Particle Physics

All hadrons are either bosons or fermions, and only hadrons are composed of quarks. Bosons are force carriers and interactions.

Particles that aren't composed of other particles are elementary particles, which consists of the 1st and 4th box only.

While a proton consists of 2 up quarks and 1 down quark, and a neutron consists of 2 down quarks and 1 up quark, there isn't a fixed number of gluons in them, as they continuosly split and combine. Gluons holding the quarks together, is known as the strong force. The study of the strong force is QCD: quantum chromodynamics.

There is a phenonemon known as the melting point of a proton, at 5 trillion K, which makes quark-gluon plasma. Quark-gluon plasma behaves like a strongly-interacting liquid. This is the hottest man-made form of matter, called heavy ion collision, to produce the quark-gluon plasma, which is usually done with lead. (This was 1st done at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, on Long Island, in Upton, New York, in which their 1st collisions were in 2000 with gold, and hit 4.6 trillion K around 2005 (400 MeV)).

The Wigner function for a proton or and electron describes the probability distribution of its internal degrees of freedom (such as position and momentum of the constituent quarks) and can also incorporate information about its spin.

Inelastic scattering is where a particle (such as an electron) interacts with a target (such as a proton) and exchanges a photon with a quark in the target. This was 1st discovered in the 1950s, but the landmark discovery came in 1968 at Stanford Linear Accelerator Center. This led to the discovery of quarks (but not published until Oct. 20, 1969).

In May 2018, a new discovery at the Jefferson National Lab, found the pressure distribution of protons. Using deeply virtual Compton scattering (DVCS), where electrons scatter off protons and emit photons, scientists were able to measure the distribution of pressure inside the proton for the 1st time. They found that the proton's quarks, are about 10x greater than the pressure inside a neutron star, or 100 decillion Pascal (10³⁵). This was done via their CLAS12 detector, which is an electron-hadron scattering detector.

Hadrons and muon colliders.

It's hard to get 2 protons to collide against each other. The 1st time that that happened, in a controlled lab experiment, was in 1959, at the CERN proton synchroton, a particle accelerater, to 28 gigavolts.

The 1st time protons were collided with either electrons or positrons, was done at DESY in Hamburg, Germany, with their HERA (particle accelerator), which was in operation from 1992 to 2007.

The most powerful proton-proton collisions occur at the Large Hadron Collider at CERN, which began operations on Sept. 10, 2008, to 13 teravolts (7 TeV in July 2011). The LHC has a 16-mile circumference, composed of superconducting magnets. About 2 billion LHC collisions are needed to produce 1 Higgs boson. Inside the accelerator, which is about 100 meter underground, 2 high-energy particle beams travel close to the speed of light before they are made to collide. They are guided around the accelerator ring by the strong magnetic field maintained by the superconducting electromagnets, which are built from coils of special electric cable that operates in a superconducting state, efficiently conducting electricity without resistance or loss of energy. This requires freezing the magnets to -271.3 C, so much of the accelerator is connected to a distribution system of liquid helium, which cools the magnets and other supplying services.

Muon colliders are much harder to make (unlike hadron colliders). Muons lifespan τ = 2.2 μs. Electrons emit synchrotron radiation at high speeds (>86% of the speed of light). Muons are massive fundamental colliders, which means it does not produce much synchroton radiation. A muon is about 206x more massive than electrons, which reduces the amount of synchrotron radiation from a muon by a factor of around 1 billion. As protons are about 1836x more massive than electrons, a proton radiates about 100 trillion times less. (Any charges particle emits radiation when it is accelerated, synchroton radiation is just the special case when the acceleration comes from being bent by a magnetic field. At slower speeds, it is called cyclotron radiation).

It has been shown that a muon collider could achieve energies in the several TeV (teraelectronvolt). A 10 TeV muon collider wouold have the physics reach comparable to that of 100 TeV hadron colliders while fitting in the same ring distance of 16 miles. A muon collider would also provide a clean and effective way to produce Higgs bosons.

In 2024, researches at the Japan Proton Accelerator Research Complex (J-PARC) successfully accelerated positive muons for the 1st time. This process involved creating muonium atoms by firing a controlled beam od antimuons into a silica aerogel. Muoniums are an atom made up of an antimuon and an electron, and was discovered in 1960 by Vernon W. Hughes.

Earlier history.

The 1st positron was discovered in 1932 by physicist Carl Anderson at the Caltech. Pions and kaons were both discovered in 1947, at Berkeley, in the same lab under C. F. Powell. The 1st antiproton was discovered in 1955 at CERN, W and Z bosons in 1983, and the Higgs boson in 2012, all at CERN.

Upcoming history.

The Jefferson Nation Lab will do experiments with Li-7 in 2026. Li-7 will be in a high magnetic field so it stays polarized.

The Brookhaven National Labs is expected to have an electron-ion collider (EIC), which will cost $3 billion, in 2034. It will be the 1st accelerator that collides the nucleus with polarized protons.

Quasiparticles and collective excitations.

These are where a group of particles can be considered a single behavior. If they are related to fermions (such as electrons and electron holes), they are called quasiparticles, and if they are related to bosons (such as phonons and plasmons), they are called collective behavior, although the precise distinction is not universally agreed upon.

Plasmons are the quantum of plasma oscillations.
Magnons are the quantum of a spin wave, associating with the electrons spin structure in a crystal lattice.
Phonons are the quantum of a sound wave, associating with the vibration of atoms in a rigid crystal structure.

Excitons are an electron and an electron hole bound together.

Magnons.

Magnons represent a special form of waves that propagate through magnetic materials. To understand their nature, one must imagine electrons as small magnets whose orientation can be changed. When an electron changes direction, this modification is transmitted to neighboring electrons, creating a wave that travels through the material without requiring the physical movement of particles.

Unlike information transport by moving electrons, magnons carry data through successive orientation changes. This characteristic allows them to avoid energy losses related to electrical resistance. These waves can reach phenomenal speeds, far exceeding the capabilities of current technologies.

Excitons.

You cannot do excitons from a light bulb because the light are random, and have different polarizations. Excitons interact strongly with light. They transport energy without transporting net electric charge. Superfluid excitons can flow without resistance.

Bose Einstein condensation.