56018915
Bunch lengthening study in BEPC
The bunch lengthening in the Beijing Electron-Positron Collider (BEPC) is investigated systematically with streak camera and the method of beam spectrum analysis. Many available results are obtained from the measurement and the corresponding scaling law is summarized in the light of the existing theoretical explanation. Due to its importance for BEPC upgrades, the related parameters and effects of bunch lengthening are studied in details.
56470793
DESIGN OF BEAM TRANSPORT LINE FROM RCS TO TARGET FOR CSNS
China Spallation Neutron Source (CSNS) uses the high energy proton beam to strike the Tungsten target to generate neutrons through spallation reaction. The proton beam is extracted from the Rapid Cycling Synchrotron (RCS), whose beam power reaches 100 kW. For the sake of target lifetime, beam distribution at the target surface is required as uniform as possible. Nonlinear beam density redistribution method with two octupole magnets has been studied. Also some simulation and theoretical calculation have been done. According to the simulation result, the beam density at the target is optimized and the beam loss is under control.
124075894
General conditions for self-cancellation of geometric aberrations in a lattice structure
In this paper we will discuss the general conditions for self-cancellation of geometric aberrations in an uncoupled or even coupled lattice structure. The self-cancellation conditions show that - I transformer even noninterleaved multipoles is not necessary. We will also give two examples for sextupole case to specify the application.
55843797
LATTICE DESIGN FOR THE BEPCII STORAGE RING
BEPCII, the upgrading project of the BEPC, has been being designed with a luminosity of 10 33 cm -2 s -1 at the J/ψ energy. It still keeps the potential to provide beams as a synchrotron radiation (SR) facility. The storage rings for collision contain a positron and an electron ring and the ring for dedicated SR uses the outer parts of the two rings. To fit all the conditions either on beam or on space limit, lattices are carefully designed for both high energy physics and SR experiments with sufficient dynamic apertures and high efficiencies for injection. The features of the lattices are also discussed in the paper. 1 DESIGN REQUIREMENTS BEPCII is an upgrade project of the Beijing ElectronPositron Collider (BEPC), in which a new inner ring will be installed inside the old one. It will provide colliding beams with the center-of-mass energy from 1.0GeV×2 to 2.0GeV×2 and also the dedicated synchrotron radiation beam with 2.5 GeV. For the colliding beams the luminosity is optimized at 1.89 GeV with 1×10 33 cm -2 s -1 . For the dedicated synchrotron radiation beam, the current is 250 mA with an emittance as low as possible. There have been several beam-lines in the BEPC for the synchrotron radiation experiments, so the current bending magnets and insertion devices in the southern region have to be fixed at their present positions. In order to increase the average luminosity, the “topoff” injection scheme up to 1.89 GeV is adopted. This requires that the injection and collision optics must be the same. The main parameters are shown in Tables 1 and 2.
123594822
Transfer matrices of dipoles with bending radius variation
With the increasing demand of high brightness in light source, the uniform dipole can not meet the needs of low emittance, and thus the dipole with bending radius variation is introduced in this paper. The transfer matrix of a non-uniform dipole whose bending radius is linearly changed is chosen as an example and a very simple calculation formula of non-uniform dipole transfer matrices is given. The transfer matrices of some common profile non-uniform dipoles are also listed. The comparison of these transfer matrices and the matrices calculated with slices method verifies the numerical accuracy of this formula. This method can make the non-uniform beam dynamic problem simpler, very helpful for emittance research and lattice design with non-uniform dipoles.
60626146
ILC Reference Design Report: ILC Global Design Effort and World Wide Study
126182293
Evidence of psi(3770) nonD anti-D decay to J / psi pi+ pi-
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.
120186826
Physics at BES-III
This physics book provides detailed discussions on important topics in $\tau$-charm physics that will be explored during the next few years at \bes3 . Both theoretical and experimental issues are covered, including extensive reviews of recent theoretical developments and experimental techniques. Among the subjects covered are: innovations in Partial Wave Analysis (PWA), theoretical and experimental techniques for Dalitz-plot analyses, analysis tools to extract absolute branching fractions and measurements of decay constants, form factors, and CP-violation and \DzDzb-oscillation parameters. Programs of QCD studies and near-threshold tau-lepton physics measurements are also discussed.
209869998
Observation of the decay psi(2S) ---> K*(892)anti-K + c.c.
123664055
Light Hadrons and New Enhancements in J/$\psi$ Decays at BESII
Based on 58 million $J/\psi$ samples collected by the BESII detector at the BEPC, many mesons, baryons, and new resonances have been reported. Here, I will review some recent results of glueball candidates and new enhancement.