Coherent production of single pions andρmesons in charged-current interactions of neutrinos and antineutrinos on neon nuclei at the Fermilab Tevatron

The coherent production of $\pi$ and $\rho$ mesons in ${\nu }_{\mu } \left({\overline{\nu }}_{\mu }\right)$-neon charged-current interactions has been studied using the Fermilab 15-foot bubble chamber filled with a heavy Ne-${\mathrm{H}}_2$ mix and exposed to the Tevatron quadrupole triplet (anti)neutrino beam. The ${\nu }_{\mu } \left({\overline{\nu }}_{\mu }\right)$ beam had an average energy of 80 GeV (70 GeV). From a sample corresponding to approximately 28 000 charged-current interactions, net signals of (53±9) ${\mu }^{\pm }{\pi }^{\mp }$ coherent events and (19±7) ${\mu }^{\pm }{\pi }^{\mp }{\pi }^0$ coherent events are extracted. For $E>\mathrm{}10\mathrm{}$ GeV, the coherent pion production cross section is determined to be (3.2±0.7)×${10}^{-38\mathrm{}}$ ${\mathrm{cm}}^2$ per neon nucleus whereas the coherent $\rho$ production cross section is (2.1±0.8)×${10}^{-38\mathrm{}}$ ${\mathrm{cm}}^2$ per neon nucleus. These cross sections and the kinematical characteristics of the coherent events at $\mathrm{}\left|t\right|<0.1\mathrm{}$ Ge${\mathrm{V}}^2$ are found to be in general agreement with the predictions of a model based on the hadron dominance and, in the pion case, on the partially conserved axial-vector current hypothesis. Also discussed is the coherent production of systems consisting of three pions.