Building on their extensive work at CERN, a team from the University of Rochester recently achieved an “incredibly precise” measurement of the electroweak mixing angle, a key element of the Standard Model of particle physics. Credit: Samuel Joseph Herzog, Julian Marius Ordan
Researchers from the University of Rochester, in collaboration with the CMS Collaboration, CERNhas made great strides in measuring the electroweak mixing angle, improving our understanding of the Standard Model of particle physics.
Their research helps explain the fundamental forces of the universe and is supported by experiments such as those conducted at the Large Hadron Collider, which explore similar conditions after the collapse of the universe. big bang.
Unraveling a universal mystery
For decades, researchers at the University of Rochester have worked in international collaborations at the European Organization for Nuclear Research (CERN) to unlock the mysteries of the universe.
Building on their extensive involvement at CERN, specifically the CMS (Compact Muon Solenoid) Collaboration, the Rochester team, led by Arie Bodek, the George E. Paquet Professor of Physics, recently achieved a groundbreaking milestone: Their work centers on measuring the electroweak mixing angle, a key component of the Standard Model of particle physics. This model describes how particles interact with each other and accurately predicts numerous phenomena in physics and astronomy.
“Recent measurements of the electroweak mixing angle, calculated from proton collisions at CERN, are incredibly accurate and advance our understanding of particle physics,” Bodek says.
of CMS Collaboration brings together members of the particle physics community from around the world to better understand the fundamental laws of the universe. In addition to Bodek, the CMS Collaboration’s Rochester cohort includes physics professor Regina DeMina and associate professor of physics Alan Garcia-Bellido as principal investigators, as well as postdoctoral researchers, graduate students, and undergraduate students.
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University of Rochester researchers have worked at CERN for many years, including playing a key role in the discovery of the Higgs boson in 2012 as part of the Compact Muon Solenoid (CMS) collaboration. Photo by Samuel Joseph Herzog and Julian Marius Ordan.
A legacy of discovery and innovation at CERN
Located in Geneva, Switzerland, CERN is the world’s largest particle physics laboratory, known for its groundbreaking discoveries and cutting-edge experiments.
Rochester researchers have been working at CERN for many years as part of the CMS collaboration. 2012: Discovery of the Higgs particle—An elementary particle that helps explain the origin of mass in the universe.
The collaboration’s work involves collecting and analyzing data gathered from the Compact Muon Solenoid Detector in CERN’s Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. The LHC consists of a 17-mile ring of superconducting magnets and accelerating structures built underground across the Swiss-French border.
The LHC’s main goal is to explore the fundamental building blocks of matter and the forces that govern them. It does this by accelerating beams of protons or ions to nearly the speed of light and smashing them into each other at extremely high energies. These collisions recreate conditions similar to those that existed a fraction of a second after the Big Bang, allowing scientists to study the behavior of particles under extreme conditions.
Unraveling the unified force
In the 19th century, scientists discovered that the distinct forces of electricity and magnetism are related: changing electric fields produce magnetic fields and vice versa. This discovery formed the basis of electromagnetism, which describes light as a wave and explains many phenomena in optics, as well as the interaction of electric and magnetic fields.
Building on this understanding, physicists discovered in the 1960s that the electromagnetic force is connected to another force: the weak force. The weak force acts inside the atomic nucleus and is responsible for processes such as radioactive decay and powering the sun’s energy production. This discovery led to the development of electroweak theory, which posits that the electromagnetic and weak forces are actually low-energy manifestations of a unified force called the unified electroweak interaction. Important discoveries such as the Higgs boson have supported this concept.
Advances in electroweak interactions
The CMS Collaboration recently carried out one of the most precise measurements to date related to this theory by analysing billions of proton-proton collisions at CERN’s LHC. Their focus was on measuring the weak mixing angle, a parameter that describes how the electromagnetic and weak forces mix together to form particles.
Previous measurements of the electroweak mixing angle have sparked debate in the scientific community, but the latest results are largely consistent with the predictions of the Standard Model of particle physics. Graduate student Rhys Taus and postdoctoral researcher Aleko Khukhunaishvili of the University of Rochester introduced new techniques to minimize the systematic uncertainties inherent in this measurement and increase its precision.
Understanding the weak mixing angle sheds light on how the universe’s various forces work together on the smallest scales, improving our understanding of the fundamental nature of matter and energy.
“Since 2010, our team at Rochester has been developing innovative techniques to measure these electroweak parameters and implement them at the Large Hadron Collider,” Bodek said. “These new techniques herald a new era of rigorous testing of the predictions of the Standard Model.”