OU Physicists Receive a Nearly $1.7 Million Grant to Support High Energy Physics Experiments

July 14, 2021

OU Physicists Receive a Nearly $1.7 Million Grant to Support High Energy Physics Experiments

Howard Baer (left) and Phillip Gutierrez (right)

NORMAN, OKLA. – Located on the border between France and Switzerland is a laboratory operated by CERN and the location of a 17-mile (27-kilometre) ring underground, the Large Hadron Collider. This site is where University of Oklahoma physicists Phillip Gutierrez and Howard Baer carry out their work, now supported by a nearly $1.7 million grant from the Department of Energy.

“The College of Arts and Sciences congratulates Phil Gutierrez, chair of the Homer L. Dodge Department of Physics and Astronomy, George Lynn Cross Professor Howard Baer, and their larger team of high energy physicists in the department, including professors Brad Abbott, Mike Strauss, John Stupak and Kuver Sinha, and professor emeritus Pat Skubic, on this prestigious award from the Department of Energy,” said David Wrobel, dean of the College of Arts and Sciences. “The team’s work to develop a quantum theory of gravity through superstring theory is an exciting example of the large-scale research being undertaken at the famous CERN lab’s Large Hadron Collider and it is wonderful to see our faculty at the center of this international initiative.”

Gutierrez and Baer are the co-principle investigators on this grant and their research team is additionally supported by several postdoctoral researchers and both graduate and undergraduate student researchers.

“Our present understanding of the laws of physics is based on quantum mechanics and Einstein’s theory of relativity,” Baer said. “That understanding works very well at present for what we call electromagnetism and the two types of nuclear forces – strong and weak, but it doesn’t work as easily for gravity. In order to have a quantum theory of gravity, you have to move to what is called superstring theory. …One of the main goals of the Large Hadron Collider is to detect new states of matter which would usher in a view toward a deeper level of unification of both gravity and the electromagnetic and nuclear forces that we know about today.”

“About nine years ago a particle called the Higgs boson was discovered that had been postulated 40 years earlier,” he added. “It was only once the Large Hadron Collider started functioning that you could really dig out the signal of this Higgs boson. That carries with it a lot of mysteries itself. So physicists are really trying to focus and measure every possible property of the Higgs particle and it is expected that the Higgs boson is intimately linked with supersymmetric matter states.”

ATLAS Detector Higgs Boson Candidate Event

The Large Hadron Collider accelerates protons to the energies of 6.5 trillion electron-volts alongside another counter-circulating proton beam at the same energy, causing the protons to collide. This enables physicists to test the predictions of different theories of particle physics, including measuring the properties of the Higgs boson, searching for the large family of new particles predicted by supersymmetric theories and other unresolved questions in particle physics.

“Out of these scatting events occurring within the Large Hydron Collider, all sorts of new particles can be created,” Baer said. “(Physicists) sift through these particles to see if they agree with the theory scientists presently accept or whether we need to move beyond that theory.”

“We make precision measurements and compare to what is normally referred to as the standard model of particle physics,” Gutierrez said. “We try to make as accurate measurements as we can in order to be able to say if the experiment agrees or doesn’t agree with the theory. We try and make the measurements as precise as we can in order to be able to look for deviations because we know that the standard model is not complete.”

“Another thing we do is look for exotic phenomena, things that are not predicted by the standard model but are predicted by work that other theorists are doing,” he added. “This includes work in supersymmetry, string theory and other exotic models that don’t fit into either of those categories. We go through the data, try to understand the data for what it contains and how it compares with theory.”

The data from these collisions is initially filtered through fast electronics to select qualifying events, then very fast computer algorithms go through the data and make decisions to determine whether to keep or discard the event. The research team members look for events that produce large amounts of energy, sorting the data to identify instances of congruence or deviation from the standard theory. Students involved in the experimental work are learning about data analytics, statistical analysis and machine learning, as well as learning about the electronics used to record the data.

“One of the outstanding issues now is that the universe seems to be made up of only 5% of the material that we’re made up of – protons, neutrons and electrons,” Baer said. “But the bulk of the matter in the universe is some unknown dark matter that gives the gravity to bind galaxies together but is so far completely unknown. There’s also a dark energy that is accelerating the expansion of the universe, so these laws of physics that we’re playing with really impact heavily on our understanding of the origin of the universe itself.”

“If you take quantum mechanics and relativity and put them together, it seems to imply that our universe is but one of a much vaster multiverse with different universes that are causally disconnected from ours, but with different laws of physics,” he added.

In addition to this research, Gutierrez and Baer are working with physicists at Argonne National Laboratory and collaborators around the world to develop more sophisticated detectors that can handle higher intensity rates that will result from a planned upgrade to the Large Hadron Collider. The introduction of the High Luminosity Large Hadron Collider in 2025 will have increased beam intensity to produce more events.

“We’re developing detectors similar to pixel devices that are in a camera, except these are far more sophisticated in that we have to be able to extract the data every 25 billionth of a second and then be able to process that data quickly,” Gutierrez said. “We’re developing these new detectors to be radiation-hard so they can withstand the intensities and also increase the data collection rate.”

The planned High Luminosity Large Hadron Collider will enable increased precision measurements that will help usher in the next stage of high energy physics.

More information about the DOE High Energy Physics initiative is available at https://science.osti.gov/hep