Possibility of using elastic scattering of low energy electron neutrinos ($\nu_e$s) on polarized electron target (PET) for testing time reversal symmetry violation (TRSV) and neutrino nature (NN) in leptonic interactions is considered. We analyze the two theoretically possible scenarios of physics beyond the Standard Model (SM) in which flavor-conserving (FC) standard and non-standard...
In the field of charged lepton flavour violation (cLFV), one is investigating various decays, some of which contain photons in the final state. To discriminate between signal and background, detectors providing excellent resolutions in all particle variables are crucial.
The photons in muonic charged lepton flavour violating decays are expected to be on an energy scale in the range of 10 to...
The Mu3e Experiment at PSI is designed to search for the lepton-flavour violating decay of a positive muon to two positrons and an electron with an ultimate sensitivity of one in 1016 muon decays. The detector is based on ultra-thin high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurement. Already in the first phase of...
At the present level of uncertainty, the EM radiative corrections to the pion vector form factor become relevant in the HVP contribution to the anomalous magnetic moment of the muon. So far, their treatment is based essentially on scalar QED. In order to have a better understanding of these radiative corrections, we use unitarity and dispersion relations to express them in terms of integrals...
We report on a Hanle-type magnetometer that uses the same physics package as the free spin preccession magnetometer published in [1]. The magnetometer is most sensitive at zero magnetic field and uses four laser beams to gain measurements of the magnetic field vector components along two orthogonal directions. The influence of the common mode power fluctuations in the laser beams is greatly...
A study on the aging of the photomultiplier tubes used in the liquid xenon calorimeter for the MEG and the MEG II experiment
The $\tau$SPECT experiment aims to measure the neutron lifetime $\tau_n$ using a 3D magnetic storage technique. Due to the neutronโs magnetic moment, very low-energetic neutrons (ultracold neutrons, UCN) with a maximum energy of $\approx 50\,\mathrm{neV}$ can be stored in the magnetic trap with a volume of $\approx 8$ litres. $\tau$SPECT is designed to determine $\tau_n$ using two independent...
Neutrino flavor oscillation experiments prove that neutrinos have non-zero masses. Extensions to the Standard Model of Particle Physics have been developed to explain the non-zero masses and can be directly tested by a measurement of the absolute neutrino mass scale. The mass of the electron antineutrino $m_\bar{\nu_e}$ can be determined from the highest precision measurement of the...
The current best estimate for the universeโs matter content consists of 84% dark matter, and the search for its composition remains of great interest. One possible candidate is a so far undetected ultra-low-mass axion. Various astronomical observations, and only one laboratory experiment, using ultra-cold neutrons, currently constrain the axion mass and its interaction strength in the allowed...
Scintillation detectors read out by silicon photomultipliers (SiPMs) are used in a variety of experiments as a means to detect charged particles. In particular, series connection of SiPMs have recently been attracting more and more attention for precise timing measurement. Series-connected SiPMs yield smaller capacitance than a single SiPM, which leads to narrower signal waveform and better...
The first phase of the Mu3e experiment will search for the charged flavour violating decay of a positive muon into 2 positrons and one electron with a single events sensitivity of 2e-15. For this purpose, a DC muon beam will be stopped inside a Si pixel tracker constructed from High-Voltage Monolithic Active Pixel Sensors (HV-MAPS), complemented with timing detectors. The entire experiments...
The electron capture (EC) decay of $^{163}$Ho to $^{163}$Dy is a promising candidate for the determination of the electron neutrino mass in the sub-eV range. For this purpose the ECHo collaboration [1] aims to perform a calorimetric measurement of the $^{163}$Dy$^{*}$ de-excitation spectrum. With its Penning-trap setup the \textsc{Pentatrap} [2] experiment performs a precision mass...
A new ultra-cold neutron (UCN) detector is required for the n2EDM experiment since the previous $^6$Li-doped glass scintillator (NANOSC) model, used in the nEDM experiment, is constrained by its small size and high price (\textcolor{red}. Hence, the authors propose a novel detector (GADGET) composed of a chamber filled with $^3$He and CF$_4$ gases, and three perpendicular photo-multiplier...
We are studying in detail the feasibility of a dedicated search for a permanent electric dipole moment (EDM) of the muon at PSI. This would be the first dedicated search with a potential sensitivity of $5\times10^{-23}~e\!\cdot\!\mathrm{cm}$ employing the frozen-spin method in a compact magnetic storage ring. Such an experiment is an excellent probe for physics beyond the Standard Model (SM)...
