University of California, Riverside

Faculty Profile System

Owen R. Long

Owen R. Long

Associate Professor

Department of Physics & Astronomony
Physics 3015
(951) 827-6084

Research Areas

  • Experimental High Energy Physics: CP violation and physics beyond the standard model

Professor Long has been an active member of the Babar Collaboration since 1997. The Babar experiment at the Stanford Linear Accelerator Center is dedicated to the study of CP violation in B meson decays. The measurement of sin(2β), the CP asymmetry in the decay B0 → J/ψ Ks, was the first precision test of the Kobayashi-Maskawa mechanism for CP violation. Prof. Long played a central role in the measurement of sin(2β) as one of the primary analysts and as working group co-convener. He also  investigated the feasibility of determining γ, another Unitarity Triangle angle, from direct CP violation in B → D K decays and contributed to the determination of the Unitarity Triangle α in the B → ρ ρ system.

Prof. Long is interested in using rare charmless B decays in the enormous Babar dataset to look for physics beyond the Standard Model. Corrections from loop diagrams containing virtual particles at high mass scales can lead to significant deviations in the measured CP asymmetries with respect to the precise predictions of the Standard Model. A significant discrepancy would be the "smoking gun" telling us that the Standard Model of particle physics is incomplete.

The CMS experiment is at the Large Hadron Collider, the worlds highest energy accelerator.  Prof. Long is an active member of the CMS collaboration, where he is searching for signs of supersymmetry in events with large missing transverse energy and bottom quark jets.

Many of the Babar measurements of observables that are most sensitive to physics beyond the Standard Model are limited by the size of the Babar dataset.  There are plans to build a Super B factory in Italy near Rome, which would have a beam intensity 100 times higher than the PEP-II accelerator which served the Babar experiment.  Prof. Long is contributing to the development of the particle identification system for the SuperB experiment.


Ph.D. 1997, University of Pennsylvania


U.S. Department of Energy's Outstanding Junior Investigator Award (2005)


  1. J. P. Lees et al. (The Babar Collaboration), "Measurements of branching fractions and CP asymmetries and studies of angular distributions for B → φφK decays," Phys. Rev. D 84, 012001 (2011).
  2. B. Aubert et al. (The Babar Collaboration), "Improved measurement of B+ → ρ+ ρ0 and Determination of the Quark-Mixing Phase Angle α," Phys. Rev. Lett. 102, 141802 (2009).
  3. B. Aubert et al. (The Babar Collaboration), "Search for the decay B+ → K+ τ μ,"  Phys. Rev. Lett. 99, 201801 (2008).
  4. B. Aubert et al. (The Babar Collaboration), "Search for the decay B0 → KS KS KL," Phys. Rev. D 74, 032005 (2006).
  5. B. Aubert et al. (The Babar Collaboration), " Search for B± →[K π±]DK± and upper limit on the b→u amplitude in B±→DK±," Phys. Rev. Lett. 93, 131804 (2004).
  6. O. Long, M. Baak, R. N. Cahn and D. Kirkby, "Impact of tag-side interference on time dependent CP asymmetry measurements using coherent B0B0 pairs," Phys. Rev. D 68, 034010 (2003).
  7. B. Aubert et al. (The Babar Collaboration), "Measurement of the CP-violating asymmetry amplitude sin(2β) with B0 mesons," Phys. Rev. Lett. 89, 201802 (2002).
  8. B. Aubert et al. (The Babar Collaboration), "A study of time dependent CP-violating asymmetries and flavor oscillations in neutral B decays at the Υ(4S)," Phys. Rev. D 66, 032003 (2002).
  9. B. Aubert et al. (The Babar Collaboration), "Observation of CP violation in the B0 meson system," Phys. Rev. Lett. 87, 091801 (2001).
  10. B. Aubert et al. (The Babar Collaboration), "Measurement of CP-violating asymmetries in B0 decays to CP eigenstates," Phys. Rev. Lett. 86, 2515 (2001).

More Information 

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University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

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Department of Physics & Astronomy
Physics Building

Tel: (951) 827-5331
Fax: (951) 827-4529