C. M. Lewis

University of Chicago

*This is an algorithmically generated author record based on publicly available information.

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University of Chicago

Research Subjects

High Energy Physics

Research Interests

C. M. Lewis has a total of 16 co-authors. Here are the top co-authors by number of shared publications:

J. I. Collar
University of Chicago
9 shared publications
Ander Simón Estévez
CSIC & Universitat de València
3 shared publications
S. G. Yoon
University of Chicago
3 shared publications
A. R. L. Kavner
Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA
2 shared publications
J. Colaresi
Mirion Technologies Canberra, 800 Research Parkway, Meriden, Connecticut 06450, USA
2 shared publications
K. M. Yocum
Mirion Technologies Canberra, 800 Research Parkway, Meriden, Connecticut 06450, USA
2 shared publications

Latest Publications

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- 10 September 2026
- Published by American Physical Society (APS) in Physical Review C
Scintillation response of cryogenic CsI to few-keV and sub-keV nuclear recoils
by J. I. Collar, C. M. Lewis, A. Simón, S. G. Yoon
Monochromatic neutron emissions from photonuclear sources $^{88}\mathrm{Y}/\mathrm{Be}$ and $^{124}\mathrm{Sb}/\mathrm{Be}$ are employed to obtain the response of pure (undoped) cesium iodide at 80 K. The use of a low-noise, high-quantum-efficiency avalanche photodiode in combination with a novel wave shifter results in a 70 eV analysis threshold. This reach allows us to observe signals from sub-keV nuclear recoils originating in neutron scattering. The extracted quenching factor drops much faster towards low energy than the extrapolation of a model developed for room-temperature CsI[Na]. We comment on the impact of our measurement on planned use of cryogenic CsI in neutrino physics and dark matter experiments.
Website
Google Scholar
- 10 September 2026
- Published by American Physical Society (APS) in Physical Review C
Scintillation response of cryogenic CsI to few-keV and sub-keV nuclear recoils
by J. I. Collar, C. M. Lewis, A. Simón, S. G. Yoon
Monochromatic neutron emissions from photonuclear sources $^{88}\mathrm{Y}/\mathrm{Be}$ and $^{124}\mathrm{Sb}/\mathrm{Be}$ are employed to obtain the response of pure (undoped) cesium iodide at 80 K. The use of a low-noise, high-quantum-efficiency avalanche photodiode in combination with a novel wave shifter results in a 70 eV analysis threshold. This reach allows us to observe signals from sub-keV nuclear recoils originating in neutron scattering. The extracted quenching factor drops much faster towards low energy than the extrapolation of a model developed for room-temperature CsI[Na]. We comment on the impact of our measurement on planned use of cryogenic CsI in neutrino physics and dark matter experiments.
Open Access
Website
Google Scholar
- 24 August 2026
- Published by Springer Nature in The European Physical Journal C
Cryogenic pure CsI as a probe for neutrino electromagnetic interactions
by C. M. Lewis
Searches for neutrino electromagnetic interactions at reactor sites require an unusual combination of ultra-low thresholds and a stable low-background environment. It is shown here that cryogenic undoped cesium iodide (CsI) naturally satisfies these conditions in a way prior detectors have not. Although suppression of nuclear recoil ionization efficiency at low energies limits the use of this scintillator for coherent elastic neutrino-nucleus scattering, that same property renders the detector effectively blind to those nuclear recoils from MeV-scale reactor antineutrinos. This leaves the low-energy regime free to expose neutrino-electron ( $${\bar{\nu }}_{e} -e^{-}$$ ${\bar{ν}}_{e} - e^{-}$ ) scattering as the dominant observable channel and converts cryogenic CsI into a targeted probe of electromagnetic couplings. This work presents a conceptual design based on pure CsI crystals immersed in an active xenon-doped liquid argon veto evaluated under realistic intrinsic and environmental backgrounds. Under present detector capabilities, order-of-magnitude improvements over current reactor limits on the neutrino magnetic moment and millicharge are achievable. Cryogenic pure CsI therefore offers a distinctive and scalable route to leading studies of $${\bar{\nu }}_{e} -e^{-}$$ ${\bar{ν}}_{e} - e^{-}$ physics.
