We compute nuclear matrix elements of neutrinoless double-beta decay mediated by light Majorana-neutrino exchange in the A = 6 system. The goal is to benchmark two many-body approaches, the No-Core Shell Model and the Multi-Reference In-Medium Similarity Renormalization Group. We use the SRG-evolved chiral N3LO-EM500 potential for the nuclear interaction, and make the approximation that isospin is conserved. We compare the results of the two approaches as a function of the cutoff on the many-body basis space. Although differences are seen in the predicted nuclear radii, the ground-state energies and neutrinoless double-beta decay matrix elements produced by the two approaches show significant agreement. We discuss the implications for calculations in heavier nuclei.

中文翻译：

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轻核中无中微子双β衰变矩阵元素的基准

我们计算了 A = 6 系统中由轻马约拉纳-中微子交换介导的无中微子双 β 衰变的核矩阵元素。目标是对两种多体方法进行基准测试，即无核壳模型和多参考介质中相似性重整化组。我们使用 SRG 进化的手性 N3LO-EM500 势进行核相互作用，并近似认为同位旋是守恒的。我们将两种方法的结果作为多体基空间上的截止函数进行比较。尽管在预测的核半径中看到了差异，但两种方法产生的基态能量和中微子双β衰变矩阵元素显示出显着的一致性。我们讨论了对较重原子核计算的影响。