Ulrich Heintz
Faculty
(Associate Professor)
Office: Physics Research Building, Room 371
Phone: 617-353-9057
Office: Fermi National Accelerator Lab
Phone: 630-840-4097
Lab: Physics Research Building, Room 366
Phone: 617-358-2242
Lab: Physics Research Building, Room 366
Phone: 617-353-6043
Email: heintz@physics.bu.edu
In the news:
Research Descriptions:
The ATLAS Experiment at CERN
The ATLAS experiment is a large detector system being developed by a collaboration of physicists from all around the world to study very-high-energy proton-proton interactions at the Large Hadron Collider (LHC) at CERN, a laboratory for high energy physics near Geneva, Switzerland. It will be completed in 2007. This experiment will probe the origins of electroweak symmetry breaking and the particles associated with the new physics (such as the hypothetical Higgs Boson) that must appear at energies at the symmetry breaking scale. A figure illustrating the various parts of ATLAS is shown below.
Boston University personnel are involved in the construction and installation of the muon detectors for ATLAS. The muon detector will occupy a region the size of a five-story building and will measure the trajectories of muons in a magnetic field with a precision of better than 1/10 of a millimeter. This permits the determination of the muon momentum, which will be an important ingredient in searches for new phenomena at the LHC’s energy scale, which will be an order of magnitude greater than currently available. The detectors are now built, and are currently being assembled into “sectors” that will be moved to the ATLAS experimental hall in early 2006. A photo of the first sector is shown below.
Boston University is also playing a leading role in the development of computing and analysis tools that will be crucial when data begins to flow from the experiment in 2007. It is expected that many important discoveries in particle physics will be made at the LHC in the coming decade. These discoveries will improve our understanding of the fundamental particles and their interactions, and also of the nature of the early universe. One important goal of the LHC is to search for particles that may be responsible for the so-called “dark matter” of the universe. One possible type of particle that could account for this mysterious phenomenon are the particles associated with so-called Supersymmetry Theories.
The DØ Experiment
The DØ experiment studies proton-antiproton collisions at the world’s highest energy accelerator, the Fermilab Tevatron. These collisions release energy equivalent to 2000 times the proton mass. The DØ detector is a large, highly sophisticated instrument that measures the fragments of these collisions and allows scientists to study the structure of matter at these high energies.
According to our current understanding, the basic constituents of matter are quarks and leptons. All the matter surrounding us is made of the lightest quarks, called up and down, and the lightest leptons, the electron and its neutrino. However there exist two additional families of quarks and leptons with identical properties, except much larger masses. The heaviest of the quarks, the “top” quark, was discovered in 1995 by the DØ and CDF collaborations at Fermilab. The top quark turned out to have an extraordinarily large mass, approximately the same as an entire gold atom. Particle physicists believe that its further study will provide clues to the origins of mass.
The members of the Boston University DØ group were actively involved in the discovery of the top quark and the study of the carrier of the weak force, the “W boson”. The group is now participating in the second data-taking run which began in 2001 and will continue until 2009. During this run, thousands of top quarks will be created, allowing a detailed study of the properties of this intriguing particle. The data from the Fermilab Tevatron will also provide the best opportunity until the LHC begins operation to find the Higgs boson and new physics beyond the standard model.
The Boston University group has taken leadership roles in the construction of the muon detector system and the silicon microstrip tracker, the development of algorithms to identify bottom quarks and muons, and the “Top and Higgs Physics” analysis group. The group has designed and built a significant fraction of the electronics for the muon system trigger, the silicon track trigger, and the central fiber tracker trigger. The group’s physics interests center on the top quark and the search for new particles and forces beyond the standard model.
