• Early Subatomic Discoveries:
  The discovery of the electron (1897), the atomic nucleus (by Rutherford in 1911), and later the neutron (1932) set the stage for exploring the constituents of matter. At this point, research on these particles was generally part of what we now call atomic or nuclear physics.
  
• Emergence of “Elementary Particles”:
  In the 1920s and 1930s, as quantum mechanics was being developed, the concept of “elementary” or “fundamental” particles started to take shape. For example, the discovery of the positron in 1932 by Carl Anderson opened the door to the idea that not all particles fit neatly into the classical picture of the atom. Still, most work was labeled under nuclear physics or cosmic ray research rather than “particle physics” per se.
  

• Advent of Particle Accelerators:
  The development of particle accelerators (building on cyclotron work by Ernest Lawrence in the 1930s) allowed scientists to create and study high-energy collisions in a controlled laboratory environment. This marked a turning point by enabling systematic studies of short-lived particles that were previously accessible only via cosmic rays.
  
• Birth of the “Particle Zoo”:
  In the 1950s, experiments began revealing a proliferation of new, short-lived particles (often referred to as the “particle zoo”). Researchers needed new classification schemes and theoretical frameworks to understand these myriad particles. It was during this period that many scientists started to see their work as probing the most fundamental building blocks of matter—a viewpoint that gradually led to the self-identification as particle physicists.
  

• Theoretical Advances:
  The mid-1960s saw major theoretical breakthroughs. Murray Gell-Mann’s and George Zweig’s independent proposals of the quark model (circa 1964) provided a way to organize the growing list of particles into a coherent framework. This was a pivotal moment: by offering an explanation for the particle zoo, it further distinguished the work of these researchers from other branches of physics.
  
• Dedicated Laboratories and Research Groups:
  The establishment of large, specialized laboratories such as CERN (founded in 1954) in Europe, and later Fermilab (in the 1960s) in the United States, signaled the coming of age of high-energy experiments. Within universities, dedicated research groups and, eventually, formal “high-energy” or “particle physics” divisions began to appear. Although most physics departments never split into completely separate “particle physics departments,” the creation of specialized research centers and courses helped solidify the identity of particle physics as a distinct discipline.
  
• Self-Identification:
  By the 1960s and early 1970s, when the experiments, theories, and institutional supports converged, scientists working in high-energy experiments and related theory commonly began to call themselves “particle physicists.” Their focus was clearly distinct from the broader realms of nuclear physics or condensed matter physics.
  

• The Standard Model and Beyond:
  The consolidation of the Standard Model in the 1970s and its experimental confirmations (such as the discoveries of the W and Z bosons in the early 1980s) further cemented particle physics as a standalone field. Today, particle physics is often interchangeably called “high-energy physics,” and it remains a vibrant area of research at major laboratories and in specialized university groups worldwide.
  
• Institutionalization in Academia:
  Although very few universities have a separate “particle physics department,” the field is well represented within physics departments as a distinct research area. Graduate programs, specialized courses, and research centers reflect the maturity of particle physics as a discipline.
  

• Before the 1940s: Research on subatomic particles was carried out mainly under the banners of nuclear physics and cosmic ray physics.
  
• 1940s–1950s: Advances in accelerator technology and the discovery of many new particles led to a reorientation of the field; researchers began to focus explicitly on the fundamental constituents of matter.
  
• 1960s–1970s: With theoretical breakthroughs (like the quark model) and the creation of dedicated high-energy laboratories, the community solidified its identity, and many scientists began to proudly call themselves “particle physicists.”
  
• 1980s–Today: Particle physics is a mature and distinct field, often integrated into the broader framework of high-energy physics, with well-established academic and research institutions supporting its work.
  

In short, while the roots of particle physics stretch back to early 20th-century discoveries, the clear self-identification as “particle physicists” and the establishment of dedicated research structures primarily took shape in the 1950s and 1960s, a trend that has only grown stronger over the decades.