119683268
Super-translations, superstrings and Chern-Simons forms
Abstract A three-dimensional Chern-Simons theory is formulated with gauge potentials taking values in the algebra of a non-degenerate super-translation group. This algebra, in which the D bosonic generators do not commute with supersymmetries, is only defined when D =3,4,6 or 10. The related WZW sigma model describes superstring theory in a fixed gauge.
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.
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.
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.
121755839
PHASE CONTOURS AND BOOTSTRAPS. I.
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.
20920211
The Inductive Coupling of the Magnets in MICE and its Effect on Quench Protection
The inductive coupling between various MICE magnet circuits is described. The consequences of this coupling on magnet charging and quenching are discussed. Magnet quench protection is achieved through the use of quench-back. Calculations of the quenching of a magnet due to quench-back resulting from circulating currents induced in the magnet mandrel due to quenching of an adjacent magnet are discussed. This report describes how the MICE magnet channel will react when magnets in that channel are quenched
122003703
Quench back in thin superconducting solenoid magnets
Abstract Superconducting magnets with well coupled, low resistance, secondary circuits have been observed to become fully normal faster than quench propagation in the coil would permit. This process is referred to as ‘quench back’. Quench back observed at the Lawrence Berkeley Laboratory (LBL) was caused by heating the secondary circuit from the current induced from the primary circuit as normal region in the superconducting coil propagated. This paper develops the theory for thermal quench back in thin solenoid magnets and compares this theory with measurements made in two one-meter diameter superconducting solenoid magnets.
54854389
The Effect of Extending the Length of the Coupling Coils in a Muon Ionization Cooling Channel
RF cavities are used to re-accelerate muons that have been cooled by absorbers that are in low beta regions of a muon ionization cooling channel. A superconducting coupling magnet (or magnets) are around or among the RF cavities of a muon ionization-cooling channel. The field from the magnet guides the muons so that they are kept within the iris of the RF cavities that are used to accelerate the muons. This report compares the use of a single short coupling magnet with an extended coupling magnet that has one or more superconducting coils as part of a muon-cooling channel of the same design as the muon ionization cooling experiment (MICE). Whether the superconducting magnet is short and thick or long and this affects the magnet stored energy and the peak field in the winding. The magnetic field distribution also affects is the muon beam optics in the cooling cell of a muon cooling channel.
122853350
A thin superconducting solenoid for use in a phase rotation induction linac
One of the proposals for delivering a cooled muon beam to a muon collider or a high intensity neutrino source uses an induction linac to phase rotate the muons that result from the decay of pions produced by a high intensity proton beam on a target. An induction linac with an acceleration gradient of 2 MV per meter is proposed to produce bunches of muons that have a momentum of 200 MeV/c. The induction accelerator is assembled around the 3 T superconducting solenoids needed to contain the muon beam. The superconducting solenoid must have a warm 100 mm gap at 1000 mm intervals down the phase rotation channel. The acceleration structure for the induction linac is around this gap. The superconducting solenoid will have an inside warm radius of 201 mm. The thickness of the superconducting magnet and its cryostat must be about 60 mm near the acceleration gap. An access region of 85 mm between induction linac sections is allowed for the superconducting coil cold mass supports, the electrical leads and the supply of cryogenic cooling. This report presents a design for a 3 T phase rotation induction linac superconducting magnet system, its cryostat, and its cooling system.
27453676
The Design and Construction of the MICE Spectrometer Solenoids
The purpose of the MICE spectrometer solenoid is to provide a uniform field for a scintillating fiber tracker. The uniform field is produced by a long center coil and two short end coils. Together, they produce 4T field with a uniformity of better than 1% over a detector region of 1000 mm long and 300 mm in diameter. Throughout most of the detector region, the field uniformity is better than 0.3%. In addition to the uniform field coils, we have two match coils. These two coils can be independently adjusted to match uniform field region to the focusing coil field. The coil package length is 2544 mm. We present the spectrometer solenoid cold mass design, the powering and quench protection circuits, and the cryogenic cooling system based on using three cryocoolers with re-condensers.