Measurements for Control of Magnetic Field Related Systematic Effects for the PSI Neutron Electric Dipole Moment Experiment
N. J. Ayres on behalf of the PSI nEDM Collaboration
The neutron's electric dipole moment (nEDM) is an observable with extraordinary sensitivity to CP violating new physics phenomena. While the Standard Model predicts a negligibly small value, a wide variety of...
The measurement of cross-section for the nuclear fusion reaction $d+^3He{\to}^4He+p$ at ultra-low energies is of interest in pure and applied physics. This fusion process is involved in the primordial nucleo-synthesis of the light elements in the early Universe. This reaction is a mirror reaction of the $d+t{\to}^4He+n$ fusion process and can be considered as a perspective source of...
NA64 is a fixed target experiment at the CERN SPS aiming at a sensitive search for hidden sectors. In this talk, we will present our latest results on the search for a new sub-GeV vector gauge boson (Aโฒ) mediated dark matter (ฯ) production. The Aโฒ, called dark photon, could be generated in the reaction eโZโeโZAโฒ of 100 GeV electrons dumped against an active target which is followed by the...
The COHERENT collaboration operates multiple detectors at Oak Ridge National Laboratory to measure coherent elastic neutrino-nucleus scattering (CEvNS) in a variety of target nuclei. CEvNS cross sections scale as the square of the number of constituent neutrons in a given nucleus, thus giving large event rates compared to other neutrino detection modes. At the same time, the low recoil...
The Baryon Antibaryon Symmetry Experiment (BASE) at the antiproton decelerator of CERN is dedicated to high-precision measurements of the fundamental properties of the proton and the antiproton. Using single-particle multi-Penning-trap techniques, we compare the proton/antiproton charge-to-mass ratios [1] and magnetic moments [2,3] with ultra-high precision. Such experiments provide stringent...
At the Paul Scherer Institute, we are developing a novel positive muon beam at low energy with high brightness by compressing the 6-dimensional phase space of a standard surface muon beam.
Muons are stopped in a helium gas target with a density gradient at cryogenic temperature and compressed by making use of complex-shaped B- and E-fields. Compression stages that act along two different...
High-precision mass-ratio measurements with relative uncertainties below $10^{-11}$ have applications, among others, in tests of the theory of special relativity (SRT) [1], bound-state quantum electrodynamics (QED) [2] and neutrino physics research [3, 4]. This precision is achievable in Penning-trap mass spectrometry, where the mass of a charged particle is determined by measuring its free...
The $a$SPECT experiment is a retardation spectrometer built to measure the proton energy spectrum in free neutron $\beta$-decay. From the shape of the spectrum, the $\beta$-$\overline{\nu}_e$ angular correlation coefficient $a$ can be derived and thus $\lambda(a)$, the ratio of the weak axial-vector $(A)$ to vector $(V)$ coupling constant $\lambda=g_A/g_V$.
In 2013, $a$SPECT had a...
Currently a new experiment is being built for the measurement of the neutron
electric dipole moment at PSI called n2EDM.
Compared to its predecessor, many improvements will be made not only to
the apparatus itself, but also to the supervisory control and data acquisition
system.
For nEDM it is essential to not only record, but also to influence the
experiment automatically which...
The Mu3e Experiment at PSI is designed to search for the lepton-flavour violating decay of a positive muon to two positrons and an electron with an ultimate sensitivity of one in 1016 muon decays. The detector is based on ultra-thin high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurement. The poster will discuss...
The energy spectrum of ultra-cold neutrons (UCN) is an important factor in determining the systematic effects in precision measurements utilizing UCN. The oscillating ultra-cold neutron spectrometer (OTUS) is a new tool designed for monitoring the energy distribution and its time evolution in different places of the transport system connecting a UCN source with experiments. We will present the...
An ongoing experiment at PSI aims to determine the nuclear charge radius of $^{226}$Ra - needed by an experiment aiming at measuring atomic parity violation in a radium ion - by means of muonic atom spectroscopy. An intermediate test was performed with a $^{185,187}$Re target which is the last stable element whose nuclear charge radius has not been measured and shows similar nuclear structure...
