The rate of semitauonic and electroweak penguin decays in the B sector
show hints of lepton-flavour universality violation. Belle and Belle II
data is well suited to probe such anomalies. The low-background
collision environment along with the possibility of partially or fully
reconstructing one of the two B mesons in the event offer high precision
measurements of semileptonic and...
The BESIII experiment has collected an integrated luminosity corresponding to 2.93 fb$^{-1}$ of data at 3.773 GeV, and 6.3 fb$^{-1}$ of data between 4.18 and 4.23 GeV, respectively, which allows for precision tests with D meson decays. We will present an overview of the recent results on lepton flavour universality tests with (semi-)leptonic decays of charmed mesons. We will also report the...
The Mu2e experiment at Fermilab will search for a neutrino-less muon to electron conversion with a single event sensitivity of ~3E-17. This is an improvement of four orders of magnitude in sensitivity over the current best limit. Mu2e will indirectly probe a broad class of New Physics models with mass scales up to 10,000 TeV. The Mu2e is currently under the construction with a goal to start...
International Centre for Advanced Training and Research in Physics,
P.O. Box MG12, 077125 Bucharest-Magurele, Romania
Abstract
Double beta decay (DBD) is a currently hot research topic as it can offer a wide range of physics investigations beyond the Standard Model (BSM). These refer to some fundamental neutrino properties, yet unknown (neutrino nature – is it a Dirac or a Majorana...
The TUCAN collaboration is building a next generation ultracold neutron (UCN) source, based on spallation neutron production using protons from TRIUMF's 500 MeV cyclotron. A large cold neutron flux is created via moderator shells of room-temperature heavy water and 20-K liquid deuterium surrounding a near-spherical volume of superfluid liquid helium-4. At around 1 K, the ultracold neutrons...
abstract provided as attached pdf-file
At the Paul Scherrer Institute we are developing of a high precision instrument to measure the muon electric dipole moment (EDM) using the frozen-spin technique. The presence of a permanent EDM in an elementary particle implies Charge-Parity symmetry violation and, within the context of the Standard Model, the electric dipole moment of elementary particles is extremely small. However, many...
The hyperons from charmonia decays are produced with a non-zero spin polarization that is described by one global parameter in electron-positron annihilation into hyperon-antihyperon pair. This provides a method to measure precisely parity-violating (anti)hyperon decay amplitudes and directly test CP violation. These CP tests were performed for J/psi decays into Lambda Lambdabar, Sigma+...
We present recent results of charm $CP$ symmetry violation (CPV) based on about 1 ab$^{-1}$ collected at the Belle experiment, including the decay asymmetry parameters ($\alpha$) and $\alpha$-included $CP$ asymmetry ($A_{CP}^{\alpha}$) for decays of $\Lambda_c^+$ and $\Xi_c^0$ baryons, search for CPV via time-integrated $CP$ asymmetry in $D$ three-body decays and T-odd asymmetry in $D$...
KLOE and KLOE-2 full data sample, corresponding to 8 fb−1, has been collected at the Frascati DAΦNE φ–factory of INFN Laboratories and repre- sents the world largest data sample of this kind: about 2.4 × 1010 φ mesons and 8 × 109 K0K ̄ 0 entangled pairs. The neutral kaon system has unique properties such as entanglement, flavour oscillations, charge-parity (CP) and time-reversal (T) violation...
Chiral symmetry, linked to the smallness of the quark masses compared to the QCD bound states, and its breaking pattern are exploited in effective field theory to describe a multitude of phenomena by a few low-energy constants. Those concern light-meson dynamics and decays, their couplings to photons and meson-nucleon interactions. Special emphasis is given to the pion properties, in terms of...
Experiments with single ions confined in a Penning trap enable access to a broad range of observables that are of fundamental importance for our understanding of fundamental physics. In the magnetic field of the trap, the cyclotron frequency of an ion can be determined with unique precision and gives direct access to the charge-to-mass ratio. Furthermore, we have access to the gyromagnetic...
