TY - JOUR
T1 - Strings on orbifolds (II)
AU - Dixon, L.
AU - Harvey, J.
AU - Vafa, C.
AU - Witten, E.
N1 - Funding Information:
Superstring theories are serious candidates for unified theories of all known interactions \[1-3\]. However if they are to make contact with the real world it will be necessary to understand how the enormous symmetry of these theories is broken down to something like that which we observe at low energies. In a previous paper \[4\]w e discussed a simple but powerful method of achieving symmetry breaking in string theories via twisted boundary conditions. Depending on how the twists act on the spacetime and internal degrees of freedom this general approach can describe toroidal compactification, symmetry breaking by Wilson lines, a singular limit of compactification on certain Calabi-Yau spaces, and may even be used to derive one heterotic string theory from the other! In addition to its generality this method has the advantage of allowing explicit calculations of tree and loop string amplitudes with realistic symmetry breaking. In this paper we will present a general framework for discussing strings with twisted boundary conditions and explore some of the phenomenological consequences of this approach to symmetry breaking. Twisted boundary conditions naturally arise when one considers string propagation on an orbifold. We will define an orbifold to be the object one obtains by dividing a manifold by the action of a discrete group G. (More generally an orbifold is locally, but not necessarily globally, Joseph Henry Laboratories, Princeton University, Princeton. NJ 08544. USA. i Supported by a Charlotte Elizabeth Proctor Fellowship. -" Supported by NSF Grant PHY80-19754. ~Junior Fellow, Harvard Society of Fellows, Lvman Laboratory of Physics, Harvard ('ambridgc, MA 02138, USA. Supported bv NSF (;rant PHY82-15249.
PY - 1986/9/15
Y1 - 1986/9/15
N2 - A general framework for analyzing string propagation on the quotient of a manifold by a discrete group is presented.The conditions necessary for modular invariance and absence of tachyons are discussed. Models with four or fewer generations which correspond to the standard embedding of the spin connection in the gauge group are analyzed. We all discuss some generalizations which may lead to more phenomenologically promising models.
AB - A general framework for analyzing string propagation on the quotient of a manifold by a discrete group is presented.The conditions necessary for modular invariance and absence of tachyons are discussed. Models with four or fewer generations which correspond to the standard embedding of the spin connection in the gauge group are analyzed. We all discuss some generalizations which may lead to more phenomenologically promising models.
UR - http://www.scopus.com/inward/record.url?scp=4243560915&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4243560915&partnerID=8YFLogxK
U2 - 10.1016/0550-3213(86)90287-7
DO - 10.1016/0550-3213(86)90287-7
M3 - Article
AN - SCOPUS:4243560915
SN - 0550-3213
VL - 274
SP - 285
EP - 314
JO - Nuclear Physics, Section B
JF - Nuclear Physics, Section B
IS - 2
ER -