122365527
The ghost structure of the superstring
Abstract The infinite towers of ghost fields that arise in the space-time supersymmetric formulation of the superstring fit into vector and metaplectic (spinor) representations of OSp(p, q|2m) supergroups. Conventional and “twisted” metaplectic representations of these groups are presented and the conditions on p, q and m that allow the OSp analogues of Majorana and Majorana-Weyl constraints are found. Invariant inner products of these representations are constructed and possible connections with the quantum action of the superstring are discussed.
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.
15960460
Instantons in supersymmetric Yang-Mills and D-instantons in IIB superstring theory
The one-instanton contributions to various correlation functions of superconformal currents in four-dimensional = 4 supersymmetric SU(2) Yang-Mills theory are evaluated to the lowest order in perturbation theory. Expressions of the same form are obtained from the leading effects of a single D-instanton extracted from the IIB superstring effective action around the AdS5 ? S5 background. This is in line with the suggested AdS/Yang-Mills correspondence. The relation between Yang-Mills instantons and D-instantons is further confirmed by the explicit form of the classical D-instanton solution in the AdS5 ? S5 background and its associated supermultiplet of zero modes. Speculations are made concerning instanton effects in the large-Nc limit of the SU(Nc) Yang-Mills theory.
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.
86694733
World‐Volumes and String Target Spaces
String duality suggests a fascinating juxtoposition of world-volume and target-space dynamics. This is particularly apparent in the D-brane description of stringy solitons that forms a major focus of this article (which is not intended to be a comprehensive review of this extensive and sophisticated subject). The article is divided into four sections: 
 
 
 
• The oligarchy of string world-sheets 
 
 
 
 
• p-branes and world-volumes 
 
 
 
 
• World-sheets for world-volumes 
 
 
 
 
• Boundary states, D-branes and space-time supersymmetry
136876640
VACUUM IMPREGNATION WITH EPOXY OF LARGE SUPERCONDUCTING MAGNET STRUCTURES
The Lawrence Berkeley Laboratory (LBL) has been developing a new generation of superconducting magnets which have the helium cooling system as an integral part of the magnet structure. The LBL technique calls for large sections of the magnet structure to be vacuum impregnated with epoxy. The epoxy was chosen for its impregnation properties. Epoxies which have good impregnation characteristics are often subject to cracking when they are cooled to cryogenic temperatures. The cracking of such an epoxy can be controlled by: (1) minimizing the amount of epoxy in the structure; (2) reducing the size of unfilled epoxy spaces; and (3) keeping the epoxy in compression. The technique for using the epoxy is often more important than the formulation of the epoxy. The LBL vacuum impregnation and curing technique is described. Experimental measurements on small samples of coil sections are presented. Practical experience with large vacuum impregnation superconducting coils (up to two meters in dia) is also discussed.
120781819
Cryogenic techniques for large superconducting magnets in space
Abstract A large superconducting magnet is proposed for use in a particle astrophysics experiment, ASTROMAG, which is to be mounted on the US Space Station. This experiment will have a two-coil superconducting magnet with coils which are 1.3 to 1.7 m in diameter. The two-coil magnet will have zero net magnetic dipole moment. The field 15 m from the magnet will approach earth's field in low earth orbit. The issue of high T c superconductor will be discussed in the paper. The reasons for using conventional niobium-titanium superconductor cooled with superfluid helium will be presented. Since the purpose of the magnet is to do particle astrophysics, the superconducting coils must be located close to the charged particle detectors. The trade-off between the particle physics possible and the cryogenic insulation around the coils is discussed. As a result, the ASTROMAG magnet coils will be operated outside the superfluid helium storage tank. The fountain effect pumping system which will be used to cool the coil is described in the report. Two methods for extending the operating life of the superfluid helium dewar are discussed. These include: (1) operation with a third shield cooled to 90 K with a sterling cycle cryocooler and (2) a hybrid cryogenic system where there are three hydrogen-cooled shields and cryostat support heat intercept points. Both methods will extend the ASTROMAG cryogenic operating life from 2 years to almost 4 years.
117651698
Field generated within the SSC magnets due to persistant currents in the superconductor
This report presents the results of a number of computer studies of the magnetic fields generated by persistent circulating currents in the superconductor of superconducting dipoles. These magnetic fields are referred to as residual fields throughout this report. Since the field generated by persistent currents have a hysteric behavior, they are analagous to the residual filed found in iron bound conventional solenoids. The residual field calculations presented in this report were done using the LBL SCMAG4 computer code. This code has not been well tested against measured data, but a comparison with measured CBA data given in this report suggests that good agreement is possible. The residual fields generated by persistent superconducting currents are rich in higher multipoles. This is of concern to the accelerator designer for SSC. This report shows the effect of various superconductor parameters and coil parameters on the magnitude and structure of the residual fields. The effect of the magnet charging history on residual fields is aldo discussed. 14 references.
31561398
Superconducting dipoles and quadrupoles for a 2 TeV muon collider
At 2 TeV the mean lifetime for a muon is 41.6 ms. In order to achieve high luminosity at the collider collision point, the dipole central induction for the storage ring should be over 8 T. The storage ring carries muon over 1000 turns through the ring before they decay away. Muons decay to two neutrinos and an electron or positron (depending on the charge of the decaying muon). Seventy percent of the muon energy will be taken away by the neutrinos. The electrons (at average energies of 700 GeV) and the photons (at energies up to 2.1 GeV) are quite penetrating. At the design luminosity of the muon collider, the superconducting dipoles and quadrupoles in the storage ring must contain muon beams (up to 1.4/spl times/10/sup 14/ muons per second) that will deposit over 1.8 kW per meter of energy into the storage ring. This report presents two design approaches for superconducting dipoles and quadrupoles that can be used for the muon collider storage ring.
119852414
Superconducting dipole moment correction coils for a free-flying version of ASTROMAG
Abstract ASTROMAG is a particle astrophysics experiment which will operate in space for a period of two years or more. Momentum and charge resolution of cosmic rays is achieved using particle detectors in a magnetic field. In the ASTROMAG experiment, this magnetic field is provided by a pair of superconducting solenoids. The ASTROMAG superconducting magnet is supposed to have a zero net magnetic dipole moment so that magnetic torques introduced to the space craft are kept at a low level. Dipole moment correction coils, which can provide up to 11,000 Am 2 of correction in the Z direction and 7,000 Am 2 of correction in the X and Y directions, appear to be practical using superconducting correction coils which are mounted on the superfluid helium tank in a region 0.5 meters wide halfway between the main ASTROMAG coils. The superconducting dipole moment correction coils should be capable of reducing the ASTROMAG magnet net dipole moment to 100 Am −2 or lower.