Conveners
Session: Mo - 1
- Klaus Stefan Kirch (PSI - Paul Scherrer Institut)
Session: Mo - 2
- Georg Bison (PSI - Paul Scherrer Institut)
Session: Mo - 3
- Martin Fertl (Johannes Gutenberg University Mainz)
Session: Mo - 4
- Michael Jentschel (Institut Laue Langevin)
Session: Tu - 1
- Eberhard Widmann (Stefan Meyer Institute)
Session: Tu - 2
- Dieter Achim Ries (PSI - Paul Scherrer Institut)
Session: Tu - 3
- Susan Seestrom (Los Alamos National Laboratory, Retired Senior Fellow and Guest Scientist)
Session: Tu - 4
- Kenji Mishima (RCNP, Osaka university)
Session: Wed - 1
- Claude Amsler
Session: Wed - 2
- Hirohiko Shimizu (Nagoya University)
Session
- Philipp Schmidt-Wellenburg (PSI - Paul Scherrer Institut)
Session: Thu - 1
- Torsten Soldner (Institut Laue Langevin)
Session: Thu - 2
- Oliver Zimmer (Institut Laue Langevin)
Session: Thu - 3
- Aldo Antognini (ETH)
Session: Thu - 4
- Malte Hildebrandt (PSI - Paul Scherrer Institut)
Session: Fri - 1
- Wataru Ootani (Univ. of Tokyo)
Session: Fri - 2
- Efrain Patrick Segarra (PSI - Paul Scherrer Institut)
The Muon g-2 Experiment at Fermi National Accelerator Laboratory set out to measure the muon anomalous magnetic moment, $a_{\mu}$, with a target precision of 140 parts-per-billion (ppb), representing a four-fold improvement over the predecessor measurement at Brookhaven National Laboratory in the 2000s. The Muon g-2 collaboration recently published the analysis of the final three of a total of...
In my talk, I will present the latest advances in the theoretical study of medium and heavy muonic atoms. I will discuss the four largest QED contributions, current uncertainties, and the limitations in determining nuclear radii, illustrated by the case of the doubly magic nucleus 208Pb. Finally, I will address the feasibility of obtaining model-independent values of nuclear radii.
The Universe and its history are at the same time very well understood and a big mystery. We have amazing tools from satellites to observatories to weight the universe as it is today and also as it was in the past. But the content of the Universe can simply not be explained by physicists. To get the full picture, we need to identify and understand the interactions at play throughout the life...
The extreme electronic properties of highly charged ions (HCI) render them highly sensitive probes for testing fundamental physical theories. The same properties reduce systematic frequency shifts, making HCI excellent optical clock candidates. The technical challenges that hindered the development of such clocks have now all been overcome, starting with their extraction from a hot plasma and...
The quest for an optical nuclear frequency standard, the โnuclear clockโ based on the elusive and uniquely low-energetic โthorium isomerโ $^{229m}$Th, has increasingly triggered experimental and theoretical research activities in numerous groups worldwide in the last decade. Todayโs most precise timekeeping is based on optical atomic clocks. How-ever, those could potentially be outperformed by...
Ultracold neutrons (UCN) are neutrons with kinetic energies below approximately 340 neVโlow enough to be confined using material or magnetic bottles. These unique properties make UCN an essential tool for precision experiments in fundamental physics, such as probing the Standard Model and searching for new physics beyond it.
At Los Alamos National Laboratory, we operate a UCN source that...
SuperSUN: A high-density Source of Ultracold Neutrons at ILL
SuperSUN is a newly commissioned superthermal high-density ultracold neutron (UCN) source at the Institut Laue-Langevin (ILL). It employs isotopically pure superfluid helium-4, cooled below 0.6 K, to convert a broad-spectrum cold neutron beam into UCN via inelastic scattering. The source has demonstrated a continuous, reliable...
