Did Koshiba discover proton decay?
No, that is a common misconception. The original Kamiokande experiment was designed primarily to search for proton decay, a prediction of grand unified theories. We set stringent limits on the proton lifetime—showing it exceeds 10^32 years—but we never observed a single decay event. However, this 'failure' was a blessing in disguise. The same detector proved exceptionally sensitive to neutrinos, leading to our groundbreaking solar and supernova observations. I often say that science is a team sport, and sometimes the most important discoveries come from unexpected directions. We must let the data guide us, not our initial assumptions. The detector's ability to detect neutrinos was a direct result of our meticulous calibration and the dedication of our team, who turned a null result into a new field of astrophysics.
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