107933425
First trial of BOM harmonic analysis
12798237
Overview of LEP operation in 1998
After the installation of 32 additional RF cavities in the 1997-1998 shutdown LEP was operated at a beam energy of 94.5 GeV. The total integrated luminosity for the year 1998 clearly surpassed its target and reached 198 pb/sup -1/. Vertical beam-beam tuneshifts of more than 0.07 were obtained. The performance did not seem to be beam-beam limited, but the total beam current was limited by power dissipation problems to around 6 mA. A high phase advance optics (102/spl deg/, 90/spl deg/), with a smaller natural emittance, was used for regular operation in 1998. This contributed to the excellent performance of LEP, together with the further reduction of both the horizontal and vertical beta function at the interaction points. No dynamic aperture problems were encountered.
115464633
Do We Understand the Luminosity Imbalance
10489447
LEP OPERATION AND PERFORMANCE WITH 100 GEV COLLIDING BEAMS
Luminosity production in LEP was extended to 101 GeV beam energy in 1999 and 104.4 GeV in 2000. The performance was continually optimised, resulting in 1999 peak and integrated luminosities higher than in any previous year of LEP operation. In particular, the beambeam tune shift reached 0.083 per interaction point. This was achieved with the help of a faster luminosity monitoring, a new tune working point, a reduced design vertical dispersion and new dispersion and coupling optimisation tools. A higher beam rate from the injectors, a better injection efficiency, a faster ramp and a newly automated control of the horizontal damping partition number J x maximised the time available for physics and thus contributed to the higher integrated luminosity.
54676169
Measurement of chromatic effects in LEP
The chromaticity produced by the insertions and the lattice of LEP is corrected in the FODO lattice of the arcs which has horizontal and vertical phase advances of 90/spl deg/ and 60/spl deg/ for the LEP optics presently used. This is done with two horizontal and three vertical sextupole families. To check this correction scheme the non-linear chromaticities have been measured by observing the betatron tunes as a function of RF-frequency, i.e. of momentum deviation. The differences between the results and the expected effects of the sextupoles are interpreted in terms of octupole and decapole components in the dipole magnets. To check the distribution around the ring of the chromaticities and their corrections the betatron phase advances have been measured as a function of momentum deviation. This was done by observing an excited betatron oscillation for 1024 turns in all beam position monitors for different RF-frequencies. The results clearly show the negative chromaticity produced in the straight sections and its correction in the arcs. The parasitic sextupole components are found to be spread uniformly in the arcs within the measurement errors. Under this condition one finds that they have a negligible effect on the dynamic aperture.
61569699
The RTC-a software support system for the control of the CERN SPS
The RTC (Run Time Coordinator) is described. It is a software support system designed for the SPS (Super Proton Synchrotron) control system to provide a run time environment for application software. It coordinates the execution of individual programs or processes and supervises the process control, i.e. process synchronization, interprocess communication, data transfer, and operator I/O (input/output). This supervision includes the control of processes distributed on a Unix-based network. A standard language independent data interface is part of the system. The system includes tools for data presentation, error logging, and contention resolution. Separating system-dependent features for the body of the application programs leads to high flexibility and simplifies the software development. The basic philosophy of the RTC is discussed and its implementation is described.<<ETX>>
121212703
Comment on a paper by Buckingham and Herring on the magneto-electric force in quark search experiments
Abstract Buckingham and Herring have given an explanation of the magneto-electric force that we did identify in our quark search experiment. We agree with the explanation, but show that the relation between the quantity β and the experimental data used by Buckingham and Herring in their analysis needs a 13% modification; the statements by BH implying an inconsistency in the values of some of our residual charges are shown to be incorrect. The unexpected check of internal consistency of our data implied by the BH explanation of the magneto-electric force is in fact satisfied.
114313
Baryon octet magnetic moments to all orders in flavor breaking: An application to the problem of the strangeness in the nucleon
Using the general QCD parametrization (GP) we display the magnetic moments of the octet baryons including all flavor breaking terms to any order. The hierarchy of the GP parameters allows to estimate a parameter ${g}_{0}$ related to the quark loops contribution of the proton magnetic moment; its magnitude is predicted to be inside a comparatively small interval including the value given recently by Leinweber et al. from a lattice QCD calculation.
118367014
The General QCD parametrization and the hierarchy of its parameters: Why some simple models of hadrons work so well
After summarizing the basic points of the general QCD parametrization (GP) we discuss systematically its applications to the properties of the lowest families of baryons and mesons. We show how the hierarchy of the parameters in the GP emerges clearly in the properties of hadrons. Among other things, it explains why simple models can work reasonably well and clarifies the relationship between current and constituent quarks. More details on the hadron properties discussed with the GP appear from the list of secrions at the beginning of the paper.
121640423
Preliminary results in the search for fractionally charged particles by the magnetic levitation electrometer
Abstract The operation of the magnetic levitation electrometer suggested in ref. 1 is described. Measurements on the first five graphite grains (containing altogether ∼ 10 16 nucleons) exclude the presence of quarks in them; a future program of search for terrestrial quarks by this instrument is outlined.
120916653
The relation between QCD and constituent quark models