121615877
Properties of the covariant formulation of superstring theories
Abstract The covariant two-dimensional action principle that describes the dynamics of free superstrings in a Minkowski background is reviewed. Covariant gauge conditions are formulated, which simplify the equations of motion of the superspace coordinates to free equations. In this gauge there are bosonic and fermionic constraints whose generators give a supersymmetric generalization of the Virasoro algebra. As in certain supersymmetric field theories, closure of the algebra requires using the equations of motion. Covariant constrained bracket relations are obtained for the classical theory, but it is very difficult to extend them to quantum mechanical commutation relations. Interaction vertices satisfying supersymmetry and the necessary gauge conditions are constructed. They reduce in a special frame to ones found in earlier work in the light-cone gauge, and then can be interpreted quantum mechanically.
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.
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.
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.
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.
121004261
A burnout safety condition for superconducting magnets and some of its applications
From the time evolution of the current in a superconducting coil during a quench, an upper limit can be computed for the temperature reached anywhere in the coil. A condition under which the danger of burnout is eliminated is derived here. It is used to show how the tests of superconducting magnets can be made safe against burnout and it provides constraints for the design of some type of magnets.
56416083
A compact-high performance NLC damping ring using high magnetic field bending magnets
We describe a 1.5 GeV damping ring for very low emittance e/sup /spl plusmn// beams that can be used for the NLC. A key feature of this system is the use of 7 T bending magnets to greatly reduce the size and cost of the storage ring as well as the tune and the damping ring while increasing the acceptance. We present only a preliminary study here.
124315608
Proposal to Construct an anti-Proton Source for the Fermilab Accelerator
We propose to build a small storage ring for the accumulation of antiprotons produced in an external target. Stochastic and electron cooling will be used to reduce the transverse and longitudinal phase space of the antiprotons. The dynamics of stochastic and electron cooling will also be studied in this storage ring using circulating protons. The cooled antiprotons can be re-injected into the main ring or energy doubler ring; after simultaneous acceleration along with a proton bunch the accelerator will become a colliding {bar}pp machine with a center of mass energy range of 300-2600 GeV. Luminosities in the range 10{sup 29}-10{sup 32} cm {sup -2}sec{-1} are expected.
122796888
Magnetic measurements at Lawrence Berkeley Laboratory
Recent magnetic measurement activities at LBL have been concentrated in two separate areas, electromagnets and permanent magnets for the Advanced Light Source (ALS), and superconducting magnets for the Superconducting Super Collider Laboratory (SSCL). A survey of the many different measurement systems is presented. These include AC magnetic measurements of an ALS booster dipole engineering model magnet, dipole moment measurements of permanent magnet blocks for ALS wigglers and undulators, permeability measurements of samples destined for wiggler and undulator poles, harmonic error analysis of SSC one-meter model dipoles and quadrupoles and five-meter long SSC prototype quadrupoles, harmonic error analysis of ALS dipoles, quadrupoles, and sextupoles, precision Hall probe mapping of ALS storage ring combined function magnets, and the design of the ALS insertion device magnetic mapping system. A Unix-based data acquisition system that is being developed for the SSC is also described. Probes used for magnetic measurements include Helmholtz coils, integral coils, point coils, bucking harmonic analysis coils, several different types of Hall probes, and nuclear magnetic resonance magnetometers. >
38708797
The mechanical and thermal design for the MICE coupling solenoid magnet
The MICE coupling solenoids surround the RF cavities that are used to increase the longitudinal momentum of the muon beam that is being cooled within MICE. The coupling solenoids will have a warm-bore diameter of 1394 mm. This is the warm bore that is around the 200 MHz RF cavities. The coupling solenoid is a single superconducting coil fabricated from a copper matrix Nb-Ti conductor originally designed for MRI magnets. A single coupling magnet is designed so that it can be cooled with a single 1.5 W (at 4.2 K) cooler. The MICE cooling channel has two of these solenoids, which will be hooked together in series, for a magnet circuit with a total stored-energy of the order of 12.8 MJ. Quench protection for the coupling coils is discussed. This report also 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.