hep-ex papers | Gist.Science

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

Full analysis of CP violation induced by the decay angular correlations in four-body cascade decays of heavy hadrons

This paper proposes a formalism for analyzing decay angular correlations in four-body cascade decays of heavy hadrons to uncover CP violation dynamics, demonstrating through a reanalysis of LHCb data on the $B^0\to p\bar{p}K^+\pi^-$ channel that such correlations could reveal significant CP asymmetries (~10%) that are currently missed by standard branching ratio comparisons.

Zhen-Hua Zhang, Jian-Yu Yang, Xin-Heng Guo2026-07-20

⚛️ high-energy experiments

Demonstration of deuterium's enhanced sensitivity to symmetry violations governed by the Standard-Model Extension

This paper reports hyperfine spectroscopy of ground-state deuterium that sets the first constraints on spin-independent Standard-Model Extension coefficients with momentum powers k=2 and 4, while improving bounds on spin-dependent coefficients by 4 to 14 orders of magnitude over previous hydrogen maser measurements through enhanced sensitivity to CPT and Lorentz symmetry violations.

Amit Nanda, Daniel Comparat, Olivier Dulieu, Sebastian Lahs, Chloe Malbrunot, Lilian Nowak, Martin C. Simon, Eberhard Wi (…)2026-07-20

⚛️ nuclear experiments

Measurement of the azimuthal anisotropy of charged particles in $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV $^{16}$ O $+^{16}$ O and $^{20}$ Ne $+^{20}$ Ne collisions with the ATLAS detector

This paper presents the first measurements of charged-particle azimuthal anisotropy coefficients ( $v_2$ – $v_4$ ) in 5.36 TeV $^{16}$ O+ $^{16}$ O and $^{20}$ Ne+ $^{20}$ Ne collisions with the ATLAS detector, revealing a clear $v_2 > v_3 > v_4$ hierarchy and enhanced elliptic flow in central neon collisions that aligns with theoretical predictions of prolate nuclear deformation.

ATLAS Collaboration2026-07-20

⚛️ high-energy experiments

First Experimental Demonstration of Reinforcement Learning-Based Tuning on the PSI Injector 2 Cyclotron

This paper presents the first experimental demonstration of a reinforcement learning-based framework successfully deployed on the PSI Injector 2 cyclotron, where an agent achieved robust, low-loss beam tuning across multiple operating points and high currents (up to 800 μA) within a 12-day campaign, proving the viability of automated tuning for high-power accelerator applications.

M. Haj Tahar, W. Joho, E. Solodko, M. Bocchio, S. Marquie, M. Busch, A. Barchetti, J. Grillenberger, J. Snuverink, M. Sc (…)2026-07-20

⚛️ high-energy experiments

Strange Quark Electric Dipole Moment withTopological Anomalies

This paper proposes an anomaly-based framework utilizing Chern-Simons-induced T-odd asymmetries in exclusive $e^+e^-$ hadronic final states, such as $\gamma^*\to K^+K^-\pi^0$ , to probe the strange-quark electric dipole moment with a projected precision of $10^{-18}\,e\cdot\mathrm{cm}$ , significantly surpassing current direct constraints from hyperon EDMs.

Chao-Qiang Geng, Xiang-Nan Jin, Chia-Wei Liu, Bin Wu2026-07-20

⚛️ high-energy experiments

Lagrangian-based model of the $e^+e^- \to V \bar V$ process applied to the $e^+e^- \to D^{\ast+} D^{\ast-}$ data

This paper derives a Lagrangian-based Breit-Wigner formula for the $e^+e^- \to V\bar{V}$ process and validates its parameters by successfully fitting 2022 BESIII Collaboration data for the $e^+e^- \to D^{\ast+}D^{\ast-}$ channel.

Peter Lichard2026-07-20

⚛️ high-energy experiments

Mitigating Detector Ageing Effects with Graph-Based Multi-Modal Track Reconstruction at Belle II

This paper demonstrates that a unified graph neural network-based track reconstruction algorithm, when retrained on realistic long-term detector ageing conditions, significantly outperforms the conventional Belle II baseline by reducing absolute track efficiency loss for muons from 28% to 14% while maintaining 96% track purity, thereby proving that detector degradation can be effectively managed as a domain shift rather than requiring a fundamentally new reconstruction strategy.

