The quest to measure the mass of a fundamental particle called the W boson has led physicists to question the validity of their current understanding of the laws of nature. For nearly 30 years, Ashutosh Kotwal, a Duke physicist, has been leading a worldwide effort to precisely determine the W boson’s mass.
In recent years, two precise measurements of its mass have yielded conflicting results, sparking debate in the physics community. The most recent measurement by researchers at CERN’s Large Hadron Collider came in line with theoretical predictions, but this contrasts with a previous measurement made by physicists using data from the Fermi National Accelerator Laboratory near Chicago.
Kotwal and his team used sophisticated algorithms to analyze 4.2 million W bosons produced between 2002 and 2011 at the Tevatron particle collider. They measured the energies and momenta of particles produced in the decaying bosons’ showers, using these calculations to determine the mass of the W boson.
However, Kotwal now believes that potential flaws in their analysis might be responsible for the discrepancy between the two measurements. He has conducted an internal audit of possible subtle errors, including misaligned wires within the chamber used to measure particle trajectories. The results suggest that even miniscule misalignments would not significantly impact the accuracy of the measurement.
Despite finding no evidence to support this explanation, Kotwal emphasizes the importance of transparent and transparent methods in fundamental parameter research. He hopes other experiments will adopt similar approaches to identify areas for improvement and advance our understanding of the natural world.
Source: https://phys.org/news/2025-02-boson-conundrum.html