117118930
Gentle and violent gold interactions from the BNL AGS
118728331
KLOE measurement of the $\sigma(\pi^+ \pi^- (\gamma))$ cross section and the pi+ pi- contribution to the muon anomaly
117751922
Substructural dependence of the multiparticle production in relativistic heavy-ion interactions
17251648
Measurement of the DAΦNE luminosity with the KLOE detector using large angle Bhabha scattering
We describe the method of measuring the integrated luminosity of the e+e- collider DAΦNE, the Frascati φ-factory. The measurement is done with the KLOE detector selecting large angle Bhabha scattering events and normalizing them to the effective cross section. The e+e-→e+e-(γ) cross section is calculated using different event generators which account for the $\mathcal{O}(\alpha)$ radiative initial and final state corrections, and the φ resonance contribution. The accuracy of the measurement is 0.6%, where 0.3% comes from systematic errors related to the event counting and 0.5% from theoretical evaluations of the cross section.
126297547
Experimental study of hadron inclusive production in J / psi energy region
122689361
Search for New Phenomena with the Monojet and Missing Transverse Momentum Signature Using the ATLAS Detector in $\sqrt{s}=7$ TeV Proton-Proton Collisions
A search for new phenomena in events featuring a high energy jet and large missing transverse momentum in proton-proton collisions at root s = 7 TeV is presented using a dataset corresponding to an integrated luminosity of 33 pb(-1) recorded with the ATLAS detector at the Large Hadron Collider. The number of observed events is consistent with the Standard Model prediction. This result is interpreted in terms of limits on a model of Large Extra Dimensions. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved.
201630181
THE COUPLING COMPENSATION AND MEASUREMENT IN THE INTERACTION REGION OF BEPCII
The detector solenoid field in the BEPCII interaction region will be compensated by six anti-solenoids, which are located nearby the interaction point. Skew quadrupoles are adopted for the global coupling compensation. The coupling compensation scheme and the method to tune and measure the x-y coupling at the interaction point will be introduced in detail. COUPLING COMPENSATION SCHEME The BESIII detector solenoid has maximum field strength of 1.0T over an effective length of ±1.8m around the interaction point (IP) where the particle motion between the horizontal and vertical planes will be coupled. The lattice functions, the vertical emmittance and the tilt angle of beam are strongly related to the coupling parameters. Therefore, without the dedicated coupling compensation it is impossible to meet higher luminosity. According to the requirements of high energy physics, BEPCII will be operated at the energy range from 1.0GeV to 2.1GeV, so the compensation system should be powerful enough to work perfectly for particles within the momentum range. For this purpose an anti-solenoid system has been designed in the superconducting magnet package to realize the local compensation of x-y coupling effects in the interaction region (IR). This system consists of three anti-solenoids AS1, AS2 and AS3 and a skew quadrupole inside the superconducting cryostat. AS1 locates between the IP and the superconducting quadrupole (SCQ) which acts as the first vertical focusing quadrupole. AS2 and the skew quadrupole overlap SCQ, while AS3 locates after SCQ. They are all dedicated to the compensation of the detector fields along the beam line for both e+ and erings which have the same beam energy. The local compensation layout of BEPCII and wiring schematic diagram are shown in Fig. 1. Figure 1: The local coupling compensation layout of BEPCII and wiring schematic diagram. With this compensation scheme, the integral field ∫Bzds between the IP and SCQ is zero. The longitudinal field over SCQ is nearly zero and the integral field ∫Bzds between SCQ and the first horizontal focusing quadrupole is zero too. As well known the compensation of longitudinal field within SCQ region is a key for higher luminosity. The skew quadrupole which overlaps SCQ can make fine tuning of longitudinal field over the SCQ region instead of the mechanical rotation method. AS2 and AS3, which have their own independent trim circuits to allow fine tuning of the anti-solenoid compensation scheme, are in series with AS1. Fig. 2 shows the distribution of the axial combination magnetic field Bz along the axis of BESIII detector after compensation simulated by OPERA-2D code. Figure 2: The distribution