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


M. Dierterle and 87 others, First measurement of the polarization of observable E and helicity-dependent cross sections in single π0 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 π e + e - γ Dalitz decay at the Mainz Micotron, Phys. Rev. C. 95, 025202 (2017).

V. Sokhoyan and 76 others, Determination of the scalar polarizabilities of the proton using beam asymmetry Σin 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 (2017).

S. Gardner and 101 others, Photon asymmetry measurements of γ⃗→ π0p for Eγ = 320 – 650 MeV, 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 π0 production on the proton, Phys. Rev. C 93, 055209(2016).

S. Schumann and 73 others, Threshold  πPhotoproduction on Transversely Polarised Protons at MAMI, Phys. Lett. B. 750, 252 (2015).

M. Dieterle and 65 others, Photoproduction of  π0-pairs off protons and neutrons, Eur. Phys. J. A 51, 142 (2015).

A. Käser and 73 others, The isospin structure of photoproduction of  πη pairs from the nucleon in the threshold region, Phys. Lett. B. 748, 244 (2015).

P. Adlarson and 90 others, Measurement of  πphotoproduction on the proton at MAMI C, Phys. Rev. C. 92, 024617 (2015).

J.R.M. Annand and 64 others, First measurement of target and beam-target asymmetries in the γp→π0ηp reaction, Phys. Rev. C 91, 055208 (2015).

I. I. Strakovsky and 73 others, Photoproduction of the  ω meson on the proton near threshold, Phys. Rev. C 91, 045207 (2015).

M. Martemianov and 69 others, A new measurement of the neutron detection efficiency for the NaI Crystal Ball detector, JINST 10, T04001 (2015).

P.P. Martel and 78 others, Measurements of Double-Polarized Compton Scattering Asymmetries and Extraction of the Proton Spin Polarizabilities, Phys. Rev. Lett. 114, 112501 (2015).

C.M. Tarbert and 59 others, The neutron skin of 208Pb from coherent pion photoproduction, Phys. Rev. Lett. 112, 242502 (2014).

S. Constanza et al., Helicity dependence of the γ 3He → πX reactions in the ∆+(1232) resonance region, Eur. Phys. J. A 50, 173 (2014).

C.S. Akondi et al., Measurement of the transverse target and beam-target asymmetries in η-meson production at MAMI, Phys. Rev. Lett. 113, 102001 (2014).

B.M.K. Nefkens et al., New measurement of the rare decay η→π0γγ with the Crystal Ball/TAPS detectors at the Mainz Microtron, Phys. Rev. C 90, 025206 (2014).

D. Werthmüller et al., Quasifree photoproduction of η-mesons off protons and neutrons, Phys. Rev. C 90, 015205 (2014).

T.C. Jude et al., K+Λ and K+Σ0 photoproduction with fine center-of-mass resolution, Phys. Lett. B 735, 112 (2014).

C.M. Tarbert et al., The neutron skin of 208Pb from coherent pion photoproduction, Phys. Rev. Lett. 112, 242502 (2014).

P. Aguar Bartolomé et al., A new determination of the transition form factor in the Dalitz decay η→e+e-γ with the Crystal Ball/TAPS detectors at the Mainz Microtron, Phys. Rev. C 89, 044608 (2014).

M. Dieterle et al., Photoproduction of π0-mesons off neutrons in the nucleon resonance region, Phys. Rev. Lett. 112, 142001 (2014).

Nikolaev et al., Determination of the η mass with the Crystal Ball at MAMI-B, Eur. Phys. J. A 50, 58 (2014).

M. Oberle et al., Measurement of the beam-helicity I⊙ in the photoproduction of π0π±-pairs off protons and off neutrons, Eur. Phys. J. A 50, 54 (2014).

M.H. Sikora et al., Measurement of the 1H(γ,p)π0 reaction using a novel nucleon spin polarimeter, Phys. Rev. Lett. 112, 022501 (2014).

L. Witthauer et al., Quasi-free photo production of η-mesons off 3He nuclei, Eur. Phys. J. A 49, 154 (2013).

D. Werthmueller et al., A narrow structure in the excitation function of η-photoproduction off the neutron, Phys. Rev. Lett. 111, 232001 (2013).

M. Thiel et al., In-medium modifications of the ω meson near the production threshold, Eur. Phys. J. A 49, 132 (2013).

P. Aguar Bartolomé et al., Measurement of the γp→K0Σ+ reaction with the Crystal Ball/TAPS detectors at the Mainz Microtron, Phys. Rev. C. 88, 044601 (2013).

