125870392
BaBar technical design report
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
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.
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)
52993839
OBSERVATION OF TeV GAMMA RAYS FROM THE UNIDENTIFIED SOURCE HESS J1841–055 WITH THE ARGO-YBJ EXPERIMENT
We report the observation of a very high energy γ-ray source whose position is coincident with HESS J1841–055. This source has been observed for 4.5 years by the ARGO-YBJ experiment from 2007 November to 2012 July. Its emission is detected with a statistical significance of 5.3 standard deviations. Parameterizing the source shape with a two-dimensional Gaussian function, we estimate an extension , which is consistent with the HESS measurement. The observed energy spectrum is dN/dE = (9.0 ± 1.6) × 10–13(E/5 TeV)–2.32 ± 0.23 photons cm–2 s–1 TeV–1, in the energy range 0.9-50 TeV. The integral γ-ray flux above 1 TeV is 1.3 ± 0.4 Crab, which is 3.2 ± 1.0 times the flux derived by HESS. The differences in the flux determination between HESS and ARGO-YBJ and possible counterparts at other wavelengths are discussed.
145909018
Highlights from the ARGO-YBJ experiment
— The ARGO-YBJ experiment is a multipurpose detector exploiting the full coverage approach at very high altitude. The apparatus, in stable data taking since November 2007 with an energy threshold of a few hundreds of GeV and a duty-cycle > 85%, is located at the YangBaJing Cosmic Ray Laboratory (Tibet, P.R. China, 4300 m a.s.l., 606 g/cm). A number of interesting results are available in cosmic ray physics and in gamma-ray astronomy after the first 3 years of stable data taking. In this paper gamma-ray astronomy results are summarized.
124551811
The forward particle production in the energy range of 1 PeV as seen with the Tibet hybrid experiment
We are now operating the 500 m Yangbajing air-shower core (YAC-II) array near the center of the Tibet air-shower array ( Tibet-III ) to observe cosmic-ray chemical composition at the knee energy region since February 2011. The first step of YAC, called YAC-I, containing 16 detector units, was operated from May, 2009 to February, 2010. In this paper, we used the YAC-I and Tibet-III coincident data set obtained from May, 2009 through January, 2010 to present the electromagnetic spectrum of air shower cores at around 10 eV energy region. The effective live time is calculated as 100.5 days. We would like to report the comparison of our experimental data with MC model prediction in this paper.
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.
122785773
XYZ physics at BESIII
In this talk, we present the recent study on the charmonium-like states from the BESIII Collaboration based on large data samples above D ¯ D threshold. The observation of X(3872) from the Y(4260) radiative transition, the study of the Y states from the e + e − → π + π − hc process, and the observation of the charged Zc states are included .