7533646
Ultraviolet properties of maximal supergravity.
We argue that recent results in string perturbation theory indicate that the four-graviton amplitude of four-dimensional N=8 supergravity might be ultraviolet finite up to eight loops. We similarly argue that the h-loop M-graviton amplitude might be finite for h<7+M/2.
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.
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.
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.
9850713
A 20 T hybrid solenoid for the collection of pions for a muon collider
In order to generate intense muon beams for a muon collider, intense pion beams must be produced in a stationary proton beam target. The pions produced by the target must be captured before they can go through phase rotation and decay into muons. A 20 T solenoid with a clear bore of 150 mm can capture particles with a transverse momentum of 225 MeV/c or less. As the captured particles leave the capture solenoid, the magnetic induction is decreased to 5 T while the beam pipe diameter increases to 300 mm. Phase rotation of the pions and the decay of the pions to muons will occur at 5 T. The capture solenoid and the solenoids just downstream from the capture solenoid are subject to high heat loads (up to 4.8 MW) and radiation loads from the target. The conventional inner solenoid of the 20 T hybrid magnet system and the water cooled absorber will absorb virtually all of the particle energy from the target thus protecting the superconducting part of the solenoid system from excessive radiation heating. This report also describes the solenoid magnets from the capture zone to the solenoidal beam channel within the phase rotation RF cavities.
122611866
Large diameter thin superconducting solenoid magnets
Abstract High energy physics experiments on the latest generation colliding beam machines require large superconducting solenoid magnets. The Lawrence Berkeley Laboratory is developing a new generation of high current density (∼ 10 9 A m −2 ) superconducting solenoid magnets which are thin from a radion standpoint. To meet our design objectives, an integrated magnet and cryostat design has been evolved. Recent tests of one metre diameter prototype magnets show that our design concepts are technically viable. The results of the one metre magnet test are reported here.
122984815
THE OPERATION OF A FORCED TWO PHASE COOLING SYSTEM ON A LARGE SUPERCONDUCTING MAGNET
This paper describes the operation of a forced two phase cooling system on a two meter diameter superconducting solenoid. The magnet is a thin high current density superconducting solenoid which is cooled by forced two phase helium in tubes around the coil. The magnet, which is 2.18 meters in diameter and 3.4 meters long, has a cold mass of 1700 kg. The two phase cooling system contains less than 300 liters of liquid helium, most of which is contained in a control dewar. This paper describes the operating characteristics of the LBL two phase forced cooling system during cooldown and warm up. The paper presents experimental data on operations of the magnet using either a helium pump or the refrigerator compressor to circulate two phase helium through the superconducting coil cooling tubes.
134768087
Superconducting synchrotron-storage ring (ESCAR)
Author(s): Byrns, R.; Elioff, T.; Gilbert, W.; Green, M.; Hartwig, E.; Lambertson, G.; Lou, K.; Meuser, R.; Pope, W.; Staples, J.; Tanabe, J.; Wolgast, D.