Don Lincoln

Don Lincoln is a Fermilab scientist.

Subatomic gryphons

After considerable effort, the CMS experiment submitted for publication not one, but two papers reporting on a leptoquark search. One paper looked for leptoquarks produced individually, while the other looked for leptoquarks produced in pairs.

In the children’s book “Holes,” inmates at the juvenile correction facility called Camp Green are sentenced to spend their days digging holes, looking for treasure buried under a parched desert wasteland.

On July 21, CMS submitted for publication the first physics paper using the Run II data. The analysis studied the most common collisions to characterize both the number and direction of charged particles created in the collisions.

Scientists on a recent analysis looked for an unexpected number of top quark-antiquark pairs. The data (black dots) clearly favor known physics (red and green areas) and not a prediction of new physics (dashed line). In particle physics things develop pretty rapidly. The top quark was discovered in 1995 at the Fermilab Tevatron using just a few of tens of events taken over a couple of years. Nowadays, top quarks are a lot easier to come by. For instance, at…

Heavy neutrinos are proposed cousins of the familiar light neutrinos. The masses of the heavy and light neutrinos are connected: the heavier the heavy ones are, the lighter the light ones are. This connection is called the seesaw mechanism. With the discovery of the Higgs field, scientists think they have a pretty good handle on the origins of the mass of fundamental particles. Particles that interact with the field have mass, and those that don’t, don’t. However, the neutrino poses…

Studying the angles at which muons are emitted during the decay of a Z boson is an important study of particle physics. The precision studies that CMS researchers intend to do over the next few years require this being understood in great detail. Particle physics research involves many different approaches, whether it is looking for undiscovered particles of proposed theories or searching for something entirely new. It is also about revisiting familiar topics in unfamiliar environs to see if something…

Finding pairs of Higgs bosons might be a path to discovering something entirely new. Because Higgs bosons are unstable, what experimenters really do is look for the presence of four b (bottom) quarks. It seems like only yesterday that scientists were combing diligently through their data looking for single Higgs bosons. Now that we know not only that Higgs bosons exist, but also their mass, scientists have been looking for pairs of Higgs bosons, which could be useful in searching…

As time passes, we remember the glory days of yesterday, like the time when we found the Higgs boson. Nowadays, some scientists take the existence of the Higgs boson as a given and have moved on, using it as a way to find something new. Readers of this column almost certainly remember the announcement of the discovery of the Higgs boson on July 4, 2012. It was a heady time, as it is rare that one confirms the final missing…

The purpose of particle physics is to better understand the rules that govern the universe. Long before the papers are written, accelerators and detectors must be designed, built and operated. It is technology that makes it all possible. Readers of Fermilab Today have read many articles on many experiments: CDF and DZero, LHC, the neutrino program, the muon program, astrophysics studies. These articles focus on the outcome of the measurements and what they tell us about the physical world. But…

How many forces?

Unlike in Star Wars, where there was but one force with a light and dark side, the number of fundamental forces is a much murkier question. If you’ve read many of my columns, you know quite a bit about the Standard Model. You know that there are quarks and leptons. You’ve heard about the gluon, the W and Z bosons, the photon and the graviton. And you know that this means that there are four fundamental forces: the strong and…