Website
Google Scholar
- 24 August 2026
- Published by Springer Nature in The European Physical Journal C
Open Access
Cryogenic pure CsI as a probe for neutrino electromagnetic interactions
by C. M. Lewis
Searches for neutrino electromagnetic interactions at reactor sites require an unusual combination of ultra-low thresholds and a stable low-background environment. It is shown here that cryogenic undoped cesium iodide (CsI) naturally satisfies these conditions in a way prior detectors have not. Although suppression of nuclear recoil ionization efficiency at low energies limits the use of this scintillator for coherent elastic neutrino-nucleus scattering, that same property renders the detector effectively blind to those nuclear recoils from MeV-scale reactor antineutrinos. This leaves the low-energy regime free to expose neutrino-electron ( $${\bar{\nu }}_{e} -e^{-}$$ ${\bar{ν}}_{e} - e^{-}$ ) scattering as the dominant observable channel and converts cryogenic CsI into a targeted probe of electromagnetic couplings. This work presents a conceptual design based on pure CsI crystals immersed in an active xenon-doped liquid argon veto evaluated under realistic intrinsic and environmental backgrounds. Under present detector capabilities, order-of-magnitude improvements over current reactor limits on the neutrino magnetic moment and millicharge are achievable. Cryogenic pure CsI therefore offers a distinctive and scalable route to leading studies of $${\bar{\nu }}_{e} -e^{-}$$ ${\bar{ν}}_{e} - e^{-}$ physics.
Open Access
Website
Google Scholar
Cited by 5
- 11 May 2026
- Published by Springer Nature in Journal of High Energy Physics
Coherent elastic neutrino-nucleus scattering at the Japan Proton Accelerator Research Complex
by J. I. Collar, Ivan Esteban, J. J. Gomez-Cadenas, M. C. Gonzalez–Garcia, L.-C. Ji, L. Larizgoitia, C. M. Lewis, F. Monrabal, João Paulo Pinheiro., A. Simón, et al.
A bstract: The Japan Proton Accelerator Research Complex (J-PARC) currently delivers a 1 MW, 3 GeV proton beam to the Materials and Life Science Experimental Facility (MLF). Power is expected to increase to 1.3 MW, driven by the needs of Hyper-Kamiokande. As a result, the MLF presently provides the highest neutron yield of any spallation source, while potentially holding the best current and foreseeable conditions for Coherent Elastic Neutrino-Nucleus Scattering (CE ν NS) experimentation. We explore this potential, using as examples detector technologies presently funded for construction and under development. We quantify their sensitivity to a rich variety of particle physics scenarios, finding that very-high-statistics CE ν NS measurements with significant sensitivity to relevant scenarios are feasible at this facility within the next few years.
Website
Google Scholar
- 11 May 2026
- Published by Springer Nature in Journal of High Energy Physics
Open Access
Coherent elastic neutrino-nucleus scattering at the Japan Proton Accelerator Research Complex
by J. I. Collar, Ivan Esteban, J. J. Gomez-Cadenas, M. C. Gonzalez–Garcia, L.-C. Ji, L. Larizgoitia, C. M. Lewis, F. Monrabal, João Paulo Pinheiro., A. Simón, et al.
A bstract: The Japan Proton Accelerator Research Complex (J-PARC) currently delivers a 1 MW, 3 GeV proton beam to the Materials and Life Science Experimental Facility (MLF). Power is expected to increase to 1.3 MW, driven by the needs of Hyper-Kamiokande. As a result, the MLF presently provides the highest neutron yield of any spallation source, while potentially holding the best current and foreseeable conditions for Coherent Elastic Neutrino-Nucleus Scattering (CE ν NS) experimentation. We explore this potential, using as examples detector technologies presently funded for construction and under development. We quantify their sensitivity to a rich variety of particle physics scenarios, finding that very-high-statistics CE ν NS measurements with significant sensitivity to relevant scenarios are feasible at this facility within the next few years.
Cited by 5
Open Access
Website
Google Scholar
- 10 December 2025
- Published by arXiv in arXiv
Scintillation response of cryogenic CsI to few-keV and sub-keV nuclear recoils
by J. I. Collar, C. M. Lewis, A. Simón, S. G. Yoon
