Manfred Paulini

Professor, Physics

Education

Research

My research interests touch the interface between particle physics and cosmology. As an experimental high energy physicist, I study questions connecting particle physics phenomena to the fade of the universe. One of those questions concerns the fact that our visible universe appears to exhibit a dominance of matter over antimatter. Assuming the universe started in the Big Bang with the same amount of particles and anti-particles, the disappearance of the antimatter in the universe is still an unsolved mystery. Another question concerns the nature of dark matter that makes up about one quarter of the content of the universe.

As a member of the CDF experiment located at Fermilab near Chicago, Illinois, I study particle-antiparticle oscillations and the violation of the symmetries of nature under the combined action of charge conjugation C and space inversion or parity P. Although the violation of CP invariance was first discovered in the system of neutral K mesons in 1964, the origin of CP violation is still not completely understood. However, CP violation is of great interest as it is expected to play an important role in understanding the predominance of matter over antimatter in the universe.

Decays of neutral B mesons are an ideal system to study CP violating effects as well as transitions of particles into their anti-particles and back. Examples of my research include: I was involved in an initial study of the CP violation parameter sin(2β) in B⁰ meson decays using CDF data; my group made significant contributions to the discovery of particle-antiparticle oscillation in decays of B_s⁰ mesons at CDF and currently we work on a measurement of the CP violating phase β_s in B_s⁰ → J/ψ φ decays. The first measurement of bounds on the CP violation parameter sin(2β_s) indicates an intriguing discrepancy with predictions of the Standard Model of particles physics indicating hints to new physics phenomena.

As a member of the CMC experiment operating at the Large Hadron Collider (LHC) at CERN near Geneva, Switzerland, I study the nature of dark matter. The products from the collision of protons at the LHC may include dark matter particles that compose about 25% of the mass-energy in the universe. There are actually compelling arguments that the energies reached at the LHC are in the regime of producing dark matter particles. A favoured candidate for the dark matter particles is the neutralino, the lightest and most stable of a whole set of new supersymmetric partners to each of the known particles of the Standard Model. My group is involved in the search for signatures of dark matter in the CMS data through the production of supersymmetric particles. My dark matter research is in association with the Bruce and Astrid McWilliams Center for Cosmology at CMU.

Selected Publications

• Always up-to-date list of publications available through SPIRES.
• A. Aaltonen et al. [CDF Collaboration], "First Flavor-Tagged Determination of Bounds on Mixing-Induced CP Violation in B_s⁰ → J/ψ φ Decays", Phys. Rev. Lett. 100, 161802 (2008) (see also arXiv:0712.2397 [hep-ex])
• T. Aaltonen et al. [CDF Collaboration], "Measurement of Ratios of Fragmentation Fractions for Bottom Hadrons in pp Collisions at √s=1.96 TeV", Phys. Rev. D77, 072003 (2008) (see also arXiv:0801.4375 [hep-ex])
• A. Abulencia et al. [CDF Collaboration], "Measurement of the B_s⁰ B_s⁰ Oscillation Frequency", Phys. Rev. Lett. 97, 062003 (2006) (see also arXiv:hep-ex/0606027)
• A. Affolder et al. [CDF Collaboration], "Measurement of sin(2β) in B → J/ψ K_S⁰ with the CDF Detector", Phys. Rev. D 61, 072005 (2000) (see also arXiv:hep-ex/9909003)
• F. Abe et al. [CDF Collaboration], "Measurement of B⁰-B⁰ Flavor Oscillations Using Jet-Charge and Lepton Flavor Tagging in pp Collisions at √s=1.8 TeV", Phys. Rev. D 60, 072003 (1999) (see also arXiv:hep-ex/9903011)
• M. Paulini, "CDF: The Party Crashers", SLAC Beam Line 29N2, 19 (1999)
• F. Abe et al. [CDF Collaboration], "Measurement of the B_s⁰ Meson Lifetime Using Semileptonic Decays", Phys. Rev. D 59, 032004 (1999) (see also arXiv:hep-ex/9808003)
• M. Paulini, "B Lifetimes, Mixing and CP Violation at CDF", Int. J. Mod. Phys. A 14, 2791 (1999) (see also arXiv:hep-ex/9903002)
• F. Abe et al. [CDF Collaboration], "Measurement of the CP Violation Parameter sin(2β) in B_d⁰/ B_d⁰ → J/ψ K_S⁰ Decays", Phys. Rev. Lett. 81, 5513 (1998) (see also arXiv:hep-ex/9806025)
• F. Abe et al. [CDF Collaboration], "Observation of Top Quark Production in pp Collisions with the Collider Detector at Fermilab", Phys. Rev. Lett. 74, 2626 (1995) (see also arXiv:hep-ex/9503002)
• H. Albrecht et al. [ARGUS Collaboration], "Search for Rare B Meson Decays into D_s⁺ Mesons", Z. Phys. C 60, 11 (1993)
• H. Albrecht et al. [ARGUS Collaboration], "Production of D_s⁺ Mesons in B Decays and Determination of f_Ds", Z. Phys. C 54, 1 (1992)
• H. Albrecht et al. [ARGUS Collaboration], "Study of Anti-Deuteron Production in e⁺ e^- Annihilation at 10 Gev Centre-of-Mass Energy", Phys. Lett. B 236, 102 (1990)