arXiv 2006.127862020-06hep-phhep-ex

$B_c\to J/ψ$衰变的次首对数$k_T$近似

Next-to-leading-logarithm $k_T$ resummation for $B_c\to J/ψ$ decays

Xin Liu, Hsiang-nan Li, Zhen-Jun Xiao

备注：: 8 pages, 3 figures, and 1 table; more references and clarifications added, results and conclusions remain unchanged; final version to appear in Physics Letters B
DOI：: 10.1016/j.physletb.2020.135892

摘要：

在$m_b\gg m_c \gg k_T$体系下，我们导出了含底夸克质量$m_b$、魅夸克质量$m_c$和魅夸克横动量$k_T$的含横动量粲偶素波函数的$k_T$重算，达到了次首对数（NLL）精度.由此得到的Sudakov因子被用于$B_c\to J/ψ$跃迁形状因子$A_0^{B_c \to J/ψ}(0)$和$B_c^+ \to J/ψπ^+$衰变的微扰QCD（PQCD）方法中.我们比较了NLL的再激励效应对这些过程的影响与文献中的前导对数效应，发现了$(5-10)\%$对$A_0^{B_c \to J/ψ}(0)$的形状因子的增强和$(10-20)\%$对${\rm BR}(B_c^+ \to J/ψπ^+)$的衰减速率的增强。改进后的$k_T$再确认方法适用于重介子衰变到其它粲夸克偶素的PQCD分析。

英文摘要：

We derive the $k_T$ resummation for a transverse-momentum-dependent charmonium wave function, which involves the bottom quark mass $m_b$, the charm quark mass $m_c$, and the charm quark transverse momentum $k_T$, up to the next-to-leading-logarithm (NLL) accuracy under the hierarchy $m_b\gg m_c \gg k_T$. The resultant Sudakov factor is employed in the perutrbative QCD (PQCD) approach to the $B_c\to J/ψ$ transition form factor $A_0^{B_c \to J/ψ}(0)$ and the $B_c^+ \to J/ψπ^+$ decay. We compare the NLL resummation effect on these processes with the leading-logarithm one in the literature, and find a $(5-10)\%$ enhancement to the form factor $A_0^{B_c \to J/ψ}(0)$ and a $(10-20)\%$ enhancement to the decay rate ${\rm BR}(B_c^+ \to J/ψπ^+)$. The improved $k_T$ resummation formalism is applicable to the PQCD analysis of heavy meson decays to other charmonia.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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英文摘要：

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