UB physicists awarded $1.45 million to study inner workings of universe

UB scientists have received $1.45 million from the National Science Foundation (NSF) for research in high-energy physics, a field that uses particle accelerators to smash beams of protons into one another at near-light speeds, generating data that illuminates the fundamental laws of nature.

The grant was awarded to Salvatore Rappoccio, associate professor of physics in the College of Arts and Sciences, and UB physics professors Ia Iashvili and Avto Kharchilava.

The funding began Sept. 1, just days after the latest big discovery in high-energy physics.

On Aug. 28, an international team of thousands of researchers — including Iashvili, Kharchilava and Rappoccio — announced they had observed the Higgs boson, a subatomic particle, decaying into a pair of lighter particles called a bottom quark and antibottom quark.

The sighting took place at the world’s most powerful particle accelerator, the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN).

The finding deepens our understanding of why objects have mass. It also validates the Standard Model, a set of equations that physicists use to describe elementary particles and the way they behave — in essence, the way the universe works.

For Kharchilava, the discovery was over a decade in the making. He and his UB students had been searching for evidence of the Higgs boson transforming into bottom quarks since around 2005.

“I was looking for this decay for almost 15 years, when we began the search at Fermilab, which operated the Tevatron collider,” he says. “We did not succeed back then because we did not have enough data and precision, so now we have more data and better precision and we have finally made the discovery.”

The new NSF funding will enable the UB scientists to continue their work on the Higgs boson, the Standard Model and the hunt for new phenomena in physics.

Researchers are studying the Higgs boson because it helps explain why objects — atoms, rocks, trees, water, planets, stars, people — have mass.

As Rappoccio describes it, the Higgs particle is a physical manifestation of the Higgs field, an invisible field that theoretically permeates all of space. Elementary particles — the building blocks of matter — get their mass by interacting with and creating disturbances in the Higgs field. These disturbances, akin to ripples in the ocean, can be observed in the form of Higgs bosons.

“We want to understand the Higgs boson because it is a fundamental particle,” Iashvili says. “It is understood to be an agent of mass. So without the Higgs particle and the Higgs field, fundamental particles (including electrons and quarks) would be massless, and the world would be very different.”

To learn about the Higgs boson, researchers smash protons together at the LHC. These super-high-speed impacts produce showers of subatomic particles, including, on rare occasions, the Higgs boson.

Higgs particles are notoriously fickle: They’re only created roughly once in every billion LHC collisions, and they decay into other, lighter particles very quickly.

It’s exacting work, but studying the Higgs boson and how it decays could help scientists understand the nature of mass and the limitations of the Standard Model of particle physics. The research could also uncover evidence of new, as-yet unknown particles that could account for unexplained phenomena, like dark matter.

The milestone announced on Aug. 28 — the observation of the Higgs boson decaying into a bottom quark and antibottom quark — is important in part because this is thought to be the most common way that Higgs particles decay, occurring a hypothesized 60 percent of the time.

Iashvili, Kharchilava and Rappoccio made key contributions to the discovery. They improved experimental methods and hardware used to identify the presence, trajectory and origin of bottom quarks in the LHC. Called “b-tagging,” this task is part of the rigorous detective work required to verify that a bottom/antibottom quark pair at the LHC arose from the decay of a Higgs boson.

In addition, years ago, Kharchilava and Iashvili helped to plan and build the Compact Muon Solenoid (CMS) detector, one of two particle detectors that international research teams employed to observe the Higgs-to-bottom-quarks decay.