119686406
Gating in the ALEPH Time Projection Chamber
The ALEPH TPC at LEP will use a gating grid to prevent distortions caused by space charge buildup in its 2.2 m drift region. Sets of measurements have demonstrated the feasibility of a “synchronous ion trapping” mode of gating, which reduces the positive ion flux through the grid by more than two orders of magnitude. A novel mode of gating will be discussed which would permit static operation of the gate, thereby avoiding the complexity of switching between the open and closed states of the gate. This mode would rely on the dissimilar gate penetration properties of electrons and ions in the presence of a magnetic field, and it may also provide a way to partially compensate for the E × B effect at the sense wires. A combination of these different modes is proposed for the ALEPH TPC.
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.
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
126253177
Experimental measurement of the mass of the tau lepton at the Beijing Electron Positron Collider (BEPC)
119348940
Detecting the dark matter annihilation at the ground EAS detectors
Abstract In this paper we study the possibility of detecting gamma rays from dark matter annihilation in the subhalos of the Milky Way by the ground based EAS detectors within the frame of the minimal supersymmetric Standard Model. Based on the Monte Carlo simulation we also study the properties of two specific EAS detectors, the ARGO and HAWC, and the sensitivities of these detectors on the detection of dark matter annihilation. We find the ground EAS detectors have the possibility to observe such signals. Conversely if no signal observed we give the constraints on the supersymmetric parameter space, which however depends on the subhalos properties.
53682355
The high energy cosmic-radiation detection (HERD) facility onboard China's Space Station
The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 104 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of seven X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side SKTs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R and D is under way for reading out the LYSO signals with optical fiber coupled to image intensified CCD and the prototype of one layer of CALO.
46496749
Measurement of dijet angular distributions and search for quark compositeness in pp collisions at √s = 7 TeV.
Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at √s = 7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 pb⁻¹. The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of Λ⁺ = 5.6 TeV (Λ⁻ = 6.7 TeV) for destructive (constructive) interference is obtained at the 95% confidence level.
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
52249775
Medium scale anisotropy in the TeV cosmic ray flux observed by ARGO-YBJ
B. Bartoli, P. Bernardini, X. J. Bi, I. Bolognino, P. Branchini, A. Budano, A.K. Calabrese Melcarne, P. Camarri, Z. Cao, R. Cardarelli, S. Catalanotti, S. Z. Chen, T. L. Chen, P. Creti, S.W. Cui, B. Z. Dai, A. D’Amone, Danzengluobu, I. De Mitri, B. D’Ettorre Piazzoli, T. Di Girolamo, G. Di Sciascio,* C. F. Feng, Zhaoyang Feng, Zhenyong Feng, Q. B. Gou, Y.Q. Guo, H. H. He, Haibing Hu, Hongbo Hu, M. Iacovacci, R. Iuppa, H.Y. Jia, Labaciren, H. J. Li, G. Liguori, C. Liu, J. Liu, M.Y. Liu, H. Lu, X. H. Ma, G. Mancarella, S.M. Mari, G. Marsella, D. Martello, S. Mastroianni, P. Montini, C. C. Ning, M. Panareo, B. Panico, L. Perrone, P. Pistilli, F. Ruggieri, P. Salvini, R. Santonico, S. N. Sbano, P. R. Shen, X.D. Sheng, F. Shi, A. Surdo, Y. H. Tan, P. Vallania, S. Vernetto, C. Vigorito, H. Wang, C. Y. Wu, H. R. Wu, L. Xue, Y.X. Yan, Q.Y. Yang, X. C. Yang, Z. G. Yao, A. F. Yuan, M. Zha, H.M. Zhang, L. Zhang, X.Y. Zhang, Y. Zhang, Zhaxiciren, Zhaxisangzhu, X.X. Zhou, F. R. Zhu, Q.Q. Zhu, and G. Zizzi