Speaker
Description
The Sn isotopic chain is a formidable testing ground for the study of shell evolution in various kinds of nuclear models. Even though the first 2$^{+}$ energies in even-even isotopes between $^{102}$Sn and $^{130}$Sn are quite similar, in agreement with the seniority scheme for this valence neutron space, the significant increment of the B(E2: 0$^{+} \rightarrow 2^{+}$) approaching $^{100}$Sn has remained a major puzzle over decades. Recently, the results of state-of-the-art calculations with the Monte Carlo shell model (MCSM) on Sn isotopes, performed in a large model space including single-particle orbits below and above the magic numbers 50 and 82, has explained the anomalous trend of B(E2: 0$^{+} \rightarrow 2^{+}$) by considering a core breaking contribution, namely from $g_{9/2}$ proton orbits. The MCSM calculations also suggest that the numbers of proton holes for the first 0$^{+}$, 2$^{+}$ and 4$^{+}$ states in even-even Sn isotopes will increase when approaching $N$ = 60, e.g., being around 1.2 for the 4$^+_1$ state in $^{110}$Sn. Thus, we want to measure the spectroscopic factor for the protons in the first 0$^{+}$, 2$^{+}$ and 4$^{+}$ states of $^{108,110,112}$Sn which can be produced via single-proton-transfer reactions.
The following projectile + target combinations can be candidates for the current LOI:
$^{107,109,111}$In + $^3$He $\rightarrow$ $^{108,110,112}$Sn + $^2$H;
$^{107,109,111}$In + $^4$He $\rightarrow$ $^{108,110,112}$Sn + $^3$H;
$^{109,111,113}$Sb + $^2$H $\rightarrow$ $^{108,110,112}$Sn + $^3$He;
$^{109,111,113}$Sb + $^3$H $\rightarrow$ $^{108,110,112}$Sn + $^4$He;
The secondary beams which are optimized for In or Sb isotopes can be produced by HIE-ISOLDE at the energy of 5.5~MeV/u, and the light ejectiles will be measured by Solenoidal Spectrometer.
