122819950
Search for leptoquarks in Z0 decays
Abstract We have searched for direct leptoquark production in Z0 decays from a scan of the Z0 resonance, in the energy range 88.2 ⩽ √s ⩽ 94.2 GeV, using 5.2 pb−1 of data. We exclude the existence of scalar leptoquarks with masses less than 41 to 44 GeV, depending on the charge assignments, at the 95% confidence level.
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.
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
43062196
Development of thermionic-cathode RF electron gun at IHEP
A thermionic cathode RF electron gun has been developed at the Institute of High Energy Physics, Academia Sinica, China. The gun will accelerate and prebunch electrons emitted from a L/sub a/B/sub 6/ cathode using a high electric field in a resonant cavity. The gun was fabricated and tested, and used in the Beijing free-electron laser project. Results of experimental measurements of the injector performance of a prototype gun are also presented.<<ETX>>
118515319
Reconstructing the local potential of inflation with BICEP2 data
We locally reconstruct the inflationary potential by using the current constraints on r and n(s) from BICEP2 data. Assuming small and negligible alpha(s), the inflationary potential is approximately linear in Delta phi similar to M-pl range but becomes non-linear in Delta phi similar to 10M(pl) range. However if we vary the value of alpha(s) within the range given by constraints from Planck measurement, the local reconstruction is only valid in the range of Delta phi similar to 0.4M(pl), which challenges the inflationary background from the point of view of effective field theory. We show that, within the range of Delta phi similar to 0.4M(pl), the inflation potential can be precisely reconstructed. With the current reconstruction, we show that V(phi) similar to phi(2) and phi(3) are consistent, while phi model is ruled out by 95% confidence level of the reconstructed range of potential. This sets up a strong limit of large-field inflation models.
119932492
Fine structure of alpha decay to rotational states of heavy nuclei
To gain a better insight into alpha-decay fine structure, we calculate the relative intensities of alpha decay to 2{sup +} and 4{sup +} rotational states in the framework of the generalized liquid drop model (GLDM) and improved Royer's formula. The calculated relative intensities of alpha decay to 2{sup +} states are in good agreement with the experimental data. For the relative intensities of alpha decay to 4{sup +} states, a good agreement with experimental data is achieved for Th and U isotopes. The formula we obtain is useful for the analysis of experimental data of alpha-decay fine structure. In addition, some predicted relative intensities which are still not measured are provided for future experiments.
117142150
New Color-Octet Vector Boson?
Both CDF and D0 at Tevatron reported the measurements of forward-backward asymmetry in top pair production, which showed possible deviation from the standard model QCD prediction. In this paper, we show that a new color-octet massive vector boson with mass just above twice that of top quark can simultaneously account for the asymmetry and differential distribution $d\sigma/dM_{t\bar t}$ in top pair production, without conflict with other measurements for example di-jet production. The new particle can be discovered and studied at the more powerful Large Hadron Collider.
126297547
Experimental study of hadron inclusive production in J / psi energy region