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.
114095326
BEAM DYNAMIC ISSUES IN THE BEPCII LUMINOSITY COMMISSIONING
As a τ-charm factory like collider, the upgrade project of the Beijing Electron Positron Collider (BEPCII), has reached 1/3 of the design luminosity. During the luminosity commissioning, beam optics recovery, machine parameters measurement, detector solenoid compensation, and instability cure are main problems we met. Besides commissioning the machine, beams were delivered to the users from high energy physics and synchrotron radiation. This paper summarizes the accelerator physics issues in the BEPCII luminosity commissioning from 2009. INTRODUCTION BEPCII was designed as a factory-like collider with a design luminosity of 1×10cms at the beam energy of 1.89GeV. It is characterized as “one machine, two purposes”, which means to provide beam not only for high energy physics experiment, but also for synchrotron radiation (SR) users in parasitic or dedicated mode. Using the BEPC tunnel, BEPCII keeps the linac and two transport lines same as BEPC, but was upgraded as two rings in parallel to store e and e beams, respectively, and named as BER and BPR. The two halves of the outer rings are connected as an SR ring, the third ring named as BSR, with 9 beam lines extracted from 5 wigglers, and other 6 beam lines from bending magnets. To save the budget, all the beam line extraction ports are kept the same as BEPC. The layout of BEPCII is shown in Fig. 1.
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.
1999632
Detection of scintillation light in coincidence with ionizing tracks in a liquid argon time projection chamber
A system to detect light from liquid argon scintillation has been implemented in a small, ICARUS-like, liquid argon time projection chamber. The system, which uses a VUV-sensitive photomultiplier to collect the light, has recorded many ionizing tracks from cosmic-rays in coincidence with scintillation signals. Our measurements demonstrate that scintillation light detection can provide an effective method for absolute time measurement of events and eventually a useful trigger signal. (C) 1999 Elsevier Science B.V. All rights reserved.
155098880
Design of transport lines for uniforming beam distribution with octupoles
The intensity distribution of a typical particle beam is an approximate Gaussian distribution while many applications require the beam to be uniform. Local bright spots on the targets for high-power Gaussian beams create difficult cooling problems and shorten the lifetime of the target. In this paper, we have theoretically studied uniformization of the transverse beam profile using two octupole magnets placed at particular locations in the beam transport line. The details about the requirements on magnet strength and phase advance will be shown. As an example, we take a set of China Spallation Neutron Source parameters to simulate the beam. The simulation result agrees well with theoretical formulas.
126065967
LUMINOSITY ENHANCEMENT AND PERFORMANCE IN BEPCII
122275863
Scalar mesons at KLOE
New results concerning the scalar mesons f 0 ( 980 ) produced in the ϕ → π π γ decays, and the a 0 ( 980 ) scalar mesons in the ϕ → a 0 ( 980 ) γ → η π 0 γ decays, are presented.
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.
202105722
Search for strong gravity signatures in same-sign dimuon final states using the ATLAS detector at the LHC
A search for microscopic black holes has been performed in a same-sign dimuon final state using 1.3 fb(-1) of proton-proton collision data collected with the ATLAS detector at a centre of mass energy of 7 TeV at the CERN Large Hadron Collider. The data are found to be consistent with the expectation from the Standard Model and the results are used to derive exclusion contours in the context of a low scale gravity model.
121797308
Simultaneous multiplicity and forward energy characterization of particle spectra in Au + Au collisions at 11.6-A-GeV/c
In this paper Au+Au collisions at 11.6A GeV/c are characterized by two global observables: the energy measured near zero degrees (E{sub ZCAL}) and the total event multiplicity. Particle spectra are measured for different event classes that are defined in a two-dimensional grid of both global observables. For moderately central events ({sigma}/{sigma}{sub int}{lt}12{percent}) the proton dN/dy distributions do not depend on E{sub ZCAL} but only on the event multiplicity. In contrast the shape of the proton transverse spectra shows little dependence on the event multiplicity. The change in the proton dN/dy distributions suggests that different conditions are formed in the collision for different event classes. These event classes are studied for signals of new physics by measuring pion and kaon spectra and yields. In the event classes doubly selected on E{sub ZCAL} and multiplicity there is no indication of any unusual pion or kaon yields, spectra, or K/{pi} ratio even in the events with extreme multiplicity. {copyright} {ital 1999} {ital The American Physical Society}
122316457
On the multiplicity fluctuations in relativistic heavy ion collisions
Abstract In the present letter we discuss the general features of the multiplicity distributions in relativistic heavy ion collisions. It is shown that from simple statistical considerations it is possible to predict the dependence of the dispersions of multiplicity distributions on the average multiplicities in any given rapidty wwindow. The applicability of the negative binomial distribution to multiplicity distributions from collisions with heavy ions is discussed.