29000
Chiral QCD, general QCD parameterization and constituent quark models
Several recent papers -using effective QCD chiral Lagrangians- reproduced results obtained with the general QCD parameterization (GP). These include the baryon 8+10 mass formula, the octet magnetic moments and the coincidental nature of the "perfect" -3/2 ratio between the magnetic moments of p and n. Although we anticipated that the GP covers the case of chiral treatments, the above results explicitly exemplify this fact. Also we show by the GP that -in any model or theory (chiral or non chiral) reproducing the results of exact QCD- the Franklin (Coleman Glashow) sum rule for the octet magnetic moments must be violated.
14665617
Comment on "Chiral symmetry and the intrinsic structure of the nucleon"- by D.B.Leinweber,A.W.Thomas and R.D.Young
Some remarks are presented on a recent paper (Leinweber,Thomas and Young, Phys.Rev.Lett. 86, 5011, 2001). In particular a statement of the above paper on the fact that the ratio between the magnetic moments of proton and neutron should remain constant at -3/2, independent of the change of the quark mass is discussed on the basis of the general parameterization.
120916653
The relation between QCD and constituent quark models
124837005
SEARCH FOR QUARKS WITH THE FERROMAGNETIC LEVITATION ELECTROMETER
120776511
The non-relativistic quark model
The classification scheme and decay properties of hadron states are investigated in the framework of the non relativistic quark model. The main successes and the unsolved difficulties of the model are presented indicating the future work which could be done to understand and exploit the non-relativistic quark ideas.РезюмеИсследованы схема классификации и распадные свойства адронов в рамках статической модели кварков. Изложены главные успехи и нерешенные проблемы модели, указывая задачи, которые должны быть решены для лучшего понимания и использования нерелятивистских идей.
119592224
New Results in the Search of Quarks in Matter by the Magnetic Levitation Electrometer
Abstract The results of many runs performed levitating in succession several spheres without opening the levitation chamber show the existence of an additional (magneto-electric) force acting on the sphere. Ignoring this force in the analysis of the data produces “spurious” fractional charges.
56048929
The BOM 1000 Turn Display : a Tool to Visualize the Transverse Phase-Space Topology at LEP
The LEP BOM 1000 Turn facility enables the User to acquire the position of the beam at each beam position monitor over a number of consecutive turns. By kicking the beam and acquiring the first 1000 turns after the kick, the dynamic behavior of the beam in such a condition can be studied. In particular, by selecting a position monitor and plotting the position of the beam at a given turn against the position shifted by one (or n) turn(s), the evolution of the beam in the phase-space can be observed. Fixed points in the phase-space can be put in evidence, as well as the beam behavior in their neighbourhood. Quantities like the beam damping, or the beam detuning as function of the position amplitude can also be studied in this way. Significant examples from real life will be shown.
56158732
Multiturn Measurements at the CERN SPS
The CERN SPS multiturn facility, based on the new beam orbit measurement system MOPOS, enables the User to acquire the position of the beam at each beam position monitor (BPM) over a number of consecutive turns. When the multiturn acquisition is synchronised with a perturbation imposed on the beam (for instance a fast kick), useful information about the optics of the SPS and the dynamic behaviour of the beam can be extracted from the data. A measurement of the amplitude and phase of the betatron oscillation at each BPM can be used to compare the theoretical optics functions with the real ones, and possibly to detect localised errors. Differences between two such measurements can be used to study the dependence on a variable parameter (e.g. beam intensity, beam energy, etc.) and therefore indirectly measure quantities, like the impedance, distributed along the ring. Finally, due to the 90 degrees phase advance lattice, plotting the positions measured at two consecutive BPMs against each other gives information about the behaviour of the beam in the transverse phase space. Results of measurements performed at the CERN SPS are presented.
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.
107525573
The Q-Loop : a Function Driven Feedback System for the Betatron Tunes During the LEP Energy Ramp
In normal operation LEP is ramped from injection energy, typically 22 GeV, to energies of over 90 GeV where physics taking takes place. Effective control of the betatron during the ramp is essential to ensure good transmission of stored current. The LEP Q-loop is a feedback system used to control the tunes during the energy ramp. By following a pre-programmed tune function it provides a means of avoiding dangerous resonances and thus beam loss. The basic components the Q-loop will be described, and operational results presented. Emphasis will be given to the problems encountered and the solutions found.
55438680
THE ELECTRICAL CIRCUIT DESCRIPTION FOR THE LHC
The LHC is a very complex machine, made of about 8000 superconducting magnets along a circumference of 26.7 km. The magnets are powered in about 1700 different electrical circuits with currents ranging from 60 A (for small corrector magnets) up to 13 kA for the main dipoles and quadrupoles. The layout of the powering system reflects the complexity of the accelerator. About 80000 high current connections will have to be made. A minor fault in a circuit or one of the superconducting connections would have severe consequences for accelerator operation. For the integration of the electrical equipment, for supporting the assembly and verifying the correctness of the electrical circuits, all relevant information should be included in one coherent database. A simple method for the description of the electrical circuits is proposed, while an associated tool is translating this input into database information and back, checking the circuit description at the same time for inconsistencies. Out of the database information, electrical drawings and detailed views of the electrical connections at every LHC interconnection point can be recreated. This paper describes the approach and outlines several possible applications.