Professor Neal Weiner at NYU

In 1934, Enrico Fermi wrote down his theory of the weak interactions, which contained within it an energy scale of roughly 100 GeV. While that theory has been understood as an effective theory of the weak interactions, it is remarkable that only now, almost 80 years later we are finally probing this energy scale thoroughly.

Current experiments at the Tevatron and new experiments at the LHC will probe this scale and reveal what new forces and laws of nature are hidden there. There is much reason to be excited. While dark matter provides an independent motivation for new particles with masses near 100 GeV, the “hierarchy problem” does as well.

In ordinary quantum field theories, scalar particles (particles with no intrinsic angular momentum) have masses that are corrected by quantum mechanics. This means even if you wrote down a theory with a scalar particle with mass 100 GeV, quantum corrections would make its “real” mass much, much higher, with the natural expectation being something near the quantum gravity scale of 10
19 GeV!

This is then perplexing because the Higgs boson of the standard model is just such a particle, and we know its mass is not much larger than a few hundred GeV. So why is it light?

Only a narrow set of theories have scalar masses that are not corrected: supersymmetric theories, theories where the Higgs is a bound state of other particles (i.e., composite Higgses) and theories where the Higgs is what is called a pseudo-Nambu-Goldstone boson (PNGB). In all of these theories, new particles must be present with masses in the range of 100 GeV-1 TeV - that is, the mass of the Higgs boson is naturally comparable to the masses of the new particles.

This means that new particles and forces should be waiting around the corner for us. With the Tevatron running well and the LHC just coming online, the next decade should be incredibly exciting!
Selected Publications:


Photo of simulated Higgs decay to two jets and two electrons at the CMS detector.