120075255
The quantum mechanics of the gauge-invariant O(2) Heisenberg model
The two-dimensional gauge-invariant O(2) Heisenberg (classical X-Y) model is discussed in terms of a Hamiltonian formulation on a one-dimensional spatial lattice with continuous “time”. Particular emphasis is placed on the spectrum of the model and the behaviour of the Wilson loop (which is relevant to the confinement properties). The entire energy spectrum as well as the eigenfunctions of the model are determined in a certain coupling regime by applying a WKB method suitable for periodic potentials. 
 
A tight binding (periodic Gaussian) approximation to the quantum Hamiltonian and its wave functional is introduced. The Wilson loop is explicitly calculated in terms of this approximation and is seen to be crucially influenced by the periodicity of the wave functional. The dominant contributions to be Wilson loop correspond to cross sections through the centres of vortices.
121062482
N=4 Yang-Mills and N=8 Supergravity as Limits of String Theories
The formulation of supersymmetric string theories in ten dimensions is generalized to incorporate compactified dimensions. Expressions for the one-loop four-particle S -matrix elements of N = 4 Yang-Mills and N = 8 supergravity in four dimensions are obtained by studying the string-theory loop amplitudes in the limit that the radii of the compactified dimensions and the Regge slope parameter simultaneously approach zero. If certain patterns that emerge should persist in the higher orders of perturbation theory, then N = 4 Yang-Mills in four dimensions would be ultraviolet finite to all orders, whereas N = 8 supergravity in four dimensions would have ultraviolet divergences starting at three loops.
121755839
PHASE CONTOURS AND BOOTSTRAPS. I.
120539667
Anomaly cancellations in supersymmetric D = 10 gauge theory and superstring theory☆
Abstract Supersymmetric ten-dimensional Yang-Mills theory coupled to N = 1, D = 10 supergravity has gauge and gravitational anomalies that can be partially cancelled by the addition of suitable local interactions. The remaining pieces of all the anomalies cancel if the gauge group is SO(32) or E 8 × E 8 . These cancellations are automatically incorporated in the type I superstring theory based on SO(32). A superstring theory for E 8 × E 8 has not yet been constructed.
123230985
Off-shell states in the dual model
Abstract We present a class of Lorentz invariant, gauge invariant off-shell amplitudes for the ordinary Veneziano and Ramond-Neveu-Schwarz dual models. They correspond to interactions with the string which are local in space-time.
9607753
Anomalous creation of branes
In certain circumstances when two branes pass through each other a third brane is produced stretching between them. We explain this phenomenon by the use of chains of dualities and the inflow of charge that is required for the absence of chiral gauge anomalies when pairs of D-branes intersect.
43416126
Design and Construction of a Prototype Solenoid Coil for MICE Coupling Magnets
A superconducting coupling solenoid mounted around four conventional RF cavities, which produces up to 2.6 T central magnetic field to keep the muons within the cavities, is to be used for the Muon Ionization Cooling Experiment (MICE). The coupling coil made from copper matrix NbTi conductors is the largest of three types of magnets in MICE both in terms of 1.5 m inner diameter and about 13 MJ stored magnetic energy at full operation current of 210 A. The stress induced inside the coil assembly during cool down and magnet charging is relatively high. In order to validate the design method and develop the coil winding technique with inside-wound SC splices required for the coupling coil, a prototype coil made from the same conductor and with the same diameter and thickness but only one-fourth long as the coupling coil was designed and fabricated by ICST. The prototype coil was designed to be charged to strain conditions that are equivalent or greater than would be encountered in the coupling coil. This paper presents detailed design of the prototype coil as well as developed coil winding skills. The analyses on stress in the coil assembly and quench process were carried out.
