The Flipped SU(5) String Vacua Classification: A Variation Of The SO(10)   Breaking Basis Vector
  In this paper, an extension of the classification of flipped SU(5) heterotic-string vacua from [1] with a variation of the SO(10) breaking $\alpha$ basis vector is presented. A statistical sampling in the space of $2^{45}$ flipped SU(5) vacua is explored, where $10^{11}$ distinct GGSO projection configurations are scanned in comparison to the $10^{12}$ GGSO distinct coefficients scanned in the space of $2^{44}$ vacua in [1]. A JAVA code, akin to the one used for the classification in [1], was implemented to explore these. Results presented here indicate that no three generation exophobic vacua exist, which was also found to be the case in [1] as all odd generations were projected out. This paper will also study the details on the comparison between the two classifications achieved and then reflect on future directions in the quest for finding three generation exophobic flipped SU(5) heterotic-string models. 
Hasan Sonmez
hep-th hep-ph