scholarly journals SHAPE OF GAUGE FIELD TADPOLES IN HETEROTIC STRING THEORY

2005 ◽  
Vol 20 (03) ◽  
pp. 155-168
Author(s):  
STEFAN GROOT NIBBELINK

Orbifolds in field theory are potentially singular objects for at their fixed points the curvature becomes infinite, therefore one may wonder whether field theory calculations near orbifold singularities can be trusted. String theory is perfectly well defined on orbifolds and can therefore be taken as a UV completion of field theory on orbifolds. We investigate the properties of field and string theory near orbifold singularities by reviewing the computation of a one-loop gauge field tadpole. We find that in string theory the twisted states give contributions that have a spread of a couple of string lengths around the singularity, but otherwise the field theory picture is confirmed. One additional surprise is that in some orbifold models one can identify local tachyons that give contributions near the orbifold fixed point.

1988 ◽  
Vol 03 (17) ◽  
pp. 1673-1676
Author(s):  
KEI ITO

The four-point correlation functions are calculated in the N=2 superconformal field theory corresponding to a Calabi-Yau compactification of the heterotic string theory.


1994 ◽  
Vol 03 (01) ◽  
pp. 285-288 ◽  
Author(s):  
HAN SUELMANN

Heterotic String Theory is an attempt to construct a description of nature that is more satisfying than the Standard Model. A major problem is that it is very difficult to do explicit calculations in string theory. Therefore, it is useful to construct a ’normal’ field theory that approximates HST. The way to construct such a field theory is described briefly. The result is a perturbation expansion in some parameter α′. related to the inverse string tension. There are problems concerning the supersymmetrisation of the [Formula: see text] contribution. These may be caused by the assumption that the action can be written in terms of a local Lagrangian of the physical fields only.


2004 ◽  
Vol 19 (30) ◽  
pp. 2299-2315 ◽  
Author(s):  
ALFREDO HERRERA-AGUILAR

We present a formulation of the stationary bosonic string sector of the whole toroidally compactified effective field theory of the heterotic string as a double Ernst system which, in the framework of general relativity describes, in particular, a pair of interacting spinning black holes; however, in the framework of low-energy string theory the double Ernst system can in particular be interpreted as the rotating field configuration of two interacting sources of black hole type coupled to dilaton and Kalb–Ramond fields. We clarify the rotating character of the Btφ-component of the antisymmetric tensor field of Kalb–Ramond and discuss on its possible torsion nature. We also recall the fact that the double Ernst system possesses a discrete symmetry which is used to relate physically different string vacua. Therefore we apply the normalized Harrison transformation (a charging symmetry which acts on the target space of the low-energy heterotic string theory preserving the asymptotics of the transformed fields and endowing them with multiple electromagnetic charges) on a generic solution of the double Ernst system and compute the generated field configurations for the 4-D effective field theory of the heterotic string. This transformation generates the U (1)n vector field content of the whole low-energy heterotic string spectrum and gives rise to a pair of interacting rotating black holes endowed with dilaton, Kalb–Ramond and multiple electromagnetic fields where the charge vectors are orthogonal to each other.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Keiya Ishiguro ◽  
Tatsuo Kobayashi ◽  
Hajime Otsuka

Abstract We study the impacts of matter field Kähler metric on physical Yukawa couplings in string compactifications. Since the Kähler metric is non-trivial in general, the kinetic mixing of matter fields opens a new avenue for realizing a hierarchical structure of physical Yukawa couplings, even when holomorphic Yukawa couplings have the trivial structure. The hierarchical Yukawa couplings are demonstrated by couplings of pure untwisted modes on toroidal orbifolds and their resolutions in the context of heterotic string theory with standard embedding. Also, we study the hierarchical couplings among untwisted and twisted modes on resolved orbifolds.


2002 ◽  
Vol 622 (1-2) ◽  
pp. 3-45 ◽  
Author(s):  
Katsuyuki Sugiyama ◽  
Satoshi Yamaguchi

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Keiya Ishiguro ◽  
Tatsuo Kobayashi ◽  
Hajime Otsuka

Abstract We examine a common origin of four-dimensional flavor, CP, and U(1)R symmetries in the context of heterotic string theory with standard embedding. We find that flavor and U(1)R symmetries are unified into the Sp(2h + 2, ℂ) modular symmetries of Calabi-Yau threefolds with h being the number of moduli fields. Together with the $$ {\mathbb{Z}}_2^{\mathrm{CP}} $$ ℤ 2 CP CP symmetry, they are enhanced to GSp(2h + 2, ℂ) ≃ Sp(2h + 2, ℂ) ⋊ $$ {\mathbb{Z}}_2^{\mathrm{CP}} $$ ℤ 2 CP generalized symplectic modular symmetry. We exemplify the S3, S4, T′, S9 non-Abelian flavor symmetries on explicit toroidal orbifolds with and without resolutions and ℤ2, S4 flavor symmetries on three-parameter examples of Calabi-Yau threefolds. Thus, non-trivial flavor symmetries appear in not only the exact orbifold limit but also a certain class of Calabi-Yau three-folds. These flavor symmetries are further enlarged to non-Abelian discrete groups by the CP symmetry.


2013 ◽  
Vol 21 ◽  
pp. 191-192
Author(s):  
MASAYA YATA

We solve the gaugino Dirac equation on a smeared intersecting five-brane solution in E8 × E8 heterotic string theory to search for localized chiral zeromodes on the intersection. The background is chosen to depend on the full two-dimensional overall transverse coordinates to the branes. Under some appropriate boundary conditions, we compute the complete spectrum of zeromodes to find that, among infinite towers of Fourier modes, there exist only three localized normalizable zeromodes, one of which has opposite chirality to the other two.


Sign in / Sign up

Export Citation Format

Share Document