Posted on 07/14/2015 1:55:01 PM PDT by LibWhacker
An exotic particle made up of five quarks has been discovered a decade after experiments seemed to rule out its existence.
The short-lived pentaquark was spotted by researchers analysing data on the decay of unstable particles in the LHCb experiment at the Large Hadron Collider (LHC) at CERN, Europes particle-physics laboratory near Geneva. The finding, says LHCb spokesperson Guy Wilkinson, opens a new era in physicists understanding of the strong nuclear force that holds atomic nuclei together.
The pentaquark is not just any new particle it represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before, he says. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which were all made, is constituted.
Protons and neutrons are made up of three kinds of quarks bound together, but theorists calculate that, in principle, particles could be made of up to five quarks. Such particles would be rich testing grounds for quantum chromodynamics (QCD) the theory that describes the forces that hold quarks together.
In 2002, researchers at the SPring-8 synchrotron in Harima, Japan, caused a stir when they announced that they had discovered a pentaquark, roughly 1.5 times heavier than a proton, inferring its existence from the debris of collisions between high-energy photons and neutrons. Within a year, more than ten other labs had reported finding evidence for the particle by reanalysing data.
But numerous others saw no evidence for such a state and, in 2005, the discovery was pronounced a mirage. The final straw came with an experiment at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, that repeated the SPring-8 measurement with more data and ruled out the pentaquarks existence.
(Excerpt) Read more at nature.com ...
God particle forsaken pentaquark?
Particles can be homeless too. We must have compassion on the less fortunate.
As long as it is not a stable matter consuming strangelet....
I’m glad they found it. Mine’s been missing for a while, so now I know where it is.
LOL!
I haven’t seen mine since it rolled under the fridge.
I have one of those things trapped inside the light bulb in my bedside lamp.
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