We report on a precision measurement of the neutron electric charge using the QNeutron apparatus. It consists of a Talbot-Lau interferometer for cold neutrons in the ballistic regime. The setup employs three identical absorption gratings and a differential two-beam geometry to detect potential beam deflections induced by a strong transverse electric field. During an 84-hour data-taking...
Parity-conjugated copies of standard model particles, so-called mirror particles, could provide answers for several standing issues in physics.
Since they would at first only interact with ordinary matter gravitationally, they can be viable candidates for dark matter. If mixing between standard model and mirror particles was possible, they could contribute to baryon number violation.
The...
The search for neutrinoless double-beta decay is currently one of the
most compelling challenges in physics, with the potential to reveal the origin of the neutrinoโs mass, demonstrate lepton number violation, and provide hints of the mechanism behind the matter anti-matter asymmetry we observe in our universe. Detecting this ultra-rare process, however, requires us to build very large...
Corrected transition rates ($\mathcal{F}t^{0^+โ0^+}$ values) of superallowed $0^+ \rightarrow 0^+$ beta decays have served as a benchmark for validating the conserved vector current (CVC) hypothesis in weak interactions. They now provide the most precise value of $V_{ud}$, the dominant top-row element of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix. By imposing stringent constrains...
In this talk I will discuss measurements of the $2\,^3$S$_1 \rightarrow 2\,^1$P$_1$ ($\nu_F$) transition in positronium (Ps). Although this transition is strictly forbidden by charge conjugation symmetry (C), it becomes observable in the presence of a magnetic field. Ps atoms were produced using a pulsed positron beam and optically excited to the radiatively metastable $2\,^3$S$_1$ state....
Positronium and muonium, as purely leptonic atoms without internal structure, provide ideal systems for high-precision tests of quantum electrodynamics (QED) [1] and measurements of fundamental constants. Here, we present theย recentย results weย obtainedย at ETH on the $\text{1}^\text{3}\text{S}_\text{1} \to \text{2}^\text{3}\text{S}_\text{1}$ transition in positronium, measured via two-photon...
Antihydrogenโa bound state of an antiproton and a positronโoffers a platform for precision tests of fundamental symmetries in nature. Over the past two decades, experimental progress has transformed antihydrogen studies from the demonstration phase into the precision measurement phase.
In this talk, I will review recent advances in antihydrogen research, with a focus on results from the...
ASACUSA plans to measure the ground-state hyperfine structure of antihydrogen at low magnetic field using the Rabi method, for which a slow atomic beam ($v < 1500\,\mathrm{m/s}$) is needed. We make antihydrogen by slowly combining large amounts of positrons and antiprotons in a Penning-Malmberg trap. The antiprotons are "mixed" with the positrons for $60\,\mathrm{s}$, during which time about...
The GBAR experiment at the Extra Low Energy Antiproton ring ELENA at CERN aims to produce positive antihydrogen ions (Hbar+), the pure antimatter bound state of two positrons together with one antiproton, and the charge conjugate to the (fragile) H- ion. The production of such ions requires an experimentally challenging two step formation process, but it will open the door for next generation...
The Mainz Energy-recovering Superconducting Accelerator (MESA) is a cutting-edge facility designed to push the frontiers of particle, hadron, and nuclear physics. It will enable high-precision measurements, including the weak mixing angle at low energies, and contribute to the search for physics beyond the Standard Model. MESAโs two flagship experiments, P2 and MAGIX, will offer crucial...
Rapid progress in the experimental control and interrogation of molecules is enabling new opportunities to investigate the violation of fundamental symmetries. In particular, molecules containing heavy, octupole-deformed nuclei, such as radium, can offer enhanced sensitivity for measuring parity- and time-reversal violating nuclear properties. In this talk, I will present recent results and...
Recent progress in both theory and experiment has left the unitarity of the quark mixing matrix (CKM) somewhat of an open question. The Nab experiment at the Spallation Neutron Source is designed to improve precision of the extraction of the first matrix element and shed light on experimental tensions within the neutron beta decay dataset. Nabโs asymmetric spectrometer allows coincident...
