Search for Charginos with a Small Mass Difference with the Lightest Supersymmetric Particle at \sqrt{s} = 189 GeV

A search for charginos nearly mass-degenerate with the lightest supersymmetric particle is performed using the 176 pb^-1 of data collected at 189 GeV in 1998 with the L3 detector. Mass differences between the chargino and the lightest supersymmetric particle below 4 GeV are considered. The presence of a high transverse momentum photon is required to single out the signal from the photon-photon interaction background. No evidence for charginos is found and upper limits on the cross section for chargino pair production are set. For the first time, in the case of heavy scalar leptons, chargino mass limits are obtained for any \tilde{\chi}^{+-}_1 - \tilde{\chi}^0_1 mass difference

The association between antihypertensive drugs and glioma

We pursued an association between hypertension and gliomas by investigating whether antihypertensive drugs (AHD) are associated with an increased glioma risk by a population-based nested case–control study using the PHARMO database; this links dispensing records of prescription drugs to hospital discharge data on an individual basis. Pathological data were derived from the Dutch nationwide registry of histo- and cytopathology. A total of 306 glioma cases incident between 1997 and 2003 were matched to 1108 controls for year of birth, sex, geographical region and duration of follow-up. Exposure was defined as cumulative duration of AHD use and, in an alternative analysis, as cumulative dose. We estimated the magnitude of the association with conditional logistic regression analysis. Cumulative use of any AHD for more than 6 months was associated with an increased risk of glioma (OR 1.45; 95% CI 1.03–2.04). After stratification for different groups of AHD, no significantly increased risk of glioma was found for any class of AHD. After excluding a latency period of 3 years before the date of diagnosis, no association was found. In conclusion, the use of AHD seems to be associated with an increased risk of glioma, but this is probably not causal

Search for neutral B meson decays to two charged leptons

The decays $\mathrm{B_d^0,\,B_s^0 \rightarrow e^+e^-,\,\mu^+\mu^-,\, e^\pm\mu^\mp}$ are searched for in 3.5 million hadronic ${\mathrm{Z}}$ events, which constitute the full LEP I data sample collected by the L3 detector. No signals are observed, therefore upper limits at the 90\%(95\%) confidence levels are set on the following branching fractions: % \begin{center}% {\setlength{\tabcolsep}{2pt} \begin{tabular}{lccccclcccc}% % Br$({\mathrm{B_d^0 \rightarrow {\mathrm{e^+e^-}}}})$ & $<$ & $1.4(1.8)$ & $\times$ & $10^{-5}$; & \hspace*{5mm} & Br$({\mathrm{B_s^0 \rightarrow {\mathrm{e^+e^-}}}})$ & $<$ & $5.4(7.0)$ & $\times$ & $10^{-5}$; \\% Br$({\mathrm{B_d^0 \rightarrow \mu^+\mu^-}})$ & $<$ & $1.0(1.4)$ & $\times$ & $10^{-5}$; & \hspace*{5mm} & Br$({\mathrm{B_s^0 \rightarrow \mu^+\mu^-}})$ & $<$ & $3.8(5.1)$ & $\times$ & $10^{-5}$; \\% Br$({\mathrm{B_d^0 \rightarrow {\mathrm{e^\pm\mu^\mp}}}})$ & $<$ & $1.6(2.0)$ & $\times$ & $10^{-5}$; & \hspace*{5mm} & Br$({\mathrm{B_s^0 \rightarrow {\mathrm{e^\pm\mu^\mp}}}})$ & $<$ & $4.1(5.3)$ & $\times$ & $10^{-5}$. \\% % \end{tabular}% } \end{center}% % The results for ${\mathrm{B_s^0\rightarrow{\mathrm{e^+e^-}}}}$ and ${\mathrm{B_s^0 \rightarrow {\mathrm{e^\pm\mu^\mp}}}}$ are the first limits set on these decay modes

Measurements of Cross Sections and Forward-Backward Asymmetries at the Z Resonance and Determination of Electroweak Parameters

We report on measurements of hadronic and leptonic cross sections and leptonic forward-backward asymmetries performed with the L3 detector in the years 1993-95. A total luminosity of 103 pb^-1 was collected at centre-of-mass energies \sqrt{s} ~ m_Z and \sqrt{s} ~ m_Z +/- 1.8 GeV which corresponds to 2.5 million hadronic and 245 thousand leptonic events selected. These data lead to a significantly improved determination of Z parameters. From the total cross sections, combined with our measurements in 1990-92, we obtain the final results: m_Z = 91189.8 +/- 3.1 MeV, Gamma_Z = 2502.4 +/- 4.2 MeV, Gamma_had = 1741.1 +/- 3.8 MeV, Gamma_l = 84.14 +/- 0.17 MeV. An invisible width of Gamma_inv = 499.1 +/- 2.9 MeV is derived which in the Standard Model yields for the number of light neutrino species N_nu = 2.978 +/- 0.014. Adding our results on the leptonic forward-backward asymmetries and the tau polarisation, the effective vector and axial-vector coupling constants of the neutral weak current to charged leptons are determined to be \bar{g}_V^l = -0.0397 +/- 0.0017 and \bar{g}_A^l = -0.50153 +/- 0.00053.Including our measurements of the Z -> b \bar{b} forward-backward and quark charge asymmetries a value for the effective electroweak mixing angle of sin^2\bar{\theta}_W = 0.23093 +/- 0.00066 is derived. All these measurements are in good agreement with the Standard Model of electroweak interactions. Using all our measurements of electroweak observables an upper limit on the mass of the Standard Model Higgs boson of m_H < 133 GeV is set at 95% confidence level.Comment: 97 pages, 37 figure