121009179
Strings and Superstrings
The last Nobel Symposium on elementary particle physics ended on May 25 1968. The main topics discussed at that meeting were: high energy scattering of hadrons, infinite component field theory and electroweak unification. The last of these topics is the one which is best remembered since it is associated with the revolution in our understanding of the field theoretic description of the weak and electromagnetic forces. The first two topics, however, are closely associated with the origins of string theory. This talk will survey the development of string theory from that time up to the summer of 1984, since when there has been an explosion of activity in superstring theory which forms the main topic of this meeting.
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.
121755839
PHASE CONTOURS AND BOOTSTRAPS. I.
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.
30486904
The mechanical and thermal design for the MICE focusing solenoid magnet system
The focusing solenoids for MICE surround energy absorbers that are used to reduce the transverse momentum of the muon beam that is being cooled within MICE. The focusing solenoids will have a warm-bore diameter of 470 mm. Within this bore is a flask of liquid hydrogen or a room temperature beryllium absorber. The focusing solenoid consists of two coils wound with a copper matrix Nb-Ti conductor originally designed for MRI magnets. The two coils have separate leads, so that they may be operated at the same polarity or at opposite polarity. The focusing magnet is designed so that it can be cooled with a pair of 1.5 W (at 4.2 K) coolers. The MICE cooling channel has three focusing magnets with their absorbers. The three focusing magnets will be hooked together in series for a circuit stored-energy of about 9.0 MJ. Quench protection for the focusing magnets is discussed. This report presents the mechanical and thermal design parameters for this magnet, including the results of finite element calculations of mechanical forces and heat flow in the magnet cold mass.
55893148
Measurements of Passive Correction of Magnetization Higher Multipoles in One Meter Long Dipoles
L LBL--29499 DE91 OO1812 MEASUREMENTS OF PASSIVE CORRECTION OF MAGNETIZATION HIGHER MULTIPOLES IN ONE ME'/ER LONG DIPOLES M. A. Green, R. F. Althaus, P. J. Barale, R.W. Benjegerdes, W. S. Gilbert, M. I. Green, R. M. Scanlan, and C. E. Taylor Lawrence BerkeleyLaboratory University of California Berkeley, CA 94720 1990 Applied Superconductivity Conference Snowmass, CO September 24-28, 1990 *This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, High Energy Physics Division, U.S. Dept. of Energy, under Contract No, DE-ACO3-76SF0(O)98. £)I_r RIBUTION THIS DOCUMENTISUN!,,._b, OF
122870434
A comparison of ASTROMAG coils made with aluminum and copper based superconductor
The use of an aluminum matrix superconductor in the coils for the ASTROMAG magnet will increase the integrated field for conducting particle astrophysics experiments in space as compared to equal mass coils made with a copper matrix superconductor. The increased ability to detect charged particles can be achieved without decreasing the current margin of the superconductor in the coils. The use of a low-resistivity aluminum matrix conductor increases the energy needed to initiate a quench by two orders of magnitude. The current decay time constant during a quench is substantially increased. As a result, the quench energy dumped into the helium tank is reduced (the ASTROMAG coils are thermally decoupled from the helium tank), and the forces on the shield and shells due to eddy currents will be lower. A description is also given of the problems associated with the use of an aluminum matrix superconductor in the coils.
39829406
The Helium Cooling System and Cold Mass Support System for the MICE Coupling Solenoid
The MICE cooling channel consists of alternating three absorber focus coil module (AFC) and two RF coupling coil module (RFCC) where the process of muon cooling and reacceleration occurs. The RFCC module comprises a superconducting coupling solenoid mounted around four conventional conducting 201.25 MHz closed RF cavities and producing up to 2.2 T magnetic field on the centerline. The coupling coil magnetic field is to produce a low muon beam beta function in order to keep the beam within the RF cavities. The magnet is to be built using commercial niobium titanium MRI conductors and cooled by pulse tube coolers that produce 1.5 W of cooling capacity at 4.2 K each. A self-centering support system is applied for the coupling magnet cold mass support, which is designed to carry a longitudinal force up to 500 kN. This report will describe the updated design for the MICE coupling magnet. The cold mass support system and helium cooling system are discussed in detail.
118961628
A LARGE HIGH CURRENT DENSITY SUPERCONDUCTING SOLENOID FOR THE TIME PROJECTION CHAMBER EXPERIMENT
TWO-WEEK LOAN COpy This is a Library irculating Copy which may be borrowed for two weeks. For a personal retention copy, call Tech. Info. Diuision, Ext. 6782