Structure of high spin states in ${}^{104}\mathrm{Sn}$: $E2\mathrm{}$ and $E3\mathrm{}$ polarization of the ${}^{100}\mathrm{Sn}$ core

High spin states in ${}^{104}\mathrm{Sn}$ were identified in the reaction ${}^{58}\mathrm{Ni}{(}^{50}\mathrm{Cr}$, $2p2n)$ at 200 and 205 MeV beam energies. The $\gamma$-ray energies, intensities, multipolarities, and lifetimes of high spin states were measured with the GASP spectrometer array in combination with a plunger apparatus by means of the recoil distance Doppler shift method. The deduced level scheme and transition probabilities are compared to the results of large-scale shell model calculations using three independent two-body interactions. The agreement of the level energies is satisfactory, except for a cascade of dipole transitions at high spins. The general good agreement found for $E2\mathrm{}$ transition strengths implies a large effective neutron polarization charge. The shell-model calculations do not account for the measured enhanced $E3\mathrm{}$ transitions for which a core excited octupole phonon admixture is indicated.