Stackelberg proposed
 the conservation of baryon number to account for the stability of this particle, whose lifetime is currently
 figured to be at least 10 to the 34th power years.
This particle corresponds to the "plus one-half" eigenvalue of the z-component of the isospin, and the
 dominant decay mode of the neutral lambda is into a negative pion and this particle. This particle can be
 found at the intersection of the S equals 0 and Q equals 1 lines of the baryon octet. Stackelberg proposed
 the conservation of baryon number to account for the stability of this particle, whose lifetime is currently
 figured to be at least 10 to the 34th power years. Predicted to decay in some grand unified theories, this
 particle accounts for the majority of the composition of cosmic rays, and can transform into a heavier
 baryon by capturing an electron. Consisting of two up quarks and a down quark, for 10 points, identify this
 subatomic particle, the nucleonic partner of the neutron.
This particle corresponds to the "plus one-half" eigenvalue of the z-component of the isospin, and the
 dominant decay mode of the neutral lambda is into a negative pion and this particle.
{proton}