29897332
High-gradient normal-conducting RF structures for muon cooling channels
We present a status report on the research and development of high-gradient normal-conducting RF structures for the ionization cooling of rations in a neutrino factory or muon collider. High-gradient RF structures are required in regions enclosed in strong focussing solenoidal magnets, precluding the application of superconducting RF technology. We propose using linear accelerating structures, with individual cells electromagnetically isolated, to achieve the required gradients of over 15 MV/m at 201 MHz and 30 MV/m at 805 MHz. Each cell will be powered independently, and cell length and drive phase adjusted to optimise shunt impedance of the assembled structure. This efficient design allows for relatively small field enhancement on the structure walls, and an accelerating field approximately 1.7 times greater than the peak surface field. The electromagnetic boundary of each cell may be provided by a thin Be sheet, or an assembly of thin-walled metal tubes. Use of thin, low-Z materials will allow passage of the muon beams without significant deterioration in beam quality due to scattering. R&D in design and analysis of robust structures that will operate under large electric and magnetic fields and RF current heating are discussed, including the experimental program based in a high-power test laboratory developed for this purpose.
54892068
GROUND PLANE INSULATION FAILURE IN THE FIRST TPC SUPERCONDUCTING COIL
mm I UNIVERSITY OF CALIFORNIA LBL-12326 C Q k A • V.IL . V U . I Lawrence Berkeley Laboratory Engineering & Technical Services Division To b e p r e s e n t e d a t t h e 7 t h I n t e r n a t i o n a l C o n f e r e n c e on Magnet T e c h n o l o g y , K a r l s r u h e , West Germany, March 3 0 - A p r l l 3 , 1 9 8 1 ; and t o be p u b l i s h e d In t h e P r o c e e d i n g s GROUND-PLANE INSULATION FAILURE IN THE FIRST TPC SUPERCONDUCTING COIL M.A. G r e e n , P . Del P i e r r e , K. D e r b y , J . M . D u O l i v a r e s , P . H . E b e r h a r d , B . T . F u l t z , R.D. G i a u q u e , G.H. G i b s o n , F . S . G o u l d i n g , J . I . Kim, P . S . M a r t i n , J . W . M o r r i s , M. P r i p s t e i n , R.R. R o s s , M.D. S h a p i r o , E.G. S m i t s , and J . D . T a y l o r March Prepared for the U.S. Department ot Energy under Contract W-7405-ENG-4B MsmiurtoN OF THIS n u r is WIUUTEO
118369157
BENT SOLENOID SIMULATIONS FOR THE MUON COOLING EXPERIMENT
The muon collider captures pions using solenoidal fields. The pion are converted to muons as they are bunched in an RF phase rotation system. Solenoids are used to focus the muons as their emitance is reduced during cooling. Bent solenoids are used to sort muons by momentum. This report describes a bent solenoid system that is part of a proposed muon cooling experiment. The superconducting solenoid described in this report consists of a straight solenoid that is 1.8 m long, a bent solenoid that is 1.0 m to 1.3 m long and a second straight solenoid that is 2.6 m long. The bent solenoid bends the muons over an angle of 57.3 degrees (1 radian). The bent solenoid has a minor coil radius (to the center of the coil) that is 0.24 m and a major radius (of the solenoid axis) of 1.0 m. The central induction along the axis is 3.0 T There is a dipole that generates an induction of 0.51 T, perpendicular to the plane of the bend, when the induction on the bent solenoid axis is 3.0 T.
122748175
Calculation of the pressure rise in the cooling tube of a two-phase cooling system during a quench of an indirectly cooled superconducting magnet
Large superconducting detector magnets are indirectly cooled with two-phase helium flowing in cooling tubes attached to the coil or its support structure. Large detector magnets often quench such that most of the magnet stored energy ends up as heat stored in the coil package. The time constant for energy deposition in the coil and support structure is often quite short. This paper presents a method for calculating the peak pressure rise in the magnet two-phase cooling tube during a magnet quench. A comparison of calculated peak pressure rise and measured pressure rise for the PEP-4 solenoid is presented in this report. >