As the NL-eEDM collaboration, we are searching for a permanent electric dipole moment on the electron (eEDM) in a BaF molecular beam. In preperation of such an experiment we have performed spectroscopic measurements in a supersonic BaF beam. The lifetimes of the $A^{2}ฮ _{1/2}$ and $A^{2}ฮ _{3/2}$ states were obtained using short light pulses generated from a CW laser beam with a pulsed...
The MEG II experiment is designed to achieve the worldโs most sensitive $\mu^+ \rightarrow e^+\gamma$ decay search with the most intense muon beam ($7 \times 10^7 \mu^+ / s$) in Paul Scherrer Institut . This decay is prohibited in the standard model theory but predicted to occur in the many beyond standard model theories. Thus, to find this decay means to find the new physics.
To discover...
Recently, we have performed measurements on vacuum muonium formation at room and cryogenic temperatures at the the Paul Scherrer Institute. These measurements were conducted in the context of our efforts on the investigation of the gravitational interaction of antimatter and second-generation particles. In our room temperature setup, the muon beam impinged on several targets such as zeolite...
There are indications that the measured number of antineutrinos emerging from reactor fission fragments inside a reactor is lower than theoretically predicted. Moreover, there is an additional anomaly in the energy spectrum of the antineutrinos. These observations are the reactor neutrino anomaly. One of the uncertainties in the theoretical description is the QCD influence on the ฮฒ-decay of...
Ultracold neutrons (UCN) with energies below 300 neV can be trapped for hundreds of seconds in containments made of materials with high optical potential. They are used in experiments that benefit greatly from long storage times, like the n2EDM experiment currently assembled at PSI, searching for a permanent electric dipole moment of the neutron. The PSI UCN source makes use of solid deuterium...
The search for a neutron electric dipole moment (EDM) is of significant interest in understanding the observed baryon asymmetry in the universe. Historically, two methods have been employed to measure an EDM, storage of ultracold neutrons (UCN) and cold neutron beams, with the latter being abandoned in the 1980s due to a limiting relativistic systematic effect. The Beam EDM experiment...
Results of PDE measurements for VUV-MPPCs irradiated by $\gamma$, neutron or VUV light
We present details of the simulations, design, and half scale initial tests of the Ramsey Chamber apparatus for the n2EDM experiment. The Chamber is a double chamber cylindrical geometry with a 80 cm internal diameter. The two UCN volumes are stacked vertically and separated by a central high voltage electrode. The volumes are sealed on top and bottom by an insulating spacer and ground...
We present an experimental approach based on quantum logic inspired cooling and readout techniques to contribute to CPT tests in the baryonic sector. Within the BASE collaboration [1], these techniques would allow to cool single (anti-)protons to sub-Doppler temperatures by means of coupling to a laser-cooled beryllium ion [2, 3]. For this purpose, both ions will be co-trapped in an advanced...
Neutron to mirror-neutron oscillations [1] could be an observable baryon number violating process. Baryon number violation is required for baryogenesis in order to explain the observed asymmetry between matter and antimatter in the universe. Two separate groups [2],[3] performed experiments in search of mirror-neutron oscillations and reported having found no evidence. The limit set on the...
The beta decay of the free neutron provides several probes to test the Standard Model of particle physics as well as to search for extensions thereof. NoMoS, the neutron decay products momentum spectrometer, presents a novel method of momentum spectroscopy: it utilizes the R ร B drift effect to disperse charged particles dependent on their momentum in an uniformly curved magnetic field. The...
Neutron and nuclear beta decay correlation coefficients are sensitive to the exotic scalar and tensor interactions that are not included in the Standard Model (SM). The BRAND experiment will measure simultaneously 11 neutron correlation coefficients (a, A, B, D, H, L, N, R, S, U, V ) where 7 of them (H, L, N, R, S, U, V ) depend on the transverse electron polarization โ a quantity which...
The [ASACUSA][0] (Atomic Spectroscopy And Collisions Using Slow Antiprotons) Collaboration of the AD-facility at CERN aims to measure the ground-state hyperfine structure of antihydrogen to test the CPT-Theorem [1]. For this purpose, a spectroscopy apparatus has been built and tested with hydrogen [2]. An upgrade of the interaction region enabled to induce two transitions between the hyperfine...
Muonic hydrogen, ground-state hyperfine splitting, detection system, MeV-energy X-rays, scintillation detectors.
Muonic hydrogen ($\mu$p) is a bound-state of a negative muon and a proton. Since a muon is 207 times heavier than an electron, the energy levels of $\mu$p are very sensitive to the nuclear structure. By means of laser spectroscopy, we are aiming at...
