Another famous physicist from the early 20th century Paul Dirac, came up with an equation that had a negative energy solution that was similarily ignored. Not only was it ignored but it was “violently” contested by some of the most famous scientists of the time including Werner Heisenberg (of the Heisenberg uncertainty principle) who referred to Dirac’s equation as “learned trash”.
What Dirac had done was to develop a relativistic generalization of the Schrodinger wave equation which was brilliantly successful at predicting the behaviour of the most fundamental of sub atomic particles, the electron. It also predicted (among other things) the existence of the positron, the anti-particle to the electron, which was later confirmed experimentally.
Dirac’s COMPLETE equation, however, had FOUR solutions. In other words, it predicted FOUR unique “electrons” rather than TWO. It predicted electrons and positrons of POSITIVE energy, and it predicted electrons and positrons of NEGATIVE energy. It also predicted that the entire universe could be made from these four kinds of electron(s) alone.
This implies that quarks and gluons are not fundamental particles as currently suggested by the Standard Model but are somehow made up of combinations of these FOUR electrons.
Unfortunately, his colleague(s) had a different idea of what his equation meant and despite its many successes, Dirac was forced to concede and, via a trick that basically equates to “Black equals White therefore black does not exist”, he was able to "hide" the negative energy solutions to his equations.