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.
267052
Comments on three-branes
Abstract The Born-Infeld-like effective world-volume theory of a single 3-brane is deduced from a manifestly space-time supersymmetric description of the corresponding D -brane. This is shown to be invariant under SL (2, R ) transformations that act on the abelian gauge field as well as the bulk fields. The effective theory of two nearby parallel three-branes involves massive world-volume supermultiplets which transform under SL (2, Z ) into the dyonic solitons of four-dimensional N = 4 spontaneously broken SU (2) Yang-Mills theory.
122046299
Duality Constraints on Inclusive Reactions. II. The Role of the Harari-Freund Conjecture
We present a scheme for the generalization of the two-component theory of Harari and Freund to multiparticle amplitudes and, in particular, to inclusive reactions. Our scheme is based on duality and borrows the terminology of dual perturbation theory but we do not restrict our generalizations to any specific model. We obtain a criterion for the absence of secondary (nonscaling) Regge contributions in inclusive reactions. We show how inclusive reactions may approach their limiting values from below, in contrast to total cross sections which always have positive secondary contributions. The scheme suggests a novel interpretation of diffraction dissociation which we discuss in a separate paper.
121804056
A lattice formulation of the Reggeon Field Theory and its critical behaviour
Abstract We formulate a lattice description of the Reggeon Field Theory in terms of two-dimensional vector spins of unit length (as in the x − y model). We exhibit, within the context of mean field theory, the phase transition of the Reggeon Field Theory that occurs as the (imaginary) magnetic field and temperature are varied in our statistical mechanical model.
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.
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.
29833302
Muon phase rotation using an induction linac
The proposed neutrino factory requires that the muons produced by the decay of pions and kaons produced by a target be phase-rotated before they can be cooled and then accelerated. This report describes a muon phase-rotation system that employs an induction acceleration system. The phase-rotation system consists of a 100-meter long induction accelerator, a mini-cooling system with magnetic flux reversal, and two 80-meter long induction linacs with a drift space between them. The induction linac phase-rotation system uses a 620-mm warm bore 1.25 T superconducting solenoid to guide the muons in the beam channel. The phase-rotation linac is divided into 1-meter long components each with its superconducting solenoid. This report describes the induction cells, the induction cell power system, and the superconducting solenoid contained within those cells.
36002879
Computer Simulation of the Interaction of a Superconducting Synchrotron Magnet Good Field Region with a Particle Beam
This paper illustrates how the results of several magnetic field calculation computer programs can be combined to form a single graphical representation of magnetic field quality within the aperture of a superconducting accelerator magnet. The graphical technique can be applied on a magnet by magnet basis over a range of current excitations. The paper illustrates the value of such graphics when the accelerator beam profile is shown within the simulated magnet bore.
118431021
Correction of Magnetization Sextupole in One-Meter Long Dipole Magnets Using Passive Superconductor
The generation of higher multipoles due to the magnetization of the superconductor in the dipoles of the SSC is a problem during injection of the beam into the machine. The use of passive superconductor was proposed some years ago to correct the magnetization sextupole in the dipole magnet. This paper presents the LBL test results in which the magnetization sextupole was greatly reduced in two one-meter long dipole magnets by the use of passive superconductor mounted on the magnet bore tube. The magnetization sextupole was reduced a factor of five on one magnet and a factor of eight on the other magnet using this technique. Magnetization decapole was also reduced by the passive superconductor. The passive superconductor method of correction also reduced the temperature dependence of the magnetization multipoles. In addition, the drift in the magnetization sextupole due to flux creep was also reduced. Passive superconductor correction appears to be a promising method of correcting out the effects of superconductor magnetization in SSC dipoles and quadrupoles.
117741073
Measurements of Magnetization Multipoles in Four Centimeter Quadrupoles for the SSC
Higher multipoles due to magnetization of the superconductor in superconducting dipole and quadrupole magnets has been observed in over twenty years. This report presents measurements of the 12 pole and 20 pole multipoles in a model one-meter long four-centimeter bore SSC type quadrupole built at the Lawrence Berkeley Laboratory (LBL). The measurements were compared with calculations of the field structure using magnetization theory. Good agreement was observed between the measured multipoles and the calculated multipoles. Under conditions equivalent to injection into the SSC at an energy of 2 TeV, about 1.0 unit of 12 pole was observed and 0.05 units of 20 pole was observed. (One unit of field error is a field error of one part in ten thousand). Magnetization multipole measurements were also done on the first full length (5 meter) SSC quadrupole prototype. Measurements of flux creep decay were made on three one meter quadrupoles and the first five meter long quadrupole. 7 refs., 9 figs.
6205052
The Effect of Magnetic Field on the Position of HTS Leads and the Cooler in the Services Tower of the MICE Focusing Magnet
The MICE focusing solenoids have three 4 K coolers (two for the superconducting magnet and one for the liquid absorber) and four HTS leads that feed the current to the focusing coils. The focusing solenoids produce large radial external fields when they operate with the polarity of the two coils in opposition (the gradient or flip mode). When the MICE focusing coils operate at the same polarity (the solenoid or non-flip mode), the fields are much smaller and parallel to the axis of the solenoid. The worst-case magnetic field affects the selection of the cooler and the HTS leads. This magnetic field can also determine the height of the service towers that house the three coolers and the four HTS leads. This paper shows the criteria used for Cooler selection, HTS lead selection, and the position of both the cooler and leads with respect to the solenoid axis of rotation.