Being purely leptonic, i.e. made of constituents which have (to the best of our knowledge) no internal structure, Muonium (M) is an excellent candidate to probe b-QED. I will present our recent measurement of the n=2 M Lamb Shift of 1047.2(2.5) MHz, which comprises an order of magnitud improvement upon the last determinations and matches with theory within one sigma. This allows us to set...
In the talk we demonstrate test of combined charge, parity, and time-reversal transformation (CPT) in the annihilations of the lightest leptonic bound system, the positronium atom. With the Jagiellonian Positron Emission Tomograph (J-PET) we have collected an unprecedented range of kinematical configurations of exclusively-recorded annihilations of the positronium triplet state...
The so called Standard Model is a phenomenological model, in the sense that it relies on experimental input and has been continuously refined, based on that input, for the better part of a century. It is generally accepted that the Standard Model is incomplete,for various reasons.
The Standard Model is a gauge theory, which produces floating parameters, called couplings, or "charges", for...
The high measurement precision attainable in experiments within the so-called low-energy, precision frontier can be employed to carry out a range of tests of fundamental physics and search for beyond-standard-model physics. After a brief overview of precision, low-energy tests, I will discuss two related experiments. In one of these, we study isotope shifts in an optical transition in...
Neutrons are electrically neutral and massive particles. They experience all known forces, which are electromagnetic, gravitation, weak, and strong forces. Slow neutrons with low kinetic energy are good tools for observing the effects of those interactions. They are used for various fundamental physics experiments, taking advantage of the property.
Depending on their kinetic energy, slow...
Particle/Antiparticle asymmetry (CP violation) was discovered almost six decades ago in quark bound states. CP violation was the only experimental evidence of matter and antimatter behaving differently in the Standard Model of particle physics. The discovery of neutrino oscillations at the end of the last century opened the window for similar phenomena in leptons. It has taken the neutrino...
CPT symmetry, the combination of Charge Conjugation, Parity and Time reversal, is a cornerstone of our model building strategy and therefore the repercussions of its potential violation will severely threaten the most extended tool we currently use to describe physics, i.e. local relativistic quantum fields. However, limits on its conservation from the Kaon system look indeed imposing. In this...
The KATRIN experiment is designed to measure the mass of the electron anti-neutrino by investigating the energetic endpoint of the tritium spectrum. KATRIN recently release it’s latest results and is the rst direct experiment to report a sub-eV neutrino mass limit. As a complementary result, KATRIN also reported its rst limits for eV-scale sterile neutrinos.
The TRISTAN (TRitium...
DUNE and JUNO are two leading next-generation neutrino experiments that will address some of the most important open questions in neutrino physics. DUNE is a long baseline experiment consisting of two detectors placed in what will be the world’s most intense neutrino beam: a near detector in Fermilab near the beam source, and a much larger far detector at the Sanford Underground Research...
The Fermilab muon g-2 experiment recently released its first measurement of the positive muon magnetic moment anomaly, a_mu = (g_mu-2)/2 to an accuracy of 0.46 ppm. The anomaly a_mu is of interest since it can be predicted with impressive precision and its value is sensitive, via quantum corrections, to the interactions of the muon with the other particles of the Standard Model. Comparison of...
The ATLAS experiment has measured the 𝜏-lepton pair production in ultraperipheral lead–lead
collisions, Pb+Pb Pb(𝛾 𝜏𝜏)Pb. From this measurement, constraints on the 𝜏-lepton anomalous magnetic moment, 𝑎𝜏, have been extracted. The used dataset corresponds to an integrated luminosity of 1.44 nb-1` of LHC Pb+Pb collisions at 𝑠NN = 5.02 TeV recorded by the ATLAS experiment in 2018. Selected...
Throughout its existence, the Standard Model has proven very successful in describing fundamental interactions of elementary particles. However, the asymmetry between the abundance of matter and antimatter in the universe has yet to be understood.
The BASE experiment, located at CERN’s Antiproton Decelerator (AD) facility, measures the fundamental properties of protons and antiprotons to test...
