Mark C. Chen

Ph.D. (Caltech), P.Eng. Professor CIFAR Fellow Queen's University Stirling Hall 208E (613) 533-6861 mchen@queensu.ca

Research Interests

Solar Neutrinos

Neutrino physics is one of the hottest topics in particle physics and astrophysics today.  The SNO experiment discovered that solar neutrinos undergo flavour oscillations (electron neutrinos transform into mu and/or tau neutrinos) en route from the Sun to the Earth.  The SNO experiment stopped taking data in Nov 2006 and we are now completing our final data analysis, exploring the phenomenon of neutrino oscillations and improving the precision of our measurements.

SNO+ is a proposed follow-up experiment to SNO that is being developed.  By replacing the heavy water in SNO with liquid scintillator, the SNO+ detector would be sensitive to lower energy neutrinos.  This would enable precision studies of neutrino physics, sensitive to new particle physics connected to the neutrino-matter interaction, including non-standard neutrino couplings and mass-varying neutrinos.  The low energy pep solar neutrinos serve the purpose of precision studies of neutrino properties. The CNO solar neutrinos could be detected for the first time, addressing questions related to solar chemical abundances.  SNO+ would also be a good detector for geo-neutrinos, the neutrinos emitted by natural radioactivity in the Earth.  By measuring the flux of geo-neutrinos, SNO+ would explore fundamental questions in geophysics and geochemistry.

In SNO+ we plan to dissolve about 1 ton of neodymium into the liquid scintillator. This would enable a search for the neutrinoless double beta decay of ¹⁵⁰Nd. The observation of neutrinoless double beta decay would determine if neutrinos are their own antiparticles or not, and would probe the absolute scale of neutrino mass.

Particle Astrophysics

My other interests include:
- geoneutrinos: studying the neutrinos emitted by radioactivity in the Earth
- developing low-background environments for WIMP dark matter recoil detectors
- studying ultra-high energy cosmic rays via detection of Cherenkov radio emission
- ultra-high energy neutrinos from astrophysical sources and ultra-high energy cosmic rays
- understanding the physics and detection of supernova neutrinos
- developing novel scintillators for future experiments in particle astrophysics

Teaching

PHYS 225 - Mechanics

PHYS 250 - Foundations of Experimental Physics

PHYS 352 - Measurement, Instrumentation and Experiment Design

PHYS 450 - Advanced Physics Laboratory

PHYS 841 - Experimental Methods for Particle Astrophysics

PHYS 843 - High Energy Astroparticle Physics

PHYS 844 – Neutrino Physics and Astrophysics

Selected Publications

S.N. Ahmed et al. (SNO Collaboration), Measurement of the Total Active ⁸B Solar Neutrino Flux at the Sudbury Neutrino Observatory with Enhanced Neutral Current Sensitivity,

Phys. Rev. Lett. 92 181301 (2004).

Q.R. Ahmad et al. (SNO Collaboration), Direct Evidence for Neutrino Flavor Transformation from Neutral-Current Interactions in the Sudbury Neutrino Observatory,

Phys. Rev. Lett. 89 011301 (2002).

Q.R. Ahmad et al. (SNO Collaboration), Measurement of Day and Night Neutrino Energy Spectra at SNO and Constraints on Neutrino Mixing Parameters,

Phys. Rev. Lett. 89 011302 (2002).

L. Cadonati, F.P. Calaprice and M.C. Chen, Supernova Neutrino Detection in Borexino,

Astropart. Phys. 16 361 (2002).

G. Alimonti et al. (Borexino Collaboration), Science and Technology of Borexino: A Real-Time Detector for Low Energy Solar Neutrinos,

Astropart. Phys. 16 205 (2002).

Q.R. Ahmad et al. (SNO Collaboration), Measurement of the Rate of nu_e + d  to  p + p + e^- Interactions Produced by ⁸B Solar Neutrinos in the Sudbury Neutrino Observatory,
Phys. Rev. Lett. 87 071301 (2001).

M. Chen et al., Quenching of Undesired Fluorescence in a Liquid Scintillator Particle Detector,
Nucl. Inst. Meth. A 420 189 (1999).

C.G. Rothschild, M.C. Chen and F.P. Calaprice, Antineutrino Geophysics with Liquid Scintillator Detectors,
Geophys. Res. Lett. 25 103 (1998).

G. Alimonti et al., (Borexino-CTF Collaboration), Measurement of the ¹⁴C Abundance in a Low-Background Liquid Scintillator,
Phys. Lett. B 422 349 (1998).

G. Alimonti et al., (Borexino-CTF Collaboration), Ultra-Low Background Measurements in a Large-Volume Underground Detector,
Astropart. Phys. 8 141 (1998).

Science Press

McGraw-Hill Encyclopedia of Science and Technology, 2003 Yearbook entry on Neutrino Mass and Oscillations

BBC Radio "Science in Action" - February 1998

The Economist - February 1998

Science News - January 1998

Last Revised: November 21, 2008