Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Event--Object Misclassification in the CERN AD-ELENA Antimatter Program (Caravita, Cridland Mathad, Hangst, Hori, Latacz, Obertelli, Perez, Ulmer, Widmann)

Livolsi Edoardo

Published May 7, 2026• 0 citations
Publisher

Abstract

This work presents a structural critique of the CERN AD/ELENA Antimatter Program by R. Caravita, A. Cridland Mathad, J. S. Hangst, M. Hori, B. M. Latacz, A. Obertelli, P. Perez, S. Ulmer, and E. Widmann, on behalf of the Antiproton Decelerator User Community (ADUC) (arXiv:2503.22471). The program produces and studies antiprotons, antihydrogen, and related systems through controlled experimental procedures including deceleration, trapping, cooling, transport, and manipulation. These configurations are interpreted as physically existing entities and used to perform tests of CPT invariance, gravitational behavior, and fundamental symmetries. We show that all experimentally realized configurations are externally sustained, time-dependent, and dependent on continuous interaction with the experimental apparatus. As such, they do not satisfy the structural conditions required for physical existence, which require stationarity and independence from external forcing. All observables arise from these laboratory configurations and therefore correspond to event-dependent outputs rather than autonomous physical states. The mapping from measurement to physical ontology is non-invertible, implying that observed signals cannot establish the existence of underlying physical entities. Furthermore, the assumption of a distinct antimatter sector is not derived from any structural condition and is introduced without a generating mechanism. The analysis demonstrates a systematic misclassification of externally generated configurations as physical objects. In particular, antiprotons and antihydrogen correspond to non-stationary, apparatus-dependent configurations rather than physically realized entities. All conclusions follow from structural analysis alone and do not rely on fitting procedures or external theoretical assumptions.

DOI
10.5281/zenodo.20059960

Related papers

Systematic Event--Object Misclassification in CERN and Fermilab Experiments

Livolsi Edoardo

This work establishes a formal distinction between event structures and physically realized configurations within a closed variational framework defined by a fundamental functional S[Psi]. The analysis proceeds from the stationary condition delta S / delta Psi^dagger = 0, defining the solution space and the admissible domain. The physically realized configuration is uniquely selected through a global decisional functional, while all laboratory configurations are shown to be time-dependent, externally sustained, and non-stationary. It is proven that experimental configurations Psi_lab(t) do not belong to the stationary solution set and therefore cannot correspond to physically existing objects. Observables, including the quantity g-2, are constructed as functionals of Psi_lab(t) and thus represent properties of event structures rather than intrinsic properties of physical entities. A complete structural pipeline is developed, including the explicit construction of the Hessian, its spectral decomposition with a fixed ratio L = 1/4, and the emergence of a minimal cyclic closure. The mapping from configurations to observables is shown to be non-invertible, reinforcing the impossibility of reconstructing physically realized configurations from experimental data. The central result is that high-energy experiments, including those performed at CERN and Fermilab, produce and classify controlled event structures without accessing physically existing configurations. The interpretation of experimental observables as properties of fundamental objects is therefore not supported within the variational structure. The framework is internally closed, non-extendable, and structurally rigid. All results follow from explicit variational derivation without external assumptions.

•Apr 25, 2026•0 citations

Antihydrogen Production, Trapping, and Antimatter Plasmas

J. Fajans

Since 2002, experiments at CERN have been producing slow, but untrapped, antihydrogen. The ultimate goal of these experiments is to test CPT and the gravitational interactions of matter and antimatter. Most schemes to perform CPT and gravity tests require trapped antihydrogen, but trapping antihydrogen is much more difficult than merely synthesizing it. The principle problems that must be solved before we can trap are how to cool the antiprotons, and how to keep them cold during the synthesis process. While we have already learned how to cool antiprotons by ten orders of magnitude, we must cool them by four more orders of magnitude, a scale set by the relative size of the potentials of the antimatter plasmas from which the antiatoms are synthesized compared to the antihydrogen trap well depth. In this talk, I will discuss antihydrogen synthesis and some of the techniques we are developing to control the energy of the resultant antihydrogen.

