Measurements of the top-quark mass using charged particle tracking

We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb-1 of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9+9.5-8.5 (stat) +/- 2.9 (syst) GeV/c2, and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5+8.8-8.9 (stat) +/- 3.8 (syst) GeV/c2. These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 +/- 6.3 (stat) +/- 2.6 (syst) GeV/c2.

Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF

We present results of a search for anomalous production of two photons together with an electron, muon, $\tau$ lepton, missing transverse energy, or jets using $p\bar{p}$ collision data from 1.1-2.0 fb$^{-1}$ of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs of new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy.

Measurement of the b-hadron production cross section using decays to μ-D0X final states in pp̅ collisions at √s=1.96 TeV

We report a measurement of the production cross section for b hadrons in pp̅ collisions at √s=1.96  TeV. Using a data sample derived from an integrated luminosity of 83  pb-1 collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron, we analyze b hadrons, Hb, partially reconstructed in the semileptonic decay mode Hb→μ-D0X. Our measurement of the inclusive production cross section for b hadrons with transverse momentum pT>9  GeV/c and rapidity |y|<0.6 is σ=1.30  μb±0.05  μb(stat)±0.14  μb(syst)±0.07  μb(B), where the uncertainties are statistical, systematic, and from branching fractions, respectively. The differential cross sections dσ/dpT are found to be in good agreement with recent measurements of the Hb cross section and well described by fixed-order next-to-leading logarithm predictions.

Measurement of the tt̅ production cross section in 2 fb-1 of pp̅ collisions at √s=1.96 TeV using lepton plus jets events with soft muon b tagging

We present a measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96  TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with tt̅ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF run II data sample corresponding to 2  fb-1 of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of 79.5±5.3 events, we measure a production cross section of 9.1±1.6  pb.

Measurement of the b-hadron production cross section using decays to μ-D0X final states in pp̅ collisions at √s=1.96 TeV

We report a measurement of the production cross section for b hadrons in pp̅ collisions at √s=1.96  TeV. Using a data sample derived from an integrated luminosity of 83  pb-1 collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron, we analyze b hadrons, Hb, partially reconstructed in the semileptonic decay mode Hb→μ-D0X. Our measurement of the inclusive production cross section for b hadrons with transverse momentum pT>9  GeV/c and rapidity |y|<0.6 is σ=1.30  μb±0.05  μb(stat)±0.14  μb(syst)±0.07  μb(B), where the uncertainties are statistical, systematic, and from branching fractions, respectively. The differential cross sections dσ/dpT are found to be in good agreement with recent measurements of the Hb cross section and well described by fixed-order next-to-leading logarithm predictions.

Search for Exclusive Z-Boson Production and Observation of High-Mass pp̅ →pγγp̅ →pl+l-p̅ Events in pp̅ Collisions at √s=1.96 TeV

We present a search for exclusive Z boson production in proton-antiproton collisions at sqrt(s) = 1.96 TeV, using the CDF II detector at Fermilab. We observe no exclusive Z->ll candidates and place the first upper limit on the exclusive Z cross section in hadron collisions, sigma(exclu) gammagamma->p+ll+pbar, and measure the cross section for M(ll) > 40 GeV/c2 and |eta(l)|

Measurement of the tt̅ production cross section in 2 fb-1 of pp̅ collisions at √s=1.96 TeV using lepton plus jets events with soft muon b tagging

We present a measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96  TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with tt̅ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF run II data sample corresponding to 2  fb-1 of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of 79.5±5.3 events, we measure a production cross section of 9.1±1.6  pb.

Influence of Oxide Particle Network Morphology on Ion Solvation and Transport in ``Soggy Sand''Electrolytes

The role of oxide surface chemical composition and solvent on ion solvation and ion transport of ``soggy sand'' electrolytes are discussed here. A ``soggy sand'' electrolyte system comprising dispersions of hydrophilic/hydrophobic functionalized aerosil silica in lithium perchlorate methoxy polyethylene glycol solution was employed for the study. Static and dynamic rheology measurements show formation of an attractive particle network in the case of the composite with unmodified aerosil silica (i.e., with surface silanol groups) as well as composites with hydrophobic alkane groups. While particle network in the composite with hydrophilic aerosil silica (unmodified) were due to hydrogen bonding, hydrophobic aerosil silica particles were held together via van der Waals forces. The network strength in the latter case (i.e., for hydrophobic composites) were weaker compared with the composite with unmodified aerosil silica. Both unmodified silica as well as hydrophobic silica composites displayed solid-like mechanical strength. No enhancement in ionic conductivity compared to the liquid electrolyte was observed in the case of the unmodified silica. This was attributed to the existence of a very strong particle network, which led to the ``expulsion'' of all conducting entities from the interfacial region between adjacent particles. The ionic conductivity for composites with hydrophobic aerosil particles displayed ionic conductivity dependent on the size of the hydrophobic chemical moiety. No spanning attractive particle network was observed for aerosil particles with surfaces modified with stronger hydrophilic groups (than silanol). The composite resembled a sol, and no percolation in ionic conductivity was observed.

