7325683
Determination of the Effective Electroweak Mixing Angle from Z-Decays
Abstract The effective electroweak mixing angle sin 2 θ w is measured from the production and decay of the Z boson in e+e− interactions. The data sample corresponds to an integrated luminosity of 18pb−1 with about 420 000 hadronic and 40 000 leptonic Z decays. The mixing angle sin 2 θ w is determined from several independent measurements: the leptonic and hadronic cross sections, the forward-backward asymmetries of charged leptons and b-quarks, and the τ-polarization. The results are found to be in good agreement with each other. The value of sin 2 θ w from a fit to the asymmetries in a model independent method is 0.2321±0.0021 and from a global fit to the data in the Standard Model framework is 0.2328±0.0013.
18893994
The mass production and quality control of RPCs for the Daya Bay experiment
Abstract Resistive plate chambers will be used in the Daya Bay reactor neutrino experiment to help veto backgrounds created by cosmic-ray muons. The mass production of RPCs began in 2008 and by the end of 2009, 1600 RPCs (3500 m 2 ) had been produced and tested. This paper describes the production and quality control procedures, and quality assurance using cosmic-ray testing.
125677069
TUBE CHAMBERS FOR THE MUON FILTER OF THE L3 DETECTOR
56005177
Inclusive J production in Z0 decays
Abstract Inclusive J production in Z0 decays is observed via the leptonic decay mode J → l+l− (l = e,μ). We measure the branching ratio Br(Z0 → J + X) = (4.1 ± 0.7 (stat.) ± 0.3 (sys.)) × 10−3. We have calculated the fraction of the J mesons from b-hadron decay and find a branching ratio of Br(b → J + X)= (1.3±0.2(stat.)±0.2(sys.)) × 10−2. We determine the average fractional energy of bottom hadrons 〈XE > = 0.70±0.03 (stat.)+0.02−0.01 (sys.) using the momentum spectrum of the J mesons. From a study of the angle between the J and the most energetic jet, we set an upper limit on the branching ratio Br ( Z 0 → q q g ∗ ; g ∗ → J + X ) −4 at 90% confidence level.
118039047
Physics of tau and charm
The physics of tau and charm started in early 70's after J/$\psi$ and $\tau$ were discovered. Since then several dedicated accelerators and experiments were built with increasing luminosities and studies on light hadron spectroscopy, charmonium, electroweak and QCD were never interupted. New interests and surprises are not rare in this area. With the newly built BEPCII/BESIII, an even brighter future is foreseen.
122214277
A water Cherenkov calorimeter for long baseline neutrino oscillation experiments
Abstract We propose a water-based large homogeneous calorimeter as the next generation neutrino detector for ν factories and/or conventional ν beams. The Cherenkov light produced in water is sufficient to have good energy resolution, and the pattern recognition is realized by a modular water tank structure. Monte Carlo simulations show that the detector performance is excellent for identifying neutrino CC events while rejecting backgrounds.
119263928
Made-to-measure galaxy models – III. Modelling with Milky Way observations
We demonstrate how the Syer and Tremaine made-to-measure method of stellar dynamical modelling can be adapted to model a rotating galactic bar. We validate our made-to-measure changes using observations constructed from the existing Shen et al. N-body model of the Milky Way bar, together with kinematic observations of the Milky Way bulge and bar taken by the Bulge Radial Velocity Assay. Our results for a combined determination of the bar angle and bar pattern speed (approximate to 30 degrees and approximate to 40 km s(-1) kpc(-1)) are consistent with those determined by the N-body model. Whilst the made-to-measure techniques we have developed are applied using a particular N-body model and observational data set, they are in fact general and could be applied to other Milky Way modelling scenarios utilizing different N-body models and data sets. Additionally, we use the exercise as a vehicle for illustrating how N-body and made-to-measure methods might be combined into a more effective method.
