122601384
Studies of wire gain and track distortion near the sector edges of the ALEPH time projection chamber
Abstract The materials used to hold the wires at the sector edges in a large Time Projection Chamber (TPC) inrtoduce distortions of the electric drift field near those edges. These distortions degrade tracking information and sometimes cause large changes in wire gain near the edge. We have studied these two problems for the ALEPH TPC and have found that both can be greatly reduced by the addition of two field correction strips held at appropriate voltages.
125302092
Measurements of the line shapes of D anti-D production and the ratio of the production rates of D+ D- and D0 anti-D0 in e+ e- annihilation at psi(3770) resonance
Abstract We report measurements of the line shapes of D + D − , D 0 D ¯ 0 and D D ¯ production as well as the line shape of the ratio of the production rates of D + D − and D 0 D ¯ 0 in e + e − annihilation at ψ ( 3770 ) resonance. We find that the line shapes of D + D − , D 0 D ¯ 0 and D D ¯ production are similar to an anomalous line shape of cross sections for e + e − → hadrons observed in the center-of-mass energy range from 3.70 to 3.87 GeV.
126124755
Measurement of the internal spin structure of the proton
Our final results of measurements at SLAC of the spin dependent asymmetry in the deep inelastic scattering of longitudinally polarized electrons by longitudinally polarized protons are presented. Data were obtained at a scattering angle of 10° and for incident energies of 16.2 and 22.7 GeV, which cover the kinematic range 0.18<x<0.70 and 3.5<Q2<10.0 (GeV/c)2. We compare our results with various models of proton spin structure and with the Bjorken and Ellis‐Jaffe sum rules.
182722222
First Level Trigger in the GEM Muon System
19719907
Trigger System of BESIII
The trigger system of Beijing Spectrometer III, part of the upgrade of Beijing Electron Positron Collider, has been designed and implemented, and is ready for installation. This paper describes briefly the system components, its characteristics, and some technical issues. The system consists mainly of four parts: MDC (drift chamber) tracking subsystem, EMC (electromagnetic calorimeter) subsystem, TOF (time of flight) subsystem and global trigger. Some highlights in designing of this system includes: trigger scheme optimization with software simulation; optical transmission between trigger and FEEs to realize isolation with FEEs to avoid ground loop current interference; designed with most latest FPGA (Xilinx Spartan 3, VirtexII Pro...) for simplicity, high reliability and easy maintenance and hence smaller system; FPGA in-system programming or firmware online downloadable via onboard, panel connector and/or VME bus for modification flexibility during commissioning. Different from the usual fix delay data transmission from FEE to trigger, the RocketIO has been used as SEDES.
126253177
Experimental measurement of the mass of the tau lepton at the Beijing Electron Positron Collider (BEPC)
52266731
Measurement of the cosmic ray antiproton/proton flux ratio at TeV energies with the ARGO-YBJ detector
B. Bartoli, 2 P. Bernardini, 4 X.J. Bi, C. Bleve, 4 I. Bolognino, 7 P. Branchini, A. Budano, A.K. Calabrese Melcarne, P. Camarri, 11 Z. Cao, R. Cardarelli, S. Catalanotti, 2 C. Cattaneo, S.Z. Chen, T.L. Chen, Y. Chen, P. Creti, S.W. Cui, B.Z. Dai, G. D’Aĺı Staiti, 16 Danzengluobu, I. De Mitri, 4 B. D’Ettorre Piazzoli, 2 T. Di Girolamo, 2 X.H. Ding, G. Di Sciascio, ∗ C.F. Feng, Zhaoyang Feng, Zhenyong Feng, E. Giroletti, 7 Q.B. Gou, Y.Q. Guo, H.H. He, Haibing Hu, Hongbo Hu, Q. Huang, M. Iacovacci, 2 R. Iuppa, 11, † I. James, 19 H.Y. Jia, Labaciren, H.J. Li, J.Y. Li, X.X. Li, G. Liguori, 7 C. Liu, C.Q. Liu, J. Liu, M.Y. Liu, H. Lu, X.H. Ma, G. Mancarella, 4 S.M. Mari, 19 G. Marsella, 20 D. Martello, 4 S. Mastroianni, P. Montini, 19 C.C. Ning, A. Pagliaro, M. Panareo, B. Panico, 11 L. Perrone, P. Pistilli, 19 X.B. Qu, F. Ruggieri, P. Salvini, R. Santonico, 11 P.R. Shen, X.D. Sheng, F. Shi, C. Stanescu, A. Surdo, Y.H. Tan, P. Vallania, 23 S. Vernetto, 23 C. Vigorito, 24 B. Wang, H. Wang, C.Y. Wu, H.R. Wu, B. Xu, L. Xue, Y.X. Yan, Q.Y. Yang, X.C. Yang, Z.G. Yao, A.F. Yuan, M. Zha, H.M. Zhang, Jilong Zhang, Jianli Zhang, L. Zhang, P. Zhang, X.Y. Zhang, Y. Zhang, Zhaxiciren, Zhaxisangzhu, X.X. Zhou, F.R. Zhu, Q.Q. Zhu, and G. Zizzi
