Forget equations, physicists tend to explain process in terms of sports and syrup
A computer graphic shows a typical Higgs boson candidate event,
including two high-energy photons whose energy (depicted by red towers)
is measured in the Compact Muon Solenoid's electromagnetic calorimeter.
The yellow lines are the measured tracks of other particles produced in
the collision. The pale blue volume represents the CMS' crystal
calorimeter barrel.
The infamous Higgs particle has a weighty task: It grants all
the other elementary particles their mass. Without it, they — we — would
zip around frantically at the speed of light, too foot-loose to form
atoms. But how does the Higgs do it?
In lieu of equations, physicists tend to explain the process in terms of sports and syrup.
First, each of the elementary particles acquires its unique set of
attributes by interacting with invisible entities called fields. Like
football fields, these are large stages upon which individuals (be they
electrons or running backs) dash this way and that, and occasionally
bash together. But unlike football fields, the fields of physics are
three-dimensional, and extend infinitely in all directions.
One such field is the electromagnetic (EM) field — the kind you can feel near the poles of a red and silver bar magnet,
but which actually exists everywhere all the time. Each particle
interacts with the EM field in a way that depends on its electric
charge. For example, electrons, whose charge is -1, tend to move through
the field toward the positive ends of bar magnets, and to clump
together with positively charged protons.
Like a sports field with its corresponding ball, each field of
physics has a corresponding particle. The EM field, for example, is
associated with the photon, or particle of light. This correspondence
plays out in two ways: First, when the EM field is "excited," meaning
its energy is flared up in a certain spot, that flare-up is, itself, a
photon.
Secondly, when particles interact with the EM field (for example,
when they are drawn toward the oppositely charged end of a magnet), they
experience the field by absorbing and emitting a constant stream of
"virtual photons" — photons that momentarily pop in and out of existence
just for the purpose of mediating the particle-field interaction.
There also exists a Higgs field. It gives particles mass. [ How Do You Weigh an Atom? ]
Except for massless photons and gluons, "all elementary particles get
their masses from their interactions with the (Higgs) field, kind of
like being 'slowed down' by passing through a thick syrup," explained
James Overduin, a physicist at Towson University in Maryland.
Some particles have a harder time trudging through the syrupy Higgs
field than others, and as a result, they're heavier. However, it isn't
known why certain particles, such as the extremely corpulent top quark,
are thousands of times more encumbered by the Higgs field than are
lightweight particles, such as electrons and neutrinos. "Theorists have
been searching for some way to actually predict (particle) masses from
first principles. No convincing theory has yet emerged," said John
Gunion, author of "The Higgs Hunter's Guide" (Basic Books, 1990) and a
professor of physics at the University of California, Davis. [ Are There Higgs Bosons in Space? ]
But here's where the Higgs particle comes in: Just as the photon
mediates interactions with the EM field and is itself an excitation of
the EM field, the Higgs particle mediates interactions with the Higgs
field, and is itself an excitation of the Higgs field.
Particles trudge through the Higgs field by exchanging virtual Higgs
particles with it. And a real Higgs particle surfaces when the field
becomes excited, like a slosh of the syrup. Detecting such a slosh (i.e.
the particle) is how physicists can be sure the syrup (i.e. the field)
exists. "You have to get enough energy to excite the field so that it
looks like a particle to us. Otherwise we don't know the field is
there," Craig Blocker, a Higgs-hunting physicist at Brandeis University,
told Life's Little Mysteries.
But because the Higgs particle is extremely high-energy (or,
equivalently, very heavy), it's tough to excite the Higgs field enough
to create one. That's where the Large Hadron Collider comes in: by
smashing together high-speed protons, it generates enough juice to slosh
the syrupy Higgs field around now and again, producing Higgs bosons.
http://www.msnbc.msn.com/id/48062124/ns/technology_and_science-science/#.T_Xzb783nQY
No comments:
Post a Comment