120127236
Systematic study of tensor effects in shell evolution
In the framework of the Hartree-Fock-Bogoliubov approach with the Skyrme interactions SLy5, SLy5+T, SLy5+T{sub w}, and several sets of the TIJ parametrizations (Skyrme effective interaction parametrizations including the tensor terms), the effect of the tensor force on the shell evolution at Z,N=8, 20, and 28 is investigated. It is shown that the evolution of the gap (defined as the energy difference between the last occupied and first unoccupied single-particle orbits) with SLy5+T is similar to that with SLy5+T{sub w}, and the gap values with SLy5+T are smaller than those with SLy5+T{sub w} in the cases of Z,N=8, 20. At Z, N = 28, the gap values with SLy5 are smaller than those with SLy5+T and larger than those with SLy5+T{sub w}. To understand these features, we analyze the spin-orbit potentials with and without the tensor contributions and the radial wave functions of relevant orbits. Meanwhile, we find that the deviation of the calculated gaps with SLy5+T{sub w} from the experimental ones is larger than that with SLy5+T. This indicates that SLy5+T{sub w} is not suitable for investigating the properties of the ground-state gap evolution. Finally, it is seen that the gap evolutions with different sets of the TIJ parametrizations aremore » similar to each other except for the ones with T22, and there is almost no difference between the tensor effect in gap evolution with the perturbative method and the one with the complete fitting method.« less
118654448
Constraints on the universal varying Yukawa couplings: from SM-like to fermiophobic
A bstractVarying the Standard Model (SM) fermion Yukawa couplings universally by a generic positive scale factor $ ({F_{{Y\,u}}}) $, we study the phenomenological fit to the current available experimental results for the Higgs boson search at hadron colliders. We point out that the Higgs production cross section and its decay branching ratio to γγ can be varied oppositely by $ {F_{{Y{ ~ }u}}} $ to make their product almost invariant. Thus, our scenario and the SM Higgs are indistinguishable in the inclusive H → γγ channel. The current measurements on direct Yukawa coupling strength in the $ H \to b\overline b /\tau \tau $ channel are not precise enough to fix the scale factor $ {F_{{Y{ ~ }u}}} $. The most promising is the vector-boson-fusion channel in which the CMS has already observed possible suppression effect on the Yukawa couplings. Further more, the global χ2 fit of the experimental data can get the optimal value by introducing a suppression factor $ {F_{{Y{ ~ }u}}} \sim {1}/{2} $ on the SM Yukawa couplings.
121868996
Development of multi-gap resistive plate chambers with low-resistive silicate glass electrodes for operation at high particle fluxes and large transported charges
Abstract Using electrodes made of semi-conductive glass is an innovative way of improving the rate capability of resistive plate chambers. To address this issue, we developed 6- and 10-gap counters with low-resistive silicate glass electrodes (bulk resistivity ∼10 10  Ω cm) suited for time-of-flight (TOF) applications at high rates and high transported charges. Measurements were performed at GSI-Darmstadt under uniform an irradiation by secondary particles stemming from proton reactions at 2.5 GeV/A. For the 10-gap MRPC, time resolutions below 90 ps and efficiencies larger than 90% were obtained at counting rates up to 25 kHz/cm 2 . When the particle flux increases every 5 kHz/cm 2 , the efficiency decreases by 1% and the time resolution deteriorates by 4 ps. A tolerable decrease of the material conductivity was also observed for a total transported charge of 1 C/cm 2 .
119459312
Evidence for the isoscalar giant dipole resonance in Pb-208 using inelastic alpha scattering at and near 0 degrees
The isoscalar giant dipole resonance (ISGDR) in Pb-208 has been investigated using inelastic scattering of 200 MeV alpha particles at and near 0 degrees where the angular distribution of the ISGDR can be clearly differentiated from those of other modes. The ''difference of spectra'' technique was employed to separate the ISGDR from the high-energy octupole resonance (HEOR). These data provide the dearest evidence yet for the ISGDR adjacent to the HEOR. With these results, all expected isoscalar lambda less than or equal to 3 resonances in Pb-208 have been identified.