Antihydrogen studies aim to shed light on the observed
baryon/antibaryon asymmetry in the Universe by comparing the properties
of matter and antimatter with very high precision. In the context of the
GBAR experiment [1] located at CERN, our aim is to perform a measurement
of the antihydrogen Lamb shift with an uncertainty of 100 ppm, which
allows extracting the antiproton charge radius at...
Our scheme aims to measure the parity violating energy difference between the enantiomers of chiral molecules which has been predicted to be very small, e.g. about 100 aeV for CHFClBr [2] and 1 feV for 1,2 Dithiine [3], but so far has never been measured. The effect might be important for the origin of biomolecular homochirality and for precision tests of the standard model of particle physics...
The possibility of experimentally determining the ratio ฮป of the axial weak-interaction constant G$_A$ to the vector weak-interaction constant G$_V$ by simultaneously measuring the electron and neutrino asymmetries at the same setup is discussed. The proposed measurement and data-processing procedures are described. The determination of ฮป by the method in question permits disregarding the...
The P2 experiment at the new electron accelerator MESA in Mainz aims for a determination of the weak mixing angle at low momentum transfer with unprecedented precision. To this end, the parity violating asymmetry in electron proton scattering is studied with integrating Cherenkov detectors at very high rates of scattered electrons. In order to determine the average momentum transfer...
Low-energy experiments with leptons such as MEG, Mu3e, MUonE and MUSE complement the research at the high-energy frontier. However, to fully exploit the experimental data, the corresponding Standard Model background has to be known to a high accuracy. For this reason we calculate the fully differential NNLO QED corrections to the processes $\mu\rightarrow e\nu\nu$, $\mu e\rightarrow \mu e$,...
The first experiments designed to control the translational motion and the internal state of the hydrogen atom were performed almost 100 years ago by Rabi [1] using the beam methods developed by Gerlach and Stern [2]. We present a method with which paramagnetic atoms and molecules can be generated in a specific magnetic sublevel of a selected internal state and with which the atom or molecule...
Presentation of the preparations regarding the nuclear charge radius measurement of radium.
I. Brief Intriduction to 2HDM with Soft CP-violation (Type I,II,III,IV)
II. Current Constriants through Collider, Flavor, S-T parameter, and especially the ACME II electron EDM measurement;
III. The importance of neutron EDM: current constraint on CP-even and -odd mixing angle, and why is it irreplacement in constraining Type II and III models: possible cancellation in electron EDM;
IV....
- Development of calibration measurements for VUV-sensitive MPPCs in MEG II Liquid Xenon Gamma-ray detector
- Performance evaluation of VUV-sensitive MPPCs under high-intensity muon beam
NoMoS, the neutron decay products momentum spectrometer, aims to measure the momentum spectra of the charged decay products (electron and proton) in neutron beta decay with high precision. It uses the so-called R x B effect in a uniformly curved magnetic field to separate and a spatially resolving detector to measure the charged decay particles according to their momentum. In this poster, the...
Beyond Standard Model (BSM) theories can be probed in two types of experiments. In collider experiments, such as those carried out at LHC, exotic bosons are directly produced in high-energy proton - proton collisions. Another way to test BSM's, is by studying low-energy observables. This is facilitated by the small effects/currents of the same exotic bosons on these observables[1]. The shape...
The ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration, based at the Antiproton Decelerator facility of CERN aims to measure the ground state hyperfine structure of antihydrogen at a ppm level relative precision with a Rabi-type beam experiment [1,2]. ASACUSA produces antihydrogen atoms by the mixing of antiprotons with positrons in a double cusp trap with strong...
Positronium is a purely leptonic object self annihilating into photons. It is an atom bound by a central potential and thus the states of positronium are parity eigenstates. Furthermore, as an atom composed of a particle (e-) and its antiparticle (e+), it is an eigenstate of the charge conjugation operator. Therefore, the positronium is a unique laboratory to study discrete symmetries whose...
An electric dipole moment of the neutron (nEDM) is intrinsically violating the combined symmetry of charge and parity (CP). One necessary condition to create a matter/antimatter asymmetric universe from symmetric starting conditions is a sufficiently strong source of charge/parity violation (CPV) in the fundamental physics describing the early Universe. A discovery of a nEDM value larger than...
