Up quarks have a charge of + 2 ⁄ 3 and down antiquarks have a charge of + 1 ⁄ 3, so π + has charge of +1 (like a proton).Īntiparticles have charge opposite to their particles, so up antiquarks have a charge of − 2 ⁄ 3 and down quarks have a charge of − 1 ⁄ 3. The ( superscript) +, –, or 0 simply refers to the (electromagnetic) charge of the pion. Π + for the positively charged pion π – for the negatively charged pion, and π 0 for the neutral pion. The three types of pion have the Greek letter pi in their symbols: Pions are the lightest hadrons (particles made up of quarks) and pions with a positive or negative charge are the mesons with the longest mean lifetime (the average time that passes before they decay into leptons). These interactions hold the nucleus together. Pions are significant to our lives because they are one of the ways for strong force interactions to take place between nucleons like the protons and neutrons of ordinary matter. ( On average, charged pions exist for around 26 nanoseconds neutral pions last a tiny fraction of this). The charge is negative when a down quark pairs with an up antiquark. This charge is positive when an up quark pairs with a down antiquark. But when the two quarks have different flavours (up and down), the pion will have a charge. Quarks have charge, so two quarks of the same flavour (both up or both down) make a neutral pion.
![up quark up quark](https://www.ex-astris-scientia.org/gallery/artoftrek/unknown-alien1.jpg)
There are six types of quark (called flavours) but only two flavours go together to make a pion. One up quark (u) and one down antiquark are one combination to make a pionĪ pion or π meson is a meson, which is a subatomic particle made of one quark and one antiquark.