elementary particles history
... Photons • Robert Millikan’s experiments (1914-1916) verified Einstein’s photoelectric theory. • Arthur Holly Compton’s measurements of x-ray scattering by electrons in metals (1922-23) verified existence of photons. ...
... Photons • Robert Millikan’s experiments (1914-1916) verified Einstein’s photoelectric theory. • Arthur Holly Compton’s measurements of x-ray scattering by electrons in metals (1922-23) verified existence of photons. ...
Evolution of the Atomic Theory
... • 1. a large majority of alpha particles passed directly through the foil. • 2. few particles were deflected when shot at the foil. • 3. rarely, one particle would come back almost directly at the alpha source ...
... • 1. a large majority of alpha particles passed directly through the foil. • 2. few particles were deflected when shot at the foil. • 3. rarely, one particle would come back almost directly at the alpha source ...
2.1.7 particle movement in magnetic fields
... can be to change speed or direction. The effect of a magnetic field on a charged particle can only be to change its direction. This is because the force applied is always perpendicular to its motion. ...
... can be to change speed or direction. The effect of a magnetic field on a charged particle can only be to change its direction. This is because the force applied is always perpendicular to its motion. ...
A modern view of forces - HEP Educational Outreach
... • Theories we teach about have proven to be predictive, and therefore we believe them… but they are still falsifiable. Even Deeper Theory ...
... • Theories we teach about have proven to be predictive, and therefore we believe them… but they are still falsifiable. Even Deeper Theory ...
Particle Zoo - University of Birmingham
... cannot be accounted for by orbital angular momentum. Although the direction of its spin can be changed, an elementary particle cannot be made to spin faster or slower. Spin cannot be explained by postulating that they are made up of even smaller particles rotating about a common centre of mass. Trul ...
... cannot be accounted for by orbital angular momentum. Although the direction of its spin can be changed, an elementary particle cannot be made to spin faster or slower. Spin cannot be explained by postulating that they are made up of even smaller particles rotating about a common centre of mass. Trul ...
subatomic particle
... radioactive decays would not conserve energy or momentum. • The 2002 Physics Nobel prize to Davis & Koshiba was for detecting neutrinos emitted by fusion in our sun. ...
... radioactive decays would not conserve energy or momentum. • The 2002 Physics Nobel prize to Davis & Koshiba was for detecting neutrinos emitted by fusion in our sun. ...
divinity - Particle Theory Group
... …for any important assertion evidence must be produced; …prophecies and bugaboos must be subjected to scrutiny; … guesswork must be replaced by exact count; ….accuracy is a virtue and inquiry is a moral imperative. To the hegemony of science we owe a feeling for which there is no name, but which is ...
... …for any important assertion evidence must be produced; …prophecies and bugaboos must be subjected to scrutiny; … guesswork must be replaced by exact count; ….accuracy is a virtue and inquiry is a moral imperative. To the hegemony of science we owe a feeling for which there is no name, but which is ...
AS Physics
... “Number of protons in the nucleus (also equal to number of electrons)” Nucleon number or Mass number “Number of protons and neutrons in an atom’s nucleus” Isotope “A form of an element with the same proton number but different neutron number” ...
... “Number of protons in the nucleus (also equal to number of electrons)” Nucleon number or Mass number “Number of protons and neutrons in an atom’s nucleus” Isotope “A form of an element with the same proton number but different neutron number” ...
The Big Bang, the LHC and the Higgs boson
... Higgs decay channels For low Higgs mass mh 150 GeV, the Higgs mostly decays to two b-quarks, two tau leptons, two gluons and etc. In hadron colliders these modes are difficult to extract because of the large QCD jet background. The silver detection mode in this mass range is the two photons mode: ...
... Higgs decay channels For low Higgs mass mh 150 GeV, the Higgs mostly decays to two b-quarks, two tau leptons, two gluons and etc. In hadron colliders these modes are difficult to extract because of the large QCD jet background. The silver detection mode in this mass range is the two photons mode: ...
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle whose substructure is unknown, thus it is unknown whether it is composed of other particles. Known elementary particles include the fundamental fermions (quarks, leptons, antiquarks, and antileptons), which generally are ""matter particles"" and ""antimatter particles"", as well as the fundamental bosons (gauge bosons and Higgs boson), which generally are ""force particles"" that mediate interactions among fermions. A particle containing two or more elementary particles is a composite particle.Everyday matter is composed of atoms, once presumed to be matter's elementary particles—atom meaning ""indivisible"" in Greek—although the atom's existence remained controversial until about 1910, as some leading physicists regarded molecules as mathematical illusions, and matter as ultimately composed of energy. Soon, subatomic constituents of the atom were identified. As the 1930s opened, the electron and the proton had been observed, along with the photon, the particle of electromagnetic radiation. At that time, the recent advent of quantum mechanics was radically altering the conception of particles, as a single particle could seemingly span a field as would a wave, a paradox still eluding satisfactory explanation.Via quantum theory, protons and neutrons were found to contain quarks—up quarks and down quarks—now considered elementary particles. And within a molecule, the electron's three degrees of freedom (charge, spin, orbital) can separate via wavefunction into three quasiparticles (holon, spinon, orbiton). Yet a free electron—which, not orbiting an atomic nucleus, lacks orbital motion—appears unsplittable and remains regarded as an elementary particle.Around 1980, an elementary particle's status as indeed elementary—an ultimate constituent of substance—was mostly discarded for a more practical outlook, embodied in particle physics' Standard Model, science's most experimentally successful theory. Many elaborations upon and theories beyond the Standard Model, including the extremely popular supersymmetry, double the number of elementary particles by hypothesizing that each known particle associates with a ""shadow"" partner far more massive, although all such superpartners remain undiscovered. Meanwhile, an elementary boson mediating gravitation—the graviton—remains hypothetical.