118906662
Instanton-induced Yang-Mills correlation functions at large N and their AdS5 x S5 duals
Correlation functions of chiral primary operators and their superconformal descendants in the = 4 supersymmetric SU(N) Yang-Mills theory are studied in detail in a one-instanton background and at large N. Whereas earlier calculations were restricted to correlation functions that are saturated by the 16 exact superconformal fermionic moduli, here the effect of the set of additional fermionic moduli associated with the embeddings of the SU(2) instanton in SU(N) is considered. The presence of the extra fermionic modes is essential for matching Yang-Mills instanton effects in various correlation functions with D-instanton effects in type-IIB string theory via the AdS/CFT conjecture. The leading terms of this kind on the string side contribute at order (α')−1 (where the Einstein-Hilbert terms are of order (α')−4), which is the same order as the 4 interaction. For example, the instanton contributions to correlation functions of higher dimensional chiral primary operators are seen to match amplitudes involving Kaluza-Klein excitations of the supergravity fields, as expected. Another example is the matching of certain multi-fermion correlation functions which correspond to certain multi-fermion interactions required by supersymmetry of the IIB string effective action. Careful analysis of a variety of competing effects makes it possible to decipher contributions corresponding to higher derivative interactions in the IIB effective action. In this manner it is possible to check for the presence of terms of order α'. Comments are also made on the structure of instanton contributions to near-extremal correlation functions of chiral primary operators.
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.
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.
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.
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.
135926847
Quench Protection and Magnet Supply Requirements for the MICEFocusingand Coupling Magnets
This report discusses the quench protection and power supply requirements of the MICE superconducting magnets. A section of the report discusses the quench process and how to calculate the peak voltages and hotspot temperature that result from a magnet quench. A section of the report discusses conventional quench protection methods. Thermal quench back from the magnet mandrel is also discussed. Selected quench protection methods that result in safe quenching of the MICE focusing and coupling magnets are discussed. The coupling of the MICE magnets with the other magnets in the MICE is described. The consequences of this coupling on magnet charging and quenching are discussed. Calculations of the quenching of a magnet due quench back from circulating currents induced in the magnet mandrel due to quenching of an adjacent magnet are discussed. The conclusion of this report describes how the MICE magnet channel will react when one or magnets in that channel are quenched.
54925012
MEASUREMENT OF RESISTANCE AND STRENGTH OF CONDUCTOR SPLICES IN THE MICE COUPLING MAGNETS
The superconducting magnets for the Muon Ionization Cooling Experiment [1] (MICE) use a copper based Nb‐Ti conductor with un‐insulated dimensions of 0.95 by 1.60 mm. There may be as many as twelve splices in one MICE superconducting coupling coil. These splices are to be wound in the coil. The conductor splices produce Joule heating, which may cause the magnet to quench. A technique of making conductor splices was developed by ICST. Two types of 1‐meter long of soldered lap‐joints have been tested. Side‐by‐side splices and up‐down one splices were studied theoretically and experimentally using two types of soft solder made of eutectic tin‐lead solder and tin‐silver solder. The resistances of the splices made by ICST were tested at LBNL at liquid helium temperatures over a range of magnetic fields up to 5 T. The breaking strength of 250 mm long splices was also measured at room temperature and liquid nitrogen temperature.
122379741
The UCLA Phi Factory Detector, the Integration of Superconducting Compensation Solenoids and the Final Focus Interaction Region Quadrupoles
Abstract The proposed Phi Factory for the University of California at Los Angeles (UCLA) is a small 510 MeV electron-positron colliding beam storage ring with high luminosity (greater than 10 32 cm −2 s −1 ). In order to do high quality Phi physics, a particle detector system with a large solid angle (preferably greater than 98 percent) is required. Particle detection and analysis will be done within a 0.5 tesla solenoidal magnetic field. The solenoidal field within the detector causes coupling between beam oscillations in the horizontal and vertical directions. Therefore, compensation solenoids are required to keep the circulating particle beams from seeing the effects of the field from the main detector solenoid. Since high luminosity and a large solid angle are required, the detectors and a pair of compensation solenoids must be integrated with the final focus quadrupoles within the detector straight section. This report describes the design of two tapered, 0.5 tesla, superconducting compensation solenoids which must go around six rare earth permanent final focus quadrupoles or six superconducting quadrupoles on either side of the beam collision point. A cryogenic cooling system for these two solenoids, which will be coupled with the cooling system for the primary detector solenoid, is also described.
122023958
Tests on large diameter superconducting solenoids designed for colliding beam accelerators
Two prototype large diameter thin coil solenoids which use the mechanical structure to moderate quenches, have been built and systematically tested. The solenoids are cooled by two phase helium flowing in tubes which form a part of the coil structure. The coils have been tested by inducing a series of quenches at various currents. The results of these tests are given in this paper.
