Nuclear Data Sheets for A=123

Experimental nuclear structure and decay data are evaluated for all of 15 known nuclides of mass 123 (Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce). For each nuclide, detailed evaluated spectroscopic information is presented in each reaction and decay, and the best values combining all available data are recommended for level properties, γ and β radiations, and other spectroscopic properties. No excited states have been identified in ¹²³Ru, ¹²³Rh and ¹²³Pd. For ¹²³Ag, the long-predicted 1/2⁻ β-emitting isomer has been identified at 60-keV by 2019Ch24 recently, resolving unknown excitation energies in the level scheme that was previously available only from isomeric decays of two isomers (202 ns and 393 ns) with the position and spin-parity of the former remaining unknown. Significant discrepancies exist between data on high-spin sequences based on 11/2⁽⁻⁾ isomer in ¹²³Cd (2002Hw01 and 2016Re05), which needs to be resolved with further experimental investigation. In ¹²³Cs, the 114-ns isomer as the πg_9/2 bandhead proposed at 231.6+x by 2000Gi12 has been resolved by 2004Si26 and 2004Si27 to be the 328-keV level that is proposed by 2000Gi12 as a separate level. Excited states in ¹²³La and ¹²³Ce have only been studied via (HI, xnγ) reactions, with their base levels and thus excitation energies remaining unknown. The β⁻ decay schemes for daughter nuclide ¹²³Cd, ¹²³In and ¹²³Sn and the ε decay schemes for ¹²³Xe, ¹²³Cs and ¹²³Ba are considered incomplete due to large gaps between the highest observed excited levels and the Q-values. ¹²³Sn, ¹²³Sb, ¹²³Te and ¹²³I are the most extensively studied nuclides via various reactions and decays. This work supersedes earlier full evaluations of A=123 by 2004Oh11, 1993Oh12, 1980Ta02 and 1972Au10.