[填空题]
Is the reaction $e^- + p \to n + \nu_e$ possible? Explain.
参考答案: no
本题详细解析: No, the reaction $ \text{e}^- + \text{p} \to \text{n} + \bar{\nu}_\text{e} $ is not possible. The electron lepton number is not conserved: The reactants have $ L_\text{e} = 1 + 0 = 1 $, but the products have $ L_\text{e} = 0 - 1 = -1 $. Thus, this reaction is not possible.
