After 50-year hunt, science finds
pentaquarks
Send a link to a friend
[July 14, 2015]
By Tom Miles
GENEVA (Reuters) - Data from the Large
Hadron Collider (LHC) outside Geneva appears to have proved the
existence of particles made of five quarks, solving a 50-year-old puzzle
about the building blocks of matter, scientists said on Tuesday.
|
Quarks are the tiny ingredients of sub-atomic particles such as
protons and neutrons, which are made of three quarks. The less
common and more unstable mesons, particles found in cosmic rays,
have four.
A five-quark version, or "pentaquark", has been sought, but never
found, ever since Murray Gell-Mann and George Zweig theorized the
existence of such sub-atomic particles in 1964.
Guy Wilkinson, spokesman for the LHCb experiment based at CERN, the
physics research center that houses the LHC, said a telltale "bump"
seen in a graph of billions of particle collisions could only be
explained by a five-quark particle.
![](http://archives.lincolndailynews.com/2015/Jul/14/images/ads/current/st_claras_lda_082114.png) "From the point of view of our experiment, we think it has fulfilled
all criteria of discovery. We have no other way of explaining what
we have seen. But the scientific method is such that we have
submitted a paper to a journal, the journal will consider it, then
the community will judge," he told Reuters.
The LHC, a circular 27 km (17 mile) underground particle
accelerator, has provided reams of data since it started smashing
protons together at close to the speed of light in 2010.
Analysis of the collisions has already proved the existence of the
Higgs boson, a particle that gives mass to matter, and scientists
are now looking for a "dark universe" that they believe exists
beyond the visible one.
The pentaquark discovery has opened even more new avenues.
[to top of second column] |
![](../images/ads/current/richardson_lda_040113.png)
"What we want to do now is to look for other five-quark particles
and try and understand more about their nature, and this may tell us
something about how even the matter inside our bodies is bound
together," Wilkinson said. "It may also have cosmic consequences for
... understanding what happens to stars at the end of their life."
He said it was still a mystery why it had taken 50 years to find
pentaquarks.
"There must be many, many pentaquarks out there. In fact in our
analysis we found two. One is very evident, the other is a little
harder to see. There should be many out there."
(Reporting by Tom Miles; Editing by Mark Trevelyan)
[© 2015 Thomson Reuters. All rights
reserved.]
Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
![](http://archives.lincolndailynews.com/2015/Jul/14/images/ads/current/mks_lda_061615.png) |