Direct high-energy neutral-channel dissociative recombination of coldH3+in an ion storage ring

The cross section for neutral-channel dissociative recombination of vibrationally cooled ${\mathrm{H}}_3^{+}$ at energies between 0.0025 and 30 eV has been measured by utilizing the electron cooler at the storage ring CRYRING. The molecular ions were stored at an energy of 32.6 MeV and phase-space cooled by the electron cooler for about 8 s prior to data taking. A peak in the cross section at 9.4 eV is interpreted as a direct adiabatic neutral-channel recombination through the ${}_{}{}^2{}_{}{}^{}$ ${\mathit{A}}_1$ resonant state. The cross section below 1 eV is in rather good agreement with single-pass data.