7718768
Study of electron recombination in liquid argon with the ICARUS TPC
Electron recombination in liquid argon (LAr) is studied by means of charged particle tracks collected in various ICARUS liquid argon TPC prototypes. The dependence of the recombination on the particle stopping power has been fitted with a Birks functional dependence. The simulation of the process of electron recombination in Monte Carlo calculations is discussed. A quantitative comparison with previously published data is carried out.
118728331
KLOE measurement of the $\sigma(\pi^+ \pi^- (\gamma))$ cross section and the pi+ pi- contribution to the muon anomaly
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.
126297547
Experimental study of hadron inclusive production in J / psi energy region
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.
117751922
Substructural dependence of the multiparticle production in relativistic heavy-ion interactions
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}
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
123281398
Transfer matrix of linear solenoid fringe superimposed magnet
The general transfer matrix of the superimposed solenoid magnet linear fringe field is given in this paper. It is an exact analytic matrix. The symplectic condition for the arbitrary shape solenoid will be discussed also.
56093763
DESIGN STUDIES ON 100MeV / 100kW ELECTRON LINAC FOR NSC KIPT NEUTRON SOURCE ON THE BASE OF SUBCRITICAL ASSEMBLY DRIVEN BY LINAC
In NSC KIPT, Kharkov, Ukraine a neutron source based on a subcritical assembly and driven by a 100 MeV/100kW electron linac is under design and development. Design and construction of such a linac with high average beam current, low emittance and low beam losses are challenging tasks. In this paper the linac physical design with beam simulation results are described, the accelerating structures and some key technical solutions are presented.
118531296
Suppression of the emittance growth induced by coherent synchrotron radiation in triple-bend achromats*
The coherent synchrotron radiation (CSR) effect in a bending path plays an important role in transverse emittance dilution in high-brightness light sources and linear colliders, where the electron beams are of short bunch length and high peak current. Suppression of the emittance growth induced by CSR is critical to preserve the beam quality and help improve the machine performance. It has been shown that the CSR effect in a double-bend achromat (DBA) can be analyzed with the two-dimensional point-kick analysis method. In this paper, this method is applied to analyze the CSR effect in a triple-bend achromat (TBA) with symmetric layout, which is commonly used in the optics designs of energy recovery linacs (ERLs). A condition of cancelling the CSR linear effect in such a TBA is obtained, and is verified through numerical simulations. It is demonstrated that emittance preservation can be achieved with this condition, and to a large extent, has a high tolerance to the fluctuation of the initial transverse phase space distribution of the beam.