•Sep 16, 2009•0 citations

Physics with antihydrogen

William Alan Bertsche, Eoin Butler, M. Charlton +1 more

Performing measurements of the properties of antihydrogen, the bound state of an antiproton and a positron, and comparing the results with those for ordinary hydrogen, has long been seen as a route to test some of the fundamental principles of physics. There has been much experimental progress in this direction in recent years, and antihydrogen is now routinely created and trapped and a range of exciting measurements probing the foundations of modern physics are planned or underway. In this contribution we review the techniques developed to facilitate the capture and manipulation of positrons and antiprotons, along with procedures to bring them together to create antihydrogen. Once formed, the antihydrogen has been detected by its destruction via annihilation or field ionization, and aspects of the methodologies involved are summarized. Magnetic minimum neutral atom traps have been employed to allow some of the antihydrogen created to be held for considerable periods. We describe such devices, and their implementation, along with the cusp magnetic trap used to produce the first evidence for a low-energy beam of antihydrogen. The experiments performed to date on antihydrogen are discussed, including the first observation of a resonant quantum transition and the analyses that have yielded a limit on the electrical neutrality of the anti-atom and placed crude bounds on its gravitational behaviour. Our review concludes with an outlook, including the new ELENA extension to the antiproton decelerator facility at CERN, together with summaries of how we envisage the major threads of antihydrogen physics will progress in the coming years.

Journal of Physics B Atomic Molecular and Optical Physics•Oct 6, 2015•44 citations

Collapse of Particle Ontology and Non-Closure of High-Energy Experimental Frameworks

Livolsi Edoardo

This work establishes the collapse of particle ontology within high-energy experimental frameworks by demonstrating the absence of direct ontological access in collider-based measurements. Starting from a closed quartic variational functional, the admissible configuration space is constructed, the Hessian operator is derived explicitly, and all observable content is shown to be fully contained in its spectral structure. We prove that experimental outputs consist exclusively of structured sets of observables (tracks, timing, energy deposits), which are mapped into particle labels through a classification procedure. No element identified as a particle is ever directly measured. In particular, the Muon g-2 experiment is analyzed in detail, showing that the measured quantity is a functional of reconstructed events and belongs to the spectral content of the Hessian operator, rather than to an independent physical entity. A general theorem of non-direct ontological access is formulated and proven: for any experimental chain D → E → M(E), the assigned particle label M(E) does not belong to the set of observables and therefore cannot be identified with a physically existing object. Consequently, particles are not elements of physical ontology but emerge as classification outputs applied to structured experimental data. The introduction of additional degrees of freedom to match experimental observations is shown to be a formal signature of non-closure. In contrast, the variational framework generates all observable structures without external entities, establishing a closed, self-consistent description in which physical reality coincides with the globally selected configuration. The central result is that no particle is ever observed, and no particle is required. All experimentally accessible quantities are spectral manifestations of a single variationally selected structure.

•Apr 22, 2026•0 citations

The ATHENA experiment for the study of antihydrogen

C. Amsler, G. Bonomi, A. Fontana +7 more

In 2002, the ATHENA experiment was the first to produce large amounts of antihydrogen atoms at the CERN Antiproton Decelerator (AD). In this review article, we collect and discuss all the relevant results of the experiment: antiproton and positron cooling and their recombination dynamics in the nested Penning trap, the methods used to unambiguously identify the antiatoms as well as the protonium background, the dependence of the antihydrogen formation on mixing time and temperature. An attempt to interpret the results in terms of the two-body and three-body formation reactions, taking into account the complicated nested-trap dynamics, is also made. The relevance of the ATHENA results on future experiments is discussed, together with a short overview of the current antimatter physics at the AD.

