Coherent production of single pions and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>ρ</mml:mi></mml:math>mesons in charged-current interactions of neutrinos and antineutrinos on neon nuclei at the Fermilab Tevatron

Abstract

The coherent production of $\ensuremath{\pi}$ and $\ensuremath{\rho}$ mesons in ${\ensuremath{\nu}}_{\ensuremath{\mu}} ({\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}})$-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 ${\ensuremath{\nu}}_{\ensuremath{\mu}} ({\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}})$ 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\ifmmode\pm\else\textpm\fi{}9) ${\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ coherent events and (19\ifmmode\pm\else\textpm\fi{}7) ${\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}{\ensuremath{\pi}}^{0}$ coherent events are extracted. For $E&gt;10$ GeV, the coherent pion production cross section is determined to be (3.2\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}38}$ ${\mathrm{cm}}^{2}$ per neon nucleus whereas the coherent $\ensuremath{\rho}$ production cross section is (2.1\ifmmode\pm\else\textpm\fi{}0.8)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}38}$ ${\mathrm{cm}}^{2}$ per neon nucleus. These cross sections and the kinematical characteristics of the coherent events at $|t|&lt;0.1$ 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.