120458015
LARGE SUPERCONDUCTING DETECTOR MAGNETS WITH ULTRA THIN COILS FOR USE IN HIGH ENERGY ACCELERATORS AND STORAGE RINGS
LARGE SUPERCONDUCTING DETECTOR MAGNETS WITH ULTRA THIN COILS FOR USE IN HIGH ENERGY ACCELERATORS MiD STORAGE RINGS. H. A, Green Lawrence Bemeley Laboratory llo1.versity of California Beme1ey, california MASlIR This paper describes the development of a ni!W class of large superconducting soleiwid magJ!l!ts. High energy physics on colJ,iding beam machines sometimes require the use of thin coH' solenoid magnets. ,The development of these ,magnets bas proceeded with the substitution of li'ght materials for heavy materials and by ,inCrea9ing the current density in the coils. The Lawrence Beme1ey Laboratory bas developed a 1:adtca1 approach to the pEOblem by ba'ldng the co11 operate at very high cur1:ent, densities. This approach and its implications are described in detail. Introduction Recent'developments in colliding beam physics have prompted the development of thin superconductiog solenoid magnets for use ia these experiments. The development of thin m3g0ets can be traced starting with PLUTO, the fi1:st superconducting magnet which was used to do colliding beam physics. The evolution of thin coil technology can be trsced by comparing PLUTO (which is not a thin superconducting magnet) with three other superconductiog magnets which have been built OT are being built for colliding beam experiments. All tbree of these magnets are 'designed to be thin to some degtee. A comparative' study of the four magnets illustrstes the trend of thin supercooducting co11 development over tbe last two D1: three years. first, Doe sees tbe substitution of lighter materials for heavier msterials in the CERN magnet. Then ooe sees the abandoDlll!nt of cryogeoic stsbility wben the batb cryostat is replaced witb tbe tubular cooling system in the CELLO magnet. F1oslly, tbe conductive bore tube concept is introduced in order to make a radical improvement in the ,protection' of thin solenoid magnets against burnout. This is the basis of the TPC magnet design proposed by the Lawrence Berkeley Laboratory (LBL). Over half of this pap'er will be devoted to the LBL magnet 'technique. Since the LBL tecb- nique is a radical departure from conventioosl technique, this paper will present tbe theory of the conductive bore tube and discuss the resulta of experiments on LBL test coils. Three test c.oils· have been c.onstruc.ted at LBL. Two of these coUs, each with a diameter of one meter. have been fully tested and the results are presented herein. Preliminsry tests on the third test 'magnet, which bas a diameter of two meters, are described. The results' of these tests show the viability of the LBL two-phase tubular cooling system and the conductive bore tube for diverting the magnetic current from the superconducting coil. The LBL technique ia applicable to magnets in a variety of sizes. The radiation thickness attainable is a function of diameter and central induction. Thia relaticoship is sbown in this pape::. In addition, one can apply light sUperconductors and conductive bore tubes. This can, in principle, result in reduction of the radiation thickness of solenoids whicb bave a diam- eter below a certain value. t a The development of thin solenoid technology The 'development of thin nagnet technology can be traced by comparing four colliding beam detector solenoids which have been built or are about to te built. The first of these magnets is PLUTO. This magnet, which makes no effort to bj! thin, was built in 1971 using tbe conductor and stabilization technology used in the large bubble cbsmber(l). The second magnet, ISR, built by Horpurgoat' CERN' in 1976, Bub Q !ltuted a cryt;>genica11y stabilized allllll1J1um conductor for th~ ciJpperc< iductor normally used l ). The vacuum ve,.sela and cryostat vessels are also msde of aluminum; The third step iil this progression is the msgnet, proposed for the CELLO elCPertment by !;aclsy and',Karlsrube using ilitrinaically stable aluminum conductor which operates 'at current densitieS' of 1.4 x 108 &-2(3). The fourth step 1n the progress10n is represented by the magni!t proposed for the time projectiOn cblllltJer (TPC) experiment by the Lawrence Beme1ey Laboratol.y(4). This magDet, uses superconductor at very high matrix current densities (about 109 Am- 2 h' - The msgriet uses a tVo-pbase tubular COOling system. The ,four magnets ':e clllllpsred in Table 1. The PLUTO magnet bas the largest central inductiOn 'and ~est free wI ,. ,The TPC magnet has both the,largest free volume and stored eaergy. The ISR '!liagnet bas the alliallest stored energy end i t has a central induction of 1.S T lik'l the CELLO ana' TPC magnets. The thiekeBt magnet from a radiation standpOint is' the PLUTO magnet. The,' thinnest magnet ia the TPC magnet. * Work performed urier tbe auspices of U.S. Energy Research and Develo~,,\,!l'S ~~ois~st1oi? .. ' UI.:j ~ ,(Ial l 110. 1 ,ur ,U'.I~' t..U