Most of us don’t think much about charging, except for those annoying moments when our phones run out. But for physicists, it’s a big deal. In every atom, negatively charged electrons orbit a nucleus containing positively charged protons, the whole dance being mutual attraction. It would be fair to say, then, that the position is fairly basic.
This explains why physicists have long struggled to understand its nature, and have mostly succeeded. But there is one question that has always hung in the air, without an answer. It seems that the smallest possible unit of charge is that of an electron; all other particles in nature have only multiples of it. In nature, you can find charges of -1 or +3 or -2, but never 0.25. Why is this?
You might shrug your shoulders and say that’s just the way the universe is. But in truth, there have always been good reasons to suspect that fractional charges exist, even if we haven’t caught one yet. And today’s topic is particularly alive thanks to new insights into string theory, a candidate for a theory of everything.
Now, experiments are beginning at the CERN particle physics laboratory near Geneva, near Switzerland, to look for particles that can have a thousandth the charge of an electron. If they found it, it would be…