of the axial combination magnetic field along the axis of the BESIII detector. Since the anti-solenoids AS1, AS2, AS3 and the skew quadrupole are the common elements for both e+ and erings, it is necessary to add some independent variables for the coupling adjustment of one ring with the coupling of the other ring unchanged. Due to the limitation of free space, we arrange four skew quadrupoles only for each ring, which are distributed in the interaction region, injection regions and RF region respectively for the further fine tuning of coupling. The horizontal dispersion in those regions is free so that the changes of the vertical dispersion and its slope can be neglected during the coupling adjustment. The global coupling parameter and the beam tile angle at the IP of each ring, which are induced by solenoid field, the beam vertical orbit distortion inside the sextupoles and the parasitic x-y coupling due to machine errors, can be compensated by tuning the strength of the skew quadrupoles and antisolenoids. ________________________________________ *Email: yuch@mail.ihep.ac.cn Proceedings of EPAC 2004, Lucerne, Switzerland
54722971
Study of solar neutrinos with the 600 t liquid argon ICARUS detector
Abstract The ICARUS time projection chamber can yield sound information on 8 B solar neutrinos. Owing to the high-energy resolution and the good capability of event reconstruction it can make a contribution to our understanding of neutrino intensities and their energy spectrum. Moreover, the MSW oscillation probability for sterile and active neutrinos can be well studied because both elastic scattering by electrons and absorption reaction on argon nuclei can be measured independently. The main problem in detecting the low-energy neutrino interactions arises from the environmental radioactivity. In the present work we study by Monte Carlo simulation the topology and the rates of the events, induced by neutrinos and background neutrons, in a 470 t (fiducial mass) liquid-argon TPC detector. For neutrino interactions we use the standard solar model BP98 and the recent experimental confirmation of the shell model computation of absorption cross section. The noise is estimated from new data on natural neutron background, collected in the hall C of the Gran Sasso laboratory. It is confirmed that, with a relatively modest neutron shielding and particular off-line event triggers, the weight of spurious events can be made to have little influence on the ICARUS solar neutrino measurement. Indeed, we expect 6 (26) background events per year in the 212 (759) elastic scattering (absorption reaction) sample.
195365361
An overview of design for CSNS/RCS and beam transport
The China Spallation Neutron Source (CSNS) is the first accelerator-based pulsed neutron source in China. Its accelerators are made up of an 80 MeV H− linac, a Rapid Cycling Synchrotron (RCS) and two beam transport lines. RCS accumulates and accelerates protons to the design energy of 1.6 GeV, and extracts high energy beam to strike the target. The overview of RCS is presented, and the key problems of the physics design are discussed. The two beam transport lines, from linac to RCS and from RCS to the target, are also introduced.
53403255
THE BUNCH LENGTH MEASUREMENT OF BEPC WITH A STREAK CAMERA
A dual-axis streak camera Hamamatsu model C5680-11, has been installed on Beijing Electron-Positron Collider (BEPC) to measure the bunch length and the bunch lengthening in the storage ring. The results of the measurement are more accurate and reliable than that measured with other instruments, and play important roles in the future upgrade of BEPC. In this paper we describe the synchrotron light extracting optics setup, the operating principle, features, the basic system configuration of the streak camera. Some typical results of the measurement in recent years are presented. The measurement errors including systematic and random are also analyzed.
8040521
Mass Differences within Isotopic Multiplets in a SUSY Electro-weak Theory
Based on the idea that electromagnetism is responsible for the mass differences within isotopic multiplets, and possibly also for the whole mass of the electron, a supersymmetric gauge theoretical model based on the group $SU(2)_{L} \times SU(2)_{R} \times U(1)_{Y}$ is constructed. Under some reasonable assumptions to the SUSY particle spectrum, a correct sign for the mass difference within an isotopic multiplet is obtained. This might provide a possible scenario to understand the old puzzle of the proton-neutron mass difference.