufficiently sensitive
gravity probes.
Whether unparticles exist or not, exploring the possibility that
standard thinking may need to be slightly re-jigged for the extreme
world of high energy particle collisions will surely lead to some
healthy scientific debate. For now, we wait in anticipation for when the
LHC goes online in May this year.
Source: Telegraph.co.uk
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