118274966
Search for electroweak production of charginos and neutralinos using leptonic final states in pp collisions at $ \sqrt{s}=7 $ TeV
A bstractThe 2011 dataset of the CMS experiment, consisting of an integrated luminosity of 4.98 fb−1 of pp collisions at $ \sqrt{s}=7 $ TeV, enables expanded searches for direct electroweak pair production of charginos and neutralinos in supersymmetric models as well as their analogs in other models of new physics. Searches sensitive to such processes, with decays to final states that contain two or more leptons, are presented. Final states with three leptons, with a same-sign lepton pair, and with an opposite-sign lepton pair in conjunction with two jets, are examined. No excesses above the standard model expectations are observed. The results are used in conjunction with previous results on four-lepton final states to exclude a range of chargino and neutralino masses from approximately 200 to 500 GeV in the context of models that assume large branching fractions of charginos and neutralinos to leptons and vector bosons.
119932959
Temperature effect on RPC performance in the ARGO-YBJ experiment
Abstract The ARGO-YBJ experiment has been taking data for nearly 2 years. In order to monitor continuously the performance of the Resistive Plate Chamber detectors and to study the daily temperature effects on the detector performance, a cosmic ray muon telescope was setup near the carpet detector array in the ARGO-YBJ laboratory. Based on the measurements performed using this telescope, it is found that, at the actual operating voltage of 7.2 kV, the temperature effect on the RPC time resolution is about 0.04 ns / ∘ C and on the particle detection efficiency is about 0.03 % / ∘ C . Based on these figures we conclude that the environmental effects do not affect substantially the angular resolution of the ARGO-YBJ detector.
122554631
Early warning for VHE gamma-ray flares with the ARGO-YBJ detector
Abstract Detecting and monitoring emissions from flaring gamma-ray sources in the very-high-energy (VHE, > 100 GeV) band is a very important topic in gamma-ray astronomy. The ARGO-YBJ detector is characterized by a high duty cycle and a wide field of view. Therefore, it is particularly capable of detecting flares from extragalactic objects. Based on fast reconstruction and analysis, real-time monitoring of 33 selected VHE extragalactic sources is implemented. Flares exceeding a specific threshold are reported timely, hence enabling the follow-up observation of these objects using more sensitive detectors, such as Cherenkov telescopes.
118646643
A hybrid model of GeV-TeV gamma ray emission from the Galactic center
The observations of high energy gamma-ray emission from the Galactic center (GC) by HESS, and recently by Fermi, suggest cosmic ray acceleration in the GC and possibly around the supermassive black hole. In this work we propose a lepton-hadron hybrid model to simultaneously explain the GeV-TeV gamma-ray emission. Both electrons and hadronic cosmic rays were accelerated during the previous activity of the GC. These particles would then diffuse outwards and interact with the interstellar gas and background radiation field. The collisions between hadronic cosmic rays with gas are responsible for the TeV gamma-ray emission detected by HESS. With fast cooling in the strong radiation field, the electrons would cool down and radiate GeV photons through inverse Compton scattering off the soft background photons. This scenario provides a natural explanation for the observed GeV-TeV spectral shape of gamma-ray.