Design and construction of new central and forward muon counters for CDF II

New scintillation counters have been designed and constructed for the CDF upgrade in order to complete the muon coverage of the central CDF detector, and to extend this coverage to larger pseudorapidity. A novel light collection technique using wavelength shifting fibers, together with high quality polystyrene-based scintillator resulted in compact counters with good and stable light collection efficiency over lengths extending up to 320 cm. Their design and construction is described and results of their initial performance are reported.Comment: 20 pages, 15 figure

Development and property study of the extremely thin 12 \texorpdfstring{μm\mu m} C-type straw tubes with 5-mm diameter for a Straw Tracker System of COMET

The COMET experiment focuses on searching for the direct conversion of a muon into an electron with aluminum nuclei without emitting a neutrino (so-called $\mu\rightarrow e$ conversion). This conversion violates charged lepton flavor conservation law, a fundamental principle in the Standard Model. The COMET experiment requirement is to achieve the muon-to-electron conversation sensitivity on a level of $10^{-17}$. The Straw Tracker System (STS) based on straw tubes could provide the necessary spatial resolution of 150 $\mu$m and the electron momentum resolution better than 200 keV/c. The COMET experiment will be separated into two phases. Phase-I will operate with the 3.2 kW 8-GeV-proton beam, and Phase-II will operate with beam intensity increased to 56 kW. STS must operate in a vacuum with 1 bar internal pressure applied to straws. The initial design of 10-mm-diameter straws developed for phase-I will not be as efficient with the 20 times increased beam intensity of Phase II, but the new STS design based on 5-mm-diameter 12-$\mu$m thick straws could fully satisfy the required efficiency. The mechanical properties of these straws, such as sagging, elongation, dependence of the diameter on over-pressure, etc, are discussed in this article

Combined search for the standard model Higgs boson decaying to a bb pair using the full CDF data set

We combine the results of searches for the standard model Higgs boson based on the full CDF Run II data set obtained from sqrt(s) = 1.96 TeV p-pbar collisions at the Fermilab Tevatron corresponding to an integrated luminosity of 9.45/fb. The searches are conducted for Higgs bosons that are produced in association with a W or Z boson, have masses in the range 90-150 GeV/c^2, and decay into bb pairs. An excess of data is present that is inconsistent with the background prediction at the level of 2.5 standard deviations (the most significant local excess is 2.7 standard deviations).Comment: To be published in Phys. Rev. Lett (v2 contains minor updates based on comments from PRL

Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set

We present a search for the standard model Higgs boson produced in association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45 fb-1. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H->bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by PRL