Don Lincoln

Don Lincoln is a Fermilab scientist.

While top quarks have been more commonly found produced in pairs, this analysis looked for top quarks created one at a time. The time between observation of pair production and single quark production was very short and is a strong demonstration of the performance of the CMS detector. Last week, the CMS Result described the measurement of the mass of the top quark at the LHC, as well as how frequently it is produced. However, what you might not have…

The Standard Model predicts a value near zero for one of the parameters that is associated with the difference between the production of muons and antimuons in B meson decays. The 2010 and 2011 measurements are presented here with their uncertainty (the vertical bars). The two results are definitely different from zero and consistent with each other. The newer measurement has improved precision, as demonstrated by the shorter red bars. These scientists worked on this rather difficult analysis. DZero has…

Today’s result is a prime example of the fertile intellectual collaboration between the Tevatron and LHC research programs. Scientists working at both laboratories ensure that the best Tevatron experience is transported to the CMS research program. The press sometimes likes to make a big deal about the competition between the LHC and the Tevatron. It makes for a great narrative and there is even a modicum of truth to it. However, this simplified story misses a very important point and…

DZero tried to faithfully reproduce a CDF result that had the blogosphere buzzing in early April. As is evident from the picture, no bump was observed corresponding to the one seen by CDF. The corresponding CDF figure can be seen here. Things that go bump in the night can send a chill up your spine. They are unexpected, unknown and could be anything. Bumps in data have a very similar effect on physicists. If we see an unexpected bump in…

In a search for diamonds, one has to learn to how to remove the rest of the gems. Some, like the opal and freshwater pearl are easy to remove from the pile, since they look quite different. However, eventually you are left with gems that are indistinguishable from diamonds and you need to know just how many fakes there are. If the number of predicted fakes is 10 and you have 20 gems, you know you have some diamonds. Nowadays…

We’ve come a long ways since the first Tevatron collisions in 1985. Not only did Fermilab scientists discover the top quark in 1995, but we can now measure its mass to a precision better than 1 percent. In 1985, the first pair of protons and antiprotons collided in the Fermilab Tevatron. One of the main purposes for which the Tevatron was built was to search for the top quark and, after 10 years, DZero and CDF jointly announced the particle’s…

A popular extension of the Standard Model includes the principle of supersymmetry. This extension is called the minimal supersymmetric Standard Model (MSSM) and it predicts not one, but five Higgs bosons, including some with electric charge. This analysis searched for the three electrically neutral Higgs bosons predicted by the MSSM, shown here in red. Fermilab Today readers have heard a lot about the search for the Higgs boson. What might be surprising is that scientists don’t know if it exists….

The Standard Model forbids direct production of a strange quark from the decay of a bottom. Indirect decay of the kind illustrated here is possible and is the focus of this analysis. Since observation of direct production of strange quarks from bottom quarks would indicate a discovery, we need to understand very well the indirect production described here. Subatomic particles called quarks are some of the building blocks of our universe. The heaviest of the six types of quarks are…

The Earth is a sphere with a diameter of approximately 8,000 miles. However, if you measure precisely enough, you find that the Earth is slightly pear shaped. The exaggerated figure conveys the basic idea, although the real variation is only about 0.1 percent, which is why the Earth looks spherical to the naked eye. This week’s article describes a similar concept in a DZero measurement. Suppose you needed to know the exact distance between Fermilab and CERN. To first approximation,…

A previous Result of the Week studied the difference between the masses of the top quark and antiquark. This week, DZero returns to the question, this time with a more precise scale. In July of 2009, DZero reported on a measurement of the difference between the mass of top quarks and antitop quarks. This is a very interesting topic. One of the most fundamental tenets of the Standard Model is that the laws of physics apply equally well to matter…