Search for new color-octet vector particle decaying to t tbar in p pbar collisions at sqrt{s} = 1.96 TeV

We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb$^{-1}$ of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study $t\bar{t}$ events in the lepton+jets channel with at least one $b$-tagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV$/c^2$ and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.

Study of the associated production of photons and b-quark jets in pp̅ collisions at √s=1.96 TeV

The cross section for photon production in association with at least one jet containing a $b$-quark hadron has been measured in proton antiproton collisions at $\sqrt{s}=1.96$ TeV. The analysis uses a data sample corresponding to an integrated luminosity of 340 pb$^{-1}$ collected with the CDF II detector. Both the differential cross section as a function of photon transverse energy $E_T^{\gamma}$, $d \sigma$($p \overline{p} \to \gamma + \geq 1 b$-jet)/$d E_T^{\gamma}$ and the total cross section $\sigma$($p \overline{p} \to \gamma + \geq 1 b$-jet; $E_T^{\gamma}> 20$ GeV) are measured. Comparisons to a next-to-leading order prediction of the process are presented.

Measurement of the b-hadron production cross section using decays to μ-D0X final states in pp̅ collisions at √s=1.96 TeV

We report a measurement of the production cross section for b hadrons in p-pbar collisions at sqrt{s}=1.96 TeV. Using a data sample derived from an integrated luminosity of 83 pb^-1 collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron, we analyze b hadrons, H_b, partially reconstructed in the semileptonic decay mode H_b -> mu^- D^0 X. Our measurement of the inclusive production cross section for b hadrons with transverse momentum p_T > 9 GeV/c and rapidity |y|

Observation of Electroweak Single Top-Quark Production

We report the first observation of single top quark production using 3.2 fb^-1 of pbar p collision data with sqrt{s}=1.96 TeV collected by the Collider Detector at Fermilab. The significance of the observed data is 5.0 standard deviations, and the expected sensitivity for standard model production and decay is in excess of 5.9 standard deviations. Assuming m_t=175 GeV/c^2, we measure a cross section of 2.3 +0.6 -0.5 (stat+syst) pb, extract the CKM matrix element value |V_{tb}|=0.91 +-0.11 (stat+syst) 0.07(theory), and set the limit |V_{tb}|>0.71 at the 95% C.L.

Measurement of the tt̅ production cross section in 2 fb-1 of pp̅ collisions at √s=1.96 TeV using lepton plus jets events with soft muon b tagging

We present a measurement of the $\ttbar$ production cross section in $\ppbar$ collisions at $\sqrt{s}=1.96$ TeV using events containing a high transverse momentum electron or muon, three or more jets, and missing transverse energy. Events consistent with $\ttbar$ decay are found by identifying jets containing candidate heavy-flavor semileptonic decays to muons. The measurement uses a CDF Run II data sample corresponding to $2 \mathrm{fb^{-1}}$ of integrated luminosity. Based on 248 candidate events with three or more jets and an expected background of $79.5\pm5.3$ events, we measure a production cross section of $9.1\pm 1.6 \mathrm{pb}$.

Atmospheric particle formation in spatially and temporally varying conditions

Atmospheric particles affect the radiation balance of the Earth and thus the climate. New particle formation from nucleation has been observed in diverse atmospheric conditions but the actual formation path is still unknown. The prevailing conditions can be exploited to evaluate proposed formation mechanisms. This study aims to improve our understanding of new particle formation from the view of atmospheric conditions. The role of atmospheric conditions on particle formation was studied by atmospheric measurements, theoretical model simulations and simulations based on observations. Two separate column models were further developed for aerosol and chemical simulations. Model simulations allowed us to expand the study from local conditions to varying conditions in the atmospheric boundary layer, while the long-term measurements described especially characteristic mean conditions associated with new particle formation. The observations show statistically significant difference in meteorological and back-ground aerosol conditions between observed event and non-event days. New particle formation above boreal forest is associated with strong convective activity, low humidity and low condensation sink. The probability of a particle formation event is predicted by an equation formulated for upper boundary layer conditions. The model simulations call into question if kinetic sulphuric acid induced nucleation is the primary particle formation mechanism in the presence of organic vapours. Simultaneously the simulations show that ignoring spatial and temporal variation in new particle formation studies may lead to faulty conclusions. On the other hand, the theoretical simulations indicate that short-scale variations in temperature and humidity unlikely have a significant effect on mean binary water sulphuric acid nucleation rate. The study emphasizes the significance of mixing and fluxes in particle formation studies, especially in the atmospheric boundary layer. The further developed models allow extensive aerosol physical and chemical studies in the future.