Three new unusual particles have been found by the LHC
The Large Hadron Collider beauty (LHCb) collaboration (pictured) has announced the discovery of three new exotic particles.
Exotic particles, such as these, had only been theorized but not observed until recently. These exotic particles are built out of quarks.
“Like proton or neutrons, the particles that make up the nucleus of the atom, these new particles are made up of quarks”, explained Chris Parkes, Professor of Experimental Particle Physics at The University of Manchester. “However, protons and neutrons are made of three quarks, whereas exotic particles are made of four or five quarks”.
Exotic particles were predicted as possible by theorists about six decades ago, but only relatively recently, in the past 20 years, have they been observed by LHCb and other experiments.
“Finding exotic particles and measuring their properties will help theorists develop a model of how these particles are built, the exact nature of which is largely unknown,” according to Professor Parkes. “It will also help to better understand the theory for conventional particles such as the proton and neutron.”
The results presented today at a CERN seminar, add three new exotic members to the growing list of new particles found by experiments at the Large Hadron Collider (LHC). They will help physicists better understand how quarks bind together into these composite particles.
The LHCb collaboration is a collaboration of over 1000 scientists from twenty countries across the world. It has built and operates one of the four big detectors at the CERN LHC particle collider. The collaboration is led by Professor Parkes, while The University of Manchester has more than twenty members of staff and PhD students working on the project.
The new findings show that the international LHCb collaboration has observed three never-before-seen particles: a new kind of “pentaquark” and the first-ever pair of “tetraquarks”.
Finding exotic particles and measuring their properties will help theorists develop a model of how these particles are built, the exact nature of which is largely unknown, it will also help to better understand the theory for conventional particles such as the proton and neutron. – Professor Chris Parkes
Quarks are elementary particles and come in six flavors: up, down, charm, strange, top and bottom. They usually combine together in groups of twos and threes to form hadrons such as the protons and neutrons that make up atomic nuclei.
More rarely, however, they can also combine into four-quark and five-quark particles, or “tetraquarks” and “pentaquarks”. Particles made of quarks are known as hadrons.
While some theoretical models describe exotic hadrons as single units of tightly bound quarks, other models envisage them as pairs of standard hadrons loosely bound in a molecule-like structure. Only time and more studies of exotic hadrons will tell if these particles are one, the other or both.
Most of the exotic hadrons discovered in the past two decades are tetraquarks or pentaquarks containing a charm quark and a charm antiquark, with the remaining two or three quarks being an up, down or strange quark or an antiquark. But in the past two years, LHCb has discovered different kinds of exotic hadrons.
Two years ago, the collaboration discovered a tetraquark made up of two charm quarks and two charm antiquarks, and two “open-charm” tetraquarks consisting of a charm antiquark, an up quark, a down quark and a strange antiquark.
And last year it found the first-ever instance of a “double open-charm” tetraquark with two charm quarks and an up and a down antiquark. Open charm means that the particle contains a charm quark without an equivalent antiquark.
The discoveries announced today by the LHCb collaboration include new kinds of exotic hadrons. The first kind, observed in an analysis of “decays” of negatively charged B mesons, is a pentaquark made up of a charm quark and a charm antiquark and an up, a down and a strange quark. It is the first pentaquark found to contain a strange quark.
The finding has a whopping statistical significance of 15 standard deviations, far beyond the 5 standard deviations that are required to claim the observation of a particle in particle physics.
The second kind is a doubly electrically charged tetraquark. It is an open-charm tetraquark composed of a charm quark, a strange antiquark, and an up quark and a down antiquark, and it was spotted together with its neutral counterpart in a joint analysis of decays of positively charged and neutral B mesons.
The new tetraquarks, observed with a statistical significance of 6.5 (doubly charged particle) and 8 (neutral particle) standard deviations, represent the first time a pair of tetraquarks has been observed.
The LHCb experiment hopes to find further exotic particles in the future and start to understand the families in to which they form.
The collaboration is starting collecting data with its new detector for LHC Run 3.
Critical elements of this new detector have been designed and assembled in Manchester over the past seven years.
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Header image: CERN
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MattH
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‘Quarks are elementary particles’
There was a time when atoms were elementary particles. Then protons neutrons and electrons were elementary particles. Now six flavours of quarks. What will tomorrow bring?
Man, the inquisitive ape. With the death penalty for corruption much could be accomplished.
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Herb Rose
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When an electron and proton comes together they create a neutron and radiate energy. That neutron if not in the nucleus of an atom will then split into a proton and electron and radiate energy as gamma radiation.
Quarks, with all their flavors, are a Rube Goldberg construction intended to waste a tremendous amount of money in order to avoid the obvious.
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Tom O
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Quote – ““Finding exotic particles and measuring their properties will help theorists develop a model of how these particles are built, the exact nature of which is largely unknown,”
Now that pretty well sums it up. The only thing I would add is that knowing nothing won’t stop the know nothings from pretending they find things that no one, including themselves, no ANYTHING about The conversatioin goes –
“Scientist” 1 -“Look, here is a mystery something that I didn’t see but know it was there by the readouts.”
“Scientist” 2 – “Don’t worry I will make a model of it.”
I agree with those that say All they truly find is a way to use enormous amounts of energy -which Europe is suffering from a lack of , and burn money, probably digital money so there isn’t any carbon footprint.
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Robert Beatty
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If scientists keep finding these new exotic particles, we will eventually know how mass includes the property of gravitational attraction. As a guess, it seems the concentration of exotic particles and their type will determine the strength of gravity – and the variability shown to exist following the inverse square law.
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lloyd
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For all the Naysayers, there is nothing wrong with pushing the boundary of knowledge, even if right now you see no use for it.
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Herb Rose
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Hi Lloyd,
The problem is the accelerators are not pushing the boundary of knowledge. Everything they find is something predicted or theorized. What ever is imagined is discovered whether it be the undetectable neutrino or the Higgs particle, but there is never any surprises. With the Hubble and James Webb telescopes there were multiple unexpected discoveries but this is not the case LHC. If all you find is what you expect then you are not advancing science but confirming existing beliefs.
Herb
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yougottaloveme
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Oh Lord, please get these guys to the end of their “search” quickly, so they can pivot into doing something useful for us for a change, like figuring out how to feed more than eight billion during the cold decades coming up.
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