The Fundamental Neutron Physics Beamline at the Spallation Neutron Source provides intense, pulsed, cold-neutron beams dedicated to fundamental physics. With the termination of the nEDM@SNS experiment, we are proposing a new strategy to develop the beamline into a multi-user facility. This would include upgrades to allow measurements of correlations in the decay of polarized neutrons with the...
Very slow neutrons are excellent probes for fundamental physics at the precision frontier.
In recent years, the Institut Laue-Langevin (ILL) has been strengthening its corresponding infrastructure: The superthermal UCN source SuperSUN has been commissioned and successfully put into user operation. The work-horse of UCN physics, the instrument PF2, has been modernized, and its VCN-port...
The TUCAN collaboration is building a world-leading ultracold neutron (UCN) source at TRIUMF (Canada Particle Accelerator Center) to conduct a measurement of the neutronโs electric dipole moment (nEDM) with a sensitivity of 10^(-27) ecm. If discovered, it would be a new source of CP violation and contribute to our understanding of the Baryon Asymmetry of the universe as well as theories beyond...
This presentation details recent developments from the Ultra-Cold Neutron (UCN) Physics group at the TRIGA research reactor in Mainz, Germany. We report on the operational performance of the UCN sources, the advancement of various detector systems, and on the implementation and improvement of a dedicated UCN simulation framework supporting the ฯSPECT neutron lifetime experiment. The novel...
Recoil-order and radiative corrections to neutron decay correlations enter at the 10$^{-3}$ level, important at the precision of recent and future experiments, especially when comparing results for $\lambda = G_A / G_V$. The aCORN experiment obtains the neutron electron-antineutrino correlation ($a$-coefficient) from an asymmetry in proton-electron coincidence events, in contrast to previous...
Baryon asymmetry of the Universe offers one of the strongest hints for physics Beyond the Standard Model (BSM). Remarkably, in the general two Higgs Doublet Model (g2HDM) that possesses a second set of Yukawa matrices, one can have electroweak baryogenesis (EWBG), while the electron EDM is evaded by a natural flavor tuning that echoes SM. We show that eEDM may first emerge around 10^โ30โโ๐โcm...
Particle physics today faces the challenge of explaining the mystery of
dark matter, the origin of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent fine-tuning of the electro-weak scale, and many other aspects of fundamental physics.
Perhaps the most striking frontier to emerge in the search for answers involves new physics at mass scales comparable to...
Ultra-low-mass bosonic particles produced non-thermally in the early Universe may form a coherently oscillating classical field that can comprise the observed cold dark matter. The very high number density of such particles can give rise to characteristic wave-like signatures that are distinct from the particle-like signatures considered in more traditional searches for WIMP dark matter. In...
Searches for charged lepton flavor violation in the muon sector stand out among the most sensitive and clean probes for physics beyond the Standard Model. Currently, $\mu^+ \to e^+ \gamma$ experiments provide the best constraints in this field and, in the coming years, new experiments investigating the processes of $\mu^+ \to e^+e^+e^-$ and $\mu \to e$ conversion in the nuclear field are...
The MUonE experiment at CERN is motivated by longstanding questions surrounding the muon's anomalous magnetic moment, which would be sensitive to contributions from new physics. However, the precision of its Standard Model theory value is limited primarily by the leading-order hadronic vacuum polarization term. MUonE will determine this term using a new approach, by measuring the shape of...
Recent work of our group and collaborators will be described, including the progress towards measuring parity violation in chiral molecules [1] and a novel type of nuclear-spin oscillators [2].
[1] Erik Van Dyke, James Eills, Kirill Sheberstov, John Blanchard, Manfred Wagner, Robert Graf, Andrรฉs Emilio Wedenig, Konstantin Gaul, Robert Berger, Rudolf Pietschnig, Denis Kargin, Danila A....
