What is Quark?

Before moving into nuclear physics, students should note that matter is made up of particles called Electrons, Protons, and Neutrons. However, the fundamental or primary constituent of this matter is called quark.  Several quarks combine to form composite particles, also known as hadrons.  The protons and neutrons are also known as hadrons. Protons and neutrons are known as the constituents of matter and components of the atomic nucleus. 

Few of the Crucial Aspects of Quark Particle 




6 (bottom, top, up, down, strange, charm)


SLAC National Accelerator Laboratory

Baryon number 





Maurray Gell Mann, George Zweig 



Gravitation, weak, strong, and Electromagnetism

Electric charge 

-1/3 e, +2/3 e

Example of Quark 

As per quark physics definition, it is the fundamental most particles present inside matter. However, they cannot have an independent existence like protons or neutrons. Therefore, two or more quarks combine to form a composite particle called hadrons. 

Proton is a stable hadron which comprises one down quark and two up quarks. Furthermore, a neutron consists of one up quark and two down types of quark. These concepts will help you understand what is quark and how the standard theoretical model explaining quark also explains the presence of other elementary particles and other unobserved particles. 

Antiquark – The antiparticles of quarks are known as antiquark. They are similar to quarks in terms of lifetime and spin. However, they differ in terms of concerning charges from that of a quark. 

The Building Block of Matter – Matter is made up of two kinds of fundamental particles 

  1. Quark 

  2. Leptons 

Both are segregated in six different types, thereby, 12 different types of particles are responsible for forming matter. 

Types of Quarks

There are six types of quark, among which up, down and strange are the primary types. These are also known as the flavour of quark. Knowing the properties will help you know what is quark. 

  • Up – These particles have the lowest mass and hence are the lightest. This is one of the reasons why these quark particles are most stable. It is represented as U and antiquark is expressed as U. The up quark mass range from 1.7 to 3.1 MeV / C2, and quark charges are equal to 2/3 e. 

  • Down – These particles have low mass followed by up quark and hence are highly stable. It is represented as d and antiquark is described as d. The down quark mass range from 4.1 to 5.7 MeV / C2 and its electric charge is equal to -1/3 e.

  • Strange – This is the third-largest quark amongst the six. Strange Quark is represented as S and antiquark is represented as S. The strange quark has electric charge equal to -1/3 e.

  • Bottom – Bottom quark is represented as b and its subsequent antiquark are represented as b. The bottom quark mass approximates 4.1 GeV / C2, and quark charge is equal to -1/3 e.

  • Top – Top quark is represented as t and antiquark are represented as t. The quark mass is 172.9+1.5 GeV / C2, and quark charges are equal to 2/3 e.

  • Charm – It is represented by C and antiquark is denoted as C. The electric charge of the charm quark is equal to +2/3.

Multiple-Choice Questions 

  1. Name the Particle Which is Made up of 1 up Quark and 2 Down Quarks?

  1. Electron 

  2. Atom

  3. Proton 

  4. Tachyon 

  5. Neutron

  1. Name the Fundamental Particles Which Help Create Strong Force Between Quarks?

  1. Leptons

  2. Quarks

  3. Photons

  4. Gluons

  5. All of the above 

Learn the fundamentals of quark by reading these notes. You will also be able to learn quark definition, its types, and related concepts with the help of our Vedantu app. This can be especially helpful since you can access the study material at your convenience.

FAQ (Frequently Asked Questions)

1. Define Quark. 

Ans. To answer what is Quark, it is the most fundamental particle present in a matter. However, it can’t be present in a matter independently and has to combine with other quarks to form hadrons. 

2. What are Quarks Made of? 

Ans. Quarks are known as the fundamental most particles present in the universe, which can be measured. However, a few theories suggest, quarks might contain smaller units named as Preons. However, their presence hasn’t been testified. 

3. How Many Types of Quark Particles are Known?

Ans. There are six kinds of quark particle physics present, namely up, down, top, bottom, charm, and strange. These are also known as flavors of quark.