Studies of shell evolution using transfer reactions at ISOLDE

中微子双β衰变是一个目前未被观察到的过程，但如果这个过程被发现，它将对物理学的许多领域产生广泛的影响。它将有助于确定每个中微子的绝对质量，并将成为违反轻子数守恒的一个例子。这个过程的一个方面是确定可行的核来观察这个过程。学生将研究单粒子转移反应，以表征特定候选原子核的截面和占有率。然后将这些结果与核矩阵元素的一些理论计算进行比较以进行验证。这将进一步扩展到使用放射性光束来识别更多的候选者。这将构成项目的第一部分。该项目的下一部分将继续研究同位素壳结构的变化。自旋轨道相互作用揭示了壳层间隙产生的原因，并预测了壳层闭合的正确“神奇数字”。然而，单粒子状态的稳定性很差，因为这些神奇的数字将远离稳定线。探索原子核基本结构的这种变化将有助于发现和解释新的物理现象。为此，在ISOLDE将使用转移反应来测量单粒子轨道的占据能量，以跟踪底层壳结构的演变。这可能会继续使用稳定的目标和放射性光束来跟踪远离稳定线的结构。

Neutrinoless double beta decay is a currently unobserved process, but has wide implications for many fields in physics if the process is discovered. It would help to determine the absolute masses of each neutrino, and would be an example of the violation of lepton number conservation. An aspect of this process is determining viable nuclei for observing this process. The student will look at single-particle transfer reactions to characterise the cross-sections and occupancies for particular candidate nuclei. These results will then be compared to a number of theoretical calculations of nuclear matrix elements for validation. This will then extend further to using a radioactive beam to identify further candidates. This will make up the first part of the project. The next part of the project will follow onto examining the change in shell structure of isotopes. The spin-orbit interaction shed light on why shell gaps occur, and predicted the correct "magic numbers" for shell closures. However, single-particle state stability is poor, as these magic numbers will change far from the line of stability. Exploring this change in the fundamental structure of the atomic nucleus will help discover and explain new physics phenomena. To that end, transfer reactions will be used at ISOLDE to measure the occupation energies of single-particle orbits to track the evolution of the underlying shell structure. This may move on to using stable targets and radioactive beams to track the structure away from the line of stability.