论文标题
重新访问Hypertriton终身难题
Revisiting the hypertriton lifetime puzzle
论文作者
论文摘要
在最近的相对主义重型离子碰撞实验中提取了超三体（$_λ^{3} $ h）寿命的冲突值。爱丽丝合作报告的$_λ^{3} $ h Lifetime $τ（_λ^{3} $ h）在测量不确定性中与免费$λ$ lifetime $τ_λ$兼容，正如$_λ^{3} $ heles inerere profes in eerere of y hyper的$λ$τ_λ$，neereas $ hiperon，nererease of theeres of neerease sar， $τ（_λ^{3} $ h）值要短得多：$τ_{\ rm star}（_λ^{3} $ h）$ \ sim $（0.4-0.7）$τ_λ$。理论上，使用$_λ^{3} $ h三体波functions在手性有效的现场理论方法中生成的$_λ^{3} $hλ^{3} $ h LIFETIME GUBLIZE的此$_λ^{3} $ h Lifetime难题是在手性有效的现场理论方法中生成的，以计算衰减率$γ（_λ^{3} $ h $ h $ h $ h $ h $ h $ he $ he $ he $ he $ he $ he $ he $ he $ he $ he $，重要但相反的贡献来自$_λ^{3} $ H的$σnn$ admixtures，以及$π^ - $ - $ - $^3 $ he最终状态交互。通过分支比率$γ（_λ^} $γ{3} $ h $ h $ h $ \，\，\ to^{3} $ HE+$ $ po $ po $ ph^ - ）/γ_________________________________ Bubble-Chamber实验，并通过$ΔI= \ frac {1} {2} $ rule添加$γ_{π^0}（_λ^{3} $ h），我们得出$τ（_λ^{3} $ h），假设$λ$ unitance $λ$ sapeitage $λ$ sapeitation $λ$ b_ /得出的结论是，爱丽丝和星星的每一个报告$τ（_λ^{3} $ h）间隔意味着对$b_λ（_λ^{3} $ h）的约束：$b_λ\ lyssim 0.1 $ mev for爱丽丝，$b_λ\ gtrsim 0.2 $ mev for star for star。
Conflicting values of the hypertriton ($_Λ^{3}$H) lifetime were extracted in recent relativistic heavy-ion collision experiments. The ALICE Collaboration's reported $_Λ^{3}$H lifetime $τ(_Λ^{3}$H) is compatible within measurement uncertainties with the free $Λ$ lifetime $τ_Λ$, as naively expected for a loosely bound $Λ$ hyperon in $_Λ^{3}$H, whereas STAR's reported range of $τ(_Λ^{3}$H) values is considerably shorter: $τ_{\rm STAR}(_Λ^{3}$H)$\sim$(0.4-0.7)$τ_Λ$. This $_Λ^{3}$H lifetime puzzle is revisited theoretically using $_Λ^{3}$H three-body wavefunctions generated in a chiral effective field theory approach to calculate the decay rate $Γ(_Λ^{3}$H$\,\to ^3$He$\,+π^-$). Significant but opposing contributions arise from $ΣNN$ admixtures in $_Λ^{3}$H and from $π^-$-$^3$He final-state interaction. Evaluating the inclusive $π^-$ decay rate $Γ_{π^-}(_Λ^{3}$H) via a branching ratio $Γ(_Λ^{3}$H$\,\to ^{3}$He+$π^-)/Γ_{π^-}(_Λ^{3}$H) determined in helium bubble-chamber experiments, and adding $Γ_{π^0}(_Λ^{3}$H) through the $ΔI=\frac{1}{2}$ rule, we derive $τ(_Λ^{3}$H) assuming several different values of the $Λ$ separation energy $B_Λ(_Λ^{3}$H). It is concluded that each of ALICE and STAR reported $τ(_Λ^{3}$H) intervals implies its own constraint on $B_Λ(_Λ^{3}$H): $B_Λ\lesssim 0.1$ MeV for ALICE, $B_Λ\gtrsim 0.2$ MeV for STAR.
