Search

We propose a method to measure the electron electric dipole moment (eEDM) using ultracold entangled francium (Fr) atoms trapped in an optical lattice, yielding an uncertainty below the standard quantum limit. Among the alkali atoms, Fr offers the largest enhancement factor to the eEDM. With a Fr based experiment, quantum sensing using quantum entangled states could enable a search for the eEDM at a level below 10−30 ecm. We estimate statistical and systematic errors attached to the proposed measurement scheme based on this quantum sensing technique. A successful quantum sensing of the eEDM could enable the exploration of new physics beyond the standard model of particle physics.

Ions with similar charge-to-mass ratios cannot be separated from existing beam profile monitors (BPMs) in nuclear facilities in which low-energy radioactive ions are produced due to nuclear fusion reactions. In this study, we developed a BPM using a microchannel plate and a charge-coupled device to differentiate the beam profiles of alpha-decaying radioactive isotopes from other ions (reaction products) produced in a nuclear reaction. This BPM was employed to optimize the low-energy radioactive francium ion (Fr+) beam developed at the Cyclotron and Radioisotope Center (CYRIC), Tohoku University, for electron permanent electric dipole moment (e-EDM) search experiments using Fr atoms. We demonstrated the performance of the BPM by separating the Fr+ beam from other reaction products produced during the nuclear fusion reaction of an oxygen (18O) beam and gold (197Au) target. However, as the mass of Au is close to that of Fr, separating the ions of these elements using a mass filter is a challenge, and a dominant number of Au+ renders the Fr+ beam profile invisible when using a typical BPM. Therefore, by employing the new BPM, we could successfully observe the Fr+ beam and other ion beams distinctly by measuring the alpha decay of Fr isotopes. This novel technique to monitor the alpha-emitting radioactive beam covers a broad range of lifetimes, for example, from approximately 1 s to 10 min, and can be implemented for other alpha-emitter beams utilized for medical applications., Comment: 7 pages, 8 figures

We present an experimental technique to measure light shifts due to the nuclear spin independent (NSI) parity-nonconserving (PNC) interaction in the \( 7{S}_{1/2} \)–\( 6{D}_{3/2} \) transition in ultracold \( {}^{210}\mathrm{Fr} \) atoms. The approach we propose is similar to the one by Fortson (Phys Rev Lett 70:2383, 10) to measure the PNC-induced light shift which arises from the interference of parity nonconserving electric dipole transition and electric quadrupole transition amplitudes. Its major advantage is that it can treat more than \( {10}^4 \) ultracold \( {}^{210}\mathrm{Fr} \) atoms to enhance the shot noise limit. A relativistic coupled-cluster method has been employed to calculate the electric dipole transition amplitudes arising from the PNC interaction. Based on these calculations, we have evaluated the PNC-induced light shifts for transitions between the hyperfine levels of the \( 7{S}_{1/2} \) and \( 6{D}_{3/2} \) states and suitable transitions are identified for carrying out PNC measurements. It is possible in principle to probe new physics beyond the standard model with our proposed experimental scheme.

We are planning test experiments of fundamental symmetries based on the intrinsic properties of francium. It is expected that the laser cooling and trapping of francium will produce precision measurements. The pilot experiment using rubidium was performed with the goal of francium trapping. The ion beam generated with a francium ion source was investigated using a Wien filter. Each piece of equipment still must be studied in more detail, and the equipment should be upgraded in order to trap radioactive atoms.

The composition dependence of gravitational constant $G$ is measured at the millimeter scale to test the weak equivalence principle, which may be violated at short range through new Yukawa interactions such as the dilaton exchange force. A torsion balance on a turning table with two identical tungsten targets surrounded by two different attractor materials (copper and aluminum) is used to measure gravitational torque by means of digital measurements of a position sensor. Values of the ratios $\tilde{G}_{Al-W}/\tilde{G}_{Cu-W} -1$ and $\tilde{G}_{Cu-W}/G_{N} -1$ were $(0.9 \pm 1.1_{\mathrm{sta}} \pm 4.8_{\mathrm{sys}}) \times 10^{-2}$ and $ (0.2 \pm 0.9_{\mathrm{sta}} \pm 2.1_{\mathrm{sys}}) \times 10^{-2}$ , respectively; these were obtained at a center to center separation of 1.7 cm and surface to surface separation of 4.5 mm between target and attractor, which is consistent with the universality of $G$. A weak equivalence principle (WEP) violation parameter of $\eta_{Al-Cu}(r\sim 1\: \mathrm{cm})=(0.9 \pm 1.1_{\mathrm{sta}} \pm 4.9_{\mathrm{sys}}) \times 10^{-2} $ at the shortest range of around 1 cm was also obtained., Comment: submitted to Class. Quantum Grav

