First Measurement of the EMC Effect in ${}^{10}$B and ${}^{11}$B

Abstract

The nuclear dependence of the inclusive inelastic electron scattering cross section (the EMC effect) has been measured for the first time in ${}^{10}$B and ${}^{11}$B. Previous measurements of the EMC effect in $A\le 12$ nuclei showed an unexpected nuclear dependence; ${}^{10}$B and ${}^{11}$B were measured to explore the EMC effect in this region in more detail. Results are presented for ${}^9$Be, ${}^{10}$B, ${}^{11}$B, and ${}^{12}$C at an incident beam energy of 10.6~GeV. The EMC effect in the boron isotopes was found to be similar to that for ${}^9$Be and ${}^{12}$C, yielding almost no nuclear dependence in the EMC effect in the range $A=4-12$. This represents important, new data supporting the hypothesis that the EMC effect depends primarily on the local nuclear environment due to the cluster structure of these nuclei.

To appear in PRC