D. Hornidge et al., Accurate Test of Chiral Dynamics in the γp→pπ0 Reaction, Phys. Rev. Lett. 111, 062004 (2013).

D. Hornidge, “Asymmetries for neutral pion photoproduction in the threshold region,” in proceedings of The 7th International Workshop on Chiral Dynamics, PoS CD12 (2013) 070.

P. Aguar Bartolomé et al., First measurement of the helicity dependence of 3He photo reactions in the ∆+(1232) resonance region, Phys. Lett. B 723, 71 (2013).

Y. Maghrbi et al., Double pion photoproduction off nuclei – Are there effects beyond final-state interaction?, Phys. Lett. B 722, 69 (2013).

M. Oberle et al., Measurement of the beam-helicity I in the photoproduction of π0-pairs off the proton and off the neutron, Phys. Lett. B 721, 237 (2013).

Y. Maghrbi et al., Coherent photoproduction of π0- and η-mesons off 7Li, Eur. Phys. J. A 49, 38 (2013).

J. Robinson et al., Measurements of 12C(γ, pp) asymmetries for E = 200 − 450 MeV, Eur. Phys. J. A 49, 65 (2013).


  • 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 2015/2016  

  • PHYS 1051 General Physics I
  • PHYS 3811 Modern Physics
  • PHYS 3821 Quantum Mechanics I  
  • PHYS 3821 Quantum Mechanics I

 Recently taught:

  • PHYS 1401 Physics of Music and Sound
  • PHYS 1051 General Physics I  
  • PHYS 1551 General Physics II
  • PHYS 3201 Statistical Mechanics
  • PHYS 3811 Modern Physics  
  • PHYS 3821 Quantum Mechanics I
  • PHYS 4311 Modern Optics

 Honours theses since 2010: 

  •  Meg Morris, 2016, Neutron Scalar Polarizabilities: Background Simulations for Experimental Extraction via Compton Scattering from 3He
  •   Hannah Stegen, Neutron Multipoles from Pion Photoproduction
  •   Ryan Baker, Investigating the Crystal Ball Detector Energy Calibrations
  •   Jeremy Crowe, The Proton Detection Efficiency of the CB and TAPS Detectors  
  • Scott Clarke, 2014, Timelike Virtual Compton Scattering
  • Joshua Landry, 2014, Cross Section Calculations for Compton Scattering from the Proton Near Pion Threshold 
  •  Ryan Bennett, 2013, Kinematic Fitting for Neutral Pion Identification with Compton Scattering 
  •  Andrew MacLean, 2013, Triggers for the CB-TAPS Set-Up 
  •  Robert Lee MacDonald, 2012, Performance Testing of Experimental Nuclear Physics Data Acquisition and Detection Software 
  •  Chris Sherman, 2012, Proton Efficiency in the CB-TAPS Set-Up 
  •  Ari Silburt, 2012, Improvement of the Compton Beam Asymmetry 
  •  Monica Firminger, 2011, Dilution Factors for a Butanol Frozen-Spin Target 
  •  Darin Eddy, 2010, A First Measurement of the Beam Asymmetry for Compton Scattering 
  •  Alex Laffoley, 2010, 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 intermediate-energy nuclear physics laboratories.  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.

In 2009, we joined forces with two other Canadian groups: one from Saint Mary's University in Halifax, Nova Scotia, and one from the University of Regina in Regina, Saskatchewan. Most of our efforts are currently focused on work in the A2 Collaboration at the Mainzer Mikrotron (MAMI) in Mainz, Germany, but in the longer term, we intend to get more involved with experiments at the Jefferson Laboratory (JLab) in Newport News, Virginia.

One of the projects we are working on at present is a series of Compton scattering experiments to extract the proton spin polarizabilities.  These quantities are fundamental structure constants like the charge and mass, and are similar to the more common dipole polarizabilities, which measure the response of a system to external electric and magnetic fields. There is, however, unfortunately no classical analog for the spin polarizabilities.

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.  The Crystal Ball and TAPS detectors, arranged in a nearly 4π set-up detect the scattered photons and recoil protons in the final state.  After analyzing the data and separating out the background processes, and with the help of theoretical models of the nucleon, we hope to obtain the spin polarizabilities, which can then be compared to theoretical predictions in order to test the validity of these models.

Grants, awards & honours

2013- Paul Paré Medal - Mount Allison University

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