The MTV (Mott Polarimetry for T-Violation) experiment is running at TRIUMF-ISAC (Isotope Separator and ACcelerator), searching for a large T violation in polarized Li-8 beta decay via measurements of the triple vector correlation, R, in the beta decay rate function. The left/right backward scattering asymmetry of Mott scattering from a thin metal foil is measured using an electron tracking detector including a cylindrical drift chamber (CDC). To achieve 10-ppm precision in the Mott scattering asymmetry, we performed multiple studies on the expected systematic effects. The sources of the systematics have been identified and calibration systems have been developed to evaluate the fake effects. The first physics data was collected in 2016 and significantly improved on the result of our previous measurement, which achieved 100-ppm precision in 2010 using the first generation detector (planer drift chamber) at TRIUMF. The data measurement status, together with the results of the systematics studies, is described here. In addition to the T violation, we are preparing to test the Lorentz invariance in the weak sector via our Mott analyzer system. Unexplored Lorentz violating correlations can be tested using the MTV experimental setup. The testing principle and preparation status are also described here.

We present an experimental technique to measure light shifts due to the nuclear spin independent (NSI) parity-nonconserving (PNC) interaction in the $$7S_{1/2}$$ – $$6D_{3/2}$$ transition in ultracold $${^{210}\mathrm{Fr}}$$ atoms. The approach we propose is similar to the one by Fortson (Phys Rev Lett 70:2383, 10) to measure the PNC-induced light shift which arises from the interference of parity nonconserving electric dipole transition and electric quadrupole transition amplitudes. Its major advantage is that it can treat more than $$10^4$$ ultracold $${^{210}\mathrm{Fr}}$$ atoms to enhance the shot noise limit. A relativistic coupled-cluster method has been employed to calculate the electric dipole transition amplitudes arising from the PNC interaction. Based on these calculations, we have evaluated the PNC-induced light shifts for transitions between the hyperfine levels of the $$7S_{1/2}$$ and $$6D_{3/2}$$ states and suitable transitions are identified for carrying out PNC measurements. It is possible in principle to probe new physics beyond the standard model with our proposed experimental scheme.

The MTV experiment (Mott Polarimetry for T-Violation Experiment) is running from 2009 at TRIUMF, which aims to search a large non-standard T-Violation in polarized nuclear beta decay. Existence of transverse polarization of electrons emitted from polarized 8Li nuclei, which are produced at TRIUMF-ISAC and stopped inside an aluminum stopper, is investigated. We utilize a Mott polarimeter consists of a planer drift chamber, measuring backward scattering left-right asymmetry from a thin lead analyzer foil. In this paper, preliminary results from the first physics run performed in 2010 are described.

The tilted-foil method for producing spin-polarized radioactive isotope beams has been studied using the re-accelerated radioactive 8 Li and 123 In beams produced at Tokai Radioactive Ion Accelerator Complex (TRIAC) facility. We successfully produced polarization in a 8 Li beam of 7.3(5)% using thin polystyrene foils (4.2 μg/cm 2 ). The systematic study of the nuclear polarization as a function of the number of foils and beam energy has been performed, confirming the features of the tilted-foil technique experimentally. After the study, a spin-polarized radioactive 123 In beam, which is the heaviest ever polarized in its ground state by this method, has been successfully generated by the tilted-foil method, for the nuclear spectroscopy around the doubly magic nucleus 132 Sn.

