Before studying about the Mass Of A Quark , We should learn something about Mass
“In Newtonian Physics, Mass Of An Object Can Be Defined As The Amount Of The Matter Present In That Particular Object”.
We all know about the above definition of Mass. According to “Relativity”, We got the “Energy - Mass Equivalence” Formula i.e. E = MC². By this formula, We can say that Energy is also the source of Mass of an object. Thus, The stationary object will have it’s Mass equal to its Energy.
In Physics there is another way to define Mass of an object
“According To Physics, Mass Is The Property Of A Physical Body Or An Object To Resist The Acceleration (Change In The State Of Motion), When A Force Applied On That Particular Body Or An Object”.
According to the above statement, It is clear that Mass is the Property of an object. One of the important aspect is that, Mass & Weight both differs from each other. Weight of an object can be defined as a Force on an object due to “Gravity”. But the Mass & Weight are related to each other in a sense that, “Weight is the Force & Mass Is The Property Of That Force Which Determines The Strength Of This Force (In addition with Gravity).
Weight of an object would vary with the change in the Gravitational Force whereas, Mass of an object will be constant with regard to Gravitational Force.
For Example :
Suppose, If we travel to the Moon, Then the Weight of our Body on Moon Will be less as compared that to our Planet Earth . Because the Gravitational Force on Moon is less than that of Earth. On the other hand, The Mass of our Body will remain same on Earth as well as on Moon. Because the Mass of an Object do not change with the Gravitational Force.
As we now know that Energy is also a source of Mass & All forms of Energy i.e. Kinetic Energy, Potential Energy, Nuclear Energy, Electrical Energy, Thermal Energy, Etc. Resist Acceleration by a Force & have Gravitational Attraction. Mass also determine the Strength of “Mutual Gravitational Attraction” between other Bodies or Objects.
Moon's Gravitational Force is responsible for creating High Tides & Low Tides or Tidal Effects on Earth’s Ocean’s & Sea’s. One of the Imaginative way of Tidal Effects due Moon is given above. In above explanation you can see that how the Tidal Bulges are changing with change in Moon’s Position.
One of the main intrinsic property of Quark is there Mass. There are two types of Mass which defines the proper Mass Of A Quark. The two type of Quark Mass are :
The Mass Which A Quark Carry By Itself Is Known As “Current Mass Of A Quark” Or “Current Quark Mass”.
The Current Quark is also known as Naked Quark or Bare Quark (Quark Mass Without Covering). As we have learned before, It is very difficult to observe a Single Quark. Still a Single Quark Posses it's own Mass, That Mass is known as Current Quark Mass. By the above definition we can say that, “Current Mass Of Quark is the Actual Mass Or Real Mass Of Each Quark”. As we have learned before, There are Six Single Quarks - Three in the Up- Type Quarks & Three in the Down-Type Quarks. Up-Type Quarks are, Up Quark, Charmed Quark & Top Quark. Down-Type Quarks are, Down Quark, Strange Quark & Bottom Quark. Each Quark have its own Mass. The value of each type of Quark is give below :
Up Quark 1.8 - 2.8 MeV / C²
Down Quark 4.3 - 5.2 MeV / C²
Strange Quark 92 - 104 MeV / C²
Charmed Quark 1.3 GeV / C²
Bottom Quark 4.2 - 4.7 GeV / C²
Top Quark 156 - 176 GeV / C²
The Constituent Quark Mass Or The Constituent Mass Of A Quark Can Be Calculated By “Adding The Current Quark Mass With The Mass Of The Gluon Particle Field Surrounding The Quark”.
Constituent Quarks Are Valance Quarks (Quarks & Anti-Quarks Which Give Rise To The Quantum Number Of The Hadrons), Which Co-Relates For The Description Of Hadrons With Regards To Gluons And Sea Quarks (Hadrons, With Valance Quarks Contributing To Quantum Number, Virtual Quark & Virtual Anti - Quark Pair Known As Sea Quarks), Are Put Together To Form Effective Quark Masses Of These Valance Quarks. This Effective Quark Mass Are Known As Constituent Quark Mass.
Constituent Quark Mass = Current Quark Mass + Mass Of The GluonParticle Field.
The Constituent Quark Mass can also be referred as Current Quark Mass with the covering. What is Covering ?….. In one Constituent Quark, The Current Quark (Naked Quark or Bare Quark) is hidden inside the Covering of a Large Force around it. As per Sir “Feynman” diagram, The Constituent Quark seemed to be “Dressed Up” with Current Quarks & the Current Quarks are surrounded by the cloud of Virtual Quarks & Gluons.
There are Six Constituent Quarks. The value of Constituent Quarks are as Follows :
Up Quark 336 MeV / C²
Down Quark 340 MeV / C²
Strange Quark 486 MeV / C²
Charmed Quark 1550 MeV / C²
Bottom Quark 4730 MeV / C²
Top Quark 177000 Men / C²
In the conclusion to the Quark Mass, We can say that the value of Current Quark Mass & Constituent Quark Mass are very different. The major Mass of Hadrons is given by the Constituent Quark Mass (Gluons binding the Constituent Quarks together), As compared to Current Quark Mass or Individual Quark. The Gluons are Massless, Thus they have a specific type of Energy know as “Quantum Chromodynamics Binding Energy” or “QCBE”.
Quantum Chromodynamics Binding Energy :
Quantum Chromodynamics Binding Energy Is The Energy Which Binds The Quarks Together Into Hadrons. It Is The Energy Of The Field Of Strong Force, That Strong Force Is Carried By Gluons.
Because of this QCBE the Gluons contributes so greatly to the overall Mass of a Hadron.
For Example :
Let us take an example of Proton, The Mass of a Proton is 938 MeV/ C², The Three Valance Quarks in Proton Mass contributes about 9 MeV / C². Whereas the remaining numbers 929 MeV / C² approx is contributed by the Gluons Field Energy or Quantum Chromodynamics Binding Energy.
Still this field of Research on “Mass Of A Quark” didn’t comes to a perfect conclusion till now. Lots of Experiments are going on to get the perfect Mass Of A Quark. But we can say that the figures of the Mass, Given by the Science Of Quantum Physics (Current Quark Mass & Constituent Quark Mass) as well as the figures given above are very near to the exact figures. The Science Of Quantum Physics has open up the new ways to look up into a “Particle”, Allowing us to reach to the depth to find the “Building Blocks Of Nature”.