2026/01/26 by Yu Meng, Ning Li, Chuan Liu +3
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex #hep-lat #hep-ph
paper · pdf · doi:10.1103/3pm3-vmhh
published as PRD114,014524(2026) · 8 pages, 5 figures, accepted by PRD
openalex publication_date 2026/07/15 · arxiv created 2026/07/16 · openalex created_date 2026/07/16 · arxiv updated 2026/07/30 · openalex updated_date 2026/07/31
Searching for dark matter is a primary goal of modern astronomy and particle physics. Invisible decays of heavy quarkonia are particularly promising for probing light dark matter, attracting broad interest due to their unique sensitivity. Experiments searching for radiative invisible decays of the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>J</a:mi> <a:mo>/</a:mo> <a:mi>ψ</a:mi> </a:math> have steadily improved upper limits, and upcoming facilities will push sensitivity further—making the precise determination and subtraction of the neutrino background indispensable. Here, we present the first lattice QCD calculation of the Standard Model decay <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>J</c:mi> <c:mo>/</c:mo> <c:mi>ψ</c:mi> <c:mo stretchy="false">→</c:mo> <c:mi>γ</c:mi> <c:mi>ν</c:mi> <c:mover accent="true"> <c:mi>ν</c:mi> <c:mo stretchy="false">¯</c:mo> </c:mover> </c:math> , an irreducible background to <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"> <h:mi>J</h:mi> <h:mo>/</h:mo> <h:mi>ψ</h:mi> <h:mo stretchy="false">→</h:mo> <h:mi>γ</h:mi> <h:mo>+</h:mo> <h:mtext>invisible</h:mtext> </h:math> . Our result for the branching fraction is <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mi>Br</k:mi> <k:mo stretchy="false">(</k:mo> <k:mi>J</k:mi> <k:mo>/</k:mo> <k:mi>ψ</k:mi> <k:mo stretchy="false">→</k:mo> <k:mi>γ</k:mi> <k:mi>ν</k:mi> <k:mover accent="true"> <k:mi>ν</k:mi> <k:mo stretchy="false">¯</k:mo> </k:mover> <k:mo stretchy="false">)</k:mo> <k:mo>=</k:mo> <k:mn>1.04</k:mn> <k:mo stretchy="false">(</k:mo> <k:mn>7</k:mn> <k:mo stretchy="false">)</k:mo> <k:mo stretchy="false">(</k:mo> <k:mn>8</k:mn> <k:mo stretchy="false">)</k:mo> <k:mo>×</k:mo> <k:msup> <k:mn>10</k:mn> <k:mrow> <k:mo>−</k:mo> <k:mn>10</k:mn> </k:mrow> </k:msup> </k:math> , where the first uncertainty is statistical and the second is our systematic estimate. This work advances lattice-based determinations of neutrino backgrounds to quarkonium invisible decays, delivering an benchmark for <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"> <v:mi>J</v:mi> <v:mo>/</v:mo> <v:mi>ψ</v:mi> <v:mo stretchy="false">→</v:mo> <v:mi>γ</v:mi> <v:mo>+</v:mo> <v:mtext>invisible</v:mtext> </v:math> . Our approach generalizes to other quarkonium channels (e.g., <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"> <y:mi mathvariant="normal">ϒ</y:mi> <y:mo>/</y:mo> <y:mi>ϕ</y:mi> <y:mo stretchy="false">→</y:mo> <y:mi>γ</y:mi> <y:mo>+</y:mo> <y:mtext>invisible</y:mtext> </y:math> ) and provides critical theoretical support for dark matter searches at colliders.