A factory of laser-cooled francium (Fr) atoms is being developed to search for the electric dipole moment (EDM) of the electron. The factory has achieved the production of Fr ions of 9 × 10 5 particles/s and transport with a transmission efficiency of 2%. In pilot experiments, the magneto-optical trapping of rubidium (Rb) has been performed using a new ion-to-atom converter. To achieve the Fr trap, the development and design of each of the factory’s components are in progress.

The MTV (Mott Polarimetry for T-Violation Experiment) experiment at TRIUMF-ISAC (Isotope Separator and ACcelerator), which aims to achieve the highest precision test of time reversal symmetry in polarized nuclear beta decay by measuring a triple correlation (R-correlation), is motivated by the search for a new physics beyond the Standard Model. In this experiment, the existence of non-zero transverse electron polarization is examined utilizing the analyzing power of Mott scattering from a thin metal foil. Backward scattering electron tracks are measured using a multi-wire drift chamber for the first time. The MTV experiment was commissioned at ISAC in 2009 using an 80%polarized 8Li beam at 107 pps, resulting in 0.1%statistical precision on the R-parameter in the first physics run performed in 2010. Next generation cylindrical drift chamber (CDC) is now being installed for the future run.

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) offers the unique capability to collide polarized protons at high energies. One of the highlights of the polarized proton program performed at s = 500 GeV is that it affords the direct measurement of sea quark contribution to the proton spin via W-boson production through the measurement of the parity violating single spin asymmetry. A new trigger electronics system for forward muons, which is especially capable of W-boson detection, was developed for the PHENIX experiment. The trigger was installed as an additional electronic circuit, and it was connected in parallel with the existing cathode readout electronics of the muon tracking chamber.

The existence of a non-zero electric dipole moment (EDM) implies the violation of time reversal symmetry. As the time-reversal symmetry violation predicted by the Standard Model (SM) for the electron EDM is too small to be observed with current experimental techniques and any a non-zero EDM would indicate new physics beyond the SM. The tiny signal from the electron EDM is enhanced in the heavy atoms such as francium (Fr). We are constructing the laser-cooled Fr factory to search for the electron EDM.

The MTV experiment (Mott Polarimetry for T-Violation Experiment) is running at TRIUMF, to search for a large T-violating transverse electron-polarization in polarized 8Li β-decay. We aim at reaching precision of 10−4 for the R-correlation, which is defined as a T-violating triple vector correlation in the β-decay rate function. A Mott polarimeter system using a CDC (Cylindrical Drift Chamber) is used to measure the left-right scattering asymmetry in the Mott scattering from a thin metal foil. In the present study, we aim to discuss systematic effects in Mott polarimetry using the CDC.

Herein, we report an effective method for the generation of radio-frequency (RF) sidebands in an electro-optic modulator for the simultaneous magneto-optical trapping of two isotopes. This is achieved by switching the RF signals alternately, which suppresses the generation of unwanted frequency signals and improves the laser power per sideband. The generated sidebands are successfully applied to a dual-rubidium-isotope magneto-optical trap (MOT), which results in an increased number of trapped atoms. This simple, flexible, and robust technique can be implemented in experiments that require a large number of atoms in multiple-isotope MOTs and for various applications.

Electric quadrupole coupling constant eqQ/h of the extremely proton-rich 23Al (I π = 5/2 + , T 1/2 = 0.47 s) nucleus implanted into an Al2O3 single crystal has been measured for the first time, using the β-ray detecting nuclear quadrupole resonance method (β-NQR) in a high magnetic field. As a preliminary result, the quadrupole coupling constant was determined as |eqQ/h(23Al) | = 2.66±0.77 MHz. Using the quadrupole coupling constant of 27Al in Al2O3 as a reference, the Q moment of the ground state of 23Al was extracted as |Q(23Al)| ~ 160 mb, which is well explained by the shell model calculation in the sd-shell model space with the USD interaction.

Nuclear moment studies on nuclei situated far from the β-stability line, performed by taking advantage of the projectile fragmentation reaction, are reviewed. A method to produce spin polarization/alignment in the projectile fragments was developed and utilized for the β-NMR/NQR measurements. Several new findings in nuclear structure physics were obtained from the nuclear moment experiments done with these techniques.