Monochromatic neutron emissions from photonuclear sources $^{88}$Y/Be and $^{124}$Sb/Be are employed to obtain the response of pure (undoped) cesium iodide at 80 K. The use of a low-noise, high-quantum-efficiency avalanche photodiode in combination with a novel waveshifter results in a 70 eV analysis threshold. This reach allows to observe signals from sub-keV nuclear recoils originating in neutron scattering. The extracted quenching factor drops much faster towards low energy than the extrapolation of a model developed for room-temperature CsI[Na]. We comment on the impact of our measurement on planned use of cryogenic CsI in neutrino physics and dark matter experiments.
Website
Google Scholar
- 10 December 2025
- Published by arXiv in arXiv
Open Access
Scintillation response of cryogenic CsI to few-keV and sub-keV nuclear recoils
by J. I. Collar, C. M. Lewis, A. Simón, S. G. Yoon
Monochromatic neutron emissions from photonuclear sources $^{88}$Y/Be and $^{124}$Sb/Be are employed to obtain the response of pure (undoped) cesium iodide at 80 K. The use of a low-noise, high-quantum-efficiency avalanche photodiode in combination with a novel waveshifter results in a 70 eV analysis threshold. This reach allows to observe signals from sub-keV nuclear recoils originating in neutron scattering. The extracted quenching factor drops much faster towards low energy than the extrapolation of a model developed for room-temperature CsI[Na]. We comment on the impact of our measurement on planned use of cryogenic CsI in neutrino physics and dark matter experiments.
Open Access
Website
Google Scholar
- 14 December 2023
- Published by American Physical Society (APS) in Physical Review Letters
Search for a Nonrelativistic Boson in Two-Body Antimuon Decay
by J. I. Collar, P. S. Cooper, C. M. Lewis
We demonstrate the feasibility of probing the charged lepton-flavor-violating decay $μ^{+} \to e^{+} X^{0}$ for the presence of a slow-moving neutral boson $X^{0}$ capable of undergoing gravitational binding to large structures and, as such, able to participate in some cosmological scenarios. A short exposure to surface antimuons from beam line M20 at TRIUMF generates a branching ratio limit of $≲ 10^{- 5}$ . This is comparable to or better than previous searches for this channel, although in a thus-far-unexplored region of $X^{0}$ phase space very close to the kinematic limit of the decay, where $m_{X^{0}}$ approaches $m_{μ^{+}}$ . The future improved sensitivity of the method using a customized $p$ -type point-contact germanium detector is described.
Website
Google Scholar
- 14 December 2023
- Published by American Physical Society (APS) in Physical Review Letters
Open Access
Search for a Nonrelativistic Boson in Two-Body Antimuon Decay
by J. I. Collar, P. S. Cooper, C. M. Lewis
We demonstrate the feasibility of probing the charged lepton-flavor-violating decay $μ^{+} \to e^{+} X^{0}$ for the presence of a slow-moving neutral boson $X^{0}$ capable of undergoing gravitational binding to large structures and, as such, able to participate in some cosmological scenarios. A short exposure to surface antimuons from beam line M20 at TRIUMF generates a branching ratio limit of $≲ 10^{- 5}$ . This is comparable to or better than previous searches for this channel, although in a thus-far-unexplored region of $X^{0}$ phase space very close to the kinematic limit of the decay, where $m_{X^{0}}$ approaches $m_{μ^{+}}$ . The future improved sensitivity of the method using a customized $p$ -type point-contact germanium detector is described.
Open Access
Website
Google Scholar
- 15 August 2023
- Published by arXiv in arXiv
Search for a Non-Relativistic Boson in Two-Body Antimuon Decay
by J. I. Collar, P. S. Cooper, C. M. Lewis
We demonstrate the feasibility of probing the charged lepton flavor violating decay $μ^{+}\!\!\rightarrow \!e^{+} X^{0}$ for the presence of a slow-moving neutral boson $X^{0}$ capable of undergoing gravitational binding to large structures, and as such able to participate in some cosmological scenarios. A short exposure to surface antimuons from beamline M20 at TRIUMF generates a branching ratio limit of $\lesssim 10^{-5}$. This is comparable or better than previous searches for this channel, although in a thus-far unexplored region of $X^{0}$ phase space very close to the kinematic limit of the decay. The future improved sensitivity of the method using a customized p-type point contact germanium detector is described.