International Journal of Modern Physics A•Aug 6, 2014•5 citations

Cryogenic Particle Accumulation In ATRAP And The First Antihydrogen Production Within A Magnetic Gradient Trap For Neutral Antimatter

C. H. Storry, Adam C. Carew, D. Comeau +22 more

ATRAP has made many important improvements since CERN's Antiproton Decelerator (AD) was restarted in 2006. These include substantial increases in the number of positrons (e+) and antiprotons (Pbars) used to make antihydrogen (Hbar) atoms, a new technique for loading electrons (e−) that are used to cool Pbars and e+, implementation of a completely new, larger and more robust apparatus in our second experimental zone and the inclusion of a quadrupole Ioffe trap intended to trap the coldest Hbar atoms produced. Using this new apparatus we have produced large numbers of Hbar atoms within a Penning trap that is located within this quadrupole Ioffe trap using a new technique which shows promise for producing even colder atoms. These observed Hbar atoms resolve a debate about whether positrons and antiprotons can be brought together to form atoms within the divergent magnetic fields of a quadrupole Ioffe trap.

AIP conference proceedings•Jan 1, 2008•1 citation
This work presents a structural critique of the CERN AD/ELENA Antimatter Program by R. Caravita, A. Cridland Mathad, J. S. Hangst, M. Hori, B. M. Latacz, A. Obertelli, P. Perez, S. Ulmer, and E. Widmann, on behalf of the Antiproton Decelerator User Community (ADUC) (arXiv:2503.22471). The program produces and studies antiprotons, antihydrogen, and related systems through controlled experimental procedures including deceleration, trapping, cooling, transport, and manipulation. These configurations are interpreted as physically existing entities and used to perform tests of CPT invariance, gravitational behavior, and fundamental symmetries. We show that all experimentally realized configurations are externally sustained, time-dependent, and dependent on continuous interaction with the experimental apparatus. As such, they do not satisfy the structural conditions required for physical existence, which require stationarity and independence from external forcing. All observables arise from these laboratory configurations and therefore correspond to event-dependent outputs rather than autonomous physical states. The mapping from measurement to physical ontology is non-invertible, implying that observed signals cannot establish the existence of underlying physical entities. Furthermore, the assumption of a distinct antimatter sector is not derived from any structural condition and is introduced without a generating mechanism. The analysis demonstrates a systematic misclassification of externally generated configurations as physical objects. In particular, antiprotons and antihydrogen correspond to non-stationary, apparatus-dependent configurations rather than physically realized entities. All conclusions follow from structural analysis alone and do not rely on fitting procedures or external theoretical assumptions.
This work establishes a formal distinction between event structures and physically realized configurations within a closed variational framework defined by a fundamental functional S[Psi]. The analysis proceeds from the stationary condition delta S / delta Psi^dagger = 0, defining the solution space and the admissible domain. The physically realized configuration is uniquely selected through a global decisional functional, while all laboratory configurations are shown to be time-dependent, externally sustained, and non-stationary. It is proven that experimental configurations Psi_lab(t) do not belong to the stationary solution set and therefore cannot correspond to physically existing objects. Observables, including the quantity g-2, are constructed as functionals of Psi_lab(t) and thus represent properties of event structures rather than intrinsic properties of physical entities. A complete structural pipeline is developed, including the explicit construction of the Hessian, its spectral decomposition with a fixed ratio L = 1/4, and the emergence of a minimal cyclic closure. The mapping from configurations to observables is shown to be non-invertible, reinforcing the impossibility of reconstructing physically realized configurations from experimental data. The central result is that high-energy experiments, including those performed at CERN and Fermilab, produce and classify controlled event structures without accessing physically existing configurations. The interpretation of experimental observables as properties of fundamental objects is therefore not supported within the variational structure. The framework is internally closed, non-extendable, and structurally rigid. All results follow from explicit variational derivation without external assumptions.
Since 2002, experiments at CERN have been producing slow, but untrapped, antihydrogen. The ultimate goal of these experiments is to test CPT and the gravitational interactions of matter and antimatter. Most schemes to perform CPT and gravity tests require trapped antihydrogen, but trapping antihydrogen is much more difficult than merely synthesizing it. The principle problems that must be solved before we can trap are how to cool the antiprotons, and how to keep them cold during the synthesis process. While we have already learned how to cool antiprotons by ten orders of magnitude, we must cool them by four more orders of magnitude, a scale set by the relative size of the potentials of the antimatter plasmas from which the antiatoms are synthesized compared to the antihydrogen trap well depth. In this talk, I will discuss antihydrogen synthesis and some of the techniques we are developing to control the energy of the resultant antihydrogen.
Performing measurements of the properties of antihydrogen, the bound state of an antiproton and a positron, and comparing the results with those for ordinary hydrogen, has long been seen as a route to test some of the fundamental principles of physics. There has been much experimental progress in this direction in recent years, and antihydrogen is now routinely created and trapped and a range of exciting measurements probing the foundations of modern physics are planned or underway. In this contribution we review the techniques developed to facilitate the capture and manipulation of positrons and antiprotons, along with procedures to bring them together to create antihydrogen. Once formed, the antihydrogen has been detected by its destruction via annihilation or field ionization, and aspects of the methodologies involved are summarized. Magnetic minimum neutral atom traps have been employed to allow some of the antihydrogen created to be held for considerable periods. We describe such devices, and their implementation, along with the cusp magnetic trap used to produce the first evidence for a low-energy beam of antihydrogen. The experiments performed to date on antihydrogen are discussed, including the first observation of a resonant quantum transition and the analyses that have yielded a limit on the electrical neutrality of the anti-atom and placed crude bounds on its gravitational behaviour. Our review concludes with an outlook, including the new ELENA extension to the antiproton decelerator facility at CERN, together with summaries of how we envisage the major threads of antihydrogen physics will progress in the coming years.
This work establishes the collapse of particle ontology within high-energy experimental frameworks by demonstrating the absence of direct ontological access in collider-based measurements. Starting from a closed quartic variational functional, the admissible configuration space is constructed, the Hessian operator is derived explicitly, and all observable content is shown to be fully contained in its spectral structure. We prove that experimental outputs consist exclusively of structured sets of observables (tracks, timing, energy deposits), which are mapped into particle labels through a classification procedure. No element identified as a particle is ever directly measured. In particular, the Muon g-2 experiment is analyzed in detail, showing that the measured quantity is a functional of reconstructed events and belongs to the spectral content of the Hessian operator, rather than to an independent physical entity. A general theorem of non-direct ontological access is formulated and proven: for any experimental chain D → E → M(E), the assigned particle label M(E) does not belong to the set of observables and therefore cannot be identified with a physically existing object. Consequently, particles are not elements of physical ontology but emerge as classification outputs applied to structured experimental data. The introduction of additional degrees of freedom to match experimental observations is shown to be a formal signature of non-closure. In contrast, the variational framework generates all observable structures without external entities, establishing a closed, self-consistent description in which physical reality coincides with the globally selected configuration. The central result is that no particle is ever observed, and no particle is required. All experimentally accessible quantities are spectral manifestations of a single variationally selected structure.
In 2002, the ATHENA experiment was the first to produce large amounts of antihydrogen atoms at the CERN Antiproton Decelerator (AD). In this review article, we collect and discuss all the relevant results of the experiment: antiproton and positron cooling and their recombination dynamics in the nested Penning trap, the methods used to unambiguously identify the antiatoms as well as the protonium background, the dependence of the antihydrogen formation on mixing time and temperature. An attempt to interpret the results in terms of the two-body and three-body formation reactions, taking into account the complicated nested-trap dynamics, is also made. The relevance of the ATHENA results on future experiments is discussed, together with a short overview of the current antimatter physics at the AD.
ATRAP has made many important improvements since CERN's Antiproton Decelerator (AD) was restarted in 2006. These include substantial increases in the number of positrons (e+) and antiprotons (Pbars) used to make antihydrogen (Hbar) atoms, a new technique for loading electrons (e−) that are used to cool Pbars and e+, implementation of a completely new, larger and more robust apparatus in our second experimental zone and the inclusion of a quadrupole Ioffe trap intended to trap the coldest Hbar atoms produced. Using this new apparatus we have produced large numbers of Hbar atoms within a Penning trap that is located within this quadrupole Ioffe trap using a new technique which shows promise for producing even colder atoms. These observed Hbar atoms resolve a debate about whether positrons and antiprotons can be brought together to form atoms within the divergent magnetic fields of a quadrupole Ioffe trap.