Dan Cronin-Hennessy
Assistant Professor
260C Tate, 624-9079, email hennessy @ physics.umn.edu
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Research Areas: CP-Violation, quark- and lepton-mixing matrices.
Current Research
The Standard Model of Elementary Particle Physics describes well all terrestrial data on CP-violation yet we still do not have an adequate understanding of the source of CP-violation or mass. Over the next decade the experiments described below and others such as those at the LHC, SLAC, Fermilab, and KEK have a high potential of at least elevatingour confusion on these central questions of elementary particle physics.
Currently I am involved in charm-quark threshold physics and neutrino-oscillation measurements. I am a member of the CLEO
collaboration. CLEO is a multi-purpose high-energy particle detector
located at the Cornell Electron-positron Storage Ring (CESR). My past research at CLEO has focused on precision extraction of quark-mixing matrix elements (CKM elements) through the study of B meson decays (mesons containing one beauty quark). Recently the experiment has lowered the energy of the colliding beams to near charm threshold production (center-of-mass energy in the region of the psi resonances). The experiment is now referred to as CLEO-c and it has just started its running period. The main goal of CLEO-c is achieving precise tests of Lattice-QCD predictions but other physics that will be pursued include glueball/hybrid searches, D-mixing, charm
resonance physics, tau physics and non-Standard Model rare decays. My primary focus at this time is rare radiative D meson decays (D decays that include a prompt photon in the final state). More information on CLEO-c can be found at http://www.lns.cornell.edu/public/CLEO/.
I have recently joined the MINOS and NOvA collaborations. The MINOS detector is a 5400 metric ton steel-scintillator device located 800 meters below ground in northern Minnesota. The detector will observe neutrinos generated at Fermi National Laboratory approximately 735 kilometers from the detector. The primary goal of this experiment is to measure the probability that a muon type neutrino will transition (oscillate) to a different type neutrino during its journey from Illinois to Minnesota. The NOVA experiment is a proposed experiment which will use a 25000 metric ton detector to measure the probability that the muon neutrino will transition to an electron type neutrino. Neutrino physics is a rapidly evolving field at this time. The goal of the oscillation measurements is to quantify the relatively new neutral-lepton-mixing matrix. The realization that neutrinos have mass and can therefore mix opens the possibility of a new source of matter-antimatter asymmetry(via CP-violation). More info on MINOS and NOvA can be found at http://www-numi.fnal.gov/ and http://www-nova.fnal.gov/ respectively.
Selected Publications
R.M. Humphreys, KD, & M.D. Koppelman, Astron. J., “The early spectra of Eta Car 1892--1941 and the onset of its high-excitation spectrum.”, SYNERGISTIC ACTIVITIES (2008)
G. Weigelt et al. incl. KD, “Near-IR interferometry of Eta Car…”, Astronomy & Astrophys (2007)
K. Hamaguchi et al. incl. KD, “X-ray spectral variation of Eta Car…”, Astrophys (2007)
J.C. Martin, KD, et al. , “On the He II emission in Eta Carinae and the origin of its spectroscopic events.”, Astrophys (2006)
J.C. Martin, K. Davidson, & M.D. Koppelman, Astron. J., “The chrysalis opens? Photometry from the Eta Car HST Treasury Project 2002--2006.”, (2006)
A. H. Mahmood et al. (CLEO), Measurement of the B Meson Inclusive Semileptonic Branching Fraction and Electron-Energy Moments, Accepted Physical Review {\bf D}, 2004
S.E. Csorna et al., (CLEO), Moments of the B Meson Inclusive Semileptonic Decay Rate using Neutrino Reconstruction, Accepted Physical Review {\bf D}, 2004.
K. W. Edwards {\it et al.} (CLEO), Search for Baryons in the Radiative Penguin Decay $b \rightarrow s \gamma$, Physical Review {\bf D68:011102}, 2003.
D.~Peterson {\it et al.}), The CLEOIII Drift Chamber, Nucl. Instrum. Meth. {\bf A478:142-146}, 2002
A. H. Mahmood {\it et al.} (CLEO), Measurement of the $\Xi_c^+$ Lifetime, Physical Review {\bf D65:031102}, 2002.
Education
M.S. Physics, Duke University, 1993
B.S. Physics, Boston College, 1990