U.S. Department of Energy

Pacific Northwest National Laboratory

Why it Matters

Some of the most compelling questions in modern science fall at the intersection of nuclear physics, particle physics, astrophysics, and cosmology (NPAC). This intersection occurs not only in the intertwined science drivers recognized by the P5 report, but also by the technological means for their pursuit.

Why it matters

Our field is on the cusp of a revolution, perhaps as profound as that encountered in the early 20th century when the Newtonian view crumbled before a new paradigm of Relativity and Quantum Mechanics. Modern physics offers a quantifiable and testable connection between the physics of the very small and the physics of the very large, encompassing the following broad and intertwined questions:

  • How did the Universe originate and evolve to the one we observe today?
  • How are the fundamental forces in Nature unified?

The Standard Model of Particle Physics has been remarkably successful in explaining phenomena in High Energy Physics that we have studied in Earth-bound laboratories over the past decades. It ties together the particles that make up the visible matter and their interactions, as shown above. Yet, it is also known to be incomplete.

It is remarkable to consider that the most elusive particles in Nature, neutrinos and dark matter, could be the reason that the Universe has evolved to the one observed today and ultimately the reason for why we are here! Our Initiative will directly attack fundamental questions integral to this timely challenge:

  • What is the neutrino mass and is the neutrino its own antiparticle?
  • Is CP-symmetry violated in the neutrino sector, driving the matter-antimatter asymmetry of the Universe via leptogenesis?
  • What is the dark matter in the Universe and what are its properties?

The quest to elucidate the nature of neutrinos and dark matter naturally couples fundamental physics on the subatomic scale to that on the cosmic scale. The ability to pursue these fundamental question of Nature will rely on a non-accelerator based program that uses expertise of nuclear physics, particle physics, and the development of novel and ultra-sensitive detectors.

Achieving the goals of the NPAC Initiative encompasses the following strategic objectives:

  • Execute  and  deliver  high  impact  science  during  the  lifecycle  of  the  Initiative,  This science necessarily follows community and agency priorities as established in its decadal plans.
  • Perform, in parallel, the requisite R&D to develop detector requirements and define performance parameters for the next generation of experiments.
  • Enhance  staffing  and  external  collaborations  to  establish  the  critical  mass  and credibility  for leading the next generation of experiments.
  • Develop programmatic strategy with the Office of Science through continuous engagement and dialogue.
  • Position  PNNL  to  become  the DOE Lead Laboratory  on  an  appropriate  subset  of  the next  generation experiments.


| Pacific Northwest National Laboratory