Cern has discovered the longest-lived particle ever

From observing the particle, physicists hope to produce stable exotic particles. It has the longest decay time of any exotic matter and is composed of two quarks and two antiquarks

A new exotic matter particle with very special characteristics has been discovered by scientists at Cern and presented at the European Physical Society Conference on High Energy Physics. The key detail is that it is the longest-lived particle ever observed so far. This new particle has a longer decay time than any other exotic matter, and the discovery gives physicists hope that one day they will be able to achieve the production of stable exotic particles, that is, particles that exist outside the original formulation of two- and three-quark particles.

Discovery on the longest-lived particle ever

During the Large Hadron Collider beauty (LHCb) experiment, scientists observed that the new Tcc+ particle is a tetraquark consisting of two quarks and two antiquarks. Quarks are the fundamental components from which matter is made. They combine to form hadrons, such as the proton and neutron, which consist of three quarks, and mesons, which form as quark-antiquark pairs. Several tetraquark particles have been discovered in recent years, but Tcc+ is the first one that contains two quark charms, with no antiquark charms to balance them. Tcc+ is also the first particle found that belongs to a class of tetraquarks with two heavy quarks and two light antiquarks.

These particles decay by transforming into a pair of mesons, each consisting of one of the heavy quarks and one of the light antiquarks. According to some theoretical predictions, the mass of such tetraquarks should be very close to the sum of the masses of the two mesons. This closeness of mass makes the decay "hard," leading the particle to have a longer lifetime, which is indeed the case for Tcc+, which is the longest-lived exotic hadron found to date.

The discovery about the new tetraquark is interesting, according to physicists, for further study. The particles it decays into are all relatively easy to detect, and in combination with the small amount of energy available in the decay, this leads to excellent precision on its mass and allows analysis of the quantum numbers of this fascinating particle. Measuring its small decay energy increases confidence that a tetraquark consisting of two bottom quarks and an up and down antiquark would have a negative nuclear force decay energy, making it highly stable. A double-bottom tetraquark "is rarely produced and is out of reach of the current luminosity of the Large Hadron Collider," said Dr. Ivan Polyakov of the LHCb experiment.

In addition to predicting the possible production of stable exotic particles, Tcc+, being longer-lived than other tetraquarks, makes it easier to study mesons, while the low-energy release allows for more precise measurements. In this way it could be easier to test the accuracy of theoretical models of physics at the subatomic level.

Between the latest discoveries in the field of physics there is instead a new research concerning black holes, whose gas could trigger galactic tsunamis.

Stefania Bernardini