Website
Google Scholar
- 15 August 2023
- Published by arXiv in arXiv
Open Access
Search for a Non-Relativistic Boson in Two-Body Antimuon Decay
by J. I. Collar, P. S. Cooper, C. M. Lewis
We demonstrate the feasibility of probing the charged lepton flavor violating decay $μ^{+}\!\!\rightarrow \!e^{+} X^{0}$ for the presence of a slow-moving neutral boson $X^{0}$ capable of undergoing gravitational binding to large structures, and as such able to participate in some cosmological scenarios. A short exposure to surface antimuons from beamline M20 at TRIUMF generates a branching ratio limit of $\lesssim 10^{-5}$. This is comparable or better than previous searches for this channel, although in a thus-far unexplored region of $X^{0}$ phase space very close to the kinematic limit of the decay. The future improved sensitivity of the method using a customized p-type point contact germanium detector is described.
Open Access
Website
Google Scholar
Cited by 180
- 17 November 2022
- Published by American Physical Society (APS) in Physical Review Letters
Measurement of Coherent Elastic Neutrino-Nucleus Scattering from Reactor Antineutrinos
by J. Colaresi, J. I. Collar, T. W. Hossbach, C. M. Lewis, K. M. Yocum
The 96.4 day exposure of a 3 kg ultralow noise germanium detector to the high flux of antineutrinos from a power nuclear reactor is described. A very strong preference ( $p < 1.2 \times 10^{- 3}$ ) for the presence of a coherent elastic neutrino-nucleus scattering ( $CE ν NS$ ) component in the data is found, when compared to a background-only model. No such effect is visible in 25 days of operation during reactor outages. The best-fit $CE ν NS$ signal is in good agreement with expectations based on a recent characterization of germanium response to sub-keV nuclear recoils. Deviations of order 60% from the standard model $CE ν NS$ prediction can be excluded using present data. Standing uncertainties in models of germanium quenching factor, neutrino energy spectrum, and background are examined.
Website
Google Scholar
- 17 November 2022
- Published by American Physical Society (APS) in Physical Review Letters
Open Access
Measurement of Coherent Elastic Neutrino-Nucleus Scattering from Reactor Antineutrinos
by J. Colaresi, J. I. Collar, T. W. Hossbach, C. M. Lewis, K. M. Yocum
The 96.4 day exposure of a 3 kg ultralow noise germanium detector to the high flux of antineutrinos from a power nuclear reactor is described. A very strong preference ( $p < 1.2 \times 10^{- 3}$ ) for the presence of a coherent elastic neutrino-nucleus scattering ( $CE ν NS$ ) component in the data is found, when compared to a background-only model. No such effect is visible in 25 days of operation during reactor outages. The best-fit $CE ν NS$ signal is in good agreement with expectations based on a recent characterization of germanium response to sub-keV nuclear recoils. Deviations of order 60% from the standard model $CE ν NS$ prediction can be excluded using present data. Standing uncertainties in models of germanium quenching factor, neutrino energy spectrum, and background are examined.
Cited by 180
Open Access
Website
Google Scholar
Cited by 90
- 8 October 2021
- Published by American Physical Society (APS) in Physical Review D
First results from a search for coherent elastic neutrino-nucleus scattering at a reactor site
by J. Colaresi, J. I. Collar, T. W. Hossbach, A. R. L. Kavner, C. M. Lewis, A. E. Robinson, K. M. Yocum
The deployment of a low-noise 3 kg p-type point contact germanium detector at the Dresden-II power reactor, 8 meters from its $2.96 {GW}_{th}$ core, is described. This location provides an unprecedented (anti)neutrino flux of $8.1 \times 10^{13} \bar{ν_{e}} / {cm}^{2} s$ . When combined with the $0.2 {keV}_{e e}$ detector threshold achieved, a first measurement of $CE ν NS$ from a reactor source appears to be within reach. We report on the characterization and abatement of backgrounds during initial runs, deriving improved limits on extensions of the Standard Model involving a light vector mediator, from preliminary data.
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Google Scholar
- 8 October 2021
- Published by American Physical Society (APS) in Physical Review D
Open Access
First results from a search for coherent elastic neutrino-nucleus scattering at a reactor site
