标题： 降低α_s通过翻转SU(5) 显示英文标题

标题： Lowering alpha_s by flipping SU(5)

摘要： 我们证明在翻转SU(5)中，$\alpha_s(M_Z)$的预测值自然低于最小SU(5)，并且前者可以容纳目前实验允许的$\alpha_s(M_Z)$的全部范围。 我们的计算包括二环 ($\delta_{\rm 2loop}$) 和轻 ($\delta_{\rm light}$) 以及重 ($\delta_{\rm heavy}$) 阈值效应。 与最小SU(5)不同，在翻转 SU(5) 中，重阈值效应可以自然地降低 $\alpha_s(M_Z)$的预测值。 我们还表明，质子在主要通道$p\to e^+\pi^0$中的寿命值在SuperKamiokande的可观测范围内，并应能排除最小超对称SU(5)，其中主要模式是$p\to\bar\nu K^+$。 显示英文摘要

摘要： We show that the prediction for $\alpha_s(M_Z)$ in flipped SU(5) is naturally lower than in minimal SU(5), and that the former can accommodate the full range of $\alpha_s(M_Z)$ presently allowed by experiment. Our computations include two-loop ($\delta_{\rm 2loop}$) and light ($\delta_{\rm light}$) and heavy ($\delta_{\rm heavy}$) threshold effects. Unlike minimal SU(5), in flipped SU(5) the heavy threshold effects can naturally decrease the predicted value of $\alpha_s(M_Z)$. We also show that the value of the proton lifetime into the dominant channel $p\to e^+\pi^0$ is within the observable range at SuperKamiokande, and should discriminate against minimal supersymmetric SU(5), where the dominant mode is $p\to\bar\nu K^+$.