We have been working on the development of a new technique of atomic-beam resonance method to measure the nuclear moments of unstable nuclei. In the present study, an ion-guiding system to be used as an atomic-beam source have been developed.

The electric quadrupole moments for the ground states of 32Al and 31Al have been measured by the β ray-detected nuclear quadrupole resonance method. Spin-polarized 32Al and 31Al nuclei were obtained from the fragmentation of 40Ar projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal α-Al2O3 stopper. The measured Q moment of 32Al, |Q(32Al)| = 24(2) mb, is in good agreement with a conventional shell-model calculation with a full sd model space and empirical effective charges, while that of 31Al is considerably smaller than the sd calculations.

A new method to produce spin-polarized radioactive nuclear beams has been developed, which takes advantage of the low-energy transfer reaction in inverse kinematics. The method provides beam energies of a convenient range so that they may be implanted in a thin stopper, yet allowing the stopper to be spatially separated from the production target. The presence of polarizations of sizes at least \(\left|P\right|\sim 0.5 \%\) has been confirmed for a 17N beam obtained from 9Be(18O,17N) reaction at \(\theta_{\rm Lab} \sim -1.7\,^{\circ}\).

The electric quadrupole moment Q for the ground state of 32Al has been measured using the β-NMR technique. Spin-polarized 32Al nuclei were obtained from the fragmentation of 40Ar projectiles at E / A = 95 MeV / nucleon , and were implanted in a single crystal α-Al2O3 stopper. The quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value, | Q ( Al g.s. 32 ) | = 24 ( 2 ) mb , is remarkably small as compared with other Al isotopes, but is well explained by shell model calculations within the sd shell. The present result indicates that 32Al has a normal sd-shell structure, in contrast to the neighboring N = 19 isotone 31Mg for which a strongly deformed intruder ground state has been reported to occur.

Based on the technique of fragment‐induced spin polarization combined with the β‐NMR method, a series of experiments has been carried out at RIKEN for the nuclear‐moment measurement of light unstable nuclei. The measurement will be extended further in the RIKEN RIBF project, where radioactive‐isotope beams in the medium‐ and heavy‐mass regions will be produced at higher energies and with higher intensities compared with the RARF facility. Measurements of the isomeric‐state nuclear moments of unstable nuclei will be started with BigRIPS by utilizing fragment‐induced spin‐orientation phenomena. Also, an upgrade program of the existing fragment separator RIPS is proposed in the phase‐II program of RIBF. Then, intense beams will be delivered to RIPS at E ∼ 115 A MeV. This energy region is useful, not only because spin orientation is produced in the PF reaction but also they can be implanted into sample materials with limited thickness.

The development of techniques to produce low‐energy spin‐polarized radioactive nucleon beams (RNBs) is reported. It employs the inverse‐kinematics reactions of law energy heavy‐ion beams for the RNB production with in‐flight separator. Some plans of research are discussed that apply these well‐focused, conveniently energetic spin‐polarized RNB to nuclear structure physics and material science.

The structure of neutron-rich nuclei around the N = 20 magic number is studied through the measurements of static electromagnetic moments. Recent data on the magnetic dipole moments and electric quadrupole moments for neutron-rich Al isotopes are discussed to clarify whether the emergence of a strong deformation reported for Z = 10?12 nuclei in this region might happen also in these Z = 13 nuclei. Possibility to study the nuclear structure via the ? transition matrix elements is also discussed.

We report measurement of frequencies of tellurium lines with respect to atomic calcium employing a 423 nm commercial violet laser diode placed in an extended cavity. Doppler-free saturated absorption spectroscopy of molecular tellurium is performed on three lines, which are lower and higher in energy to the calcium 4s2 1S0–4s4p 1P1 transition. The measured frequency difference of 717(13) MHz between the strong absorption line, #1508 in the tellurium atlas and the calcium transition is in agreement within 10% of the values available from literature. Wavenumbers of two new tellurium lines are derived from the measurement. In addition, spectroscopy and laser cooling and trapping of francium (n = 7) on the ns 2S1/2–(n + 1)p 2P3/2 transition and spectroscopy of Te2 lines near francium could be performed employing the 423 nm diode laser.

