James Olsen

Professor of Physics
Phone: 
609-258-4910
Email Address: 
jolsen@Princeton.EDU
Office Location: 
317 Jadwin

Monday 14:30 - 16:30

One of the continuing mysteries of the universe is why the fundamental constituents of matter, the quarks and leptons, come in different “flavors” arranged in three separate generations of matter with large mass splittings. In the standard model of particle physics, this flavor structure is connected to another fundamental question, the origin of mass, through the Yukawa couplings of the fermions to the Higgs field. In recent years, the success of the standard model in describing a wide variety of flavor-changing processes has led to stringent constraints on the structure of possible extensions of the standard model, and possible explanations for the masses of the fundamental particles. These constraints play an important role in elucidating the nature of the discoveries anticipated at the Large Hadron Collider (LHC), located at CERN near Geneva, Switzerland.

I am currently engaged in the search for the Higgs boson in its decay to two b quarks using the CMS detector at the LHC.  This is one of the most challenging Higgs decay modes to observe at the LHC, and was originally thought to be out of reach.  In 2010 our group demonstrated its viability at CMS using simulated events, and we recently performed the first search for the Higgs in this decay channel at CMS using proton-proton collision data recorded in 2011 [1].  As part of the preparatory work for this search, we performed the first measurement of exclusive B production at the LHC [3].

Prior to joining CMS, for more than a decade our group played a leading role in elucidating the flavor structure of the quark sector through the study of CP violation using the BaBar detector at SLAC, including the first measurement of CP asymmetries in decays mediated by the b -> d flavor-changing neutral-current transition [5], and the discovery of direct CP violation in the B-meson system [4, 7].  We are continuing this research through our involvement in the Super B project in Italy.
 

Selected Publications

 

  1. D. Lopes Pegna, M. Mooney, J. Olsen, with the CMS Collaboration, "Search for the Standard Model Higgs Boson Decaying to Bottom Quarks and Produced in Association with a W or a Z Boson", CMS Physics Analysis Summary, HIG-11-012 (2011).
  2. D. Lopes Pegna, J. Olsen, and P. Schieferdecker, "Search for the Standard Model Higgs Boson Produced in Association with a W or Z Boson in pp Collisions at sqrt(s) = 10 TeV", CMS Analysis Note, AN-2010/265 (2010).
  3. D. Lopes Pegna and J. Olsen, with the CMS Collaboration, "Measurement of the B+ Production Cross Section in pp Collisions at sqrt(s) = 7 TeV", Phys. Rev. Lett. 106, 112001 (2011).
  4. J. Olsen and A. Telnov, with the BaBar Collaboration, "Observation of CP Violation in B0 -> π+ π-, K+π-", Phys. Rev. Lett. 99, 021603 (2007).
  5. J. Biesiada and J. Olsen, with the BaBar Collaboration, "Observation of B+ -> K(bar)0K+ and B0 -> K0K(bar)0", Phys. Rev. Lett. 97, 171805 (2006). [J. Biesiada won the 2008 APS Tanaka Dissertation Award for this work.]
  6. Y. P. Lau and J. Olsen, with the BaBar Collaboration, "Measurement of γ in B+/- -> D(*)0K+/- Decays with a Dalitz Analysis of D0 -> K0sπ+π- ", Phys. Rev. Lett. 95, 121802 (2005).
  7. N. Danielson and J. Olsen, with the BaBar Collaboration, "Direct CP Violating Asymmetry in B0 -> K+π- Decays", Phys. Rev. Lett. 93, 131801 (2004).
  8. N. Danielson and J. Olsen, with the BaBar Collaboration, "Measurements of Branching Fractions and CP Violating Asymmetries in B0 -> π+ π-, K+π-, K+K- Decays", Phys. Rev. Lett. 89, 281802 (2002).
  9. J. Olsen, with the BaBar Collaboration, "Measurement of Branching Fractions and Search for CP Violating Charge Asymmetries in Charmless Two-Body B Decays into Pions and Kaons", Phys. Rev. Lett. 87, 151802 (2001).