Standard Model

The CDF experiment at Fermilab measured the mass of the W boson and came up with an answer that no one expected.

From Nature Italy May 20, 2022: CDF co-spokesperson Giorgio Chiarelli tells the story of how Italy contributed to the measurement of the W boson mass, opening a door on new physics. For more than 10 years after the Tevatron detector at Fermilab produced the last crashes between protons and antiprotons, the collaboration announced the most precise measure of the W boson mass ever achieved.

From the Nature Briefing, May 13, 2022: Based on data recorded with the CDF II detector at Fermilab between 2002 and 2011 at the Tevatron, the collaboration reconstructed more than 4 million W boson candidates through their decays into an electron or muon accompanied by the respective neutrino. The CDF Collaboration stated their result “suggests the possibility of improvements to the standard model calculation or of extensions to it”.

From The Conversation, May 6, 2021: A recent series of precise measurements in the LHCb, Muon g-2 and CDF experiments have threatened to shake up physics. Now, the LHC is gearing up to run at higher energy and intensity than ever before to make very precise measurements that will test the predictions of theories by looking for deviations from the Standard Model.

From WIRED, April 18, 2022: A collaboration of over four hundred scientists, hundreds of measurements and a 0.1 percent too heavy W boson have led to a tiny discrepancy in the Standard Model theory that could be a huge shift in fundamental physics.

From AZO Quantum, April 11, 2022: The W boson, one of nature’s force-carrying particles, has been detected by the Collider Detector at Fermilab (CDF) team, which includes 400 scientists from across the world.

From Pour la Science, April 11, 2022: A new measurement of the mass of the W boson is higher than predicted by the Standard Model. Is this a sign of new physics? For experts in the field, this conclusion would be premature. But this result is nevertheless very interesting as one of the most difficult measurements in physics.

For the Muon g-2 experiment, researchers create billions of muons to study their surprising properties.

From Gizmodo, April 7, 2022: A collaboration of 400 researchers have precisely measured the mass of the W boson and to their surprise found that the boson is more massive than predicted by the Standard Model of particle physics. All the data was collected from experiments at the four-story-tall, 4,500-ton Collider Detector (CDF-II for short) at Fermilab’s Tevatron accelerator.

Scientists of the Collider Detector at Fermilab collaboration have achieved the most precise measurement to date of the mass of the W boson, one of nature’s force-carrying particles. The measured value shows tension with the value expected based on the Standard Model of particle physics.