The goal of the TUCAN collaboration is to measure the electric dipole moment (EDM) of the neutron with a sensitivity of $10^{-27}$ ecm. To achieve this within a reasonable time, we are building the world's strongest ultracold-neutron source, based on superthermal conversion of cold neutrons in superfluid helium. At TRIUMF, we recently commissioned a new proton beamline with a beam power of up...
The effect of neutron spin rotation at Laue diffraction in a weakly deformed neutron-transparent
noncentrosymmetric crystal has been described theoretically and studied experimentally. The effect is due to the bending of a Kato trajectory of the neutron in the deformed crystal. At a certain type of the deformation, one of two neutron waves excited at Laue diffraction, which propagate in...
The VIP2 experiment is a major upgrade of the VIP (Violation of the Pauli exclusion principle) experiment and is testing the Pauli Exclusion Principle (PEP) for electrons, looking for a possible forbidden transition energy which could point out a violation of PEP.
The transition energy monitored in VIP and VIP2 is that of the Kฮฑ1 line of the copper atom, which is 8047.8 eV. The transition...
Ultracold Neutrons (UCN) provide a unique tool for fundamental neutron research with long observation times.
The ฯSPECT experiment, which is currently being commissioned at the pulsed UCN source of the TRIGA Mainz research reactor, aims to utilize this fact in order to precisely measure the free neutron lifetime. In order to reduce systematic errors with respect to storage experiments using...
We investigate the correlations between tauonic B meson decays (e.g. Bโฯฮฝ, BโD(โ)ฯฮฝ, Bโฯฯฮฝ) and electric dipole moments (EDMs), in particular the one of the neutron, in the context of the S1 scalar leptoquark (LQ). This LQ naturally arises in the R-parity violating MSSM as the right-handed down-squark. We perform the matching of this model on the effective field theory taking into account the...
Possible deviations from Lorentz invariance in the framework of the Standard Model Extension are more and more studied at present, including the neutrino sector. Observable effects due to the so-called countershaded operator cannot be investigated by measurements of neutrino oscillations and time of flight, but can be in double-beta decay (DBD) experiments, for example by a detailed analysis...
Nuclear beta decay offers a very powerful tool to test the Standard Model (SM) in the electroweak sector. The wide variety of nuclei and beta transitions allows us to choose the perfect candidate for specific tests of the SM which are complementary to high energy physics studies [1]. In particular, the possible existence of scalar (resp. tensor) currents in the well-established vector โ...
This talk focuses on the control and understanding of a gravitationally interacting elementary quantum system using gravity resonance spectroscopy (GRS) with ultracold neutrons (UCN). This technique offers a new way of looking at gravitation at short distances based on quantum interference.
In the past years, the qBOUNCE collaboration has designed and built a new Ramsey-type GRS experiment at...
Measuring particle EDMs is one of the most challenging experiments in the field of high precision physics. Present neutron EDM experiments are approaching limits of the traditional measurement technique due to both, statistic and systematic limitations. nEDM@SNS collaboration is working on realization of new approach, which employs production of trapped neutrons and measurement of neutron...
The features of the NA62 experiment at the CERN SPS - high-intensity setup, trigger-system flexibility, high-frequency tracking of beam particles, redundant particle identification, and
ultra-high-efficiency photon vetoes - make it particularly suitable to search for long-lived, weakly-coupled particles within Beyond the Standard Model physics.
We report the results of a search for ฯ0 decays...
The search for the neutron electric dipole moment $d_n$, carried on by the n2EDM experiment at PSI could provide a better insight on the baryon asymmetry of the universe and/or new physics. The experimental goal to reach an order of magnitude higher sensitivity than previous efforts, means its systematic effects need to be better controlled. The appearance of a false $d_n$ ($d_{Hgโn}^{false}$)...
We propose that the $\gamma + \not{\hspace{-0.3em}E}$ signal at the Belle-II detector will be a smoking gun for supersymmetry (SUSY) in the presence of a gauged $U(1)_{L_{\mu}-L_{\tau}}$ symmetry. A striking consequence of breaking the enhanced symmetry appearing in the limit of degenerate (s)leptons is the nondecoupling of the radiative contribution of heavy charged sleptons to the $\gamma -...
on behalf of the nEDM collaboration at PSI
The quest of a permanent electric dipole moment of the neutron, a CP-violating property, is one of the highest priorities in low-energy particle physics. The design of the n2EDM apparatus, now under construction at the PSI ultracold neutron (UCN) source, was strongly supported by neutron optics simulations using the MCUCN code. In order to obtain...
on behalf of the nEDM collaboration at PSI
The n2EDM experiment hosted at the Paul Scherrer Institute is seeking an improvement in the measurement of the neutron electric dipole moment (nEDM) by one order of magnitude.
