New calculations link different pion reactions in nuclear physics

Early career physicists mathematically connect space-like form factors in timelines, opening the door to further insight into the inner workings of powerful forces. The new lattice QCD calculations link two seemingly different reactions containing the lightest particles, pion, governed by powerful interactions.

As an undergraduate at Technology Code Monterrey in Mexico, Felipe Ortegagama worked at the Thomas Jefferson National Accelerator Facility in the U.S. Department of Energy as part of the Institute of Science internship program. So Ortega Gama worked with Raul Briceño, a co-appointed staff scientist at the Lab’s Center for Theory and Computational Physics (Theory Center) and a professor at Old Dominion University.

Briceño introduced Quantum Chromodynamics (QCD), a theory that explains strong interactions. This is the force that combines quarks and gluons to form protons, neutrons, and other particles commonly called hadrons. Theorists use lattice QCD, a computational method for solving QCD, to make predictions based on this theory. These predictions are used to interpret the results of experiments involving hadrons.

“Raul showed us this plot with calculations and experimental measurements of the bundles of particles lying on top of each other,” says Ortega Gama, surprised at how well the predictions and measurements lined up. Ta. “It was the first time I realized that I could accurately predict the properties of all these particles using QCD.”

At this moment Ortega Gama was led by QCD and Jefferson Labs. Despite the success shown in the plot, physicists were still unable to use QCD to calculate all possible information about the quarks, gluons, and particles they constitute.

Ortega Gama, a student with William & Mary, whose doctoral degree is William & Mary, has taken advantage of his close relationship with the university and the lab and once again began working with Brissunho. Understand QCD.

As a result of this collaboration, Ortega Gama is the lead author of the lattice QCD calculations published in Physical Review D, and two seemingly different, including the lightest particles, pion, dominated by powerful interactions. Connect the response.

Interconnectivity in QCD calculations

One reaction is known as a spatial process, where electrons are bounced off the pion. The second reaction known as the Time Lark process is when the electrons and antilectrons collide, disappear with each other, producing two pions.

“At face value, these two processes look completely different,” Dudek said. “But in fact they are explained by the same physics. Their diagrams are just rotating with each other. Felipe is a single calculation that was done at the quark and gluon levels, and they are connected. It shows that there is a smooth and simple way.

This numerical calculation shows the interconnectivity of the different reactions described by QCD. This connection was observed experimentally, but physicists have the mathematics to support it.

Previous work by Ortega Gama motivated this initial calculation. After particles collide in an experiment, the collision product flies outward until captured by a detector, moving far farther than the “theoretical infinity,” the range of strong interactions. However, during numerical calculations, limited by available computational power, these particles are placed in finite boxes several times larger than the range of strong interactions.

“This is a question. How do you relate the results of a finite box to the infinite volume results measured by the experimental detector?” Ortega Gama said.

To solve this problem, Briceño, Dudek, and other members of the community developed formalism. This is a set of mathematical relationships that, when you get a numerical result, result in infinite capacity predictions.

Ortega Gama, alongside Brisño, further developed this formalism to calculate the form factors of other hadrons, unlike Pion, which are unstable under powerful interactions.

“Felipe had some really impressive formalism papers before this paper,” Dudeck said. “And the strongest researchers are those in our field of lattice QCD, who have expertise in both formalism and actually doing numerical calculations and working with numerical data. This guy You can do both of these at the highest level.”

As his PhD, advisor Dudek met with Ortega-Gama every week on the project, improving calculations and bounced ideas.

“For every step of the calculation, I was able to contact him and work together to adapt the code to the specific type of research we are interested in,” Ortega Gama said. Ta.

Interconnectivity in nuclear physics

Dudek and Briceño are both senior members of the Hadron Spectrum (HadSpec) collaboration, using lattice QCDs to calculate the properties of hadrons. Ortega-Gama’s work utilized the computational infrastructure developed by the collaboration.

“This project evolved from conversations with various members of this collaboration,” Ortega Gama said.

For example, members of Robert Edwards, a staff scientist at the Jefferson Labs’ Theory Center, have developed a vast set of codes that streamline lattice QCD calculations. Ortega Gama leveraged this codebase and Edwards’ expertise in this work.

Ultimately, these collaborations led Ortega Gama to his current position. This is a postdoctoral scholar at the University of California, Berkeley. He began there in September 2024 and continued to work on QCD calculations with Briceño, a professor at UC Berkeley.

“It definitely helped me to do such an important job to promote my transition from a doctoral degree to a postdoctoral scholar,” Ortega Gama said.