120775832
World-sheet dynamics of bosonic string theory
Abstract Bosonic string theory may emerge as an approximation to a two-dimensional string theory in which strings replace the usual pointlike world-sheet fields. In this context the energy of the ground state of the bosonic string (the mass of the tachyon) is shown to arise from the breaking of Atkin-Lehner symmetry on a cylindrical target space. No normal ordering infinities are encountered.
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.
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.
119655108
The effect of muon decay on the design of dipoles and quadrupoles for a muon collider
The decay of muons to neutrinos and electrons can cause heating in the superconducting dipoles and quadrupoles in the muon collider acceleration rings and the colliding beam ring. The problem is particularly acute in the colliding beam ring where heating in the magnets can be as high as 2.4 kW per meter in the bending magnets of muon collider ring with 2 TeV mu plus and mu minus beams with 2.22×1012 particles per bunch at a repetition rate of 30 Hz. The energy deposited within the helium temperature region must be reduced at least three orders of magnitude in order for the refrigeration system to begin to keep up with the heat load. Beam heating from muon decay will require changes in dipole design from the traditional cosine theta (or intersecting ellipse) design used in the SSC magnets. Some dipole and quadrupole design options are presented in this report for both the accelerator rings and the colliding beam rings.
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.
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.
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.
121794117
THE ROLE OF QUENCH BACK IN QUENCH PROTECTION OF A SUPERCONDUCTING SOLENOID
Abstract This report demonstrates the role of quench back in the quench protection of high current density superconducting solenoid magnets with well-coupled shorted secondary circuits. The phenomenon of ‘quench back’ can be used to greatly reduce the size of an external quench protection resistor or even to eliminate the need for an external quench protection system altogether. A comparison is made with conventional magnet quench protection systems with and without a closely coupled secondary circuit.