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تسجيل مستخدم جديدA Composite Axion from a Supersymmetric Product Group
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A global $U(1)_text{PQ}$ symmetry is protected from gravitational effects in the s-confining $SU(N)^k$ product group theory with $A+4Q +Noverline{Q}$ matter. If the $SU(4)$ family symmetry is gauged and an appropriate tree-level superpotential is added, then the dynamically generated superpotential spontaneously breaks $SU(4)times U(1)_text{PQ} rightarrow SU(3)_c$ and produces a QCD axion. Small values of the $CP$-violating $theta$ parameter are then possible without any fine-tuning, as long as the product group is suitably large. By introducing a second copy of the s-confining $SU(N)$ product group also coupled to the gauged $SU(4)$, we find that values as small as $N=7$ are consistent with $bartheta<10^{-10}$, even under the pessimistic assumption that the dominant contribution to the axion quality is at tree level.
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