Seth Zenz is a Dicke Fellow in the Princeton Physics Department, working on the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) in Geneva, Switzerland. The LHC has now started to answer one of the great oustanding problems in particle physics: what is the origin of the masses of the W and Z bosons and the tremendous differences between the electromagnetic and weak forces? The Standard Model (SM) of particle physics explains this via the Higgs Mechanism, which predicts a particle called the Higgs Boson. In 2012, the CMS experiment observed a particle, with a mass of about 125 GeV/c2, that decays to pairs of photons or Z bosons at approximately the rate predicted. But is it really the SM Higgs Boson?
To answer this question, Seth contributes to the CMS search for Higgs decays into pairs of bottom quarks, focusing on Higgs production in association with a W boson. He has a particular interest in investigating methods of differentiating the SM Higgs, which has spin 0, from a graviton-like "imposter" with spin 2. These studies make heavy use of the internal structure of hadronic jets, by identifying displaced decay vertices of bottom-containing particles and potentially using the substructure of merged jets when the Higgs has very high momentum.
Precision tracking of charged particles is critical to understanding these jet properties of the Higgs analysis. Seth works on the operation and maintenance of the CMS Pixel Detector, a high-precision silicon tracking device at the core of CMS, as well as measurements and modeling of the radiation damage that limits the Pixels' longevity in the intense LHC environment. He brings to bear his thesis work on jet properties measured with charged particle tracks and graduate work at UC Berkeley on the initial testing, calibration, and operation of the ATLAS experiment Pixel Detector.
1. The CMS Collaboration, "Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC," Phys. Lett. B 716, 30 (2012).
2. The ATLAS Collaboration, "Properties of jets measured from tracks in proton-proton collisions at center-of-mass energy √s = 7 TeV with the ATLAS detector," Phys. Rev. D 84, 054001 (2011).
3. The ATLAS Collaboration, "Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at √sNN = 2.76 TeV with the ATLAS Detector at the LHC," Phys. Rev. Lett. 105, 252303 (2010).
4. The ATLAS Collaboration, "The ATLAS Simulation Infrastructure," EPJC 70, 823 (2010).
5. The ATLAS Collaboration, "The ATLAS Inner Detector commissioning and calibration," EPJC 70, 787 (2010).
6. The ATLAS Collaboration, "The ATLAS Experiment at the CERN Large Hadron Collider," JINST 3, S08003 (2008).