Threshold effects in grand unified string models
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Tracas, ND
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Leontaris, GK
(EN)
A common feature in most of the string derived models is the appearance of extra matter fields, beyond those needed for the standard model content, which usually become massive at various intermediate scales. In the present work we concentrate on the free fermionic string models based on the intermediate gauge symmetries SU(5) X U(1) and SU(4) X O(4) and investigate the effect on the low energy parameters due to the inclusion of threshold corrections introduced either by string massive states or states becoming massive close to the intermediate symmetry breaking scale.
(EN)
