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北美退伍军人节(Veterans Day),12 日无更新
arXiv 1401.4482nucl-thastro-ph.HEastro-ph.SRnucl-ex
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结合从头计算和Halo EFT:${}^7{\rm Be} + p \rightarrow {}^8{\rm B} + γ$的情况

Marrying ab initio calculations and Halo EFT: the case of ${}^7{\rm Be} + p \rightarrow {}^8{\rm B} + γ$

Xilin Zhang, Kenneth M. Nollett, D. R. Phillips

摘要:

本文报道了在低能有效场论中对$^7\mathrm{Be}(p,γ)^8\mathrm{B}$的首阶(LO)计算。$^8\mathrm{B}$被视为浅质子$+^7\mathrm{Be}$核心和质子$+^7\mathrm{Be}^{*}$(核心激发)$p$ -波束缚态。使用测量的结合能和质子- $^7\mathrm{Be}$ $s$ -波散射长度以及从头计算的$^8\mathrm{B}$渐近归一化系数来固定耦合。我们得到一个零能量$S$因子为$18.2 \pm 1.2~({\rm ANC~only})$ eV b。鉴于这是LO结果,其与推荐值$S(0)=20.8\pm1.6$ eV b一致。我们计算的$S(E)$与$E <0.4$ MeV的$^7\mathrm{Be}(p,γ)^8\mathrm{B}$的实验数据相比毫不逊色。我们强调质子- $^7\mathrm{Be}$散射参数在确定$S(E)$的能量依赖性的重要作用,并表明,他们目前的不确定性显着限制尝试外推这些数据恒星的能量。

英文摘要:

We report a leading-order (LO) calculation of $^7\mathrm{Be}(p,γ)^8\mathrm{B}$ in a low-energy effective field theory. $^8\mathrm{B}$ is treated as a shallow proton$+^7\mathrm{Be}$ core and proton$+^7\mathrm{Be}^{*}$ (core excitation) $p$-wave bound state. The couplings are fixed using measured binding energies and proton-$^7\mathrm{Be}$ $s$-wave scattering lengths, together with $^8\mathrm{B}$ asymptotic normalization coefficients from ab initio calculations. We obtain a zero-energy $S$-factor of $18.2 \pm 1.2~({\rm ANC~only})$ eV b. Given that this is a LO result it is consistent with the recommended value $S(0)=20.8\pm1.6$ eV b. Our computed $S(E)$ compares favorably with experimental data on $^7\mathrm{Be}(p,γ)^8\mathrm{B}$ for $E <0.4$ MeV. We emphasize the important role of proton-$^7\mathrm{Be}$ scattering parameters in determining the energy dependence of $S(E)$, and demonstrate that their present uncertainties significantly limit attempts to extrapolate these data to stellar energies.

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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