by J. Colaresi, J. I. Collar, T. W. Hossbach, A. R. L. Kavner, C. M. Lewis, A. E. Robinson, K. M. Yocum
The deployment of a low-noise 3 kg p-type point contact germanium detector at the Dresden-II power reactor, 8 meters from its $2.96 {GW}_{th}$ core, is described. This location provides an unprecedented (anti)neutrino flux of $8.1 \times 10^{13} \bar{ν_{e}} / {cm}^{2} s$ . When combined with the $0.2 {keV}_{e e}$ detector threshold achieved, a first measurement of $CE ν NS$ from a reactor source appears to be within reach. We report on the characterization and abatement of backgrounds during initial runs, deriving improved limits on extensions of the Standard Model involving a light vector mediator, from preliminary data.
Cited by 90
Website
Google Scholar
Cited by 34
- 15 July 2021
- Published by American Physical Society (APS) in Physical Review C
Response of undoped cryogenic CsI to low-energy nuclear recoils
by C. M. Lewis, J. I. Collar
The bright scintillation of pure CsI operated at liquid-nitrogen temperature makes of this material a promising dark matter and neutrino detector. We present the first measurement of its quenching factor for nuclear recoils. Our findings indicate it is indistinguishable from that for sodium-doped CsI at room temperature. Additional properties such as light yield, afterglow, scintillation decay properties for electron and nuclear recoils, and energy proportionality are studied over the 108–165 K temperature range, confirming the vast potential of this medium for rare-event searches.
Website
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- 15 July 2021
- Published by American Physical Society (APS) in Physical Review C
Response of undoped cryogenic CsI to low-energy nuclear recoils
by C. M. Lewis, J. I. Collar
The bright scintillation of pure CsI operated at liquid-nitrogen temperature makes of this material a promising dark matter and neutrino detector. We present the first measurement of its quenching factor for nuclear recoils. Our findings indicate it is indistinguishable from that for sodium-doped CsI at room temperature. Additional properties such as light yield, afterglow, scintillation decay properties for electron and nuclear recoils, and energy proportionality are studied over the 108–165 K temperature range, confirming the vast potential of this medium for rare-event searches.
Cited by 34
Website
Google Scholar
Cited by 105
- 21 June 2021
- Published by American Physical Society (APS) in Physical Review D
Germanium response to sub-keV nuclear recoils: A multipronged experimental characterization
by J. I. Collar, A. R. L. Kavner, C. M. Lewis
Germanium is the detector material of choice in many rare-event searches looking for low-energy nuclear recoils induced by dark matter particles or neutrinos. We perform a systematic exploration of its quenching factor for sub-keV nuclear recoils, using multiple techniques: photoneutron sources, recoils from gamma-emission following thermal neutron capture, and a monochromatic filtered neutron beam. Our results point to a marked deviation from the predictions of the Lindhard model in this mostly unexplored energy range. We comment on the compatibility of our data with low-energy processes such as the Migdal effect, and on the impact of our measurements on upcoming searches.
Website
Google Scholar
- 21 June 2021
- Published by American Physical Society (APS) in Physical Review D
Germanium response to sub-keV nuclear recoils: A multipronged experimental characterization
by J. I. Collar, A. R. L. Kavner, C. M. Lewis
Germanium is the detector material of choice in many rare-event searches looking for low-energy nuclear recoils induced by dark matter particles or neutrinos. We perform a systematic exploration of its quenching factor for sub-keV nuclear recoils, using multiple techniques: photoneutron sources, recoils from gamma-emission following thermal neutron capture, and a monochromatic filtered neutron beam. Our results point to a marked deviation from the predictions of the Lindhard model in this mostly unexplored energy range. We comment on the compatibility of our data with low-energy processes such as the Migdal effect, and on the impact of our measurements on upcoming searches.
Cited by 105

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