Performance studies of the CMS strip tracker before installation

Peer reviewe

Search for electroweak single top quark production in ppbar collisions at sqrt{s}=1.96 TeV

We report on a search for Standard Model t-channel and s-channel single top quark production in ppbar collisions at a center of mass energy of 1.96 TeV. We use a data sample corresponding to 162 pb^{-1} recorded by the upgraded Collider Detector at Fermilab. We find no significant evidence for electroweak top quark production and set upper limits at the 95% confidence level on the production cross section, consistent with the Standard Model: 10.1 pb for the t-channel, 13.6 pb for the s-channel and 17.8 pb for the combined cross section of t- and s-channel.Comment: 7 pages, 2 figures, accepted by Phys. Rev.

Measurement of the t(t)over-bar production cross section in p(p)over-barcollisions at root s=1.96 TeV using kinematic fitting of b-tagged lepton plus jet events

We report a measurement of the t (t) over bar production cross section using the CDF II detector at the Fermilab Tevatron. The data consist of events with an energetic electron or muon, missing transverse energy, and three or more hadronic jets, at least one of which is identified as a b-quark jet by reconstructing a secondary vertex. The background fraction is determined from a fit of the transverse energy of the leading jet. Using 162 +/- 10 pb(-1) of data, the total cross section is found to be 6.0 +/- 1.6(stat.)+/- 1.2(syst.) pb, which is consistent with the standard model prediction

Search for doubly charged Higgs bosons decaying to dileptons in p(p)over-bar collisions at root s=1.96 TeV

We present the results of a search for doubly-charged Higgs bosons (H+/-+/-) decaying to dileptons using ~240/pb of ppbar collision data collected by the CDF II experiment at the Fermilab Tevatron. In our search region, given by same-sign dilepton mass m_ll' > 80 GeV/c^2 (100 GeV/c^2 for dielectron channel), we observe no evidence for doubly-charged Higgs production. We set limits on sigma (ppbar --> H++H-- --> l+l+l-l-) as a function of the mass of the doubly-charged Higgs boson and the chirality of its couplings. Assuming exclusive same-sign dilepton decays, we derive lower mass limits on H+/-+/-_L of 133 GeV/c^2, 136 GeV/c^2, and 115 GeV/c^2 in the ee, mu mu, and e mu channels, respectively, and a lower mass limit of 113 GeV/c^2 on H+/-+/-_R in the mu mu channel, all at the 95% confidence level.Comment: 15 pages, 3 figures, submitted to PR

Measurement of the t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV using lepton plus jets events with secondary vertex b-tagging

We present a measurement of the t (t) over bar production cross section using events with one charged lepton and jets from pp collisions at a center-of-mass energy of 1.96 TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb(-1) of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5 +/- 1.8 events are expected from background contributions. We measure a t (t) over bar production cross section of 5.6(-1.1)(+1.2)(stat.)(-0.6)(+0.9)(syst.) pb

Highly ordered and vertically oriented TiO2/Al2O3 nanotube electrodes for application in dye-sensitized solar cells

The surface of long TiO2 nanotube (NT) electrodes in dye-sensitized solar cells (DSSCs) was modified without post-annealing by using atomic layer deposition (ALD) for the enhancement of photovoltage. Vertically oriented TiO2 NT electrodes with highly ordered and crack-free surface structures over large areas were prepared by a two-step anodization method. The prepared TiO2 NTs had a pore size of 80 nm, and a length of 23 μm. Onto these TiO2 NTs, an Al2O3 shell of a precisely controlled thickness was deposited by ALD. The conformally coated shell layer was confirmed by high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The open-circuit voltage (Voc) of the DSSCs was gradually enhanced as the thickness of the Al2O3 shell of the TiO2/Al2O3 NT electrodes was increased, which resulted from the enhanced electron lifetime. The enhanced electron lifetime caused by the energy barrier effect of the shell layer was measured quantitatively by the open-circuit voltage decay technique. As a result, 1- and 2-cycle-coated samples showed enhanced conversion efficiencies compared to the bare sample.122231sciescopu

Search for electroweak single-top-quark production in p(p)over-bar collisions at root s=1.96 TeV

We report on a search for standard model t-channel and s-channel single-top quark production in p (p) over bar collisions at a center of mass energy of 1.96 TeV. We use a data sample corresponding to 162 pb(-1) recorded by the upgraded collider detector at Fermilab. We find no significant evidence for electroweak top quark production and set upper limits at the 95% confidence level on the production cross section, consistent with the standard model: 10.1 pb for the t-channel, 13.6 pb for the s-channel and 17.8 pb for the combined cross section of t- and s-channel

Search for B(s)(0)->mu(+)mu(-) and B(d)(0)->mu(+)mu(-) decays in p(p)over bar collisions at root s=1.96 TeV

We report on a search for B(s)(0)-->mu(+)mu(-) and B(d)(0)-->mu(+)mu(-) decays in p (p) over bar collisions at root of s=1.96 TeV using 171 pb(-1) of data collected by the CDF II experiment at the Fermilab Tevatron Collider. The decay rates of these rare processes are sensitive to contributions from physics beyond the standard model. One event survives all our selection requirements, consistent with the background expectation. We derive branching ratio limits of B(B(s)(0)-->mu(+)mu(-))mu(+)mu(-))<1.5x10(-7) at 90% confidence level