The QCD Axion is arguably the most elegant candidate to solve the strong CP problem and to explain missing dark matter in our universe. Some compelling theoretical models predict its mass to be around 100 μeV, a range that presently still evades experimental sensitivity. The dielectric haloscope concept has been proposed to change this. The motivation for post-inflationary dark matter axions...
The LUXE experiment (LASER Und XFEL Experiment) is a new large-scale experiment in planning at DESY Hamburg. LUXE is intended to study collisions between a high-intensity optical LASER and 16.5 GeV electrons from the XFEL electron beam, as well as collisions between the optical LASER and GeV-scale, high-flux photon beams. The main physics objective of LUXE is to experimentally study processes...
Atomic nuclei lie at the core of everything we can see; and at the first level of approximation, their atomic weights are simply the sum of the masses of all the neutrons and protons (nucleons) they contain. Each nucleon has a mass mN ≈ 1 GeV, i.e. approximately 2000-times the electron mass. The Higgs boson - discovered at the large hadron collider in 2012 - produces the latter, but what...
The latest results on the Higgs boson properties from the ATLAS and CMS experiments will be reviewed, 10 years after its discovery and
with 30 times larger statistics.
Searches of Higgs boson pair production will be presented.
In addition a few projections for the end of the high luminosity operation of the LHC will be shown.
Three mysteries stand after the discovery of the Higgs boson: (i) the
origin of the masses of the neutrinos; (ii) the origin of the baryon
asymmetry in the universe; and (iii) the nature
of dark matter. High energy colliders provide an exciting opportunity to
resolve these mysteries with the possible discovery of heavy neutral
leptons (HNLs), both at the HL-LHC from neutrinos produced...
Lorentz and CPT symmetry represent cornerstones of our present understanding of nature, but may be violated in various theoretical approaches to underlying physics. Testing these symmetries therefore establishes a promising avenue to search for physics beyond the Standard Model. The canonical theoretical tool to identify possible experimental signatures of such violations is an...
In this contribution, we discuss the precision theory of the bound-electron g factor. This quantity can be measured nowadays to high precision with the combination of Penning traps and electron beam ion traps. The collaboration of theory and experiment enables impactful and detailed tests of quantum electrodynamics in a strong background field, and a competitive determination of fundamental...
I discuss novel mechanisms for the generation of electric dipole moments in atoms and molecules, including via the exchange of low-mass axionlike particles between atomic electrons and nucleons [1,2], as well as via two-photon exchange processes between atomic electrons and the nucleus in paramagnetic systems [3]. I also discuss how oscillating electric dipole moments may be induced...
We use frequency comparisons between highly accurate optical clocks for tests of fundamental principles. In particular, the 171Yb+ optical clock based on an electric octupole transition between the S-ground state and the lowest excited F-level (radiative lifetime 1.58 yr) provides a favorable combination of low systematic uncertainty and high sensitivity to relativistic effects and potential...
Searches for electric dipole moments (EDM), axion-like particle searches, ultra-cold atom experiments in space, atomic fountains or a new neutron-antineutron oscillation search at the European Spallation Source require precisely characterized and also very small magnetic fields. Some of these experiments actually are the most accurate and precise magnetic field sensors ever...
The Penning-trap mass spectrometer PENTATRAP [1] located at the Max Planck Institute for Nuclear Physics in Heidelberg is able to determine mass-ratios of highly charged ions of long-lived nuclides with a relative uncertainty of a few ppt [2, 3]. With a broad measurement program PENTATRAP did and continues to contribute to several fields of physics, e.g. test of bound-state QED [2] with direct...
Currently PSI delivers the most intense continuous muon beam in the world with up to a few 10^8 μ+/s. The High Intensity Muon Beam (HiMB) project aims at developing a new target station and muon beam lines able to deliver 10^10 μ+/s, with a huge impact for low-energy, high-precision muon experiments.
While the next generation of proton drivers with beam powers in excess of the current...