Studies of fundamental symmetries violations in atoms and molecules provide some of the most confronting tests of the standard model and sensitive searches for new physics beyond. In this talk, I will review the current status and key challenges of the theory related to atomic parity violation and electric dipole moments. I will also discuss how atoms may be used to deduce improved nuclear...
One of the most striking mysteries in our visible universe is the origin of the large asymmetry between matter and antimatter which our standard model, despite the observed charge-parity (CP) violation, seems to be unable to explain. At MPIK we are currently developing the Lepton Symmetry (LSym) experiment. There, we will store a single positron and an electron in a deep-cryogenic Penning...
Muonium is a pure leptonic binary system that consists of a bound state of a positive muon and an electron. Its energy level structure can be calculated with high precision within the framework of bound-state quantum electrodynamics (QED). Muonium serves as an ideal probe of the electroweak interaction to rigorously test the Standard Model and search for additional unknown interactions between...
The LEMING experiment aims for measuring the gravitational acceleration of muonium, and to carry out next generation laser spectroscopy experiments in search for beyond SM physics. We developed a novel cold muonium source by converting conventional (sub)surface muons in a thin layer of superfluid helium, resulting in a high brightness atomic beam. Most recently, we verified the horizontal Mu...
Muonic atom spectroscopy is a well-established technique to measure absolute nuclear charge radii with exceptional precision, successfully utilized for nuclei throughout the entire nuclear chart โ from protons and the lightest elements to medium-mass, heavy and radioactive isotopes. These precise measurements serve as critical benchmarks for ab initio nuclear theory, important input in atomic...
I will present our latest results [1], implementing pure quantum state preparation, coherent manipulation, and non-destructive state readout of the hydrogen molecular ion H$_2^+$.
H$_2^+$ is the simplest stable molecule, and its structure can be calculated ab initio with high precision using quantum electrodynamics. By comparing the calculations with experimental data, fundamental constants...
Neutrons exhibit significant quantum mechanical wave properties in the low-energy region. This optical characteristic not only makes neutron beam transport practical but also allows for precision measurements. One well-known example in fundamental physics is neutron confinement using the total reflection phenomenon of neutrons at a material surface, resulting in a well-known experiment...
The European Spallation Source (ESS), currently under construction in
Lund, Sweden, will soon become the worldโs most powerful pulsed neutron
source and simultaneously the brightest pulsed neutrino source. Its unique capabilities open unprecedented opportunities for a precision particle physics program, complementing other facilities worldwide. Neutron sources, when combined with precision...
The PIENU experiment at TRIUMF has provided, to date, the most precise experimental determination of R$^{e/\mu}_\pi$ , the ratio of pions decaying to positrons relative to muons. While more than an order
of magnitude less precise that the Standard Model (SM) calculation, the PIENU result is a precise test of the universality of charged leptons interaction, a key principle of the Standard...
The neutron lifetime is a key parameter in nuclear physics and cosmology, yet two world-leading techniquesโthe โbottleโ and โbeamโ methodsโdisagree by almost 10 seconds. This talk will survey the experimental strategies, highlight recent advances, and discuss efforts to resolve this long-standing puzzle.
Since the potential of mirror beta transitions to provide an independent determination of the $V_{ud}$ quark-mixing matrix element was pointed out, about 15 years ago [1], many measurements of spectroscopic quantities have been performed and more detailed theoretical corrections have been addressed. These significantly improved the precision on the Ft-values of these transitions [2, 3]. In...
Precision spectrum shape measurements in nuclear beta decay can be used for testing the Standard Model and physics beyond it with accuracy being competitive with high-energy collider experiments. Such a comparison can be carried out in the framework of effective field theory. The most prominent and poorly known effect in the Standard Model is weak magnetism, the higher-order recoil correction...
Precision mass measurements of stable as well as long-lived nuclides have numerous applications among others in atomic-, nuclear-, neutrino- and particle physics. Technical developments in the manipulation and detection of radionuclides and stable species in high-precision Penning-trap mass spectrometry have boosted the field and allow for relative mass uncertainties at the level of 10-11 and...
