How to reach the correct sin**2 theta-w and alpha-s in string theory

Effective theories with the matter content of the minimal supersymmetric Standard Model below the string scale M_string predict a wrong value for the weak--mixing angle sin~2\theta_W and strong coupling constant \alpha_S at the scale M_Z. To resolve this problem one needs large threshold corrections. At the same time one would like to avoid introducing new intermediate scales that are small compared to M_string. Two requests which seem to be incompatible. We show how both requirements can be satisfied in a class of (0,2) heterotic superstring compactifications with a natural choice of the vevs of the moduli fields entering the moduli dependent string threshold corrections.

electroweak interaction
supersymmetry
string model: heterotic
Weinberg angle
strong interaction: coupling constant
coupling constant: strong interaction
threshold: correction
mass: string
string: mass
compactification

References(54)

Figures(0)

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