In order to achieve this goal, it is crucial to stabilize the magnetic fields inside the precession chamber, where neutrons are stored and Ramsey measurements are...
Karina Bernert, Roman Gernhรคuser,Stefan Huber, Igor Konorov, Bastian Mรคrkisch, Stephan Paul, Christoph Roick, Heiko Saul, Wolfgang Schott, Suzana Spasova - Physik-Department, Technische Universitรคt Mรผnchen, D-85748 Garching, Germany;
Ralf Engels - Institut fรผr Kernphysik, Forschungszentrum Jรผlich, D-52425 Jรผlich, Germany
In order to improve the non- Standard Model weak interaction scalar...
on behalf of the nEDM Collaboration at PSI
There is so far no experimental evidence of CP violation found in the strong interaction. The non-observation of a neutron electric dipole moment (nEDM) constrains the CP violating term ($\theta$-term) in the QCD Lagrangian to be nine orders of magnitude smaller than naturally expected [1]. A solution proposed in 1977 postulated that an additional...
The qBOUNCE experiment investigates gravity at small distances. This is done using high precision frequency based spectroscopic methods. Ultracold neutrons (UCNs) form macroscopic bound states above a flat surface in the gravity potential of the Earth, connecting the quantum mechanical neutron wavefunction and gravity. Using this system we developed techniques for Gravity Resonance...
Mu3e is a dedicated experiment searching for the charged lepton-flavour violating decay ยต+ -> e+ e+ e-. The experiment consists of three subdetectors: A central barrel tracking device realised as two double layers of HV-CMOS pixel detectors, a scintillating fibre detector for timing measurements in the central region and a scintillating tile detector for timing in the end regions.
The...
A particle called the axion has been proposed to explain the small size of the CP violating term in quantum chromodynamics. It would be light in weight and weakly coupled to nucleons. If sufficiently abundant, it might be a candidate for dark-matter in the universe. Axions or axion-like particles (ALPs), when coupled with gluons, introduce an oscillating Electric Dipole Moment (EDM) along the...
In the poster we observe our previous experience at the PSI muon facility, namely high precision gamma-spectroscopy with negative slow muons on the ฮผE-4 and ฮผฮ-1 beams with HPGe โ detectors and with isotopically enriched targets (solid and gas). Such experiments could be divided in to three parts: 1) Doppler profile of gamma-lines following OMC (angular correlation with neutrino) ; 2) Partial...
Nuclear muon capture (NMC) begins with a weak interaction process occurring within the nuclear volume. Information about NMC comes from the final-state particles, of which protons and deuterons are important components. However, published information is
rather limited despite being important for the design of some current searches for lepton flavor violation. $\mu^-$ Al data taken using the...
Paul Jansen, Luca Semeria, and Frรฉdรฉric Merkt
Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
Measurements of the level energies of few-electron atoms and molecules provide reference data to test the results of quantum chemical calculations. In recent years, molecular spectroscopy has reached the level of precision at which such measurements can play a role in...
The measurement of the hyperfine splitting (HFS) in muonic hydrogen at the ppm level by means of pulsed laser spectroscopy allows for extraction of the Zemach radius of the proton at the per mille level. This measurement, ongoing at the Paul Scherrer Institute, features a novel laser system to excite the HFS transition at 6.8 ยตm. To increase the transition probability, we will use a multi-pass...
Matching conditions for photon penguin diagrams in the generically extended Standard Model.
The search for the Lepton Flavor Violating decay $\mu \to e \gamma$ exploits the most intense continuous muon beams, which can currently deliver โผ 108 muons per second. In the next decade, accelerator upgrades are expected in various facilities, making it feasible to have continuous beams with an intensity of $10^9$ or even $10^{10}$ muons per second. We investigate the experimental limiting...
Neutron beta decay is an archetype for all semi-leptonic charged-current weak processes. A precise value for the neutron lifetime is required for consistency tests of the Standard Model and is needed to predict the primordial 4He abundance from the theory of Big Bang Nucleosynthesis. An effort is under way for an in-beam measurement of the neutron lifetime that is able to evaluate the...
