Masaru Takao

Spin-4 current algebra

Abstract We construct the spin-4 associative current algebra. The commutator of the spin-4 current is completely determined by the Jacobi identity.

X-band accelerating structure for Japan Linear Collider

Candidates for the accelerating structure in realizing an operation in a multibunch mode in the Japan Linear Collider (JLC) are described. The external Q value of the TM110- pi mode in a damped structure with a slotted disk is very sensitive to the geometry. The damped structure with slots in the disk was found too sensitive to apply to the actual structure for the JLC. A damped structure of a crossed waveguide type was found to be a good candidate for the characteristics of the higher modes. A detuned structure with its frequency distributed similar to a truncated gaussian showed a good cancellation of a higher mode.<<ETX>>

Estimation of the longitudinal impedance of the ATF damping ring

In order to estimate the possibility of bunch lengthening in the ATF damping ring, the longitudinal broadband impedance of the ring was evaluated. The inductance was so small, that the bunch lengthening should not be observed in the ATF damping ring. It is found that the total mod Z/sub ////n mod is less than 0.3 infinity . Therefore bunch lengthening should not be a problem in the ATF damping ring.<<ETX>>

Supersymmetric Yang-Mills theory in two-dimensional superspace and super Kac-Moody algebra

Abstract We formulate N =1 supersymmetric Yang-Mills theory in two-dimensional superspace. In constructing the superspace formalism for the gauge theory we find that we should adopt unconventional constraints. It is shown that under these constraints the gauge symmetry derives a super Kac-Moody algebra.

Longitudinal wake field characteristics of the KEK positron generator linac

The effect of a longitudinal wake field on a high current multibunched beam was investigated at the primary electron section of the KEK (Japan National Laboratory for High Energy Physics) positron generator linac. The energy spectrum of multibunches due to the beam loading was compared with a numerical analysis using the computer code TBCI.<<ETX>>

N=2 SUPERCONFORMAL ALGEBRA AND STRINGS IN BACKGROUND FIELD

We discuss N = 2 superconformal algebra of superstring in a background field by investigating the operator products of the symmetry currents. It is shown that for the presence of N = 2 superconformal symmetry the compactified space should be a Ricci-flat Kahler manifold.

Current algebras on super-Riemann surfaces

Abstract Two-dimensional N = 1 supersymmetric Yang-Mills theory is formulated in superspace, to examine the Ward identities for super Kac-Moody algebras on super Riemann surfaces of genus g (⩾ 2) in the path-integral formalism. To derive Green kernels, we use the theory of automorphic functions on super-Riemann surfaces in the Schottky parametrization. The Ward identities are experssed in terms of the Poincare theta series.

Wake-field characteristics of a high-intensity, multibunched beam

Abstract A systematic experimental study on the wake-field characteristics of a high-intensity, multibunched electron beam was carried out in detail at the primary electron section of the KEK positron generator linac. The observed energy spectrum, which indicated the energy variation of one bunch from another, was explained fairly well by the multibunch effect of a longitudinal wake field; the importance of introducing a self-wake loss and a bunch-length effect into calculations of the energy loss due to a longitudinal wake field is noted. On the other hand, a transverse motion of each bunch, showing a peculiar behavior when the transverse instability occurred, was in good agreement with the results of a numerical calculation based on a multibunch version of Wilsons two-particle model. In both cases, the wake field for our cavity was estimated using a computer code called TBCI.

Transverse wake field characteristics of the KEK positron generator linac

A multibunch transverse instability due to a wake field was investigated in detail by using a high-intensity, multibunched beam at the primary electron section of the KEK (Japan National Laboratory for High Energy Physics) positron generator linac. The transverse motion of each bunch showed a peculiar behavior when a transverse instability occurred. The experimental results were compared with a numerical calculation based on a multibunch version of P.B. Wilsons (1989) two-particle model. The transverse wake field for the cavity was estimated using TBCI-code. The calculation explains the observed behavior of each bunch.<<ETX>>

Functional integral methods for fermionic string and super Riemann surfaces

We investigate the light-cone gauge formulation of fermionic string of Mandelstam in a superspace. To formulate the fermionic string in a superspace, we use the theory of super Riemann surfaces (SRS). We define the Neumann functions and the Mandelstam mappings in a superspace by means of the so-called Abelian differentials of the first and the third kinds on SRS. In the super Schottky parametrization of SRS these superdifferentials are constructed at the multiloop level. The functional integral measure of a super light-cone diagram, which consists of 6g−6+2N even moduli parameters and 4g−4+2N odd ones, are specified in our formulation. In one-loop case with even spin structures we explicitly evaluate the superdeterminants on the super light-cone diagrams and calculate the one-loop amplitudes with N massless vector states. It is shown that the result is written in the form of a correlation function of the vertex operators. Furthermore, we evaluate the 3- and 4-particle amplitudes explicitly, which agree exactly with those calculated in the Green-Schwarz formulation.