Metaculus Help: Spread the word

If you like Metaculus, tell your friends! Share this question via Facebook, Twitter, or Reddit.

Will we discover clear evidence of proton decay by 2040?

Protons are durable little subatomic particles. Our collective best guess that they should take at least years to decay... if they do so at all.

Why do scientists want to figure this out? Symmetry Magazine explains the situation:

Much [the theoritical work on Grand Unified Theories of the universe] rests on the existence of proton decay, and yet we’ve never seen a proton die. The reason may simply be that protons rarely decay, a hypothesis borne out by both experiment and theory... Because of quantum physics, the time any given proton decays is random, so a tiny fraction will decay long before that -year lifetime. So, “what you need to do is to get a whole bunch of protons together,” says [University of California's Jonathan Feng]. Increasing the number of protons increases the chance that one of them will decay while you’re watching.

Several experiments around the world have attempted (and will be attempting) to quantify the whys and wherefores of proton decay.

Two of the most important include:

Super-Kamiokande in Japan:

If we can collect many protons and some of them decay, we can estimate proton lifetime unless waiting for so long time. Super-Kamiokande uses 50,000 tons of pure water and it contains protons. We are measuring proton lifetime with huge number of protons... however, we have not observed any evidence of proton decay yet.


Hyper-Kamiokande is about 10 times larger than SK [Super-Kamiokande] and it can overtake the current reach by SK within two years... Hyper-Kamiokande has sensitivity up to more than one order longer than the current lower lifetime of proton.

What do you think? Will we discover proton decay before 2040?

Question resolves positive if experimental evidence for proton decay is published in a top peer-reviewed journal prior to 2040.


Metaculus help: Predicting

Predictions are the heart of Metaculus. Predicting is how you contribute to the wisdom of the crowd, and how you earn points and build up your personal Metaculus track record.

The basics of predicting are very simple: move the slider to best match the likelihood of the outcome, and click predict. You can predict as often as you want, and you're encouraged to change your mind when new information becomes available.

The displayed score is split into current points and total points. Current points show how much your prediction is worth now, whereas total points show the combined worth of all of your predictions over the lifetime of the question. The scoring details are available on the FAQ.

Note: this question resolved before its original close time. All of your predictions came after the resolution, so you did not gain (or lose) any points for it.

Note: this question resolved before its original close time. You earned points up until the question resolution, but not afterwards.

This question is not yet open for predictions.

Thanks for predicting!

Your prediction has been recorded anonymously.

Want to track your predictions, earn points, and hone your forecasting skills? Create an account today!

Track your predictions
Continue exploring the site

Community Stats

Metaculus help: Community Stats

Use the community stats to get a better sense of the community consensus (or lack thereof) for this question. Sometimes people have wildly different ideas about the likely outcomes, and sometimes people are in close agreement. There are even times when the community seems very certain of uncertainty, like when everyone agrees that event is only 50% likely to happen.

When you make a prediction, check the community stats to see where you land. If your prediction is an outlier, might there be something you're overlooking that others have seen? Or do you have special insight that others are lacking? Either way, it might be a good idea to join the discussion in the comments.