The first pillar is quantum field theory. Which describes that everything is field . This theory proposed the field quanta necessarily the chunked ripples in a field that look like particle.
A boost to Quantum Field Theory came with Dirac Equation , a single particle equation which obeying both relativity and quantum mechanics . but this theory had some difficulties . to overcome these difficulties in 1940, An Gauge theory became produced. Which is known as the Standard Model of Particle Physics.
This model predict that Electromagnetic force is caused b/w two electrons by an exchange of Photons , Weak nuclear force by exchange of Bosons(W-, W+, Z) AND Strong Nuclear forces by 8 gluons.
And for gravity this theory assumed that Graviton particle appears.
The guiding principal of the standard model is that its equations are Symmetrical . All Other equations related to this are also Symmetrical .
These Symmetries beget forces that are carried by special particles called bosons.
Physicists want to unify the Strong , Weak Nuclear Force and Electromagnetic Force.
Later the theory of ELECTROWEAK FORCES as formulated by Sheldon Glashow , Steven Weinberg and Abdus Slam , who won the 1979 Nobel Prize in physics for their efforts .
The Weak Force , which is involved in radioactive beta decay , does not act on all the quarks and leptons . Each of these particles comes in mirror –image varieties , termed left-handed and right-handed , and the Beta decay Force acts only on the left-handed ones a striking fact still unexplained 50 years after its discovery. The family symmetry among the left-handed particles helps to define the electroweak theory.
In the initial stages , the theory had two essential shortcomings . First , It foresaw four long-range force particles –referred to as gauge bosons where as nature has but one : the photon.
The Other three have a short range less than about 10 root -17 meter. According to Heisenberg’s Uncertainty Principle , this limited range implies that the force particles must have a mass approaching 100 billon electron volts (Gev).
The second shortcoming is that the family symmetry does not permit masses for the quarks and leptons , yet these particles do have masses.
So we need to recognize that a symmetry of the laws of nature need not be reflected into the outcome of those laws.
Physicists Says “that the Symmetry is Broken”.
Later the inspiration came from a seemingly unrelated phenomena : SuperConductivity , in Which certain materials carry electric current with zero resistance at low temperatures . although the laws of electromagnetism themselves material is not. A photon gains mass within a superconductor. Thereby limiting the intrusion of magnetic fields into the material .
This problem is a perfect prototype for the electroweak theory . If Space is filled with a type of superconductor that affects the weak interaction rather than electromagnetism, it gives mass to the W and Z bosons and limits the range of weak interactions.