Team of physicists finds signs of pentaquark states and new matter


University of Pittsburgh and Swansea University theorists have demonstrated that recent experimental findings from the CERN collider provide compelling evidence for the existence of a novel kind of matter.

A heavy particle dubbed a Lambda b that decays to lighter particles like the well-known proton and the renowned J/psi, discovered in 1974, was the subject of an experiment at CERN, the location of the world's highest-energy particle collider.

Physics professors Tim Burns of Swansea, Wales, and Eric Swanson of Pitt contend that the findings can only be comprehended if a new sort of matter exists in a paper that was just published online in Physical Review D.

Quarks, which combine to form the known proton and neutron as well as a variety of subatomic particles that interact far more strongly than electrons or neutrinos, account for the majority of the observable mass of the universe. Hadrons are a collective name for these heavily interfering particles and are a concept from Quantum Chromodynamics theory. This hypothesis has been around for close to 50 years, but it is still notoriously challenging to understand.

The Standard Model's problem child, according to Swanson, is quantum chromodynamics. It is challenging to respond to the numerous issues this single experiment raises because learning what it says about hadrons necessitates running the fastest computers on the planet for years.

To comprehend quantum chromodynamics, hadron experiments must be conducted and the findings must be accurately interpreted.

A quark and an antiquark combination, like the J/psi, or combinations of three quarks, like the proton, could be used to explain all hadrons up until recently. Despite this, it has long been believed that other quark combinations—basically, new types of matter—are attainable. Then, in 2004, a particle known as the X(3872) was discovered, which appeared to be a mixture of two quarks and two antiquarks. Since then, further potential innovations have appeared, but none of them have been positively identified as fresh unusual quark pairings.

According to Swanson, "sometimes a bump in the data is a beautiful new thing, and other times it is just a bump."

In order to come up with a cogent explanation for each observation, the new effort integrates the CERN data with those from other tests from 2018 and 2019.

We have a model that, for the first time, takes into account all of the experimental restrictions and explains the data nicely, according to Burns. The presence of numerous new particles known as "pentaquarks," which are made up of four quarks and one antiquark, is necessary for the explanation. Additionally, according to the research, pentaquarks are just about ready to be detected in other laboratories.

Burns stated that there is really no other way to understand the data and that pentaquark states must exist. The finding suggests that further pentaquarks may exist and that the discovery of a whole new form of substance is imminent.

Reference:  Physical Review D

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