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Jai Ganesh

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Registered: 2005-06-28

Posts: 50,982

Subatomic Particle

Subatomic particle

Gist

Subatomic particles are particles smaller than an atom. They include protons, neutrons, and electrons, which are the fundamental building blocks of atoms. Additionally, there are other subatomic particles like quarks, leptons (including electrons, muons, and neutrinos), and bosons, some of which are fundamental and others are composite particles.

Summary

A subatomic particle is any of various self-contained units of matter or energy that are the fundamental constituents of all matter. Subatomic particles include electrons, the negatively charged, almost massless particles that nevertheless account for most of the size of the atom, and they include the heavier building blocks of the small but very dense nucleus of the atom, the positively charged protons and the electrically neutral neutrons. But these basic atomic components are by no means the only known subatomic particles. Protons and neutrons, for instance, are themselves made up of elementary particles called quarks, and the electron is only one member of a class of elementary particles that also includes the muon and the neutrino. More-unusual subatomic particles—such as the positron, the antimatter counterpart of the electron—have been detected and characterized in cosmic ray interactions in Earth’s atmosphere. The field of subatomic particles has expanded dramatically with the construction of powerful particle accelerators to study high-energy collisions of electrons, protons, and other particles with matter. As particles collide at high energy, the collision energy becomes available for the creation of subatomic particles such as mesons and hyperons. Finally, completing the revolution that began in the early 20th century with theories of the equivalence of matter and energy, the study of subatomic particles has been transformed by the discovery that the actions of forces are due to the exchange of “force” particles such as photons and gluons. More than 200 subatomic particles have been detected—most of them highly unstable, existing for less than a millionth of a second—as a result of collisions produced in cosmic ray reactions or particle accelerator experiments. Theoretical and experimental research in particle physics, the study of subatomic particles and their properties, has given scientists a clearer understanding of the nature of matter and energy and of the origin of the universe.

The current understanding of the state of particle physics is integrated within a conceptual framework known as the Standard Model. The Standard Model provides a classification scheme for all the known subatomic particles based on theoretical descriptions of the basic forces of matter.

Details

In physics, a subatomic particle is a particle smaller than an atom. According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles (for example, a baryon, like a proton or a neutron, composed of three quarks; or a meson, composed of two quarks), or an elementary particle, which is not composed of other particles (for example, quarks; or electrons, muons, and tau particles, which are called leptons). Particle physics and nuclear physics study these particles and how they interact. Most force-carrying particles like photons or gluons are called bosons and, although they have quanta of energy, do not have rest mass or discrete diameters (other than pure energy wavelength) and are unlike the former particles that have rest mass and cannot overlap or combine which are called fermions. The W and Z bosons, however, are an exception to this rule and have relatively large rest masses at approximately 80 GeV/c^2 and 90 GeV/c^2 respectively.

Experiments show that light could behave like a stream of particles (called photons) as well as exhibiting wave-like properties. This led to the concept of wave–particle duality to reflect that quantum-scale particles behave both like particles and like waves; they are occasionally called wavicles to reflect this.

Another concept, the uncertainty principle, states that some of their properties taken together, such as their simultaneous position and momentum, cannot be measured exactly. Interactions of particles in the framework of quantum field theory are understood as creation and annihilation of quanta of corresponding fundamental interactions. This blends particle physics with field theory.

Even among particle physicists, the exact definition of a particle has diverse descriptions. These professional attempts at the definition of a particle include:

* A particle is a collapsed wave function
* A particle is an excitation of a quantum field
* A particle is an irreducible representation of the Poincaré group
* A particle is an observed thing.

Additional Information

Subatomic Particles are the particles inside an atom. They are self-contained units of matter or energy and are the fundamental constituents of all matter. Initially, the atom was considered to be the fundamental particle which constitutes all the matter. However, with later experiments and discoveries, it was revealed that the atom is itself constituted of several particles such as Electrons, Protons and Neutrons. Further research in particle physics revealed that even protons and neutrons are composite particles, made up of some other subatomic elementary particles.

Types of Subatomic Particles

Atoms are considered the basic building blocks of matter. It was John Dalton who in 1803 postulated that an atom is indestructible and is the fundamental unit of matter. This was proved wrong by J.J. Thomson in 1897.

Electrons

Electrons were discovered by J.J Thomson after many experiments involving cathode rays. He demonstrated the ratio of mass to electric charge of cathode rays. He confirmed that cathode rays are fundamental particles that are negatively charged; these cathode rays became known as electrons.... Read more at: https://vajiramandravi.com/upsc-exam/subatomic-particles/

Protons

Eugene Goldstein in 1886 showed the existence of a positively charged particle in an atom. However, the actual discovery of protons is credited to Ernest Rutherford during his experiment on the scattering of α-particles.

Neutrons

It was inevitable from Rutherford’s experiment that there must be a neutral, sub-nuclear particle with a mass closely equal to protons. James Chadwick in 1932 discovered the neutrons.

Fundamental Particles

Subatomic particles can be further divided into elementary (fundamental) particles and composite particles (made up of elementary particles).

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

KerimF

Member

From: Aleppo-Syria

Registered: 2018-08-10

Posts: 289

Re: Subatomic Particle

I used to think that subatomic particles refer to the particles that form the matter of photons, neutron and electrons... etc.

Naturally, such subatomic particles (of the subatomic universe) cannot be detected in our days directly, only their effects in vacuum (a space having no atomic particles), as in gravity waves among matters of our universe.

Last edited by KerimF (2025-07-15 23:55:15)

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Every living thing has no choice but to execute its pre-programmed instructions embedded in it (known as instincts).
But only a human may have the freedom and ability to oppose his natural robotic nature.
But, by opposing it, such a human becomes no more of this world.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 50,982

Re: Subatomic Particle

Explanation given supra. The source is available in #2 and #3.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.