Core-excited states in 101 Sn Darek Seweryniak, ANL GS/FMA collaboration

Self-conjugate Z GT  -decay super allowed  -decay spe p decay n-n interactions 100 Sn rp process end point N Doubly-magic 100 Sn physics pp

100 Sn region experimental status Z= Sn 102 Sn 103 Sn 102 In 101 In 99 In 100 In 98 In 101 Cd 99 Ag 100 Ag 99 Pd 104 Sb 105 Te 103 Sb 99 Cd 100 Cd 98 Cd 97 Cd 96 Cd 95 Ag 94 Ag 96 Ag 97 Ag 98 Ag 94 Pd 95 Pd 96 Pd 97 Pd 98 Pd 93 Pd 92 Pd 106 Te 108 I 109 Xe 112 Cs 114 Ba 113 Cs 109 I 105 Sb 107 Te 108 Te 110 Xe 111 Xe 112 Xe 104 Sn 115 Ba 116 Ba 100 Sn Excited states Fusion-evaporation Decay properties Fusion-evaporation Decay properties Existence Fragmentation CN 103 In CN 99 Sn 95 Cd N=50  -delayed protons with sizeable branch Observed/expected 97 In 93 Ag 100 Cd 101 Ag 100 Pd

101 Sn  p recoil-decay tagging experiment 101 Sn 100 Cd  pp Total  spectrum 101 Ag Random  E p =1-5 MeV t p <5s  rays 101 Sn  g 7/2 d 5/2 172 keV GAMMASPHERE+FMA First observation 1 st exp PRL 99, (2007) Search for core excited states 2 nd exp summer Te  decay indicates that the level sequence is different in 105 Te and 101 Sn (ORNL)

Core-excited states in 101 Sn 7/2+ 5/2+ 7/2+ Fahlander et al., Phys. Rev. C63, (R) (2001) 100 Sn(2+) coupled to d 5/2 and g 7/2 states ~2.5 MeV h 11/2 single-neutron orbital ~2.5 MeV Feeding pattern can reveal the d5/2, g7/2 orbital order Other nuclei of interest: 105 Te, 100 In

Can we collect more statistics with GRETINA+FMA?  4 times larger solid angle (possibility to use  3n channel)  Higher Ge rates (higher beam intensity)  Much better Doppler correction (3 MeV)  Polarization (h 11/2 )  No dead time  Neutron Wall (Chris Chiara) VERY CHALLENGING EXPERIMENT! Original experiment: ~5 days, ~10 kHz/Ge,  ~10s nb

Interplay between rotation and proton decay in highly-deformed proton emitters Darek Seweryniak, ANL GS/FMA collaboration

Proton decay vs rotation  Proton decay probes single-particle wave function components  In deformed nuclei, protons are emitted from rotational band heads  Properties of rotational bands can shed light on the proton emitting states  Only very recently the quasi-particle non-adiabatic proton-decay model by Maglione et al. included Coriolis interaction and pairing consistently  The new model has to be confronted with more data

Proton emitter landscape ~20 mass units away from the line of stability Often less exotic neighbors not known

Rotational bands in highly-deformed proton emitters 117 La 131 Eu 141 Ho 145 Tm Several proton emitters were studied with GS and FMA 141 Ho – strongly coupled bands built on gs and isomer 145 Tm – decoupled h 11/2 band 117 La, 131 Eu –multiple bands, not enough statistics

Rotational bands in the deformed proton emitter 141 Ho D. Seweryniak et al., PRL C86(2001)1458 7/2 - [523] ½ + [411] Unexpectedly large signature splitting indicates triaxial shape!  =0.25(4) from Harris formula

131 Eu level scheme 5/2 + [413] or 3/2 + [411] ground state? 3/2 + [411] band in 159 Tb 94 after A 5/3 scaling gives: /2+ 5/2+ 9/2+ 5/2 + [413] band in 159 Eu 96 after A 5/3 scaling gives: /2+ 5/2+ 9/2+ We observed 72 keV and 105 keV. Low energy transitions present in the spectrum suggest the 3/2 + [411] assignment

117 La proton emitter  Quasi-particle non-adiabatic model predicts that protons are emitted from a 7/2 - member of the h 11/2 band  Spectrum indicates 3/2 + [422] band supported by adiabatic approach Z.Liu et al., Physics Letters B 702 (2011) 24–27

Can we collect more statistics with GRETINA and FMA?  4 times larger FMA solid angle  Higher Ge rates (more beam)  Better Doppler correction  Polarization  No dead time CHALLENGING EXPERIMENT! Original experiment: ~5 days, ~10 kHz/Ge,  ~100s nb

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