Compare the Difference Between Similar Terms

Difference Between

Home / Science & Nature / Science / Chemistry / General Chemistry / Difference Between Leptons and Quarks

Difference Between Leptons and Quarks

March 3, 2013 Posted by Madhu

The key difference between leptons and quarks is that leptons can exist as individual particles in nature whereas quarks cannot.

Until the 20th century, people believed that atoms are indivisible, but the 20th century physicists discovered that the atom can be broken into smaller pieces, and all atoms are made of different compositions. Therefore, we call them subatomic particles: namely, the proton, neutron and electron. Furthermore, investigations reveal that subatomic particles also have internal structure, and made of smaller things. Thus, these particles are known as elementary particles, and Leptons and Quarks are their two main categories.

CONTENTS

1. Overview and Key Difference
2. What are Leptons 
3. What are Quarks
4. Side by Side Comparison – Leptons vs Quarks in Tabular Form
5. Summary

What are Leptons?

Particles that we call electrons, muons (µ), tau (Ƭ) and their corresponding neutrinos are known as the family of leptons. Furthermore, electron, muon, and tau have a charge of -1, and they differ from each other only from the mass. That is; the muon is three times more massive than the electron, and tau is 3500 times larger than the electron. Moreover, their corresponding neutrinos are neutral and relatively massless. The following table summarizes each particle and where to find them.

1st Generation 2nd Generation 3rd Generation
Electron (e) Muon (µ) Tau (Ƭ)

– In atoms

– Produced in beta radioactivity

– Large numbers produced in the upper atmosphere by cosmic radiation

– Observed only in laboratories

Electron neutrino (νe) Muon neutrino (νµ) Tau neutrino (νƬ)

– Beta radioactivity

– Nuclear reactors

– In nuclear reactions in the stars

– Produced in nuclear reactors

– Upper atmospheric cosmic radiation

– Only generated in laboratories

Besides, the stability of these heavier particles directly relates to their masses. Therefore, massive particles have a shorter half-life than the less massive ones. The electron is the lightest particle; that is why the universe is abundant with electrons, and the other particles are rare. To generate muons and tau particles, we need a high level of energy. In the present day, we can see them only in instances where there is a high energy density. Furthermore, we can produce these particles in particle accelerators. In addition, leptons interact with each other by electromagnetic interaction and weak nuclear interaction. For each lepton particle, there are anti-particles we name as antileptons. And, these anti-leptons have similar mass and opposite charge. For example, the anti-particle of the electrons are positrons.

What are Quarks?

Quark is the other major category of elementary particles. We can summarize the properties of particles in the quark family as follows. (The mass of each particle is below the name itself. However, the accuracy of these numbers is highly debatable).

Charge 1st Generation 2nd Generation 3rd Generation
+2/3

 

Up

0.33

Charm

1.58

Top

180

-1/2 Down

0.33 

Strange

0.47

Bottom

4.58

Quarks interact strongly with each other by strong nuclear interaction to form combinations of quarks. These combinations are known as Hadrons. In fact, isolated quarks do not exist in our universe at present. Moreover, it is reasonable to say that all the quarks in this universe are in some form of hadrons. (Most common and known types of the hadrons are protons and neutrons).

Difference Between Leptons and Quarks

Figure 01: Standard Model of Elementary Particles

Besides, quarks have an internal property known as the baryon number. All quarks have a baryon number of 1/3, and anti-quarks have baryon numbers -1/3.  Furthermore, in a reaction involving elementary particles, this property known as the baryon number is conserved.

Moreover, quarks have another property called the flavour. A number is assigned to denote the flavour of the particle known as the flavour number. The flavours are referred to as Upness (U), Downness (D), Strangeness (S) and so on. The up quark has an upness of +1 while 0 strangeness and Downness.

What is the Difference Between Leptons and Quarks?

Electrons, muons (µ), tau (Ƭ) and their corresponding neutrinos are known as the family of leptons while quarks is a type of elementary particle and a fundamental constituent of matter. When comparing both, the key difference between leptons and quarks is that leptons can exist as individual particles in nature whereas quarks cannot.

Moreover, leptons have integer charges while quarks have fractional charges. Also, there is a further difference between leptons and quarks when considering the forces these particles can be subjected to. That is; the leptons are subjected to weak force, gravitational force and electromagnetic force whereas quarks are subjected to strong force, weak force, gravitational force and electromagnetic force.

Difference Between Leptons and Quarks in Tabular Form

Summary – Leptons vs Quarks

In brief, quarks and leptons are two categories of the elementary particles. When taken together, they are known as fermions. Above all, the key difference between leptons and quarks is that leptons can exist as individual particles in nature whereas quarks cannot.

Reference:

1. “Lepton.” Wikipedia, Wikimedia Foundation, 30 Mar. 2019, Available here.

Image Courtesy:

1. “Standard Model of Elementary Particles” By MissMJ – Own work by uploader, Also, PBS NOVA [1], Fermilab, Office of Science, United States Department of Energy, Particle Data Group (Public Domain) via Commons Wikimedia

Related posts:

Difference Between Molecule and AtomDifference Between Molecule and Atom Difference Between Atoms and ElementsDifference Between Atoms and Elements Difference Between Dilution and ConcentrationDifference Between Dilution and Concentration Difference Between Antineutrino and NeutrinoDifference Between Antineutrino and Neutrino Difference Between Actinides and LanthanidesDifference Between Actinides and Lanthanides

Filed Under: General Chemistry Tagged With: Leptons, quarks

About the Author: Madhu

Madhu is a graduate in Biological Sciences with BSc (Honours) Degree and currently persuing a Masters Degree in Industrial and Environmental Chemistry. With a mind rooted firmly to basic principals of chemistry and passion for ever evolving field of industrial chemistry, she is keenly interested to be a true companion for those who seek knowledge in the subject of chemistry.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Request Article

Featured Posts

Difference Between Coronavirus and Cold Symptoms

Difference Between Coronavirus and Cold Symptoms

Difference Between Coronavirus and SARS

Difference Between Coronavirus and SARS

Difference Between Coronavirus and Influenza

Difference Between Coronavirus and Influenza

Difference Between Coronavirus and Covid 19

Difference Between Coronavirus and Covid 19

You May Like

Difference Between Plasma and Gas

Difference Between Test Cross and Backcross

Difference Between Test Cross and Backcross

Difference Between Primary and Secondary Standard Solution

Difference Between Primary and Secondary Standard Solution

Difference Between Wind Power and Tidal Power

Difference Between Angiogram and Angioplasty

Latest Posts

  • What is the Difference Between Penta and Hexa Vaccine
  • What is the Difference Between Vital and Supravital Staining
  • What is the Difference Between Post Transcriptional and Post Translational Modification
  • What is the Difference Between Gingelly Oil and Sesame Oil
  • What is the Difference Between Patent Ductus Arteriosus and Truncus Arteriosus
  • What is the Difference Between Lagophthalmos and Ptosis
  • Home
  • Vacancies
  • About
  • Request Article
  • Contact Us

Copyright © 2010-2018 Difference Between. All rights reserved. Terms of Use and Privacy Policy: Legal.