Tevatron team tackles top mass measurement

CDF and DZero team up to tackle the measurement of the mass of the top quark.

When two big players team up to tackle a challenge, they can make a big impact in the hard-hitting world of particle physics. Collisions at the Tevatron created massive opponents for teams of physicists, including the heaviest observed particle in the Standard Model, the top quark. Pinning down the mass of the top quark plays a pivotal part in probing the Standard Model, which predicts a particular relationship between the masses of the Higgs boson, W boson and the top quark. By teaming together, the CDF and DZero collaborations have triumphed over the top quark by making the most precise measurement of its mass to date and further testing the consistency of the Standard Model.

Individually, the CDF and DZero top quark mass groups are already waging a war on two fronts, battling two types of uncertainty while aiming for the most precise measurement possible. Adding more data to an analysis can reduce the statistical uncertainty of its measurement but will not help improve the final precision much when the limiting factor is the understanding of the biases, known as the systematic uncertainty. By teaming up their different detectors, the analyzers at CDF and DZero can combine many analysis channels in a way that reduces the total systematic uncertainty.

Together, the Tevatron experiments measured the top quark mass to 0.5 percent, making it the most precise mass measurement of any of the Standard Model quarks. This precise measurement can be used to test the internal consistency of the Standard Model, since the mass of the top quark factors into many Standard Model calculations. Together with the W boson mass, this new top quark measurement tightens the constraints on the mass of the Higgs boson but still prefers the mass of the newly observed particle that may be the Higgs. This Tevatron team has tackled the top quark and made a massive impact that will affect the field of high-energy physics for years.

—Mike Cooke

These physicists led the effort to combine the Tevatron top quark mass results.