Three new exotic particles on the board


Many particles have already been discovered at the Large Hadron Collider (LHC, France-Switzerland). Now physicists say they have found evidence for three never-before-seen combinations of quarks: a pentaquark and a pair of tetraquarks.

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The list of discovered particles a Large Hadron Collider (LHC, France-Switzerland) is long. There is the famous Higgs boson, of course. But also about 65 hadrons. And today there are no fewer than three new items exotic that are added to it. A new pentaquark and the first pair of tetraquarks ever detected.

To understand, remember that the elementary particles what are the quark have the habit of associating in twos or threes. They thus form hadrons, among which the proton and the neutron who are quite familiar to us. But sometimes – much rarer – quarks accumulate by four or even five. To form exotic hadrons called tetraquarks and pentaquarks respectively.

A pentaquark and a pair of tetraquarks

The pentaquark discovered this time around is unique in that it is the first to incorporate an s quark. Understand, a quark of flavor – here’s how physical to qualify the different types of existing quarks; they know six – ” strange “ os for “strange”. much more “classic”this pentaquark also contains a c – per quark “charm” – and its antiquark, a quark – for “on” – is one d-quark – for “down”.

The two observed tetraquarks form a pair. It’s the first time that physical detect one. One of the pair’s tetraquarks has a double electrical charge. The other is neutral. Both correspond to what researchers call a tetraquark charm apparent. Understand that these tetraquarks are made up of a c quark – but also an antiquark s, a u quark, and an antiquark d – without its antiquark.

And for those wondering, here’s what Chris Parkes, the spokesperson for the collaboration with LHCb, replies: “Finding new types of tetraquarks and pentaquarks and measuring their properties will help theorists develop a unified model of exotic hadrons – as isolated units of tightly bound quarks or as pairs of loosely bound hadrons, similar to molecules -, but also to better understand the classical hadrons. “

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