Hep-Ex explores the fascinating intersection where particle physics meets experimental reality. This field investigates how scientists build massive detectors and accelerate particles to test the fundamental laws of nature, turning abstract theories into measurable data. It is the rigorous process of searching for new particles or forces that could reshape our understanding of the universe, often requiring years of collaboration and engineering.

At Gist.Science, we ensure these discoveries become accessible to everyone. We process every new preprint in this category directly from arXiv, generating both plain-language explanations for curious readers and detailed technical summaries for specialists. Our goal is to bridge the gap between complex experimental results and public understanding without losing scientific nuance.

Below are the latest papers in Hep-Ex, freshly summarized and ready for you to explore.

⚛️ high-energy experiments

Search for Magnetic and Spin-Independent Inelastic Dark Matter with XENONnT

Using 2.1 tonne-years of data from the XENONnT experiment, this study searches for magnetic and spin-independent inelastic dark matter by identifying unique signatures of nuclear recoils followed by delayed de-excitation photons, ultimately finding results consistent with background expectations and setting 90% C.L. upper limits across the GeV/c² to TeV/c² mass range.

E. Aprile, J. Aalbers, K. Abe, M. Abu Rmilah, M. Adrover, S. Ahmed Maouloud, L. Althueser, B. Andrieu, E. Angelino, D. A (…)2026-08-18
⚛️ phenomenology

Dark Charge Conjugation and Complementary Constraints from D0D^0 Mixing and Rare Decays with Massless Dark Photons

This paper demonstrates a symmetry-resolved complementarity between D0D^0 mixing and rare decays involving massless dark photons, showing how combining these constraints allows for the analytical elimination of flavor dependence to derive direct bounds on invisible decay rates and conditional limits on dark charge conjugation breaking portals.

X. Zhong, X. Q. Shen2026-08-18
⚛️ phenomenology

Exploring charmonia ηc(6S,7S)\eta_c(6S,7S) in the Λc+Λˉc\Lambda_c^+\bar{\Lambda}_c^- invariant mass spectrum of B0KS0Λc+ΛˉcB^0 \to K_S^0\Lambda_c^+\bar{\Lambda}_c^-

This paper analyzes the B0KS0Λc+ΛˉcB^0 \to K_S^0 \Lambda_c^+ \bar{\Lambda}_c^- decay to propose that the observed 4.63 GeV enhancement in the Λc+Λˉc\Lambda_c^+\bar{\Lambda}_c^- spectrum corresponds to the charmonium state ηc(6S)\eta_c(6S), while noting a significant discrepancy between the fitted production rate and theoretical predictions from factorization and hadron-loop mechanisms.

Cheng-Xi Liu, Jun-Zhang Wang, Xiang Liu2026-08-18
⚛️ high-energy experiments

Measurement of Branching Fraction and Transition Magnetic Moment of the Hyperon Dalitz Decay Σ0Λe+e\Sigma^0 \rightarrow \Lambda e^+e^-

Using a sample of 10 billion J/ψJ/\psi events from the BESIII detector, this study reports the first experimental observation of the Dalitz decay Σ0Λe+e\Sigma^0 \rightarrow \Lambda e^+e^-, measuring its branching fraction as (6.34±0.25stat.±0.23syst.)×103(6.34 \pm 0.25_{\rm stat.} \pm 0.23_{\rm syst.}) \times 10^{-3} and determining the transition magnetic moment to be (1.74±0.03stat.±0.09syst.)μN(1.74 \pm 0.03_{\rm stat.} \pm 0.09_{\rm syst.})\,\mu_N, with the branching fraction result showing a 2σ2\sigma discrepancy from previous theoretical predictions.

BESIII Collaboration, M. Ablikim (collapse list), M. N. Achasov (collapse list), P. Adlarson (collapse list), X. C. Ai ( (…)2026-08-18
⚛️ high-energy experiments

First measurements of the branching fractions of J/ψJ/\psi and ψ(3686)Σ0Σˉ0η\psi(3686) \to \Sigma^{0} \bar{\Sigma}^{0}\eta

Using data collected by the BESIII detector, this paper reports the first observation of the hadronic decays J/ψΣ0Σˉ0ηJ/\psi \to \Sigma^{0} \bar{\Sigma}^{0} \eta and ψ(3686)Σ0Σˉ0η\psi(3686) \to \Sigma^{0} \bar{\Sigma}^{0} \eta, measuring their branching fractions and finding that their ratio is consistent with the 12%-rule while revealing no significant intermediate states or threshold enhancements.

BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. (…)2026-08-18
🔬 physics

Unknown Unknowns: Model Misspecification in Machine Learning for Physics

This paper addresses the critical challenge of model misspecification in machine learning applications for physics, arguing that robust analysis requires an iterative cycle of complementary diagnostics and model updates, underpinned by a mindset that anticipates and accommodates unforeseen errors to distinguish between new discoveries and analytical biases.

Juan Cruz-Martinez, Carolina Cuesta-Lazaro, Alexander Held, Michael Kagan2026-08-17