Figure 11.24. The kaon (K+) is an unstable particle that spontaneously decays into a pion pair (Ï€+ and Ï€°).
Hadrons − Hadrons are particles that interact using the strong nuclear force. Mesons are hadrons that do not decay into protons, such as: pions and kaons. Pions and kaons can be positive, neutral and negative. Baryons and mesons aren't fundamental particles and so can be split into smaller particles known as quarks.
Muons are unstable elementary particles and are heavier than electrons and neutrinos but lighter than all other matter particles. They decay via the weak interaction. Thus all muons decay to at least an electron, and two neutrinos.
The proton is the only stable baryon into which other baryons eventually decay. The pion as the exchange particle of the strong nuclear force. The kaon as a particle that can decay into pions. Leptons: electron, muon, neutrino (electron and muon types only) and their antiparticles.
A pion or π meson is a meson, which is a subatomic particle made of one quark and one antiquark. There are six types of quark (called flavours) but only two flavours go together to make a pion.
A particle made up of an anti quark and a quark is called a meson, and you should know that all mesons have a baryon number of 0. The antiparticle of the positive Kaon is the K- meson. Its quark structure is an anti up and a strange quark.
Physicist Enrico Fermi popularized the name “neutrinoâ€, which is Italian for “little neutral one.†Neutrinos are denoted by the Greek symbol ν, or nu (pronounced “newâ€). But not all neutrinos are the same. They come in different types and can be thought of in terms of flavors, masses, and energies.
Strange particles are always created in pairs by strong processes in such a way that the total strangeness remains zero. An example of strange particle production is when a negative pion collides with proton, giving rise to a neutral lambda particle and a neutral kaon.
Since neutral kaons carry strangeness, they cannot be their own antiparticles. There must be then two different neutral kaons, differing by two units of strangeness. The two diagonal elements must be equal, since the particle and antiparticle have equal masses in the absence of the weak interactions.
: an unstable meson that occurs in both charged and neutral forms and is about 970 times more massive than an electron.
: a meson that is a combination of up and down quarks and antiquarks, that may be positive, negative, or neutral, and that has a mass about 270 times that of the electron.
The pion is a meson. The π+ is considered to be made up of an up and an anti-down quark. The neutral pion is considered to be a combination of quark-antiquark pairs: The pions π+ and π- have spin zero and negative intrinsic parity (Rohlf Sec 17-2).
More than 200 mesons have been produced and characterized in the intervening years, most in high-energy particle-accelerator experiments. All mesons are unstable, with lifetimes ranging from 10−8 second to less than 10−22 second.
Atoms are constructed of two types of elementary particles: electrons and quarks. Protons and neutrons are composed of two types: up quarks and down quarks. Each up quark has a charge of +2/3. Each down quark has a charge of -1/3.
Experiments in which electrons are scattered from nucleons have revealed that neutrons and protons are not fundamental particles but are composed of yet smaller particles, quarks. There are three quarks: up, down and strange and each has a corresponding antiquark of opposite charge.
1* The neutral Kaons K0s and K0L represent symmetric and antisymmetric mixtures of the quark combinations down-antistrange and antidown-strange. Decay times in this range indicate decay by the weak interaction.
hyperons. …they are often produced—were named strange particles. This behaviour has since been ascribed to the weak decays of the specific quarks—also called strange—that they contain.
CP eigenstates are not the same (having already noted that the lifetimes are different). This might be a bit worrisome – the C operation does not change mass. quantum mechanics that particle and anti-particle have the same mass (as well as the same total lifetime).
