A shock measurement of the mass of a fundamental particle called the W boson ignited the physics world in April, as it appeared to flout the standard model of particle physics.
Hundreds of papers have been written since then to try to explain the result, which seems to defy our best theory of how the universe works. Experiments have been proposed to confirm the findings, while the facts and figures have been pored over to look for possible mistakes in the data from the Tevatron collider at Fermilab in Illinois. 鈥淎 lot of what happened in the first three months was an information transfer,鈥� says at Duke University in North Carolina, who led the Collider Detector at Fermilab (CDF) experiment that produced the result.
Because it was so different from past measurements, for example those at the Large Hadron Collider (LHC) near Geneva, Switzerland, much of the analysis has focused on identifying procedural differences between CDF and the LHC鈥檚 ATLAS and LHCb experiments. The LHC collides electrons and their antimatter counterparts, positrons, whereas the now-defunct Tevatron used protons and antiprotons.
Advertisement
鈥淭he response has been very cautious because of the differences between the different measurements,鈥� says Chris Hays at the University of Oxford. But overall, the particle physics community has been positive, he says.
People are already working to reanalyse the data to rule out any biases or mistakes linked to these factors, says Hays. They are also attempting to combine the various measurements into one, which is difficult due to the significant experimental differences.
Apart from reinspecting existing data, some people have suggested ideas that could explain the anomalous W boson mass by like extra Higgs bosons, the fundamental particle that, through the Higgs field, gives particles like the W boson their mass. These extra particles include or ones that could be responsible for .
New particles like these could be found by future particle accelerators, such as an upgraded LHC that is due to fire up in 2028, or even by telescopes through high-energy gamma rays and antiprotons.
But even without hunting for new particles, the next precise measurement of the W boson mass, due to come from LHCb in the next year or so, could shed light on the discrepancy. Beyond that, future LHC experiments will be able to improve on the precision of the CDF result. 鈥淕iven time, I think the LHC can make a measurement that is comparable or even more precise,鈥� says at the University of Oxford, who works on LHCb.
The CDF result has put the spotlight on the W boson mass, says Wilkinson, who believes it wasn鈥檛 seen as a priority before. 鈥淚 think it鈥檚 really got people excited and the amount of resources and efforts being devoted to it now has ramped up,鈥� he says.
Sign up to Lost in Space-Time, a free monthly newsletter on the weirdness of reality
