EDM Search Research Articles

Quasi-Frozen Spin Concept at NICA for EDM Search and Its Matrix Analysis

Quasi-Frozen Spin Concept at NICA for EDM Search and Its Matrix Analysis

Studies of reflection asymmetry in heavy nuclei

For certain combinations of protons and neutrons it is expected that the shape of atomic nuclei can undergo octupole deformation, which would give rise to reflection asymmetry or a ‘pear shape’. Here it is described how recent experiments carried out at CERN using the HIE-ISOLDE facility to accelerate radioactive beams and detect the subsequent γ-emission using the Miniball spectrometer have provided evidence that several radium and radon isotopes have either stable pear shapes or are octupole vibrational in nature. Their behaviour is compared with that of nuclei with A ≈ 150 exhibiting strong octupole correlations. It will be shown that the data on transition moments present some challenges for theory. The relevance of these measurements for atomic EDM searches will also be discussed.

ByPass optics design in NICA storage ring for experiment with polarized beams for EDM search

Experiments with polarized beams for EDM search in the NICA accelerator complex implies the design of an additional ByPass channels. Such alternative channels will make possible to use NICA as a storage ring and get enough statistical data.

Designing Bypass Channels in NICA Accelerator Complex for Polarized Beam Experiments for EDM Search

Designing Bypass Channels in NICA Accelerator Complex for Polarized Beam Experiments for EDM Search

Nature of Spin Decoherence of a Polarized Beam of Light Nuclei in a Storage Ring for EDM Search

Nature of Spin Decoherence of a Polarized Beam of Light Nuclei in a Storage Ring for EDM Search

Studies of Heavy Pear-shaped Nuclei

For certain combinations of protons and neutrons it is expected that the shape of atomic nuclei can undergo octupole deformation, which would give rise to reflection asymmetry or a “pear shape”. Here it is described how recent experiments carried out at CERN using REX-ISOLDE and HIE-ISOLDE and the Miniball gamma-ray spectrometer have provided evidence that several radium and radon isotopes have either stable pear shapes or are octupole vibrational in nature. It will be shown that the data on transition moments present some challenges for theory. The relevance of these measurements for atomic EDM searches, and the future prospects for this field, will also be discussed.

High-performance HV-CMOS sensors for future particle physics experiments — an overview

HV-CMOS (High Voltage-CMOS) sensors are emerging as a prime candidate for future tracking detectors that have extreme requirements on material budget, pixel granularity, time resolution and radiation tolerance. These sensors have the advantages of full monolithic structure, low manufacture cost, fast charge collection and high radiation tolerance. Confirmed and potential tracking applications in physics experiments include the Mu3e experiment, proton EDM searches, future upgrades of LHC (Large Hadron Collider) and CEPC (Circular Electron Positron Collider). The HV-CMOS group at Liverpool is doing generic R&D to push the boundaries of HV-CMOS sensors performance, especially in terms of single point resolution, fast-timing capability and radiation tolerance. This contribution gives an overview of the latest research by the Liverpool HV-CMOS group and presents the HV-CMOS prototypes developed in Liverpool.

Theoretical aspects of radium-containing molecules amenable to assembly from laser-cooled atoms for new physics searches

We explore the possibilities for a next-generation electron-electric-dipole-moment experiment using ultracold heteronuclear diatomic molecules assembled from a combination of radium and another laser-coolable atom. In particular, we calculate their ground state structure and their sensitivity to parity- and time-reversal () violating physics arising from flavor-diagonal charge-parity () violation. Among these species, the largest -violating molecular interaction constants—associated for example with the electron electric dipole moment—are obtained for the combination of radium (Ra) and silver (Ag) atoms. A mechanism for explaining this finding is proposed. We go on to discuss the prospects for an electron EDM search using ultracold, assembled, optically trapped RaAg molecules, and argue that this system is particularly promising for rapid future progress in the search for new sources of violation.

