  The Protvino accelerator facility located in the Moscow region, Russia, is in
a good position to offer a rich experimental research program in the field of
neutrino physics. Of particular interest is the possibility to direct a
neutrino beam from Protvino towards the KM3NeT/ORCA detector, which is
currently under construction in the Mediterranean Sea 40 km offshore Toulon,
France. This proposal is known as P2O. Thanks to its baseline of 2595 km, this
experiment would yield an unparalleled sensitivity to matter effects in the
Earth, allowing for the determination of the neutrino mass ordering with a high
level of certainty after only a few years of running at a modest beam intensity
of $\approx$ 90 kW. With a prolonged exposure ($\approx$ 1500 kW*yr), a
2$\sigma$ sensitivity to the leptonic CP-violating Dirac phase can be achieved.
A second stage of the experiment, comprising a further intensity upgrade of the
accelerator complex and a densified version of the ORCA detector (Super-ORCA),
would allow for up to a 6$\sigma$ sensitivity to CP violation and a
10$^\circ$-17$^\circ$ resolution on the CP phase after 10 years of running with
a 450 kW beam, competitive with other planned experiments. The initial
composition and energy spectrum of the neutrino beam would need to be monitored
by a near detector, to be constructed several hundred meters downstream from
the proton beam target. The same neutrino beam and near detector set-up would
also allow for neutrino-nucleus cross section measurements to be performed. A
short-baseline sterile neutrino search experiment would also be possible.
