Sunday, April 10, 2022

Mass of the "W" boson is measured for the first time with high precision at CERN

Physicists from the ATLAS experiment at the European Center for Particle Physics (CERN) were able to measure for the first time with high precision at the Large Hadron Collider (LHC) the mass of the "W" boson, one of the heaviest particles in the Universe, published on Monday. fair the "European Physical Journal C".

The "W" boson is one of the two fundamental particles - along with the "Z" boson - responsible for the weak force, one of the four forces that govern the behavior of matter in our Universe.

The "W" boson, which was discovered in 1983 and is electrically charged, changes the very composition of particles: it transforms protons into neutrons and vice versa through the weak force, explains CERN.

Specifically, the particle triggers nuclear fusion and lets the stars burn, which creates heavier elements.

When stars die, these elements are launched into space as "building blocks" for planets and even people, adds CERN.

Although its characteristics have been studied for over 30 years, measuring its mass with high precision remains a challenge.

The measurement published by the European Physical Journal C gives a value of 80370±19 mega-electron volts (MeV) of mass, which fits the expectations of the Standard Model of Particle Physics, the theory that describes the known particles and their interactions, indicated CERN.

The measurement is based on 14 million "W" bosons recorded in a single year, 2011, when the LHC operated at an energy of 7 tera electron volts (TeV).

The process coincides with previous measurements at the LEP, the predecessor of the LHC at CERN, and the Tevatron, a former accelerator at Fermilab in the United States, whose data has made it possible to continually refine the measurement over the past 20 years.

Given the complexity of the analysis, it took the ATLAS team five years to arrive at this new result.

"Achieving such an accurate measurement despite the demanding conditions present in a hadron collider like the LHC is a major challenge," said ATLAS Collaboration Physics Coordinator Tancredi Carli in a statement.

"Achieving similar precision, as previously achieved in other colliders, with only one year of data (...) is remarkable. It is an extremely promising indication of our ability to improve our understanding of the Standard Model and look for signs of new physics." through precision measurements", he added.

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