1301.2322 (Nana Geraldine Cabo Bizet et al.)

R-charge Conservation and More in Factorizable and Non-Factorizable
Orbifolds    [PDF]

Nana Geraldine Cabo Bizet, Tatsuo Kobayashi, Damian Kaloni Mayorga Pena, Susha L. Parameswaran, Matthias Schmitz, Ivonne Zavala

We consider the string theory origin of R-charge conservation laws in heterotic orbifold compactifications, deriving the corresponding string coupling selection rule for factorizable and non-factorizable orbifolds, with prime ordered and non-prime ordered point groups. R-charge conservation arises due to symmetries among the worldsheet instantons that can mediate the couplings. Among our results is a previously missed non-trivial contribution to the conserved R-charges from the Gamma-phases in non-prime orbifolds, which weakens the R-charge selection rule. Symmetries among the worldsheet instantons can also lead to additional selection rules for some couplings. We make a similar analysis for Rule 4 or the 'torus lattice selection rule'. Moreover, we identify a new string selection rule, that we call Rule 6 or the 'coset vector selection rule'.

View original: http://arxiv.org/abs/1301.2322