127424011
Search for lepton flavor violation in Z0 decays
Abstract We have searched for lepton flavour violation in Z 0 boson decays into lepton pairs, Z 0 →μτ, Z 0 →eτ, and Z 0 →eμ. The data sample is based on an integrated luminosity of 10.4 pb -1 corresponding to 370 000 Z 0 's produced. We obtain upper limits on the branching ratios of 4.8×10 -5 for the μτ, 3.4×10 -5 for the eτ and 2.4×10 -5 for the eμ decay modes at the 95% confidence level.
120261584
Overveiw of the BES physics
Recent physics results at Beijing Electron-Positron Collider (BEPC) are reviewed, especially on excited baryons. Substantial improvements are expected at the newly built BESIII experiment, which is operational since 2008. The detector performance is excellent and a total of 100 million Ψ(2S) and 200 million J/Ψ event are collected in 2009. Preliminary results shows that a new era of excited baryon physics will begin.
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
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.
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.
34106953
Crosstalk research of long strip timing RPC
The time-of-flight (TOF) wall of CBM is proposed to be assembled with MRPCs. In a relative high particle multiplicity situation (about 20kHz/cm2), multi-hit capability is one of the most demanding requirement of the detector. Crosstalk is an important reason for the deterioration the multi-hit capability of a detector. To reduce the crosstalk level, a kind of shielded long-strip two-end readout MRPC was developed. 1mm width guard strips were added between strips of a 1m-long MRPC. Beam test with 2.5GeV protons was performed in GSI in August, 2009. Horizontal and vertical scans were done. Combined with data from silicon detector, we get the crosstalk between four neighbor strips. The results show that the crosstalk level can be reduced and double hits can affect the time resolution. It also shows that the crosstalk increase with high voltage and decrease with surface resistivity of electrode.
118404205
Thermodynamic geometry of black hole in the deformed Hořava-Lifshitz gravity
We investigate the thermodynamic geometry and phase transition of Kehagias-Sfetsos black hole in the deformed Hořava-Lifshitz gravity with coupling constant λ = 1. The phase transition in black-hole thermodynamics is thought to be associated with the divergence of the capacities. And the structures of these divergent points are studied. We also find that the thermodynamic curvature produced by the Ruppeiner metric is positive definite for all r+ > r− and is divergent at η2 = 0 corresponding to the divergent points of CΦ and CT . These results suggest that the microstructure of the black hole has an effective repulsive interaction, which is very similar to the ideal gas of fermions. These may shed some light on the microstructure of the black hole.
123655843
Back-streaming ion emission and beam focusing on high power linear induction accelerator
Ions released from target surfaces by impact of a high intensity and current electron beam can be accelerated and trapped in the beam potential, and further destroy the beam focus. By solving the 2D Poisson equation, we found that the charge neutralization factor of the ions to the beam under space charge limited condition is $1/3$, which is large enough to disrupt the spot size. Therefore, the ion emission at the target in a single-pulse beam/target system must be source limited. Experimental results on the time-resolved beam profile measurement have also proven that. A new focus scheme is proposed in this paper to focus the beam to a small spot size with the existence of back-streaming ions. We found that the focal spot will move upstream as the charge neutralization factor increases. By comparing the theoretical and experimental focal length of the Dragon-I accelerator (20 MeV, 2.5 kA, 60 ns flattop), we found that the average neutralization factor is about 5% in the beam/target system.
17823222
LHC reach for gauge mediated supersymmetry breaking models via prompt photon channels
Abstract We evaluate the supersymmetry reach of the Large Hadron Collider within the gauge-mediated low energy supersymmetry breaking framework, assuming that a neutralino is the second lightest sparticle and that it decays promptly into a gravitino which escapes detection. We find that the maximum reach is obtained via a search for inclusive γγ+ E / T events coming dominantly from chargino and neutralino production. Assuming an integrated luminosity of 10 fb −1 , we find that LHC experiments will be able to probe values of the model parameter Λ ≲400 TeV, corresponding to m g ≤2.8 TeV. A measure of the model parameter Λ may be possible from the photon p T spectrum.
131752593
Search for Diffuse Gamma Rays from the Galactic Plane in Multi-TeV Region with the Tibet Air Shower Array
Diffuse gamma rays from the Galactic plane were searched combining the Tibet II data with energies more than 4 TeV and III data obtained during 1999-2002 with energies more than 1.5 TeV. The Tibet III increased available data by a factor ∼1.8 than the Tibet II only. The sky regions searched are the inner Galaxy, 20◦ < l < 55◦, and outer Galaxy, 140◦ < l < 225◦ with the plane thickness |b| ≤ 2◦, and the Cygnus region, 67◦ < l < 92◦ with |b| ≤ 5◦. Although no significant excess was observed, the intensity upper limits are given with 99% confidence level at mode energies 3∼20 TeV, assuming a differential spectral index of -2.4. The present results give the most stringent upper limits on the inverse Compton model with a source electron spectral index of -2.0.