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by Katia Moskvitch
Science reporter, BBC News
3 November 2010
from
BBC Website
Simulated
lead-lead collision
The ALICE experiment
has been designed for lead ions collisions (simulation)
Researchers at the Large Hadron Collider
(LHC) are getting set to create the Big Bang on a miniature scale.
Since 2009, the world's highest-energy particle accelerator has been
smashing together protons, in a bid to shed light on the fundamental
nature of matter.
But now the huge machine will be colliding lead ions instead.
The experiments are planned for early November and will run for four
weeks. The LHC is housed in a 27km-long tunnel on the Franco-Swiss
border and is managed by the European Organization for Nuclear
Research (CERN).
The collider consists of four different experiments and one of them,
ALICE, has been specifically designed to smash together lead ions.
The goal of these collisions is to investigate what the infant
Universe looked like. Colliding protons at high energies was aimed
at other aspects of physics, such as finding the elusive Higgs boson
particle and signs of new physical laws, such as a framework called
supersymmetry.
Cern's spokesman James Gillies told BBC News that besides
ALICE, the ATLAS and Compact Muon Solenoid (CMS) experiments will
also be temporarily colliding ions.
Big Bang
He said the tests could provide an insight into the conditions of
the Universe some 13.7 billion years ago, just after the Big Bang.
They will look at the Universe fractions of a second after a tiny
but very dense ball of energy exploded to create the cosmos as we
know it today.
At the temperatures generated, even
protons and neutrons will melt, resulting in a hot dense soup of
quarks and gluons”
End Quote David Evans
University of Birmingham, UK
Scientists believe that it was back then
that a special state of matter existed, different from the matter
the Universe is formed of now.
"Matter exists in various states:
you can take a material like water and if you deep freeze it,
it'll be solid, and if you put it on a table, it'll turn into a
liquid, and if you put it into a kettle, it'll turn into a gas,"
said Dr Gillies.
"It's all the same stuff, but those are different states of
matter. And if you take materials into laboratories, you can
pull the electrons off the atoms and you have another state of
matter which is called plasma."
But at the very beginning of the
Universe, there might have been yet another state of matter.
Physicists have dubbed this "stuff" the
quark-gluon plasma.
"And this is the state of matter you
have if you're able to effectively melt the nuclear matter that
makes up atoms today, releasing the things that are inside,
which are quarks and gluons," Dr Gillies explained.
Quark and
gluon soup
If the researchers at the LHC are able to recreate that state of
matter and study it, they could get important clues about how it,
"evolved into the kind of matter
that can make up you and me".
One of the scientists who will be taking
a part in the experiment is David Evans from the University
of Birmingham, UK.
Dr
Evans is one of the scientists who will take part in the new
experiment
"Although the tiny fireballs will
only exist for a fleeting moment (less than a trillionth of a
trillionth of a second) the temperatures will reach over ten
trillion degrees, a million times hotter than the centre of the
Sun," said Dr Evans.
"At the temperatures generated, even protons and neutrons, which
make up the nuclei of the atoms, will melt, resulting in a hot,
dense soup of quarks and gluons."
The researcher said that the
temperatures and densities that the collider will aim to create will
be the highest ever produced in an experiment.
Large Hadron Collider (LHC) Generates A...
'Mini-Big Bang'
by Katia Moskvitch
Science reporter, BBC News
8 November 2010
from
BBC Website
Dr David Evans:
"From conception to
design and building this, it's taken about 20 years."
The Large Hadron Collider has successfully created a "mini-Big Bang"
by smashing together lead ions instead of protons.
The scientists working at the enormous machine achieved the unique
conditions on 7 November.
The experiment created temperatures a million times hotter than at
the centre of the Sun.
The LHC is housed in a 27km-long circular tunnel under the
French-Swiss border near Geneva.
Up until now, the world's highest-energy particle accelerator -
which is run by the European Organization for Nuclear Research (CERN)
- has been colliding protons, in a bid to uncover mysteries of the
Universe's formation.
Proton collisions could help spot the elusive Higgs boson particle
and signs of new physical laws, such as a framework called
super-symmetry.
But for the next four weeks, scientists at the LHC will concentrate
on analyzing the data obtained from the lead ion collisions.
This way, they hope to learn more about the plasma the Universe was
made of a millionth of a second after the Big Bang, 13.7 billion
years ago.
One of the accelerator's experiments,
ALICE, has been specifically
designed to study the smashing together of lead ions, but the
ATLAS
and
Compact Muon Solenoid (CMS) experiments have also switched to
the new mode.
'Strong force'
David Evans from the University of Birmingham, UK, is one of the
researchers working at ALICE.
He said that the collisions obtained were able to generate the
highest temperatures and densities ever produced in an experiment.
"We are thrilled with the achievement," said Dr Evans.
One of the lead ion collisions
at the LHC
"This process took place in a safe, controlled environment,
generating incredibly hot and dense sub-atomic fireballs with
temperatures of over ten trillion degrees, a million times hotter
than the centre of the Sun.
"At these temperatures even protons and neutrons, which make up the
nuclei of atoms, melt resulting in a hot dense soup of quarks and
gluons known as a quark-gluon plasma."
Quarks and gluons are sub-atomic particles - some of the building
blocks of matter. In the state known as quark-gluon plasma, they are
freed of their attraction to one another.
He explained that by studying the plasma, physicists hoped to learn
more about the so-called strong force - the force that binds the
nuclei of atoms together and that is responsible for 98% of their
mass.
After the LHC finishes colliding lead ions, it will go back to
smashing together protons once again.
The ALICE experiment
has been designed specifically for lead ion collisions
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