# Why does the Strange Quark have Strangeness -1?

I have been trying to find an explanation for the strange quarks negative strangeness value, I understand the term strangeness predates the quark model, but I'm unsure if terminology carry over is the reason for the naming convention.

Apparently, it is also convention to give quantum numbers a positive or negative value depending on the charge of the particle. Does the strange quark's negative charge give it a negative strangeness?

• to keep with the convention used when the kaon was discovered , en.wikipedia.org/wiki/Kaon at the quark level May 8 at 13:07
• For the same reason electrons are negatively charged: we guessed wrong which convention would be most useful.
– J.G.
May 8 at 15:06
• If either of you would like to write your comments up into a full answer I'd happily accept one of them. May 8 at 15:23
• A strange quark with strangeness +1 would be just what you'd expect, and therefore not strange at all :) May 9 at 4:23

• @Connor This is the very point of the paragraph: The strangeness of the $K^-$ was assigned to be -1, same as its charge. The charm of the $D^+$ is assigned to be +1, same as its charge. May 8 at 16:04
Having this in mind, a subnuclear physics reason can be that the Gell-Mann & Nishijima formula that relates electric charge $$Q$$, strong isospin $$I_3$$, barionic number $$B$$ and strangeness $$S$$ (the sum of these two and all other quark numbers is called strong hypercharge, $$Y$$) states: $$Q = \frac{B+S}{2} + I_3$$ Because of this, reminding that the charge of quark strange is $$-\frac{1}{3}$$ we obtain the correct solution if we put $$I_3 = 0$$, $$B = \frac{1}{3}$$ and $$S = -1$$.