We will report on our progress to measure the fine-structure constant ๐ผ with improved accuracy to resolve the currently unexplained discrepancy between recent ๐ผ measurements [1,2]. The fine-structure constant ๐ผ characterizes the strength of electromagnetic interactions. Precision measurement of ๐ผ with atom interferometry combined with precision measurement of ๐ผ with electron g - 2 enables one...
The GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment seeks to measure the gravitational acceleration of antimatter with precision better than 1% using ultracold antihydrogen atoms. To obtain ultracold antihydrogen atoms, a multi-step process is used: first, antihydrogen ions are formed and sympathetically cooled using $\mathrm{Be^+}$ ions. Afterward, the extra positron is...
On behalf of the AEgIS collaboration
The Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEgIS) at CERN's antimatter factory has achieved remarkable performance in trapping antiprotons for the pulsed creation of antihydrogen, as well as other antimatter-bound systems, such as positronium. Currently, a new technique is being developed using the AEgIS infrastructure to...
Electric dipole moments (EDM) of fundamental particles inherently violate the combined symmetry of charge-conjugation and parity inversion (CP) .
At PSI we plan to measure the EDM of the muon using the frozen-spin technique within a compact storage trap. This method exploits the high effective electric field, E = 165 MV/m, experienced in the muonโs rest frame with a momentum of about 23 MeV/c...
The Standard Model of Particle Physics is a versatile and well-tested theory. However, it does not explain the extreme imbalance of matter over antimatter observed in our Universe. A possible mechanism that could explain this asymmetry includes new sources of CP violation, which could result in the existence of a permanent electric dipole moment in fundamental particles such as the...
Status and progress of the NL-eEDM experiment
Jelmer Levenga, on behalf of the NL-eEDM collaboration
Within the Standard Model fundamental particles are predicted to have a permanent electric dipole moment (EDM). An EDM is a CP-violating signature which is small within the standard model, but can be greatly enhanced in Beyond the Standard Model (BSM) physics. EDM experiments are...
The characterization of size and structure of hadrons and nuclei has been the focus of a large work effort over multiple decades. Recently, this topic garnered new interest for various reasons, including the proton charge radius puzzle and advances in determinations of the gravitational form factors. The accurate extraction of quantities does not only rely on precise data, but also on...
The charge radii of the isotopes of hydrogen and helium serve as important benchmarks for understanding of nucleon and nuclear structure, and are essential input the QED tests or determinations of fundamental constants via high-precision laser spectroscopy of ordinary atoms.
Our laser spectroscopy of muonic H through He-4 has provided precision measurements of the 4 lightest nuclei. I will...
Kaon physics has played a foundational role in particle physics, from the discovery of strangeness and CP violation to some of the most precise tests of the Standard Model (SM). Today, it continues to provide a uniquely sensitive probe of potential new physics through the study of rare processes and flavor-changing neutral currents. This talk will present an overview of the current status and...
The rate for $\mu\to e$ conversion in nuclei is set to provide one of the most stringent tests of lepton-flavor symmetry and a window into physics beyond the Standard Model. However, to disentangle new lepton-flavor-violating interactions, in combination with information from $\mu\to e\gamma$ and $\mu\to 3e$, it is critical that uncertainties at each step of the analysis be controlled and...
The Mu3e experiment searches for the charged lepton-flavour violating decay of a muon into two positrons and one electron. Due to the negligible Standard Model branching ratio, any observation would provide unequivocal evidence of new physics. A first phase of the experiment aims for a single-event sensitivity of one in $2 \cdot 10^{15}$ muon decays.
To reach this goal, the collaboration...
Precision measurements capture an increasing amount of attention in probing physics beyond the Standard Model (BSM). Worldwide, a multitude of experiments aim at reaching high precision, ~0.1% , and will have comparable control over systematic uncertainties. By this, these experiments will augment LHC constraints on models of BSM physics.
These efforts entail a need in Standard-Model...