The measurements of the 3-α decay from the Hoyle and the broad 10 MeV state in12C have been performed using an inverse kinematic method of the12C(12C,3α)12C reaction at E12C = 110 MeV. In the measurement of the Hoyle state, the upper limit of the direct decay was improved to be 0.2 %. This was inconsistent with the recent reported nonzero value of 0.9 %, but an order larger than the direct decay branch predicted in the 3-α model. The branching ratios of the sequtial decay for the broad 10 MeV state were also obtained. They were higher than those obtained in the RCNP experiment, since they contained the contributions of higer multipole components. Their contributions will be estimated.

The Mott polarimetry for T-violation (MTV) experiment tests time-reversal symmetry in polarized nuclear [Formula: see text]-decay by measuring an electron’s transverse polarization as a form of angular asymmetry in Mott scattering using a thin metal foil. A Mott scattering analyzer system developed using a tracking detector to measure scattering angles offers better event selectivity than conventional counter experiments. In this paper, we describe a pilot experiment conducted at KEK-TRIAC using a prototype system with a polarized 8Li beam. The experiment confirmed the sound performance of our Mott analyzer system to measure T-violating triple correlation (R correlation), and therefore recommends its use in higher-precision experiments at the TRIUMF-ISAC.

The direct 3α decay branch from the 02+ state at Ex=7.65 MeV in 12C, which is known as the Hoyle state, is considered to affect the triple-α reaction rate strongly and to give crucial information on its structure. We have performed a high-precision measurement of the 3α decay from this state using the 12C(12C,3α)12C reaction at E12C=110 MeV. The branching ratio of the direct 3α decay was under the detection limit in the present experiment. By comparing with Monte Carlo simulations for three decay mechanisms as the sequential decay through the ground state of ^{8}Be, the direct decay with equal energies of three α particles, and the direct decay to the phase space uniformly, we have obtained the upper limit of 0.2% on the direct 3α decay.

The MTV-G (MTV-Gravity) experiment is aiming to detect a strong gravitational field at around nuclear scale, utilizing an electron polarimeter of the MTV (Mott Polarimetry for T-Violation) experiment [1], which is searching a large T-Violating electron transverse polarization emitted in polarized Li-8 beta decay. The MTV experiment is running at TRIUMF-ISAC since 2009, yielding the highest precision test of T-Violation. The extreme sensitivity of the MTV polarimeter gives us an opportunity to perform a new type of gravity experiment. A modification of gravitational inverse square law at a microscopic scale is predicted by a large extra-dimension model in order to explain the hierarchy problem. The strong gravitational field can be detected as a large spin precession of electrons scattered from nuclei, caused by the “Geodetic precession” as a result of a warped space-time around the nuclear mass. In this experiment, longitudinal polarization of electrons emitted from a 90 Sr source is transferred into a transverse polarization via electromagnetic Thomas precession and possibly via the Geodetic precession.

th , 2013) The MTV (Mott polarimetry for T-Violation) experiment is running from 2009 at TRIUMF, which aims to search a large non-standard T-Violation in polarized nuclear beta decay. Existence of a large transverse polarization of electrons emitted from polarized Li-8 nuclei, which are produced at TRIUMF-ISAC and stopped inside an aluminum stopper, is investigated. We utilize a Mott polarimeter consists of a CDC (Cylindrical Drift Chamber), measuring backward scattering left-right asymmetry from a thin lead analyzer foil. In this paper, results from the final performance test run using CDC performed in 2012 are described.

The search for the electric-dipole moment (EDM) of laser-cooled francium (Fr) atoms could lead to a measurement for the electron EDM. It is predicted that the electron EDM would be enhanced by approximately three orders of magnitude in heavy atoms such as Fr. Laser-cooling and trapping techniques are expected to suppress statistical and systematic errors in precision measurements. The magneto-optical trap was achieved using stable rubidium in a developing factory of laser-cooled radioactive atoms. In light of the results from the rubidium experiments, we found that an upgrade of each apparatus is preferred for Fr trapping.

