Yes, when the electromagnetic and weak forces merge into a single unified force at high temperatures, it is predicted that the associated particles also combine to form new particles. This phenomenon is known as electroweak symmetry breaking.
At high energies or temperatures, the electromagnetic force and the weak force are described by a unified theory called the electroweak theory. In this unified theory, the electromagnetic force is mediated by the photon, while the weak force is mediated by three particles called the W+, W-, and Z bosons.
As the temperature decreases or the energy scale drops, the electroweak symmetry is believed to spontaneously break, resulting in the separation of the electromagnetic and weak forces and the emergence of distinct particles. This is often associated with the Higgs mechanism, where the Higgs field acquires a non-zero vacuum expectation value, leading to the generation of mass for the W and Z bosons.
After electroweak symmetry breaking, the photon remains as the particle mediating the electromagnetic force, while the W+ and W- bosons combine to form the charged W boson, and the Z boson becomes the neutral Z boson. In addition, the Higgs boson itself is a new particle that arises from the Higgs field.
The experimental discovery of the Higgs boson at the Large Hadron Collider (LHC) in 2012 was a significant confirmation of the electroweak symmetry breaking mechanism and provided important evidence for the unified nature of the electromagnetic and weak forces at high energies.
It's important to note that the process of electroweak symmetry breaking and the emergence of new particles is still an active area of research, and further studies are ongoing to explore the properties and interactions of these particles in order to gain a deeper understanding of the fundamental forces and particles in the universe.