论文标题
寿命
Lifetime of the hypertriton
论文作者
论文摘要
在过去的十年中，Hypertriton寿命$τ（{}_λ^3 \ mathrm {h}）$的值是在相对论重离子（RHI）碰撞实验中得出的。最近一次的爱丽丝合作测量是唯一的实验，其中报告的$τ（{}_λ^3 \ mathrm {h}）$足够接近免费的 - $ up $λ$ lifetime $τ_λ$，正如预期的那样，预期的是$ {}_λ^3 \} $ nake thairy trecription thairmy thairmy trecription trecried trecried nake trieldife。我们从理论上对此进行了回顾，使用$ {}_λ^3 \ Mathrm {h} $ {} $ { $γ（{}_λ^3 \ mathrm {h} \ to {}^3 \ mathrm {he}+π^ - ）$。我们发现$ {}_λ^3 \ mathrm {h} $和$π^ - {}^3 \ mathrm {he} $ final-state交互作用是由$ {}_λ^3 \ mathrm {h} $ in $ {}_λ^3 \ mathrm {h} $产生的重大但相反的贡献。为了得出$τ（{}_λ^3 \ mathrm {h}）$，我们使用测量的分支分支率，评估了包含$π^ - $ decay速率$γ_{}_λ^3 \ Mathrm {}_λ^3 \ mathrm {h}）$ $γ（{}_λ^3 \ Mathrm {h} \ to {}^3 \ Mathrm {He}+π^ - ）/γ_{π^ - }（{}_λ^3 \ 3 \ 3 \ 3 \ Mathrm {h}） 规则。所得的$τ（{}_λ^3 \ mathrm {h}）$差异很大，鲜为人知的$λ$分离能量$ e _ {\ mathrm {sep}}}}（{}_λ^3 \ 3 \ Mathrm {h}）$ an $τ（{}_λ^3 \ mathrm {h}）$测量$ e _ {\ mathrm {sep}}}}}（{}_λ^3 \ Mathrm {h h}）$。
Conflicting values of the hypertriton lifetime $τ({}_Λ^3\mathrm{H})$ were derived in relativistic heavy ion (RHI) collision experiments over the last decade. A very recent ALICE Collaboration measurement is the only experiment where the reported $τ({}_Λ^3\mathrm{H})$ comes sufficiently close to the free-$Λ$ lifetime $τ_Λ$,as expected naively for a very weakly bound $Λ$ in ${}_Λ^3\mathrm{H}$. We revisited theoretically this ${}_Λ^3\mathrm{H}$ lifetime puzzle, using ${}_Λ^3\mathrm{H}$ and ${}^3\mathrm{He}$ wave functions computed within the abinitio no-core shell model employing interactions derived from chiral effective field theory to calculate the two-body decay rate $Γ({}_Λ^3\mathrm{H}\to{}^3\mathrm{He}+π^-)$. We found significant but opposing contributions arising from $ΣNN$ admixtures in ${}_Λ^3\mathrm{H}$ and from $π^- -{}^3\mathrm{He}$ final-state interaction. To derive $τ({}_Λ^3\mathrm{H})$, we evaluated the inclusive $π^-$ decay rate $Γ_{π^-}({}_Λ^3\mathrm{H})$ by using the measured branching ratio $Γ({}_Λ^3\mathrm{H}\to{}^3\mathrm{He}+π^-)/Γ_{π^-}({}_Λ^3\mathrm{H})$ and added the $π^0$ contributions through the $ΔI = \frac{1}{2}$ rule. The resulting $τ({}_Λ^3\mathrm{H})$ varies strongly with the rather poorly known $Λ$ separation energy $E_{\mathrm{sep}}({}_Λ^3\mathrm{H})$ and it is thus possible to associate each one of the distinct RHI $τ({}_Λ^3\mathrm{H})$ measurements with its own underlying value of $E_{\mathrm{sep}}({}_Λ^3\mathrm{H})$.
