What are the properties of proton+proton fusion reaction
$p + p → 2H + e^+ + ν_e + 0.42 MeV$$$p + p → 2H + e^+ + ν_e + 0.42 MeV$$
making it hard to replicate on Earth?
If we aim beam of protons to a can of water, won't we observe some number of these p-p$p+p$ fusions?
Do we have p-p$p+p$ fusion events on some well known accelerator like LHC or old ones?