PHYSICAL REGULARIZATION AND FINITENESS OF SUPERSTRING THEORIES

1986 ◽  
Vol 01 (05) ◽  
pp. 365-376
Author(s):  
F. ARDALAN ◽  
H. ARFAEI ◽  
J. PARVIZI
Keyword(s):  
Complex Plane ◽  
World Sheet ◽  
Regularization Procedure ◽  
Physical Picture ◽  
Superstring Theories ◽  
String Theories

We provide a regularization procedure for loops in string theories based on the physical picture of joining and splitting strings. This procedure justifies the 1-loop finiteness of superstring theories. To find the regularization, maps from the string world-sheet to the complex plane are studied in detail.

FOUR DIMENSIONAL SUPERSTRING THEORIES IN ORBIFOLD-LIKE CONSTRUCTION

1988 ◽  
Vol 03 (15) ◽  
pp. 1431-1440
Author(s):  
Y. KIKUCHI ◽  
MARCELO R. UBRIACO
Keyword(s):  
Boundary Condition ◽  
Simple Model ◽  
World Sheet ◽  
The World ◽  
Superstring Theories ◽  
String Theories

We present a construction of string theories based on the orbifold-like boundary condition on the world sheet fields in the NSR formalism. A simple model is given.

ON TIME VARIATION OF FUNDAMENTAL CONSTANTS IN SUPERSTRING THEORIES

1988 ◽  
Vol 03 (03) ◽  
pp. 243-249 ◽  
Author(s):  
KEI-ICHI MAEDA
Keyword(s):  
String Theory ◽  
Symmetry Breaking ◽  
Time Variation ◽  
Susy Breaking ◽  
Internal Space ◽  
Fundamental Constants ◽  
Breaking Mechanism ◽  
Dimensional Gravity ◽  
Superstring Theories ◽  
String Theories

Assuming the action from the string theory and taking into account the dynamical freedom of a dilaton and its coupling to matter fluid, we show that fundamental ‘constants’ in string theories are independent of the ‘radius’ of the internal space. Since the scalar related to the ‘constants’ is coupled to the 4-dimensional gravity and matter fluid in the same way as in the Jordan-Brans-Dicke theory with ω=−1, it must be massive and can get a mass easily through some symmetry breaking mechanism (e.g. the SUSY breaking due to a gluino condensation). Consequently, time variation of fundamental constants is too small to be observed.

scholarly journals ON HIGHER-SPIN GENERALIZATIONS OF STRING THEORY

1994 ◽  
Vol 09 (09) ◽  
pp. 1527-1543 ◽  
Author(s):  
H. LU ◽  
C. N. POPE ◽  
X. J. WANG
Keyword(s):  
String Theory ◽  
Gauge Field ◽  
Virasoro Algebra ◽  
Two Dimensional ◽  
Minimal Models ◽  
World Sheet ◽  
The World ◽  
Higher Spin ◽  
String Theories

We construct BRST operators for certain higher-spin extensions of the Virasoro algebra, in which there is a spin-s gauge field on the world sheet, as well as the spin-2 gauge field corrresponding to the two-dimensional metric. We use these BRST operators to study the physical states of the associated string theories, and show how they are related to certain minimal models.

REVIEW OF RECENT DEVELOPMENTS IN SUPERSTRING THEORY

1987 ◽  
Vol 02 (03) ◽  
pp. 593-643 ◽  
Author(s):  
JOHN H. SCHWARZ
Keyword(s):  
Degrees Of Freedom ◽  
Classical Solutions ◽  
Type Ii ◽  
World Sheet ◽  
Superstring Theory ◽  
Recent Developments ◽  
Local Symmetries ◽  
Superconformal Theories ◽  
Superstring Theories ◽  
Internal Degrees Of Freedom

After proposing a procedure for classifying string theories, we describe the various local symmetries that can occur on the world sheet with special emphasis on Kac–Moody algebras in superconformal theories. The construction of multiloop amplitudes is briefly reviewed. Then the constraint of modular invariance is analyzed for models in which the internal degrees of freedom are described by fermions. Next we consider the construction of consistent classical solutions. A few examples are presented for both the heterotic and type II superstring theories. A brief description of some recent work in string field theory and other approaches to a nonperturbative formulation of string theory is presented.

DETERMINANTS, DIRAC OPERATORS, AND ONE-LOOP PHYSICS

1989 ◽  
Vol 04 (06) ◽  
pp. 1467-1484 ◽  
Author(s):  
STEVEN K. BLAU ◽  
MATT VISSER ◽  
ANDREAS WIPF
Keyword(s):  
Dirac Operator ◽  
Dirac Operators ◽  
World Sheet ◽  
Four Dimensions ◽  
Arbitrary Genus ◽  
String Theories

We consider the Dirac operator. Its determinant is examined and in two Euclidean dimensions is explicitly evaluated in terms of geometrical quantities. This leads us to consider a generalization of the Wess-Zumino action that is applicable to arbitrary genus. Our analysis is relevant to a number of interesting systems: Schwinger models on curved two-manifolds; string theories with world-sheet vectors; and as an exploration of possible directions in evaluating determinants in four dimensions.

VERTEX FUNCTIONS IN THE PATH INTEGRAL FORMALISM OF OPEN STRING THEORIES

1988 ◽  
Vol 03 (11) ◽  
pp. 2601-2620 ◽  
Author(s):  
YOSHIAKI TANII ◽  
YOSHIYUKI WATABIKI
Keyword(s):  
Path Integral ◽  
Open String ◽  
Integral Approach ◽  
Operator Formalism ◽  
Integral Formalism ◽  
Systematic Method ◽  
Path Integral Formalism ◽  
Path Integral Approach ◽  
Superstring Theories ◽  
String Theories

We study a systematic method to obtain the general vertex functions (of Neveu-Schwarz sector), which are used in the covariant path integral approach to the open bosonic and superstring theories. For the superstring the superspace formulation in the Wess-Zumino gauge is used to construct the vertices at the boundaries of world sheets. For both theories the vertex functions are explicitly obtained for the first four mass levels and coincide with those in the operator formalism.

ON RADIATIVELY INDUCED GAUGINO MASSES IN SUPERSTRING BASED LOW ENERGY SUPERGRAVITY

1987 ◽  
Vol 02 (01) ◽  
pp. 49-55 ◽  
Author(s):  
PARTHASARATHI MAJUMDAR
Keyword(s):  
Supergravity Models ◽  
Supersymmetry Breaking ◽  
Low Energy ◽  
Regularization Procedure ◽  
Self Energy ◽  
The One ◽  
Superstring Theories ◽  
Gaugino Masses

The gravitino contribution to the one loop gaugino self energy in low energy N=1 supergravity models derived from superstrings is considered. This contribution is shown to vanish when a supersymmetric regularization procedure is used. An identical conclusion is seen to hold for the contribution of the fermionic component of the gauge singlet chiral supermultiplet that arises out of gaugino condensation in the Hidden (‘shadow’) sector. Implications for supersymmetry breaking in the observable sector of superstring theories are briefly discussed.

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