Probing the CP-Violation effects in the hττ coupling at the LHC

A new method used to calculate the neutrino for all major tau hadronic decay event by event at the LHC is presented. It is possible because nowadays better detector description is available. With the neutrino fully reconstructed, matrix element for each event can be calculated, the mass of the Higgs particle can also be calculated event by event with high precision. Based on these, the prospect of measuring the Higgs CP mixing angle with h→ττ decays at the LHC is analyzed. It is predicted that, with a detailed detector simulation, with 3 ab−1 of data at s=13 TeV, a significant improvement of the measurement of the CP mixing angle to a precision of 5.2∘ can be achieved at the LHC, which outperforms the sensitivity from lepton EDM searches up to date in the hττ coupling.

Color breaking baryogenesis

We propose a scenario that generates the observed baryon asymmetry of the Universe through a multi--step phase transition in which SU(3) color symmetry is first broken and then restored. A spontaneous violation of $B-L$ conservation leads to a contribution to the baryon asymmetry that becomes negligible in the final phase. The baryon asymmetry is therefore produced exclusively through the electroweak mechanism in the intermediate phase. We illustrate this scenario with a simple model that reproduces the observed baryon asymmetry. We discuss how future electric dipole moment and collider searches may probe this scenario, though future EDM searches would require an improved sensitivity of several orders of magnitude.

\u03f5\u2032/\u03f5 anomaly and neutron EDM in SU(2)L \xd7 SU(2)R \xd7 U(1)B\u2212L model with charge symmetry

The Standard Model prediction for ϵ′/ϵ based on recent lattice QCD results exhibits a tension with the experimental data. We solve this tension through WR+ gauge boson exchange in the SU(2)L × SU(2)R × U(1)B−L model with ‘charge symmetry’, whose theoretical motivation is to attribute the chiral structure of the Standard Model to the spontaneous breaking of SU(2)R × U(1)B−L gauge group and charge symmetry. We show that {M_W}_{{}_R}<58 TeV is required to account for the ϵ′/ϵ anomaly in this model. Next, we make a prediction for the neutron EDM in the same model and study a correlation between ϵ′/ϵ and the neutron EDM. We confirm that the model can solve the ϵ′/ϵ anomaly without conflicting the current bound on the neutron EDM, and further reveal that almost all parameter regions in which the ϵ′/ϵ anomaly is explained will be covered by future neutron EDM searches, which leads us to anticipate the discovery of the neutron EDM.

Statistical precision in charged particle EDM search in storage rings

Currently, the “Jülich Electric Dipole moment Investigations” (JEDI) collaboration, together with present EDM experiments at the COSY ring, is developing the conceptual design of a ring specifically for the search for the deuteron electric dipole moment (dEDM). One of the main problems in the EDM study is the spin precession in the vertical plane caused by the non-ideal positioning of accelerator elements through the magnetic dipole moment (MDM). The idea of how to separate the EDM from MDM is based on measuring the spin tune in different processes and comparing the results. The high precision of the spin tune measurement is achieved by collecting huge amounts of data. The JEDI collaboration aims at detecting the EDM at a level better than 10−29 e · cm, for which one requires a precision in the frequency estimate ∼ 10−9 rad/sec. An estimate’s statistical precision is conditional on the following factors: the total measurement time, determining the independent variable spread; measurement error; temporal modulation and spacing of sample points. In this paper we analyze the interplay between these factors, and estimate the best achievable precision under given conditions.

Contributions of axionlike particles to lepton dipole moments

Contributions of a spin 0 axion-like particle (ALP) to lepton dipole moments, g-2 and EDMs, are examined. Barr-Zee and light-by-light loop effects from a light pseudoscalar ALP are found to be capable of resolving the long-standing muon g-2 discrepancy at the expense of relatively large ALP-gammagamma couplings. The compatibility of such large couplings with direct experimental constraints and perturbative unitarity bounds is discussed. Future tests of such a scenario are described. For CP violating ALP couplings, the electron EDM is found to probe much smaller, theoretically more easily accommodated ALP interactions. Future planned improvement in electron EDM searches is advocated as a way to not only significantly constrain ALP parameters but also, to potentially unveil a new source of CP violation which could have far reaching ramifications.

