David Hornidge | Mount Allison

David Hornidge

Dunn 218 and 204 (Lab)
Office hours


Ph.D., P.Phys.

Experimental subatomic physicist

Member of the Royal Society of Canada's College of New Scholars, Artists, and Scientists

Principal investigator for CRC1044 of the German Science Foundation

Adjunct professor at Dalhousie and Regina

NSERC Subatomic Physics Evaluation Section, Member 2018-21 and Co-chair 2019-20


  • C.    Mullen and 81 others, Single πº production off neutrons bound in deuteron with linearly polarized photons, Eur. Phys. J. A. 57, 205 (2021).
  • D.    Paudyal and 92 others, Spin polarizabilities of the proton measured by Compton double-polarization observables, Phys. Rev. C. 102, 035205 (2020).
  • M. Dieterle and 81 others, Helicity-dependent cross sections for the photoproduction of πº   pairs from nucleons, Phys. Rev. Lett. 125, 062001 (2020).
  • M. Bashkanov and 73 others, Signatures of the d*(2380) hexaquark in
    , Phys. Rev. Lett. 124, 132001 (2020).
  • V. Sokhoyan and 90 others, Measurement of the beam-helicity asymmetry in photoproduction of πº η pairs on carbon, aluminum, and lead, Phys. Lett. B. 802, 135243 (2020).
  • W.J. Briscoe and 92 others, Cross section for 'yn→ πº n at the Mainz A2 experiment, Phys. Rev. C 100, 065205 (2019).
  • M. Bashkanov and 72 others, Deuteron photodisintegration by polarized photons in the region of the d * (2380), Phys. Lett. B 789, 7 (2019).
  • C.S. Akondi and  85 others, Experimental  study of  the
    reactions at the Mainz Microtron, Eur. Phys. J. A 55, 11 (2019).
  • A. Kaser and 82 others, First measurement of helicity-dependent cross sections in πº η photoproduction from quasi-free nucleons, Phys. Lett. B 786, 305 (2018).
  • M. Dieterle and 83 others, Photoproduction of πº Mesons off Protons and Neutrons in the  Second  and Third Nucleon Resonance Region, Phys. Rev. C 97, 065205 (2018).
  • S.  Prakhov  and  94  others,  High-statistics  measurement   of  the η →    3 πº decay at MAMI, Phys. Rev. C. 97, 065203 (2018).
  • V. Sokhoyan and 96 others, Experimental study of the yp → πº ηp reaction with the A2 setup at MAMI , Phys. Rev. C. 97, 055212 (2018).
  • P. Adlarson and 88 others, Measurement of the decay η' → πº πº η at MAMI , Phys. Rev. D. 98 , 012001 (2018).
  • M. Dieterle and 87 others, First measurement of the polarization observable  E  and  helicity-dependent cross sections in single πº photoproduction from quasi-free nucleons, Phys. Lett. B 770, 523 (2017).
  • V.L. Kashevarov and 90 others, Study of η and η' Photoproduction at MAMI, Phys. Rev. Lett. 118, 212001 (2017).
  • L. Wittauer and 84 others, Helicity-dependent cross sections and double-polarization observable E in η photoproduction from quasifree protons and neutrons, Phys. Rev. C. 95, 055201 (2017).
  • P. Adlarson and 97 others, Measurement of the
    Dalitz decay at the Mainz Microtron, Phys. Rev. C. 95, 025202 (2017).
  • V. Sokhoyan and 76 others, Determination of the scalar polarizabilities of the proton using beam asym­metry  Σ3 in Compton scattering, Eur. Phys. J. A 53 14 (2017).
  • L. Wittauer and 83 others, Insight into the Narrow Structure in η Photoproduction on the Neutron from Helicity-Dependent Cross Sections, Phys. Rev. Lett. 117, 132502 (2016).
  • S. Gardner and 101 others, Photon asymmetry measurements of
    Eur. Phys. J. A 52, 333 (2016).
  • A. Kaser and 69 others, Photoproduction of ηπ-pairs off nucleons and deuterons, Eur. Phys. J. A 52, 272 (2016).
  • J.R.M. Annand and 64 others, T and F asymmetries in πº photoproduction on the proton, Phys. Rev. C 93 , 055209 (2016).



  • Postdoctoral Fellow, Experimental Subatomic Physics, Johannes Gutenberg Universität Mainz, Germany, 1999-2003

  • Ph.D. Experimental Subatomic Physics, University of Saskatchewan, 1999

  • M.Sc. Theoretical Subatomic Physics, University of Saskatchewan, 1995

  • B.Sc. with High Honours, University of Saskatchewan, 1992


In 2021/2022

  • PHYS 2251 Classical Waves
  • PHYS 3451 Mathematical Methods for Physics
  • PHYS 4831 Quantum Mechanics II
  • PHYS 4990 Honours Thesis

 Recently taught:

  • PHYS 1401 Physics of Music and Sound
  • PHYS 1051 General Physics I  
  • PHYS 1551 General Physics II
  • PHYS 3811 Modern Physics  
  • PHYS 3821 Quantum Mechanics I
  • PHYS 4311 Modern Optics
  • PHYS 4831: Advanced Quantum Mechanics
  • PHYS 4851: Fundamental Particles