Various measurements aiming at the precise determination of the fundamental physical quantities of muons (mass, magnetic moment) are underway at the J-PARC Materials and Life Science Experimental Facility, Muon Facility (MUSE). These include muonium HFS and 1s-2s measurements, HFS measurements of muonic helium and muon trapping. Preliminaries results have already been obtained for the first...
COMET is an experiment at the Japan Proton Accelerator Research Complex (J-PARC), which will search for coherent neutrinoless tran- sition of muons to electrons in the coulomb eld of atomic nuclei (𝜇− + N → 𝑒− + N). Since this process violates charged lepton avor conservation it is highly suppressed in the Standard Model and thus provides a promising channel to probe new physics.
In order...
We revisit charged lepton flavor violating (CLFV) scattering $\ell_{i}N \to \ell_{j}X$ mediated by scalar interaction. We point out that a new subprocess $\ell_{i}g \to \ell_{j}g$ via the effective interactions of CLFV mediator and gluon gives large contribution. Furthermore, in the light of quark number conservation, we consider quark pair-production processes $\ell_{i}g \to \ell_{j} Q...
The main source of systematic uncertainty on neutrino cross section measurements at the GeV scale is represented by the poor knowledge of the initial flux. The goal of cutting down this uncertainty to 1% can be achieved through the monitoring of charged leptons produced in association with neutrinos, by properly instrumenting the decay region of a conventional narrow-band neutrino beam. Large...
The ASACUSA-CUSP experiment located at CERN’s antiproton decelerator aims at measuring the ground state hyperfine splitting of antihydrogen (H̄) using a beam technique to test CPT symmetry. For this purpose, a beam of cold (~50K) hydrogen has been developed to characterize the antihydrogen spectroscopy apparatus [1]. Beyond serving as a test bench for the H̄ experiment, the hydrogen beamline...
Despite its many successes, the Standard Model of particle physics is thought to be incomplete, because it leaves unanswered several major questions. One of these is the origin of the observed asymmetry between the amount of matter and antimatter in the visible universe. While we cannot currently explain what caused the asymmetry, we know that it requires the presence of new interactions...
The JEDI experiment is dedicated to the search for the electric dipole moment (EDM) of charged particles using storage rings, which can be a very sensitive probe of physics beyond the Standard Model. In order to reach the highest possible sensitivity, a fundamental parameter to be optimized is the Spin Coherence Time (SCT), i.e., the time interval within which the particles of the stored beam...
A positron trap is a powerful and adaptable tool for performing experiments with
positrons and positronium. These devices use a strong magnetic field, a stepped
potential well and Nitrogen and CF4 buffer gas. Positrons are initially trapped via the
electronic excitation of N2, CF4 is added for efficient cooling via vibrational and
rotational excitations. This type of positron trap can...
abstract provided as attached pdf-file
A number of experiments at CERN’s Antiproton Decelerator aim to measure the properties of antihydrogen to find structural differences hinting at CPT symmetry breaking that would explain the observed baryon-antibaryon asymmetry in our universe. These experiments detect antihydrogen through annihilation making the antiproton-nucleus (pbar-A) annihilation one of the main processes of...
The Standard Model Extension (SME) [1, 2] serves as a motivation for many experiments
performing precision tests of the CPT symmetry. It includes all CPT and Lorentzviolating
operators in addition to the Standard Model Lagrangian and hence, manifesting
Lorentz and CPT violating signals in different experimental searches.
According to the SME, the shifts in the hyper-fine energy levels of...
At very low energies, an atom above a horizontal surface can experience quantum reflection due to the attractive Casimir-Polder potential. The quantum reflection holds the atom against gravity and leads to gravitational quantum states (GQS), in analogy to what has been observed with ultracold neutrons [1]. The GRASIAN-collaboration pursues the first measurement of GQS of atomic hydrogen. For...
Doing high-precision measurements on molecules is a promising way to explore physics beyond the Standard Model of particle physics. One such measurement is the search for the P,T-violating electric dipole moment of the electron (eEDM). The effect if the eEDM is expected to be strongly enhanced in diatomic molecules with one heavy atom, because of small rotational splittings and an enhanced...
