A physicist in the College of Arts and Sciences is the lead contributor to the discovery of two never-before-seen baryonic particles. The finding, which is the subject of a forthcoming article in Physical Review Letters (American Physical Society, 2014), is expected to have a major impact on the study of quark dynamics.
Steven Blusk, associate professor of physics, has identified particles known as Xi_b'- and Xi_b*-. Although the particles had been predicted to exist, nobody had seen them until now. The discovery is part of his ongoing work at the Large Hadron Collider beauty (LHCb) experiment at CERN in Geneva, Switzerland.
“The particles we’ve discovered are quite unique,” says Blusk, a leader in experimental high-energy particle physics. “Each one contains a beauty [b] quark, a strange [s] quark and a down [d] quark.”
A baryon is a subatomic particle made up of three quarks, bound together by strong force. Two other familiar baryons, the proton and neutron, combine with the electron to form all the known elements of the periodic table.
“The building blocks of all known things, including cars, planets, stars and people, are quarks and electrons, which are tied together by strong, electromagnetic forces,” Blusk says.
Unique to each newly discovered particle is its mass, which is approximately six times larger than that of the proton. Blusk attributes its size to the presence of a heavyweight b quark and to the particle’s angular momentum—a property known as “spin.”
In the Xi_b'- state, the spins of the two lighter quarks point in opposite directions; in the Xi_b*- state, they are aligned. The difference is what makes the Xi_b*- a little heavier.
"The Xi_b'- is close in mass to the sum of the masses of its decay products. If it had been just a little lighter, we wouldn't have seen it at all,” Blusk adds.
Much of Blusk’s work draws on the theory of Quantum Chromodynamics, which describes the interaction of quarks. As a result, he and his colleagues have studied the masses of both particles, along with their relative production rates, widths and decays.
"This is a very exciting result,” Blusk adds. “Thanks to LHCb's excellent hadron identification, which is unique among LHC experiments, we’ve been able to separate a clean, strong signal from the background. It demonstrates, once again, both the sensitivity and precision of the LHCb detector.”
Blusk is part of a team of Syracuse researchers, led by Distinguished Professor of Physics Sheldon Stone, working at CERN, which is the world’s leading laboratory for particle physics. There, they have been involved with the LHCb experiment, which seeks to identify new forces and particles, in addition to those already known and codified in the Standard Model, a theory describing the physical makeup of the visible Universe.
“Fourteen billion years ago, the Universe began with a bang, and matter and anti-matter were formed,” Stone says. “But just one second after the Big Bang, anti-matter all but disappeared. … The LHCb experiment is designed to find out what really happened after the Big Bang that has allowed matter to survive and build the Universe we inhabit today.”
Rob Enslin | EurekAlert!
Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen
New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy