The main goal of the PUMA [1] (antiProton Unstable Matter Annihilation) experiment is to use antiprotons as a tool to investigate the matter density of short-lived nuclei. For this, antiprotons produced at the Antiproton Decelerator (AD) facility at CERN and decelerated by the Extra Low Energy Antiproton storage ring (ELENA) will be captured, cooled and transported to the ISODLE facility at...
Candidates for dark matter are proposed and searched from the sub meV to TeV scales. The indirect observations don’t provide sufficient power to constrain to a narrow parameter space of the searches. One of the dark matter candidates, a deeply bound (uuddss) sexaquark, S, with mass in the GeV range is hypothesized to be long lived and very compact, described within the Standard Model of...
The annihilation of antiprotons is a fundamental process that still lacks a precise description. When the annihilation involves a nucleus, the initially produced pions can trigger various secondary reactions with differing probabilities, significantly increasing the complexity of the interaction. Despite previous extensive experimental and theoretical efforts, existing models are, to varying...
The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station. Over 12 years, AMS has collected more than 230 billion cosmic rays, from elementary particles to iron nuclei, at energies up to multi-TeV. The precision spectrometer measures elementary particles and nuclei to ~1% accuracy, yielding many surprising results. The latest AMS results...
One of the major tasks of astrophysics is to understand the emission mechanisms of observed sources and regions in the sky. Only by pinpointing down these mechanisms, it is possible to derive physical parameters and learn about the evolution of astrophysical objects. Alas, many observations of high-energy phenomena are ambiguous, requiring more and orthogonal information. The nature of several...
Positronium atom (Ps), a fascinating purely leptonic system, serves as an excellent testbed for probing quantum electrodynamics (QED) in the bound state [1, 2]. Ps can manifest in one of two states, depending on the total spin number (S): a short-lived state with spin zero (para-Ps) and long-lived meta stable state with spin one (ortho-Ps). Prior to 1995, a significant discrepancy existed...
We report the results of a new measurement of the $2\,^3$S$_1 \rightarrow 2\,^1$P$_1$ transition ($\nu_F$) in positronium (Ps). Though this transition is forbidden by charge conjugation symmetry (C), it can be observed in a magnetic field. We optically excite Ps from a pulsed beam to produce radiatively metastable $2\,^3$S$_1$ atoms and drive them to the $2\,^3$P$_1$ level in a rectangular...
Positronium (Ps), an exotic atom composed of an electron and its antiparticle, the positron, serves as an excellent system for fundamental physics investigations. Its unique composition of light leptons makes it an ideal system for testing Quantum Electrodynamics (QED) and probing physics beyond the Standard Model. A key aspect of such studies involves comparing calculated energy intervals...
Positronium (Ps), the bound state of an electron and its antiparticle positron, serves as a good probe for fundamental physics. As the lightest purely leptonic atom containing an antiparticle, Ps offers unique opportunities for precision tests of bound-state quantum electrodynamics (QED) and investigations into matter-antimatter asymmetry—the mystery underlying our matter-dominated...
Muonic helium is a hydrogen-like atom composed of a helium atom with one of its two electrons replaced by a negative muon. Its ground-state hyperfine structure (HFS), which results from the interaction of the negative muon magnetic moment and the remaining electron, is very similar to muonium HFS but inverted. Precise measurements of the muonium ground-state HFS interval using a microwave...
The search for low energy anti-nuclei in cosmic rays allows a test of fundamental physics problems such as the possible presence of primordial antimatter or the nature of Dark Matter.
The “PHeSCAMI” (Pressurized Helium Scintillating Calorimeter for AntiMatter Identification) project is aiming to study a new signature for the identification of anti-nuclei in cosmic rays.
In particular,...
We have proposed a spectroscopic study of antihydrogen ($\mathrm{\bar{H}}$) Lamb shift using a neutral antiatomic beam at keV energies. Direct spectroscopy of the $n=2$ Lamb shift transition of $\mathrm{\bar{H}}$ atoms would enable the first measurement of the antiproton ($\bar{p}$) charge radius. Recently, the GBAR experiment demonstrated the production of 6.1 keV $\mathrm{\bar{H}}$ atoms via...
The neutron-antineutron oscillation violates baryon number conservation and is of great importance in the context of testing Grand Unified Theories and understanding the origin of the baryon asymmetry in the universe [1].
Currently, the oscillation time is constrained to be $> 0.86 \times 10^8$ s for free neutrons, and $> 2.7\times 10^8$ s for bound neutrons [2,3]. In view of experiments...
The Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEgIS) at CERN's Antimatter Decelerator (AD) is used for the production and study of antimatter bound systems, such as antihydrogen for the gravitational influence on a horizontal beam of cold antihydrogen atoms [1]. AEGIS has achieved remarkable performance in trapping antiprotons and successfully demonstrated the pulsed...
Positronium is the bound state of an electron and its antimatter counterpart, a positron. With just two times the mass of the electron and no nucleus, this exotic compound is the lightest of all known atoms with no gluon contribution to its mass. Its electronic structure resembles the one of hydrogen with a factor two lower reduced mass. Positronium is therefore a system of particular interest...
The formation mechanism of light (anti)nuclei in high-energy hadronic collisions remains an open question in high-energy physics. Their production mechanism is investigated by comparing experimental data with phenomenological models using statistical hadronization or a coalescence approach.
In particular, the coalescence mechanism finds an essential application in cosmic antinuclei studies...
We report on the design and characterization of an antiproton deceleration beamline, based on a pulsed drift tube, for the PUMA experiment at the Antimatter Factory at CERN. The design has been tailored to high-voltage (100 kV) and ultra-high vacuum (below $10^{-10}$ mbar) conditions. A first operation achieved decelerating antiprotons from an initial energy of 100 keV down to $(3898 \pm 3)$...
The advent of the LHC as antimatter factory has enabled an unprecedented effort to measure the production of light (anti)nuclei from pp to heavy-ion collisions, providing input for a detailed study of nucleosynthesis in high-energy interactions. However, the production of these bound states is not modelled in commonly used event generators. Yet the detection of cosmic antinuclei is predicted...
The world’s only source of low-energy antiprotons is currently the AD/ELENA facility located at CERN. Precision measurements on single antiprotons have been conducted at this facility and provide stringent tests of fundamental interactions and their symmetries. However, magnetic field fluctuations from the facility operation limit the precision of upcoming measurements. To overcome this...
The ASACUSA CUSP experiment upgraded the MUSASHI antiproton trap with a drift tube accelerator to receive antiproton beams from ELENA, which replaced the Radio-Frequency Quadrupole decelerator. ELENA provides antiprotons at a fixed energy of 100 keV. The drift tube adjusted the injection energy of antiproton beams for the thin energy degrader at the entrance of the trap by 19 keV. The number...
The decay of antiprotonic atoms may lead to the formation of hypernuclei that can be produced via strangeness exchange reactions following the antiproton-nucleon annihilation. To estimate the hypernuclei yields that can be expected by these kind of reactions, simulations were performed within the GiBUU transport framework.
Using $^{16}$O, $^{40}$Ar, $^{84}$Kr and $^{132}$Xe as target nuclei,...
3D Simulation studies of mixed plasma confinement at AEgIS
Bharat Singh Rawat 1,2,3, Narender Kumar1,2, Benjamin Riena ̈cker1,3, Carsten P Welsch1,2,3
and
The AEgIS Collaboration3
1 Department of Physics, University of Liverpool, Liverpool L69 3BX, United Kingdom.
2 The Cockcroft Institute, Daresbury, Warrington, WA44AD,UK.
3 AEgIS Collaboration, CERN, Geneva, Switzerland....
AEgIS experiment at CERN utilizes a charge-exchange reaction with Rydberg positronium for the formation of a pulsed antihydrogen (Hbar) beam for a gravity measurement in the absence of external fields [1]. Hbar formation with all its intermittent steps is achieved in cryogenic, Ultra High Vacuum conditions, inside of a Penning-Malmberg trap system.
The controlled environment of the AEgIS...
One of the compelling areas of focus in nuclear and atomic physics are isotopes and isomers of different atoms. Many different isotopes are highly desired for experimental studies; however, accessing them is challenging with existing methods. A novel method that involves antiprotonic atoms has been suggested in [1]. In this method, the creation of isotopes is achieved by forcing the...
The ALPHA-g experiment recently made the news for the first direct measurement of the gravitational free-fall of anti-hydrogen. Crucial to this milestone is a detector system capable of accurately recording the vertical position of annihilating anti-atoms, with two critical requirements: precise localization of anti-hydrogen annihilations into the "up" or "down" regions, and effective...
The Mu2e experiment at Fermilab aims to observe coherent neutrinoless conversion of a muon to an electron in the field of an aluminum nucleus, with a sensitivity improvement of 10,000 times over current limits.
The Mu2e Trigger and Data Acquisition System (TDAQ) uses \emph{otsdaq} framework as the online Data Acquisition System (DAQ) solution.
Developed at Fermilab, \emph{otsdaq} integrates...
Experimental Investigation of QED Effects through Antiprotonic Atom X-ray spectroscopy: first test beams with TES detectors and solid targets
Senetaire Quentin, Paul Nancy, Baptista Gonçalo and Indelicato Paul
Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, Case 74; 4, place Jussieu, F-75005 Paris, France
...
Quantum Electrodynamics (QED) postulates that the photons emitted during the self-annihilation of the singlet state of positronium atoms (Ps) in a vacuum are maximally entangled in their polarization [1]. Despite theoretical support for this behavior, experimental verification has proven to be challenging [2,3]. This challenge may arise from the interference of alternative decay processes,...
The paper proposes obtaining exotic moving muonium atoms Mu through the capture of valence electrons from carbon atoms by antimuons $\mu^{+}$channeled (the channeling effect is described, for example, in [1]) along the axes of carbon nanotubes (CNTs). The probability of such captures, as in previous works [2,3], is calculated using non-stationary perturbation theory. However, in [2, 3], exotic...
A low energy particle confined by a horizontal reflective surface and gravity settles in gravitationally bound quantum states. These gravitational quantum states (GQS) were so far only observed with neutrons [1,2]. However, the existence of GQS is predicted also for atoms.
The GRASIAN collaboration pursues the first observation of GQS of atoms, using a cryogenic hydrogen beam. This endeavor...
Hypertriton, as the simplest hypernucleus, provides essential benchmarks for hypernuclear physics. However, we have struggled with the so-called “hypertriton lifetime puzzle” these years. To pin down the situation, we are proceeding with a new experiment at J-PARC to measure the lifetimes of light hypernuclei using the (K^-, \pi^0) reaction. The spin-none-flip nature of the reaction and the...
Positronium (Ps) atom, consisting of an electron and a positron bound together, represents a unique and intriguing system for fundamental physics research. This composite particle offers an exceptional opportunity for conducting precise tests, owing to its properties that are accurately described by Quantum Electrodynamics (QED) within the framework of the Standard Model (SM). Moreover, the...
Keywords: muonic atoms; nuclear structure; hyperfine structure
The study of exotic atoms, such as muonic hydrogen-like ions [1-3], provides an intriguing way to probe the internal structure of their atomic nuclei. In this work, we use nuclear structure simulations to accurately calculate the hyperfine splitting of muonic hydrogen-like ions, focusing in particular on the incorporation of...
Even though the existence of 33 molecules containing positronium has been predicted using various methods [1], so far only the simplest of them (PsH) has been observed experimentally in vacuum, with that discovery dating back more than 30 years [2]. We aim to confirm the previous result [2], and additionally observe further molecules such as PsO and PsF, as well as measure their binding energy...
An analysis is conducted on both the elastic scattering and annihilation cross-sections of antiproton-nucleus data at low energy, aiming to identify shared parameters for a Woods-Saxon optical potential.
Given the limited data available at low energies, it is important to conduct new measurements in these energy ranges and using diverse nuclear targets to enhance our comprehension of the...
The cross sections for the production of different composite hadronic and leptonic objects in photon-photon fusion processes in proton-proton, proton-nucleus, and nucleus-nucleus ultraperipheral collisions at the CERN Large Hadron Collider (LHC) and Future Circular Collider (FCC), as well as in Au-Au collisions at the BNL Relativistic Heavy-Ion Collider (RHIC), are estimated. First, the...
We present ongoing efforts to characterize forward-emitted positronium (Ps) from transmission positron/Ps converters. Utilizing innovative silicon membranes with pass-through nanochannels [1], we aim to build upon recent developments within the AEgIS collaboration. Our focus lies on understanding the velocity distribution of forward-emitted Ps and its interaction with ultraviolet (UV) laser...
One of the enduring challenges in fundamental physics is rigorously quantifying deviations from, or upholding the exactness of, discrete symmetries observed in nature. Measurements of angular correlations in the decays of polarized positronium (Ps) provide a sensitive probe for testing CPT symmetry in the electroweak interactions [1]. Due to its unique nature as the lightest bound state of an...
The generation of low-energy anti-nuclei for experimentation is a formidable challenge, stemming from the difficulty of primarily producing anti-nuclei in more than minuscule quantities during high-energy collisions. A notable exception is the antideuteron, for which several production mechanisms are known with a variety of efficiencies (from 0.1 to 10-5) and momentum/energy distributions....
Muonium (Mu), an exotic atom composed of a positive muon and an electron ($\mu^+ e^-$), is a suitable probe for precise tests of bound-state QED as well as for searching for new physics beyond the Standard Model. MuSEUM collaboration at J-PARC has so far succeeded in measuring the ground-state hyperfine splitting (HFS) of the muonium atom under the zero magnetic field, and is now aiming at a...
The 4M€ Accelerators Validating Antimatter physics (AVA) project has enabled an interdisciplinary and cross-sector R&D program on low energy antimatter research. The network comprised 13 universities, 9 national and international research centers and 13 partners from industry.
Between 2016 and 2021, AVA has successfully trained 16 early-stage researchers that were based at universities,...
As antimatter is mostly detected through its annihilation, the antiproton-nucleus ($\bar{p}A$) interaction is a crucial process. Various models, compared mostly to older data from experiments at LEAR, show deviations from measurements by large factors, indicating that, despite its significance, the annihilation mechanism is not well established.
A study of $\bar{p}A$ annihilations at rest on...
The Hyper-mu experiment at PSI aims at the first measurement of the ground state hyperfine splitting in muonic hydrogen (μp) with an accuracy of 1 ppm. Such a measurement would lead to the extraction of the two photon exchange, encoding the proton Zemach radius and polarizability, with an unprecedented relative uncertainty.
Toward the measurement of the ground state hyperfine splitting in...
One of the prevailing enigmas in contemporary physics is the observed disparity between the abundance of matter and antimatter in the universe, posing a fundamental challenge to the principles of the Standard Model of particle physics.
Within the LSym experiment we plan to compare the fundamental properties, specifically the charge-to-mass ratios and the g-factors, of the electron and the...
Detecting charged pions emitted from antiproton annihilation on nuclei is a well-established technique utilized to determine annihilation vertex positions, crucial also for several experiments in the antimatter field. For the past decade, a detector composed of plastic scintillating bars has been integral to the ASACUSA experiment, employed in both antihydrogen formation experiments and...
The current theory of General Relativity is based on the Weak Equivalence Principle (WEP), which states that the inertial and gravitational mass are equivalent. Tests of the WEP with matter have resulted in its confirmation to a relative precision of 10-15 [1], but there have been hardly any results from experiments involving antimatter. A difference in the gravitational behaviour of matter...
High-precision matter-antimatter comparisons allow to test CPT symmetry and to search for new physics beyond the standard model. The BASE collaboration contributes to these tests by measuring the charge-to-mass ratio and $g$-factor of protons and antiprotons in cryogenic Penning traps [1-3]. The BASE experiment at the Leibniz University Hannover is developing measurement schemes based on...
Ultracold neutrons (UCNs), neutrons with kinetic energies of ≲ 300 neV, have the unique property of being stored in a vessel with an appropriate surface material for a time on the order of 100 s, and have been used for key experiments in fundamental physics. Originally, very cold neutrons were mechanically decelerated to obtain UCNs. In 1977, the so called super-thermal method was proposed,...
BASE is a collaboration whose main experiment is located at CERN, with the goal of contributing to resolving the puzzle of the striking matter-antimatter imbalance and the mystery of the origin of dark matter. The related experiments are conducted by performing ultra-precise comparisons of the fundamental properties of single antiprotons and protons trapped in a sophisticated four Penning-trap...
The ground state hyperfine splitting was recently measured to 0.4 ppb for a beam of hydrogen in the ASACUSA spectrometry line (Nowak 2024). We plan to repeat the experiment using an antihydrogen beam. So far (Kuroda 2014, Kolbinger 2021), the beam intensity is too low (<1 ground state atom per cycle) to distinguish signal from background. In an upgraded mixing trap, we cool up to 4x10^7...
An attractive approach for testing CPT invariance is the comparison of a vibrational transition frequency of anti-H$_2^+$, composed of two antiprotons and a positron, with that of its matter counterpart H$_2^+$ [1,2].
The motivation for considering this - so far not existent - system is that its rovibrational transitions are intimately related to the presence of the antiproton-antiproton...
Cosmic rays are messengers of distant Galactic places and times. Due to the baryon asymmetry of the Universe, antinuclei in cosmic rays inherently point to origins in baryon-symmetric high energy particle physics or very exotic places. This talk reviews sources of cosmic ray antinuclei --observed, plausible or possible-- and the role that antinuclei may play in their detection.
Antihydrogen positive ions ($\bar{\rm H}^+$) consisting of an antiproton and two positrons are utilized to produce cryogenic antihydrogen atoms. The $\bar{\rm H}^+$ can be collected with an electric field, sympathetically cooled by lasers with Be$^+$ ions, and subsequently neutralized by stripping off one of the positrons. The $\bar{\rm H}^+$ is integrated in the mixture of antihydrogen...
The recent measurement of the antihydrogen gravitational acceleration [Nature 621, 716–722 (2023)] relies upon the detection of the annihilation of the anti-atoms that are released from their magnetic confinement and that move under the influence of gravity. The ALPHA-g magnetic trap is surrounded by a Time Projection Chamber designed to identify the annihilation products and to reconstruct...
The LSym experiment is a new cryogenic Penning trap experiment currently being designed at the Max-Planck-Institut für Kernphysik of Heidelberg. The goal of LSym is to conduct a stringent CPT test by comparing the properties of matter and antimatter with unprecedented sensitivity by trapping simultaneously one electron and one positron in a Penning trap, which allows performing a...
This work is a sequel to our two publications from 2023 (1,2) where
14 experimental 1s and 1p single-particle binding energies of $\Lambda$ in
hypernuclei led to a quite well-defined optical potential for the
$\Lambda$-nucleus interaction. The potential contains a traditional
linear density term and a quadratic density term, the latter representing
$\Lambda NN$...
In the era of ever-increased precision measurements of the fundamental properties of antihydrogen at the ALPHA experiment at CERN, knowledge of the antihydrogen energy distribution has become vital; for example, it provided a significant contribution to the uncertainty in the first direct measurement of the gravitational acceleration of antihydrogen [1]. Increased precision in ALPHA's...
The ALPHA experiment (CERN) performs precise tests of fundamental Physics using spatially confined samples of antihydrogen atoms ($\bar{\mathrm{H}}$). For a direct $\mathrm{H} - \bar{\mathrm{H}}$ spectroscopic comparison, methods for loading atomic hydrogen into the apparatus are being considered. In this direction, we have demonstrated a novel source for low energy ions, capable of producing...
By using a superconducting transition-edge-sensor (TES) microcalorimeter with ultra-high resolution $\Delta E\sim5~\mathrm{eV}$ (FWHM), a spectroscopic measurement of $dd\mu^*$ was successfully performed for the first time.
The $dd\mu^*$, in which $\mu^-$ is resonantly coupled with two deuterons, is predicted by the latest few-body calculations to emit dissociative X-rays with...
The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source (ESS) to search for baryon number violation [1]. The goal of the program is to produce new insights into the origins of baryogenesis by performing searches for neutron–antineutron oscillations, increasing the sensitivity by three orders of magnitude compared with the previously established limit from...
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET scanner based on plastic scintillators [1]. It is designed to measure momentum vectors and the polarization of photons originating from the decays of positronium [2,3]. In combination with the newly invented positronium imaging method [4], J-PET enables the study of discrete symmetries in positronium without the use of...
Precision comparisons of atomic hydrogen and its antimatter counterpart, antihydrogen, provide stringent tests of fundamental symmetries between matter and antimatter such as CPT invariance and the Weak Equivalence Principle. The most precise measurements of atomic hydrogen properties have traditionally been performed in atomic beams. In contrast, precision measurements of antihydrogen to date...
Laser spectroscopy of muonic hydrogen (μp) is an ideal platform to probe the proton structure. At the Paul Scherrer Institute, the CREMA collaboration aims to measure the ground-state hyperfine splitting (1S‑HFS) with a relative accuracy of $10^{-6}$ to infer the proton structure contribution (two photon exchange correction) with a relative accuracy of $10^{-4}$. This opens the way for testing...
The PANDA experiment represents one of the scientific pillars of the Facility for Antiproton and Ion Research by utilizing an antiproton beam for unsurpassed high statistics and high precision hadron physics in the meson and baryon sector with flavors up to charm. The PANDA experiment will use a multipurpose magnetic detector with full particle ID comprising a target and a forward spectrometer...
High precision spectroscopic measurements in trapped cold ions, have enabled various sensitive searches for new physics beyond the Standard Model [1]. Local Lorentz invariance (LLI) is suggested to be violated in extensions of the Standard Model that include quantum-gravity [2]. We here report on a stringent test of local Lorentz invariance (LLI) in the electron-photon sector based on a novel...
Some dark matter candidates, such as the Weakly Interacting Massive Particles (WIMPs), are expected to annihilate in our galaxy and produce, among other particles, light antinuclei, which can be observed as cosmic rays. However, the same antinuclei can also be produced in ordinary cosmic ray collisions with the interstellar gas. Thus, precise modelling of signal and background cosmic ray...
test
