Very recently, the Muon g − 2 experiment at Fermilab has confirmed the E821 Brookhaven result, which hinted at a deviation of the muon anomalous magnetic moment from the Standard Model (SM) expectation. The combined results from Brookhaven and Fermilab show a difference with the SM prediction δa_μ = (251 ± 59) × 10⁻¹¹ at a significance of 4.2σ, strongly indicating the presence of new physics. Motivated by this new result we reexamine the contributions to δa_μ from both: (i) the ubiquitous U(1) gauge bosons of D-brane string theory constructions and (ii) the Regge excitations of the string. We show that, for a string scale , the contribution from anomalous U(1) gauge bosons which couple to hadrons could help to reduce (though not fully eliminate) the discrepancy reported by the Muon g − 2 Collaboration. Consistency with null results from LHC searches of new heavy vector bosons imparts the dominant constraint. We demonstrate that the contribution from Regge excitations is strongly suppressed as it was previously conjectured. We also comment on contributions from Kaluza-Klein (KK) modes, which could help resolve the δa_μ discrepancy. In particular, we argue that for 4-stack intersecting D-brane models, the KK excitations of the U(1) boson living on the lepton brane would not couple to hadrons and therefore can evade the LHC bounds while fully bridging the δa_μ gap observed at Brookhaven and Fermilab.

中文翻译：

---

D-膜弦致密化中的介子差异

最近，费米实验室的 Muon g − 2 实验证实了 E821 Brookhaven 结果，该结果暗示了 μ 子异常磁矩与标准模型 (SM) 预期的偏差。Brookhaven 和 Fermilab 的综合结果显示与 SM 预测 δ a _μ = (251 ± 59) × 10 ^-11的差异，显着性为 4.2σ，强烈表明新物理学的存在。受这个新结果的启发，我们重新检查了对 δ a _μ的贡献：（i） 无处不在的U（1）D 膜弦理论构造的规范玻色子和（ii） 弦的 Regge 激发。我们证明，对于弦音阶，与强子耦合的异常U (1) 规范玻色子的贡献可以帮助减少（尽管不能完全消除）Muon g - 2 合作报告的差异。与 LHC 搜索新重矢量玻色子的空结果的一致性赋予了主导约束。我们证明了 Regge 激发的贡献被强烈抑制，正如之前的推测一样。我们还评论了 Kaluza-Klein (KK) 模式的贡献，这有助于解决 δ a _μ差异。特别是，我们认为对于 4 叠相交 D 膜模型，U的 KK 激发(1) 生活在轻子膜上的玻色子不会​​与强子耦合，因此可以避开 LHC 界限，同时完全桥接在布鲁克海文和费米实验室观察到的 δ a _μ间隙。