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$Z_2\times Z_2$ orbifold compactification -- the origin of realistic free fermionic models

Alon Faraggi
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Abstract

All the realistic free fermionic models utilize a set of basis vectors, the NAHE set, that correspond to $Z_2\times Z_2$ orbifold compactification with nontrivial background fields. I argue that the realistic features of free fermionic models, like the number of generations and the fermion mass spectrum are due to the underlying $Z_2\times Z_2$ orbifold compactification.

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Alon Faraggi. 1995-01-16. $Z_2\times Z_2$ orbifold compactification -- the origin of realistic free fermionic models. https://arxiv.org/abs/hep-ph/9501288

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