This proposal requests continuing support for a program of research for the Sokoloff/Meadows group at the University of Cincinnati Main Campus in experimental elementary particle physics based primarily on the BaBar experiment at SLAC and the proposed LSST experiment.
The BABAR Collaboration was created in 2004 to design, construct, and operate a detector at an asymmetric B-factory to study the origins of CP-violation in the decays of B mesons. In addition to many discoveries made related to B meson physics, BABAR has discovered new particles (the DSJ and the Y(4260) as examples) and has discovered new phenomena such as the oscillations (mixing) of particles into anti-particles, and vice versa, in the neutral D meson system. During the coming grant period, the group will pursue it studies of D0 − D 0-bar mixing, CP-violation in D meson decays, fundamental properties of D mesons, B meson decays related to measuring the Cabibbo-Kobayashi-Maskawa (CKM) matrix angle a, and of decays of the Y(4260).
Looking to the future, they have begun working on the Large Synoptic Survey Telescope (LSST) project to study the distribution of dark matter in the universe. Both the characteristics of dark matter and its distribution within the universe provide important constraints on any theory of the fundamental forces of nature. Precise measurements of the distribution of dark matter via weak lensing, made in parallel with direct observations of high mass particles produced at the Tevatron and/or the LHC, direct observations of dark matter in the laboratory, and indirect observations of the interactions or decays of dark matter in astrophysics experiments will lead to a fundamental unification of physics at the smallest and largest scales. Now the Standard Model does not include a candidate for the cold dark matter which is so much more abundant than its baryonic cousin. Their work on BABAR constrains theories of physics beyond the Standard Model and may help point the way to new physics. Studying the distribution of dark matter in the universe will connect the particle interactions one observes in the laboratory today with those observed in the universe at the earliest times.
On Broader Impacts, the group will continue its work primarily within the QuarkNet program as well as employing undergraduates in the research. In research, they will collaborate closely with astronomers on the LSST. While they have very, very much to learn from them, they also offer new perspectives and experience that should lead to better conventional astronomy, as well as first-rate cosmology. They bring experience working in large collaborations, with tremendously large datasets, where reducing and understanding systematic uncertainties is critical to the science. Integrating the techniques of experimental particle physics with those of astronomy promises the greatest reach for answering fundamental scientific questions related to dark matter and dark energy.
We published several hundred papers as part of the BaBar collaboration. Members of our group were principal authors of BaBar papers including Search for CP Violation in Neutral D Meson Cabibbo-suppressed Three-body Decays, Phys. Rev. D78, 051102 (2008) based on Kalanand Mishra's Ph.D. thesis (awarded earlier in 2008) and Measurement of D0 − antiD0 mixing parameters using D0 → Kshort π+π− and D0 → Kshort K+K− decays, Phys. Rev. Lett. 105, 081803 (2010) based, in part, on Rolf Andreassen's Ph.D. thesis (awarded in 2010), and Measurement of Rate Asymmetries in the Rare Decays B → K(*) l+l-, Phys. Rev. D86, 032012 (2012) based, in large measure, on work done by our post-doctoral fellow, Liang Sun. In addition to these experimental papers, Brian Meadows and Kalanand Mishra (from our group) and two others published a phenomenology paper based on BaBar results, Isospin analysis of D0 decay to three pions, Phys. Rev. D78, 014015 (2008); Brian Meadows and two others published a review article, Charm Meson Decays, Ann. Rev. Nucl. Part. Sci. 58, 249 (2008); Michael Sokoloff and another author published a phenomenology paper, On Indirect CP Violation and Implications for D0 − antiD0 and Bs−antiBs mixing, Phys. Rev. D80, 076008 (2009).; and Brian Meadows with two others published a phenomenology paper, Time-dependent CP asymmetries in D and B decays, Phys. Rev. D84, 114009 (2011). We did a lot of work preparing white papers for the proposed SuperB flavor factory in Italy, SuperB Progress Reports -- Physics, arXiv:1008.1541 (2010) and SuperB Progress Reports -- Detector, arXiv:1007.4241 (2010), primarily related to studies of charm mixing and CP violation reach. Leading up to this, we helped develop the simulation framework described in, FastSim: A fast simulation for the SuperB detector, J. Phys. Conf. Ser. 331, 032038 (2011). An undergraduate, Carol Fabby, first worked on the FastSim program and later completed her capstone project analyzing Babar data. Two other undergraduates, Philip Campos and Cheryl Pappenheimer began working with us during this grant period. Working with Jeff Rodriguez from Anderson High School, we sponsored QuarkNet programs for high school teachers and students during all years of this grant period. Summer Institutes for teachers were held each summer. Starting in the summer of 2010, four high school students and one teacher spent six weeks doing research with us each year. The overarching goal of the BaBar experiment was the study of CP violation in B meson decays. Half of the 2008 Nobel Prize in Physics was awarded, 'jointly to Makoto Kobayashi and Toshihide Maskawa "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature" ', based in large part on the observations of the BaBar and Belle collaborations. The full citation includes, "The spontaneous broken symmetries that Nambu studied, differ from the broken symmetries described by Makoto Kobayashi and Toshihide Maskawa. These spontaneous occurrences seem to have existed in nature since the very beginning of the universe and came as a complete surprise when they first appeared in particle experiments in 1964. It is only in recent years that scientists have come to fully confirm the explanations that Kobayashi and Maskawa made in 1972. It is for this work that they are now awarded the Nobel Prize in Physics. They explained broken symmetry within the framework of the Standard Model, but required that the Model be extended to three families of quarks. These predicted, hypothetical new quarks have recently appeared in physics experiments. As late as 2001, the two particle detectors BaBar at Stanford [emphasis added], USA and Belle at Tsukuba, Japan, both detected broken symmetries independently of each other. The results were exactly as Kobayashi and Maskawa had predicted almost three decades earlier." BaBar finished taking data in early 2008, and many of the subsequent analyses, including searches for CP violation in charm decays and studies of D0 - antiD0 mixing, are sensitive probes of physics beyond the Standard Model, also called New Physics (NP). Our work on the proposed SuperB experiment was oriented towards more sensitive NP searches. When the U.S. government decided not to support the Italian SuperB project, we decided to join the LHCb experiment at CERN which shares strongly overlapping physics goals. Brian Meadows arranged to take his sabbatical working on LHCb at Oxford in the 2012-2013 academic year, and Michael Sokoloff began working on LHCb in late 2011 and 2012, during his sabbatical year. We have subsequently been supported by a new NSF grant to work on LHCb, and our post-doc and new students are working on that experiment while we finish analyses of BaBar data.
