This award provides continued support for the frontier collider-physics program of the experimental high-energy physics (HEP) group at the University of Nebraska-Lincoln (UNL) for a three-year period. The intellectual merit follows from the new era of discovery and understanding which has and will continue to progress in the fields of particle physics and astrophysics. The research effort is focused on operations and data analysis for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC), where the UNL group has leadership roles in Tier-2 computing, operation of the forward pixel detector, and tracker and trigger upgrades. In addition, the group will complete ongoing analyses and continue its service commitments to the D0 experiment, principally the luminosity measurement. The group will also maintain complementary efforts in ultra-high energy cosmic-ray physics through contributions to the Pierre Auger Observatory and the Radio Ice Cherenkov Experiment (RICE) and the Neutrino Array Radio Calibration (NARC) experiment. Broader impacts result from the extensive education and outreach efforts of the group. These include the NSF-funded Cosmic Ray Observatory Project (CROP), a Bilingual English Speaking Tutor program (BEST) for elementary school children, networking with rural schools to bring the excitement of particle physics to the classroom and integration of high-school teachers and students with cosmic-ray research.
This award supported the main activities of the experimental high-energy physics (HEP) research group in the Department of Physics and Astronomy at the University of Nebraska-Lincoln (UNL) during the period 2010-2013. Group members -- professors, postdoctoral researchers, graduate and undergraduate students -- participated in the most important and exciting elementary particle physics experiments of our time, developed and built novel scientific instruments and computing infrastructures, and led significant education and outreach efforts to students in Lincoln and the rest of Nebraska. A particular highlight of this period was group members’ participation in the discovery of the Higgs boson, the long-sought subatomic particle that may explain why certain particles have mass. The intellectual merit of the project was the scientific work performed at two large colliding-beam experiments and two experiments that use cosmic-ray particles to explore astrophysics. At the Compact Muon Solenoid (CMS) experiment at CERN’s Large Hadron Collider in Geneva, Switzerland, protons are collided at the highest energies ever achieved in a laboratory. UNL HEP group members contributed to this experiment by deploying and running a large computing cluster used to simulate and analyze experimental data, constructing, operating and maintaining a component of the CMS detector that measured the positions of charged particles produced in the collisions, and calibrating and validating software that identifies tracks, electrons and bottom quarks in collision events. Besides the Higgs observation, where group members searched for the new particle in a variety of production and decay modes, the UNL group has measured the rate of top-quark pair production using slow-moving leptons to identify bottom quarks from top decay, searched for new physics processes in events with hadronic dijets, measured the production rate of di-electron pairs across a large invariant mass range, and recently made the first observation of a very rare decay mode of the Bs meson that is a strong validation of the standard model of particle physics. Group members also lead the CMS PhD Thesis Award program and are now working on the design and construction of the next-generation charged-particle detector to be installed in CMS in 2018. The other collider project is the D0 experiment at the Department of Energy’s Fermilab in Batavia, IL. This experiment concluded data-taking in September 2011. UNL group members were in charge of measuring the total number of collisions recorded by the experiment, that is, the proton-antiproton luminosity. Physics studies have included a search for the Higgs boson, a search for charged massive stable particles, a search for heavy neutral bosons decaying to electron-positron pairs. In astrophysics, UNL HEP staff participate in the Auger Observatory, located in Mendoza Province, Argentina. This facility studies extensive air showers triggered by cosmic-ray particles of extremely high energy, and has made discoveries such as the correlation of cosmic rays with active galactic nuclei. UNL group members oversee the Observatory’s education and outreach activities (such as the visitor center, science fairs, and involvement with area schools) and participate in the Observatory’s atmospheric monitoring. In a separate activity, the UNL HEP group has participated in the RICE/NARC and ARA experiments at the South Pole; both experiments seek to observe high-energy neutrinos from the cosmos through the detection of radio pulses. The analysis of the data collected by these South Pole experiments released recently helped to disprove several theories that predict appearance on Earth of neutrino particles coming from distant astrophysical sources. The broader impacts of the project are in the form of a wide array of education and outreach activities. The Cosmic Ray Observatory Project (CROP) is bringing real experimentation in particle physics to six new Nebraska high school teams, three in rural Sandhills area covered by Educational Service Unit 10. Seven teachers and 30 students are learning to maintain and operate equipment to detect cosmic rays. The Bilingual English Speaking Tutors (BEST) program has paired up tens of English language learner students in Lincoln elementary schools with bilingual high-school and college students, with measurable improvements in the younger students’ reading skills. Senior members of the group regularly make public presentations and appear in local media and write blogs. In addition, the group has sponsored eight postdoctoral researchers, nine graduate students and 14 undergraduates during the three years of the award. Three postdocs went on to tenure-leading positions in the field of particle physics, three graduate students received MS degrees and one received a PhD degree.
