Electroweak physics at the Tevatron

The most recent Electroweak results from the Tevatron are presented. The importance of precise Standard Model measurements in the Higgs sector, quantum chromodynamics and searches for new physics is emphasized. Analyzed data correspond to 1–7 fb−1 of integrated luminosity recorded by the CDF and DØ detectors at the Tevatron Collider at √s = 1.96TeV during the period between 2002 and 2010

Dissipation in nanocrystalline-diamond nanomechanical resonators

We have measured the dissipation and frequency of nanocrystalline-diamond nanomechanical resonators with resonant frequencies between 13.7 MHz and 157.3 MHz, over a temperature range of 1.4–274 K. Using both magnetomotive network analysis and a time-domain ring-down technique, we have found the dissipation in this material to have a temperature dependence roughly following T^(0.2), with Q^(–1) ≈ 10^(–4) at low temperatures. The frequency dependence of a large dissipation feature at ~35–55 K is consistent with thermal activation over a 0.02 eV barrier with an attempt frequency of 10 GHz

Measurement of Trilinear Gauge Couplings at a gamma-gamma and e-gamma Collider

The processes gamma gamma -> WW and e gamma -> nu W are sensitive to triple gauge boson interactions. Both reactions have been simulated for hadronically decaying W-bosons and the sensitivity to anomalous couplings has been estimated.Comment: Talk presented at LCWS2002, August 2002, Jeju Island, Kore

Studies for a Photon Collider at the ILC

One option at the International Linear Collider is to convert the electron beams into high energy photon beams by Compton scattering a few millimetres in front of the interaction region. Selected physics channels for this option have been analysed and technical issues have been studied. So far no showstoppers for this option have been found.Comment: V2: Minor changes, accepted by NI

Search for Charged Massive Long-Lived Particles

This is the publisher's version, also available electronically from http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.108.121802.We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2  fb^(−1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron ppbar collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss (dE/dx) inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gauginolike charginos below 267 GeV and Higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV

Combination of measurements of the top-quark pair production cross section from the Tevatron Collider

This is the publisher's version, also available electronically from http://journals.aps.org/prd/abstract/10.1103/PhysRevD.89.072001

Measurement of direct CP violation parameters in B(±)→J/ψK(±) and B(±)→J/ψπ(±) decays with 10.4 fb(−1) of Tevatron data

This is the publisher's version, also available electronically from http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.110.241801.We present a measurement of the direct CP-violating charge asymmetry in B(±) mesons decaying to J/ψK(±) and J/ψπ(±) where J/ψ decays to μ(+)μ(−), using the full run II data set of 10.4  fb(−1) of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. A difference in the yield of B(−) and B(+) mesons in these decays is found by fitting to the difference between their reconstructed invariant mass distributions resulting in asymmetries of A(J/ψK)=[0.59±0.37]%, which is the most precise measurement to date, and A(J/ψπ)=[−4.2±4.5]%. Both measurements are consistent with standard model predictions

Measurement of the ZZ production cross section and search for the standard model Higgs boson in the four lepton final state in pp-bar collisions

This is the publisher's version, also available electronically from http://journals.aps.org/prd/abstract/10.1103/PhysRevD.88.032008