Direct measurement of the γHe / γXe ratio at ultralow magnetic field

A co-located 3He and 129Xe nuclear spin free precession measurement at sub-μT magnetic field was carried out in a magnetically shielded environment. The uncorrected quotient of the gyromagnetic ratios between neutral 3He and 129Xe atoms is determined to be 2.754 082 81(07), accounting for only statistical error. Our measurement shows that this ratio has a stability of 1.4×10-5/ √τ, demonstrating the ability to reach the current precision limit of the quotient in a 10000 s of averaging time τ. This precision is enough for the next-generation EDM search in neutral 129Xe atoms based on a similar comagnetometer scheme.

Storage Ring Based EDM Search — Achievements and Goals

This paper summarizes the experimental achievements of the JEDI (Jülich Electric Dipole moment Investigations) Collaboration to exploit and demonstrate the feasibility of charged particle Electric Dipole Moment searches with storage rings at the Cooler Synchrotron COSY of the Forschungszentrum Jülich. Recent experimental results, design and optimization of critical accelerator elements, progress in beam and spin tracking, and future goals of the R &amp; D program at COSY are presented.

Search for an EDM in diamagnetic atom 129Xe with nuclear spin maser technique

Present status of the development of a nuclear spin maser for a 129Xe atomic EDM search is reported. We studied the frequency behavior of the spin maser presently under operation, and found that the drift in the frequency is correlated with the maser amplitude drift. Also, a high-voltage application system for the 129Xe precession cell was constructed. The leakage current measured is at present on the level of nA when a high voltage of 10 kV was applied, and is a subject of improvement to be achieved in near future.

Detailed discussion of a linear electric field frequency shift induced in confined gases by a magnetic field gradient: Implications for neutron electric-dipole-moment experiments

The search for particle electric dipole moments (edm) is one of the best places to look for physics beyond the standard model because the size of time reversal violation predicted by the standard model is incompatible with present ideas concerning the creation of the Baryon-Antibaryon asymmetry. As the sensitivity of these edm searches increases more subtle systematic effects become important. We develop a general analytical approach to describe a systematic effect recently observed in an electric dipole moment experiment using stored particles \cite{JMP}. Our approach is based on the relationship between the systematic frequency shift and the velocity autocorrelation function of the resonating particles. Our results, when applied to well-known limiting forms of the correlation function, are in good agreement with both the limiting cases studied in recent work that employed a numerical/heuristic analysis. Our general approach explains some of the surprising results observed in that work and displays the rich behavior of the shift for intermediate frequencies, which has not been previously studied.

Laue diffraction method of a neutron EDM search. Project of the experiment

Experiment for the search for the neutron electric dipole moment using Laue diffraction in a noncentrosymmetric crystal is proposed. The method is based on the effect of depolarization of the diffracted neutron beam due to interaction with an interplanar electric field of a noncentrosymmetric crystal. The value of this field can exceed ∼10 8 V/cm . An essential feature of the proposed Laue diffraction method is the possibility to increase more than by the order of value the time τ of neutron passage through the crystal and, accordingly, the time of interaction with the electric field using the Bragg angles close to π/2. The sensitivity of the method can be ∼10 −25 e cm / day for a really existing quartz crystal.

Muon physics possibilities at a muon-neutrino factory

New intense proton accelerators with above GeV energies and MW beam power, such as they are discussed in connection with neutrino factories, appear to be excellently suited for feeding bright muon sources for low-energy muon science. Muon rates with several orders of magnitude increased flux compared to present facilities will become available. This will allow higher precision in experiments which were statistics limited so far such as searches for rare decays, muonium spectroscopy, muon capture, muon catalyzed fusion, muon decay studies and measurements muon moments and parameters. Novel and most important experiments will become possible. For example a permanent electric dipole moment (edmμ) of a muon could be searched with by far unprecedented accuracy and with a physics potential well beyond the possibilities of present electron, neutron and nuclear edm searches. Investigations of short lived radioactive nuclei using muonic atom spectroscopy would become feasible.

New possibilities for neutron EDM search using diffraction by crystal without a centre of symmetry

In the present work we report the analysis of spin effects for neutrons diffracted by a noncentrosymmetric crystal in a Laue diffraction scheme. New method of a search for neutron electric dipole moment is proposed. It is based on the predicted new effect of depolarization of the diffracted neutron beams (direct and reflected) due to neutron interaction with the strong interplanar electric field (up to 10 9 V/cm).