Friday , August 19 2022

Physicists discover a new class of pentaquarks


Hadron Collider's large bipolar dipole magnets. Credit: CERN

Tomasz Skwarnicki, professor of physics at the College of Arts and Sciences at Syracuse University, has revealed new information about a class of particles called pentaquarks. His findings could lead to a new understanding of the structure of an issue in the universe.

With the help of Liming Zhang, associate professor at Tsinghua University in Beijing, Skwarnicki has analyzed data from the great beauty of the Hadron Collider (LHCb) experimenting in the large Hadron Hadron (LHC) processor in Switzerland. The experimental physicist has revealed evidence of three pentaquars that have never been seen from the front, divided into two parts.

"So far, we thought that pentaquark contained five elementary particles [called quarks], stuck with each other. Our findings prove otherwise, "said Skwarnicki, Fellow of the American Physical Society.

Skwarnicki is part of a team of researchers, including members of Syracuse's High-Energy Physics Group (HEP), studying particles and fundamental forces in the Universe. Most of their work takes place at CERN laboratory, whose LHC is the largest, most powerful particle detector in the world.

It is within the LHC that protons are thrown together on high energy, just to collide with each other. What lies inside the particles, when it is cracked open, helps scientists to explore the mysteries of the basic universe.

Studying proton collisions from 2015-18, Skwarnicki has confirmed that there is infrastructure in a pentac. The donation, which he said, was a trio of narrow peaks in the Kinematic LHC data.

Each peak refers to a special pentack – in particular, one has been divided into two parts: baryon, which includes three quarks, and a meson, with two sharks.

Peak also suggests resonance, a short-lived phenomenon during particle decay, where one unstable particle transforms into many others. Resonance occurs when protons (a type of baryon) meet – or, more accurately, glide into each other – during the LHC collision.

What is unique about each of these three pentaquarks is that its mass is slightly lower than the sum of its parts – in this case, masses of the baryon and meson. "The pentaquark was not rotting according to its normal, easy-to-separate routine," said Skwarnicki. "Instead, it was rotting by rearranging its slow and laborious insects, forming a narrow resonance."

Understanding how particles interact with each other and binding with each other is Skwarnicki's specialty. In 2015, he and then Ph.D. Student Nathan Jurik G 16, Professor Sheldon Stone and Zhang made notable the headlines with their role in finding pentacquac by LHCb. With her theory half a century earlier, their discovery was based on LHC data from 2011-12.

The latest LHCb data used an energy beam which was almost twice as strong. This method, together with more detailed data selection criteria, produced a wider range of proton collisions.

"It has also given us 10 times more data and has allowed us to observe pentaquark structures more clearly than from the front," Skwarnicki said. "What we thought was one pentaquark in two that was narrow, with little space between them."

The data also revealed a third pentaquark "companion". "Each of the three pentaquar had the same pattern – baryon with a meson infrastructure. Their masses were below the baryon-meson thresholds," he adds.

Skwarnicki's discovery took place relatively quickly, considering that the LHCb had given up the best data collection less than three months ago.

Eric Sedore, who links CIO for infrastructure services in Information Technology Services (ITS), played a supporting role. His Research Computing Team provided Skwarnicki with the necessary computer fire engine to achieve its goals.

In addition to Skwarnicki and Stone, HEP includes Professors Marina Artuso and Steven Blusk and Assistant Professor Matthew Rudolph. The group is currently building equipment on campus from Upstream Tracker (UT), being transported to CERN next year as part of a major upgrade at the LHCb.

"The UT will significantly improve LHCb, which includes about 10 different sub-sensors. I am hopeful that the UT will lead to more discoveries," said Skwarnicki, adding that Artuso and Stone is the leader and deputy Project of UT, respectively.

Skwarnicki is excited about LHCb because it helps to explain how the smallest electors behave. His latest discovery, for example, proves that pentaquarks are built in the same way as protons and neutrons, which are bound together in the nucleus of us.

"Pentaquarks may not play a significant part in the issue that we have to do," he said, "but their existence may affect our models of the issue found in other parts of the universe." significantly, like neutron stars. "

Explore further:
The CERN experiment of the CERN reports exotic pentaquark particle observation

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Syracuse University

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