Motivated by a search for a new physics beyond the standard model, the MTV experiment (Mott Polarimetry for T-Violation Experiment) is intended to achieve the highest precision test of time-reversal symmetry in polarized nuclear beta decay by measuring a triple correlation (the R -correlation). The first physics run of the MTV experiment was performed in 2010 at TRIUMF-ISAC. This paper gives preliminary results and describes the next generation setup, which involves a cylindrical drift chamber.

Francium is the heaviest species among the alkali elements. Due to its properties, francium is said to be of advantage in measurements of tiny observations, such as atomic parity violation and electric dipole moment. Before executing experiments with francium, it must be produced artificially because it is one of the most unstable elements. We produced francium with the nuclear fusion reaction of an oxygen beam and gold target, ionized the produced francium through a thermal ionization process, and extracted the ion with electrostatic fields. However, the thermal ionization process is known to ionize not only an objective atom but also other atomic species. Therefore, a Wien filter was installed to analyze the composition of the ion beam and purify the beam. This allowed us to improve the beam purity from ∼10(-6) to ∼10(-3).

The tilted-foil method for producing spin-polarized radioactive isotope beams has been studied for the application to nuclear physics and materials science, using the radioactive nucleus 8Li ( $\ensuremath I^{\pi}=2^+$ , g = 0.82678(9) , $\ensuremath T_{1/2}=0.838(6)$ s) produced at the Tokai Radioactive Ion Accelerator Complex (TRIAC). We successfully produced polarization in a 8Li beam of $\ensuremath 7.3\pm0.5$ % using 15 thin polystyrene foils (4.2 $\ensuremath \mu \mathrm{g/cm}^2$ fabricated especially for this purpose. A systematic study of the nuclear polarization as a function of the number of foils, beam energy, tilt angle and foil material has been performed, confirming the features of the tilted-foil technique experimentally. The contributions made to the nuclear polarization of 8Li nuclei by the atomic states was investigated.

The new scheme to produce a spin‐polarized RI beam is being developed, in which the atomic beam resonance method is utilized for spin polarization. A gas‐filled chamber to stop the incoming RI ions and to drift them into vacuum area has been developed. The measurement of RI‐stopping in the gas was performed, and experiments for drifting and extracting of the stopped ions are now being performed. The status of the R&D for realizing the scheme is reported in this letter.

Precision measurement of nuclear beta decay correlations at newly constructing RIKEN‐RIBF and KEK‐TRIAC is planned. Measurements of beta neutrino correlation and T‐violating electron transverse polarization using spin polarized RI beams are aimed to be performed using slow radioactive nuclei.

Based on the technique of fragment‐induced spin polarization combined with the β‐NMR method, we have recently carried out experiments at RIKEN to measure nuclear moments of neutron‐rich aluminum isotopes. In the measurements, the nuclear magnetic‐dipole moments of 30, 32Al and the electric‐quadrupole moments of 31,32Al have been determined. The obtained magnetic moments, as well as the other known magnetic moments of aluminum isotopes, agree well with shell model calculations with the USD interaction. The obtained quadrupole moments are smaller than those of 27, 28Al, suggesting spherical shapes of 31, 32Al. These results seem to suggest that 31Al and 32Al are located outside the island of inversion. In near future, studies on nuclear moments will be extended further in the RIKEN RIBF project, in which medium‐ and heavy‐mass regions come within our scope by using superconducting fragment separator BigRIPS. Also, an upgrade program for the existing fragment separator RIPS is in progress. In the RIBF projec...

A new Mott polarimeter using multi‐wire drift chamber has been developed. Time‐reversal symmetry can be tested by using the Mott scattering. We have built and tested the performance of the prototype detector, and estimated the acceptance of the detector by the Monte‐Carlo simulation.

The magnetic moment and electric quadrupole moment of 32Al (Z = 13,N = 19) have been measured. We performed β-NMR spectroscopy with spin-polarized 32Al nuclei produced via the projectile fragmentation reaction. Both the moments are well reproduced by full sd-shell model calculations using the USD effective interaction. The result has provided clear evidence that 32Al is located out of the island of inversion.