标题： 终态再散射作为$B \to ργ$的贡献 显示英文标题

标题： Final state rescattering as a contribution to $B \to ργ$

摘要： 我们给出了辐射跃迁到$B \to \rho \gamma$的长程分量的一个新估计。 我们的机制涉及非轻子$B$衰变的非弹性散射末态粒子的软散射，如同在链式反应$B \to \rho\rho \to \rho\gamma$中一样。 我们利用一个经验拟合来估算这种效应。 这里考虑的具体中间态以大约$5 \to 8%$的精度修改了$B \to \rho \gamma$的衰变率，尽管其潜在影响可能更大。 与文献中讨论的其他长程物理机制不同，这将对$B^0 \to \rho^0 \gamma$通道产生不可忽略的修正，因此将在$V_{td}$的提取过程中引入不确定性。 这一机制还会影响 $B^- \to \rho^-\gamma$ 和 $B^0 \to \rho^0 \gamma$ 的速率之间的同位旋关系，并可能产生可观测量的 CP 不对称性。 显示英文摘要

摘要： We provide a new estimate of the long-distance component to the radiative transition $B \to \rho \gamma$. Our mechanism involves the soft-scattering of on-shell hadronic products of nonleptonic $B$ decay, as in the chain $B \to \rho\rho \to \rho\gamma$. We employ a phenomenological fit to scattering data to estimate the effect. The specific intermediate states considered here modify the $B \to \rho \gamma$ decay rate at roughly the $5 \to 8%$ level, although the underlying effect has the potential to be larger. Contrary to other mechanisms of long distance physics which have been discussed in the literature, this yields a non-negligible modification of the $B^0 \to \rho^0 \gamma$ channel and hence will provide an uncertainty in the extraction of $V_{td}$. This mechanism also affects the isospin relation between the rates for $B^- \to \rho^-\gamma$ and $B^0 \to \rho^0 \gamma$ and may generate CP asymmetries at experimentally observable levels.