CDF II

Part of Experimental Particle Physics

Boudreau and Shepard are responsible for CDF II. This project has been a CDF-oriented task since about 1992. In Run I we participated in the discovery of the top quark and more fully in the subsequent discovery of the Bc meson. A major activity was the CDF upgrade for Run II in which Shepard was a co-leader (along with Jeff Spalding) for building the inner silicon detector (the SVX II). This project also included all of the electronics for all of the silicon components starting with the readout chip up through the DAQ. Since the beginning of Run II, the group has concentrated more heavily on data analysis. Shepard has continued to work on the investigation of the Bc meson in the semileptonic channel Bc®J/ymX and that effort (Shepard, G. Pope, T. Nigmanov and M. Hartz) has now produced a collaboration-approved result on the relative cross section for production times branching ratio for Bc®J/ymX compared to B®J/yK. A website summary of this analysis can be viewed at
http://www-cdf.fnal.gov/physics/new/bottom/bottom.html.
A postdoc, Y. Gotra, made a very large contribution to the measurement of the J/ inclusive cross section in Run II which has now been published. Additional work on the Bc lifetime (thesis of Mark Hartz) is in progress. The current state of the Bc lifetime analysis can be viewed at http://agave.phyast.pitt.edu/paul/cdf8155_v1.pdf.

Boudreau has been involved in the CDF experiment since 1994. He contributed initially by writing track fitting code for the silicon detectors as well as other key pieces of the CDF’s offline software for Run II. His physics interests in CDF are in B physics. Last year, he and his graduate student Luis Flores Castillo finished a measurement of the lifetime of B0 in the decay mode J/yK0s which can be viewed at
http://agave.phyast.pitt.edu/ paul/cdf6387_lt_ratio.pdf
this year, with his new graduate student Chunlei Lui, he hopes to revisit this channel and apply tagging algorithms to this important decay to a CP eigenstate. With Postdoctoral Research Associate Azizur Rahaman he is involved in lifetime measurements of the B mesons collected using the hadronic B trigger, measurements which we perform in collaboration with the University of Oxford’s CDF group (http://agave.phyast.pitt.edu/paul/cdf6756.pdf). This measurement is ultimately aimed at measuring the width difference in the B0s meson, and is in addition viewed as important to the B0s-B0s¯ effort within CDF, which depends on both lifetime measurement and flavor tagging. The CDF experiment continues to be an excellent facility, especially for students and postdocs to develop scientifically.