Lea Reuter, Tristan Brandes, Giacomo De Pietro, Torben Ferber2026-07-20

⚛️ high-energy experiments

Search for the lepton number violating process $Ξ^- \rightarrow Σ^+ e^- e^- +c.c.$

Using a dataset of approximately $10^7$ $J/\psi$ events collected by the BESIII detector, the authors conducted a blind analysis searching for the lepton number violating decay $\Xi^- \rightarrow \Sigma^+ e^- e^- + \text{c.c.}$ , found no significant signal, and established an upper limit on its branching fraction of $2.0 \times 10^{-5}$ at the 90% confidence level.

BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, R. Aliberti, A. Amoroso, Q. An, Y. Bai, O. Bakin (…)2026-07-17

⚛️ high-energy experiments

Cross section measurement of $e^{+}e^{-}\rightarrow π^{0}π^{0}ψ(3686)$ from $\sqrt{s}=$ 4.008 GeV to 4.951 GeV

Using 22.1 fb⁻¹ of data collected by the BESIII detector, this study measures the cross section of the $e^{+}e^{-}\rightarrow \pi^{0}\pi^{0}\psi(3686)$ process across center-of-mass energies from 4.008 to 4.951 GeV, confirming isospin symmetry expectations and providing significant evidence for the $Y(4390)$ and $Y(4660)$ resonances with parameters consistent with previous measurements in the charged pion channel.

BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, R. Aliberti, A. Amoroso, Q. An, Y. Bai, O. Bakin (…)2026-07-17

⚛️ high-energy experiments

Observation of $CP$ violation in $B^{0}\!\to{J\mskip-3mu/\mskip-2muψ}ρ(770)^0$ decays

Using LHCb proton-proton collision data, this paper reports the first observation of time-dependent $CP$ violation in $B^{0}\!\to{J\mskip-3mu/\mskip-2mu\psi}\rho(770)^0$ decays and utilizes these results, combined with previous measurements under SU(3) flavor symmetry, to establish the most stringent constraint to date on the penguin contribution to the $CP$ -violating phase in $B^{0}_{s}\!\to{J\mskip-3mu/\mskip-2mu\psi}\phi(1020)$ decays.

LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. A (…)2026-07-17

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hep-ex

Full analysis of CP violation induced by the decay angular correlations in four-body cascade decays of heavy hadrons

Demonstration of deuterium's enhanced sensitivity to symmetry violations governed by the Standard-Model Extension

Measurement of the azimuthal anisotropy of charged particles in sNN=5.36\sqrt{s_{\mathrm{NN}}}=5.36sNN​​=5.36 TeV 16^{16}16O+16+^{16}+16O and 20^{20}20Ne+20+^{20}+20Ne collisions with the ATLAS detector

First Experimental Demonstration of Reinforcement Learning-Based Tuning on the PSI Injector 2 Cyclotron

Strange Quark Electric Dipole Moment withTopological Anomalies

Lagrangian-based model of the e+e−→VVˉe^+e^- \to V \bar Ve+e−→VVˉ process applied to the e+e−→D∗+D∗−e^+e^- \to D^{\ast+} D^{\ast-}e+e−→D∗+D∗− data

Mitigating Detector Ageing Effects with Graph-Based Multi-Modal Track Reconstruction at Belle II

Search for the lepton number violating process Ξ−→Σ+e−e−+c.c.Ξ^- \rightarrow Σ^+ e^- e^- +c.c.Ξ−→Σ+e−e−+c.c.

Cross section measurement of e+e−→π0π0ψ(3686)e^{+}e^{-}\rightarrow π^{0}π^{0}ψ(3686)e+e−→π0π0ψ(3686) from s=\sqrt{s}=s​= 4.008 GeV to 4.951 GeV

Observation of CPCPCP violation in B0 ⁣→J ⁣/ψρ(770)0B^{0}\!\to{J\mskip-3mu/\mskip-2muψ}ρ(770)^0B0→J/ψρ(770)0 decays

Measurement of the azimuthal anisotropy of charged particles in $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV $^{16}$ O $+^{16}$ O and $^{20}$ Ne $+^{20}$ Ne collisions with the ATLAS detector

Lagrangian-based model of the $e^+e^- \to V \bar V$ process applied to the $e^+e^- \to D^{\ast+} D^{\ast-}$ data

Search for the lepton number violating process $Ξ^- \rightarrow Σ^+ e^- e^- +c.c.$

Cross section measurement of $e^{+}e^{-}\rightarrow π^{0}π^{0}ψ(3686)$ from $\sqrt{s}=$ 4.008 GeV to 4.951 GeV

Observation of $CP$ violation in $B^{0}\!\to{J\mskip-3mu/\mskip-2muψ}ρ(770)^0$ decays