Probing Solar Chameleons with XENONnT Ionization-Only Data
Abstract
Screened scalar fields provide a possible connection between dark energy and laboratory-scale new physics while remaining compatible with existing fifth-force constraints. Solar production offers a direct probe of these models, and ionization-only measurements extend the sensitivity of liquid-xenon detectors into the sub-keV regime. We present the first search for solar chameleons using low-energy S2-only data, based on the 7.83 tonne-year XENONnT ionization-only data set. The predicted electronic-recoil spectrum is folded through the run-dependent detector response and tested directly in corrected-S2 (cS2) space. A joint binned likelihood combines the seven cS2 bins of science runs SR0, SR1, and SR2. We sample the five-dimensional parameter space {βe,βγ,Me,Λ,n} and derive posterior constraints on the conformal and disformal electron couplings. The data extend the recoil-energy reach to approximately 0.04 keVee, where the few-electron detector response and instrumental backgrounds must be modeled explicitly. In the disformal-dominated regime, the result is expressed in terms of βeff≡βγ(eV/Me)4. We obtain the upper limit log10βeff<−3.64. Although the present analysis reaches a lower energy threshold than our previous XENONnT electronic-recoil analysis, the resulting constraint is weaker, primarily because the disformal absorption rate decreases rapidly toward low recoil energies, where the background rate also becomes larger. This analysis establishes low-energy ionization data as a new experimental channel for testing solar chameleons and screened dark-energy models.
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BibTeX
@misc{yuan2026probing,
title = {{Probing Solar Chameleons with XENONnT Ionization-Only Data}},
author = {Guan-Wen Yuan},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.33198},
eprint = {2609.33198},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.33198},
}
RIS
TY - UNPB
TI - Probing Solar Chameleons with XENONnT Ionization-Only Data
AU - Guan-Wen Yuan
PY - 2026
DA - 2026/09/27
PB - arXiv
DO - 10.48550/arxiv.2609.33198
UR - https://arxiv.org/abs/2609.33198
AB - Screened scalar fields provide a possible connection between dark energy and laboratory-scale new physics while remaining compatible with existing fifth-force constraints. Solar production offers a direct probe of these models, and ionization-only measurements extend the sensitivity of liquid-xenon detectors into the sub-keV regime. We present the first search for solar chameleons using low-energy S2-only data, based on the 7.83 tonne-year XENONnT ionization-only data set. The predicted electronic-recoil spectrum is folded through the run-dependent detector response and tested directly in corrected-S2 (cS2) space. A joint binned likelihood combines the seven cS2 bins of science runs SR0, SR1, and SR2. We sample the five-dimensional parameter space {β_e,β_γ,M_e,Λ,n} and derive posterior constraints on the conformal and disformal electron couplings. The data extend the recoil-energy reach to approximately 0.04 keV_ee, where the few-electron detector response and instrumental backgrounds must be modeled explicitly. In the disformal-dominated regime, the result is expressed in terms of β_eff≡β_γ(eV/M_e)^4. We obtain the upper limit log_10β_eff<−3.64. Although the present analysis reaches a lower energy threshold than our previous XENONnT electronic-recoil analysis, the resulting constraint is weaker, primarily because the disformal absorption rate decreases rapidly toward low recoil energies, where the background rate also becomes larger. This analysis establishes low-energy ionization data as a new experimental channel for testing solar chameleons and screened dark-energy models.
ER -