56101537
Q value of the superallowed decay of Mg22 and the calibration of the Na21(p,γ) experiment
The masses of the radioactive nuclei {sup 22}Mg and {sup 22}Na have been measured with the Canadian Penning trap on-line mass spectrometer to a precision of 3x10{sup -8} and 1x10{sup -8}, respectively. A Q{sub EC} value of 4124.39(73) keV for the superallowed {beta} decay of {sup 22}Mg is obtained from the difference of these two masses. With this precise Q value, the Ft value for this decay is determined with improved precision and is found to be consistent with the existing precision data set of superallowed Fermi emitters. This provides an important test of the isospin symmetry-breaking corrections. If the mass of {sup 22}Mg determined here is used in the calibration of a recent {sup 21}Na(p,{gamma}){sup 22}Mg measurement, part of the discrepancy observed in that measurement is removed.
122717574
Search for neutralinos in Z decays
Abstract We have searched for neutralinos produced via the reactions e + e − → χχ′ and e + e − → χ′χ′, where the next-to lightest neutralino, χ′, decays into the lightest neutralino, χ, and either a photon or a fermion pair. Based on 1.8 × 10 6 hadronic Z decays collected with the L3 detector at LEP, no signal has been observed. We present upper limits of a few times 10 −5 on the branching ratios Z → χχ′ and Z → χ′χ′. In the framework of the Minimial Supersymmetric Standard Model, we exclude a lightest χ with m χ less than 18 GeV, if either tan β > 2 or the gluino mass m ≈ g > 100 GeV.
18308235
Search for new particles in hadronic events with isolated photons
Abstract A search for the neutral Higgs boson in the processes e + e − → Z → H 0 γ → q q γ and e + e − → Z → Z ∗ H 0 → q q γγ has been performed using 2.8 million hadronic Z decays collected with the L3 detector at LEP from 1991 through 1994. No evidence for these processes has been observed. Upper limits at 95% confidence level for the corresponding cross sections have been set and the results have been compared with theoretical predictions beyond the Standard Model.
122751074
Production of single W bosons at LEP
We report on the observation of single W boson production in a data sample collected by the L3 detector at LEP2. The signal consists of large missing energy final states with a single energetic lepton or two hadronic jets. The cross-section is measured to be 0.61(-0.33)(+0.43) +/- 0.05 pb at the centre of mass energy root s = 172 GeV, consistent with the Standard Model expectation. From this measurement the following limits on the anomalous gamma WW gauge couplings are derived at 95% CL: -3.6 < Delta kappa gamma < 1.5 and -3.6 < lambda gamma < 3.6. (C) 1997 Published by Elsevier Science B.V.
14588649
Production of e, mu and tau pairs in untagged two-photon collisions at LEP
The two-photon collision reaction e+e- --> e+e-l+l- has been studied at root(s) ~ 91 GeV using the L3 detector at LEP for l = e, muon , tau. We have analysed untagged configurations where the two photons are quasi-real. Good agreement is found between our measurements and the order alpha**4 QED expectation.
122052372
Angular multiplicity fluctuations in hadronic Z decays and comparison to QCD models and analytical calculations
Abstract Local multiplicity fluctuations in angular phase space intervals are studied using factorial moments measured in hadronic events at s ≃91.2 GeV , which were collected by the L3 detector at LEP. Parton shower Monte Carlo programs agree well with the data. On the other hand, first-order QCD calculations in the Double Leading Log Approximation and the Modified Leading Log Approximation are found to deviate significantly from the data.
122603752
CMS Data Processing Workflows during an Extended Cosmic Ray Run
The CMS Collaboration conducted a month-long data taking exercise, the Cosmic Run At Four Tesla, during October-November 2008, with the goal of commissioning the experiment for extended operation. With all installed detector systems participating, CMS recorded 270 million cosmic ray events with the solenoid at a magnetic field strength of 3.8 T. This paper describes the data flow from the detector through the various online and offline computing systems, as well as the workflows used for recording the data, for aligning and calibrating the detector, and for analysis of the data.
7637272
Improved measurement of B(D+ --> mu+nu) and the pseudoscalar decay constant fD+.
We extract a relatively precise value for the decay constant of the meson by measuring B(D+ --> mu+nu) = (4.40 +/-0.66(+0.09)(-0.12) x 10(-4) using 281 pb(-1) of data taken on phi(3770) the resonance with the CLEO-c detector. We find fD+ = (222.6 +/- 16.7(+2.8)(-3.4)) MeV, and compare with current theoretical calculations. We also set a 90% confidence upper limit on B(D+e+nu)< 2.4 x 10(-5) which constrains new physics models.
17594084
RF systems for the NLCTA
This paper describes an X-band RF system for the Next Linear Collider Test Accelerator. The RF system consists of a 90 MeV injector and a 540 MeV linac. The main components of the injector are two low-Q single-cavity prebunchers and two 0.9-m-long detuned accelerator sections. The linac system consists of six 1.8-m-long detuned and damped detuned accelerator sections powered in pairs. The RF power generation, compression, delivery, distribution and measurement systems consist of klystrons, SLED-II energy compression systems, rectangular waveguides, magic-T's, and directional couplers. The phase and amplitude for each prebuncher is adjusted via a magic-T type phase shifter/attenuator. Correct phasing between the two 0.9 m accelerator sections is obtained by properly aligning the sections and adjusting two squeeze type phase shifters. Bunch phase and bunch length can be monitored with special microwave cavities and measurement systems. The design, fabrication, microwave measurement, calibration, and operation of the sub-systems and their components are briefly presented.
118363385
Resummation Prediction on Top Quark Transverse Momentum Distribution at Large $$p_T$$
The top quark is one of the third-generation quarks, proposed to exist in 1973 by Kobayashi and Maskawa to explain the observed CP violations in kaon decay [1]. However, it has not been directly observed until 1995 by CDF and DO collaborations at the Tevatron [2, 3]. The reason is that the top quark is the heaviest particle discovered so far, with a mass close to the electroweak symmetry breaking scale.
24513418
Observation of radiative B-->phi K gamma decays.
The radiative decay B-->phi K gamma is observed for the first time. The branching fraction for the charged B--->phi K- gamma decay mode is measured to be B(B--->phi K- gamma)=(3.4+/-0.9+/-0.4)x10(-6). The photon energy distribution for the B--->phi K- gamma decay is presented. The signal for the neutral B(0)-->phi K(0)gamma decay mode is not statistically significant and an upper limit, B(B(0)-->phi K(0)gamma)<8.3x10(-6) at 90% C.L., is set. The analysis is based on a data set of 90 fb(-1) collected by the Belle experiment at the e(+)e(-) asymmetric collider KEKB.