For his studies of t-tbar pair production in the all-jets channel at D0.
On Tuesday, July 21, join Michael Begel of the Physics Department as he gives the Sambamurti Memorial Lecture, entitled “Spotlight on the Gluon,” in the Large Seminar Room of the Physics Department, Bldg. 510. Refreshments will be served at 3 p.m. and the lecture will start at 3:30 p.m.
Among the fundamental forces of nature that cause particles to interact is the strong force. This force binds quarks — the building blocks of matter — together into protons and neutrons, which form the atomic nucleus. To describe the strong interaction of quarks via the exchange of gluons, which carry the strong force, physicists use the theory of quantum chromodynamics (QCD). Although the force is very strong, gluons act over a very short range, roughly the size of the proton, making QCD predictions complex and experimental measurements difficult to interpret.
When protons are collided together at very high energies, for example, at the Tevatron at Fermi National Accelerator Laboratory (Fermilab) or the Relativistic Heavy Ion Collider at BNL, many of the interesting interactions involve the strong force. From these collisions, physicists typically observe collimated sprays of particles, commonly called jets. Rarely, a photon particle will also be produced. Unlike the jets, which are only distant relatives of the quarks and gluons that actually collided, the photon is well measured and easier to understand — allowing researchers to peer deep inside the collision.
Begel will use results from the Fermilab D0 and E706 experiments to explain how the production rate and energy spectrum of photons produced during proton collisions can clarify how the energy inside the proton is shared between quarks and gluons. This improves scientists’ understanding of the strong force, which is essential to searches for new physical phenomena such as the Higgs boson, supersymmetry, or large extra dimensions.
Begel, an assistant physicist who joined BNL in 2007, earned his Ph.D. in physics from the University of Rochester. He is currently a member of BNL’s ATLAS collaboration at CERN, the European particle physics laboratory, and the Fermilab D0 and E706 collaborations.