123010874
Production of the new resonances in hadronic collisions
SummaryThe variation with energy and with Feynman’s variablex of the production of ψ and ψ’ is a sensitive test of their production mechanism. A simple parton model predicts that at relatively low energies production nearx=0 is strongly favoured and that the invariant crosssection atx=0 increases by two orders of magnitude between BNL and ISR energies. A sharp increase is also predicted for the ratio of ψ or ψ’ production to the nonresonant lepton pair background.RiassuntoLa variazione della produzione di ψ e ψ’ con l’energia e con la variabilex di Feynman è un test sensibile del loro meccanismo di produzione. Un semplice modello a partoni predice che ad energie relativamente basse la produzione pressox=0 è fortemente favorita e che la sezione d’urto adx=0 aumenta di due ordini di grandezza fra la energia del BNL e quella degli ISR. Si predice anche un netto incremento per il rapporto tra la produzione di ψ o ψ’ e il fondo di coppie leptoniche non risonante.
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.
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.
121755839
PHASE CONTOURS AND BOOTSTRAPS. I.
25171382
Design and Construction of Test Coils for MICE Coupling Solenoid Magnet
The superconducting coupling solenoid to be applied in the Muon Ionization Cooling Experiment (MICE) is made from copper matrix Nb-Ti conductors with inner radius of 750 mm, length of 285 mm and thickness of 102.5 mm at room temperature. The magnetic field up to 2.6 T at the magnet centerline is to keep the muons within the MICE RF cavities. Its self inductance is around 592 H and its magnet stored energy is about 13 MJ at a full current of 210 A for the worst operation case of the MICE channel. The stress induced inside the coil during cool down and charging is relatively high. Two test coils are to build and test in order to validate the design method and develop the fabrication technique required for the coupling coil winding, one is 350 mm inner diameter and full length same as the coupling coil, and the other is one-quarter length and 1.5 m diameter. The 1.5 m diameter coil will be charged to strain conditions that are greater than would be encountered in the coupling coil. This paper presents detailed design of the test coils as well as developed winding skills. The analyses on stress in coil assemblies, AC loss, and quench process are carried out.
121321569
A report on Russian magnet technology for use in phi factory and light source bending magnets
108163413
Progress on the MICE RFCC Module for the MICE Experiment
PROGRESS ON MICE RFCC MODULE FOR THE MICE EXPERIMENT* Allan DeMello, Nord Andresen, Michael Green, Derun L i , Heng Pan, Steve Virostek, Michael Zisman ( L B N L , Berkeley C A 94720, USA), Don Summers, Mike Reep (University of Mississippi, Oxford M S 38677, USA) An Bin Chen, Xiao-Kun Liu, Feng-Yu X u , Shi-Xian Zheng (HIT, Harbin, China), Yun Cao, Sen Sun, L i Wang, Lixin Y i n (SINAP, Shanghai, China) Abstract We describe the recent progress on the design and fabrication of the R F C C (RF and Coupling Coil) module for the international Muon Ionization Cooling Experiment (MICE). The M I C E cooling channel has two R F C C modules; each has four 201-MHz normal conducting R F cavities and one superconducting solenoid magnet. The magnet is designed to be cooled by three cryocoolers. Fabrication of the R F cavities is complete; design and fabrication of the magnets are in progress. The first magnet is expected to be finished by the end of 2011. pneumatic actuator (Fig. 3). Six flexure tuners are currently being fabricated (University of Mississippi) for a full cavity test of the R F tuner system. This test will include the electronic pressure control, EPICS software interface and the R F feedback system. This system will be assembled into a single cavity vacuum vessel (see below) for testing. INTRODUCTION M I C E is an international experiment designed to demonstrate muon beam cooling using ionization cooling (Fig. 1). Muons are captured in a strong magnetic field, cooled in 4D phase space and re-accelerated in the beamline direction by the normal conducting R F cavities in the R F C C . This demonstration is key to the success of a future Neutrino Factory or Muon Collider. The experiment is being hosted at Rutherford Appleton Laboratory ( R A L ) in the U K , where beamline commissioning is underway. Institutions participating in the collaboration include national laboratories and universities in Europe, the U.S., China, and Japan. Figure 2: 90° sectioned view of the M I C E cooling channel R F C C module. Figure 1 : The M I C E cooling channel. RFCC M O D U L E CAVITIES Lawrence Berkeley National Laboratory is responsible for the design of the R F Cavity and Coupling Coil (RFCC) module for M I C E (Fig. 2). Each R F C C module will contain four 201 M H z normal conducting R F cavities and one superconducting coupling coil magnet [4]. Each cavity will have its frequency actively tuned using six stainless steel flexure tuners moved with a dual action * This work was supported by the Office of Science, U.S. Department of Energy under D O E contract number DE-AC02-05CH11231. Figure 3: The prototype RF tuner flexure and actuator mounted on a 201-MHz cavity.
10901357
Superconducting solenoids for the muon collider
The muon collider is a new idea for lepton colliders. The ultimate energy of an electron ring is limited by synchrotron radiation. Muons, which have a rest mass that is 200 times that of an electron can be stores at much higher energies before synchrotron radiation limits ring performance. The problem with muons is their short life time (2.1 /spl mu/s at rest). In order to operate a muon storage ring large numbers of muons must be collected, cooled and accelerated before they decay to an electron and two neutrinos. As we see it now, high field superconducting solenoids are an integral part of a muon collider muon production and cooling systems. This report will describe the design parameters for superconducting and hybrid solenoids that are used for pion production and collection, RF phase rotations of the pions as they decay into muons and the muon cooling (reduction of the muon emittance) before acceleration.
123081787
PROGRESS ON THE SUPERCONDUCTING MAGNET FOR THE TIME PROJECTION CHAMBER EXPERIMENT (TPC) AT PEP
The TPC (Time Projection Chamber) experiment at PEP will have a two meter inside diameter superconducting magnet which creatests a 1.5 T uniform solenoidal field for the TPC. The superconducting magnet coil, cryostat, cooling system, and the TPC gas pressure vessel (which operatests at 11 atm) were designed to be about two thirds of a radiation length thick. As a result, a high current density coil design was chosen. The magnet is cooled by forced flow two phase helium. The TPC magnet is the largest adiabatically stable superconducting magnet built to date. The paper presents the parameters of the TPC thin solenoid and its subsystems. Tests results from the Spring 1980 cryogenic tes are presented. The topics to be dealt with in the paper are cryogenic services and the tests of magnet subsystems such as the folded current leads. Large thin superconducting magnet technology will be important to large detectors to be used on LEP.