 Honours theses since 2010: 

  • 2022 (in progress):Alicia Postuma, The Compact A2 Time Projection Chamber
  • 2021: Jenna Chisholm, Extraction of Spin-Dependent Polarizabilities Through Compton  Scattering  Events
  • 2021: Isabelle Dolan, Implementing wavelength shifting compound in active 3 He target to determine neutron polarizabilities
  • 2021: Selina Gaudreault, Compton Scattering  from the Proton in the (1232) Region
  • 2020:Michael Perry, 3- and 4-Helium Targets for Compton Scattering Experiments
  • 2019: Matthew Mullins, An Active Target Cell for High Pressure Helium-3 Gas
  • 2018: Robert Materi, A Global Fitting Routine to Extract the Spin Polarizabilities
  • 2018: Sara Ripley, Tracking Studies using GenFit  for  the  MUSE  Experiment
  • 2018: Maeve Wentland, An Active Helium Target for Neutron Polarizabilities
  • 2017: Kalli Hood, Proton Detection Efficiency of a Polarized Active Target
  • 2016: Meg Morris, Neutron Scalar Polarizabilities: Background Simulations for Experimental Extraction via Compton Scattering from 3He
  •  2016: Hannah Stegen, Neutron Multipoles from Pion Photoproduction
  •  2016: Ryan Baker, Investigating the Crystal Ball Detector Energy Calibrations
  •  2016:Jeremy Crowe, The Proton Detection Efficiency of the CB and TAPS Detectors  
  • 2014: Scott Clarke,  Timelike Virtual Compton Scattering
  • 2014: Joshua Landry, Cross Section Calculations for Compton Scattering from the Proton Near Pion Threshold 
  •  2013: Ryan Bennett, Kinematic Fitting for Neutral Pion Identification with Compton Scattering 
  •  2013: Andrew MacLean, Triggers for the CB-TAPS Set-Up 
  •  2012: Robert Lee MacDonald, Performance Testing of Experimental Nuclear Physics Data Acquisition and Detection Software 
  •  2012: Chris Sherman, Proton Efficiency in the CB-TAPS Set-Up 
  •  2012: Ari Silburt, Improvement of the Compton Beam Asymmetry 
  •  2011: Monica Firminger, Dilution Factors for a Butanol Frozen-Spin Target 
  •  2010: Darin Eddy, A First Measurement of the Beam Asymmetry for Compton Scattering 
  •  2010: Alex Laffoley, Polarization Analysis for a Near-Threshold Neutral Pion Production Measurement 


My field of research is medium-energy experimental subatomic physics, with the specific goal of testing models of the strong nuclear force through the study of hadron structure.  To this end, we carry out experiments at low- and intermediate-energy nuclear physics laboratories such as the Mainz Microtron (MAMI) in Mainz, Germany, the Jefferson Laboratory (JLab) in Newport News, Virginia, and the Triangle Universities Nuclear Laboratory (TUNL) at Duke University in Durham, North Carolina.  In the past we have participated in measurements at the now defunct Saskatchewan Accelerator Laboratory in Saskatoon (now the Canadian Light Source), and MaxLab in Lund, Sweden.   Most of our current efforts are focused on work in the A2 Collaboration at the Mainz Microtron but in the longer term we intend to get more involved with experiments at JLab and TUNL.  Additionally, we are one of the founding groups in the nascent Electron-Ion Collider Canada Collaboration, and our contributions will ramp up over the next few years.

One of our present projects is a program of Compton scattering experiments to extract the scalar and spin polarizabilities of the nucleon, i.e. the proton and neutron.  These quantities are fundamental structure constants like the charge and mass, but contain information on the internal structure and dynamics of the nucleon.  To conduct these experiments, we use the relativistic electron beam of MAMI and the tagging system to produce both polarized and unpolarized photon beams, which are incident on targets of both polarized and unpolarized protons and neutrons.  The Crystal Ball and TAPS detectors, arranged in a nearly 4\pi set-up, detect the scattered photons and recoil nucleons in the final state.  After analyzing the data and separating out the background processes, and with the help of theoretical models, we obtain the polarizabilities, which can then be compared to theoretical predictions in order to test the validity of these models.


Grants, awards & honours

2021- 2023 - NSERC Subatomic Physics- Project, Canadian Participation in the Electron-Ion Collider , Co-applicant with four others, $73,500 per year

2018- 2022 - NSERC Subatomic Physics- Project, Investigations of Hadron  Structure  using  CB-TAPS  at  the  Mainz Microtron , Principal Investigator and co-applicant with two others, $145,000 per year

2013- Paul Paré Medal - Mount Allison University

2012- 2020 - Deutsche Forschungsgemeinschaft, Collaborative Research Center  1044,  The  Low  Energy  Frontier  of the Standard Model: From Quarks and Gluons to Nucleons and Nuclei , Mainz, Germany, Teilprojektleiter (Principal Investigator) along with 18 others,€ 3,000,000 ($4,500,000) per year

2011- Paul Paré Excellence Award - Mount Allison University

2011- Professor of the Year (co-winner with D. Fleming) - Physics Society

2008- Paul Paré Excellence Award - Mount Allison University

2006- Professor of the Year - Physics Society