Jul 06, 2022 16:00:00

CERN reports three newly discovered 'exotic particles', the dawn of a new 'particle zoo' era and researchers

by

CERN

The European Joint Nuclear Research Institute (CERN) announced on July 5, 2022 that it has succeeded in observing three new subatomic particles that do not fit in the existing framework by LHCb experiments using the Large Hadron Collider . Did. It is hoped that this discovery will deepen our understanding of the structure of atoms and the nature of matter.

Observation of a strange pentaquark, a doubly charged tetraquark and its neutral partner.
https://lhcb-outreach.web.cern.ch/2022/07/05/observation-of-a-strange-pentaquark-a-doubly-charged-tetraquark-and-its-neutral-partner/

LHCb discovers three new exotic particles | CERN
https://home.cern/news/news/physics/lhcb-discovers-three-new-exotic-particles

Quarks , which are a type of elementary particles, have six types ( flavors ) of up, down, charm, strange, top, and bottom, and these are usually combined in groups of two to three to form hadrons such as protons and neutrons. Form. For example, a proton is a type of hadron ( baryon ) made up of a total of three quarks, two up quarks and one down quark.

However, in rare cases, a tetraquark made up of four quarks and a pentaquark made up of five quarks can be formed. These particles, called ' exotic hadrons ' that do not fit within the framework of normal hadrons, were predicted to exist together with normal hadrons in the 1960s, but they were considered as candidates by LHCb experiments and the like. It was not until the 2000s that the particles of hadrons began to be observed.

And the research team of the LHCb experiment, which has found many exotic hadrons so far, now analyzes the moment of decay of the negatively charged B quark to charm quark, anti-charm quark, up quark, down. We have succeeded in discovering a pentaquark made up of quarks and strange quarks. CERN explains this as 'a tremendous statistical significance of 15 standard deviations, well beyond the 5 standard deviations required to claim to have observed particles in the field of particle physics.' increase.

The following is a graphic representation of the predominant theory of the structure of the pentaquark found this time. Charm (c), anti-charm (c¯), up (u), down (d), and strange (s) quarks form a loose molecular bond as a pair of standard hadrons. This is the first time that the existence of pentaquark containing strange quark has been confirmed.

by

CERN

In addition, a 'double-charged tetraquark (left)' in which charm, anti-strange up, and anti-down quark are strongly linked, and a companion neutral partner (right) were also discovered this time.

by CERN

'The more we analyze, the more exotic hadrons we find,' said Niels Tuning, physics coordinator of the LHCb experiment. , A situation similar to the subsequent establishment of hadron and quark models in the 1960s. We are making, so to speak, Particle Zoo 2.0. '