Electric Dipole Moments

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Search for electric dipole moments in storage rings

Search for electric dipole moments in storage rings

The fact that we and the world around us are made of matter and only a minimal amount of antimatter is observed, constitutes one of the fundamental puzzles in modern physics, motivating a variety of theoretical speculations and experimental investigations. The combined standard models of cosmol- ogy and particle physics suggest that at the end of the inflation epoch immediately following the Big Bang, the number of particles and antiparticles were almost in precise balance. Yet the laws of physics contrived to act differently on matter and antimatter to generate the apparently large imbalance that we observe today. One of the necessary mechanisms required for this to happen – namely CP viola- tion – is very small in the Standard Model of particle physics and therefore only able to account for a tiny fraction of the actual imbalance. New sources of CP violation are needed, and one such potential signature would be the appearance of electric dipole moments (EDMs) in fundamental particles.
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Search for electric dipole moments

Search for electric dipole moments

ζ is the angle between magnetic and electric field, started to dominate the sensitivity [30]. Although a new scheme for a competitive neutron beam EDM experiment has been proposed [31], most of today’s and next generation experi- ments use ultracold neutrons [32]. These are neutrons with velocities below about 6 m/s which are reflected by suit- able material surfaces under all angles of incidence. This permits the construction of experiments, where neutrons are locked into a macroscopic storage chamber (volume tens of liters) and exposed to strong electric fields E ≈ 1.1 MV/m for times T up to 180 s [17]. Passive magnetic shields made of several layers of an alloy (i.e. mu-metal) with a high permeability µ surround the neutron storage chamber to reduce magnetic field drifts during measure- ment. In the past, remaining magnetic field changes were canceled by taking a relative measurement. Either us- ing a second adjacent precession chamber exposed to the same magnetic field but inverse electric field [33] or by us- ing 199 Hg as cohabiting magnetometer [34, 35] within the
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Searching for t -> c(u)h with dipole moments

Searching for t -> c(u)h with dipole moments

The main goal of this paper is to derive and to compare the direct and indirect con- straints that apply in the case of the t → c(u)h transitions. Our particular focus will thereby be on CP-violating observables such as electric dipole moments (EDMs). In the context of lepton-flavour violation the contributions to EDMs from complex flavour-violating cou- plings of the Higgs boson have received notable attention lately (see e.g. [16–18]), while, to the best of our knowledge, the bounds on the tuh couplings (1.1) that arise from the EDM of the neutron have only been considered in [16]. Our work refines this analysis and extends it to the case of the tch interactions. In both cases we resum large leading logarithms, which in the latter case requires to perform a two-loop calculation, while considering one-loop effects is sufficient in the former case. We also present a systematic study of direct as well as indirect CP violation in the D-meson sector that is induced by the FCNC Higgs-boson couplings (1.1). These calculations allow us to derive model-independent bounds on certain combinations of the flavour-changing couplings Y tq and Y qt that apply to all BSM scenarios
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Does the electron have an anomalous electric dipole moment?

Does the electron have an anomalous electric dipole moment?

Although these studies have led the author to the rediscovery of Dirac’s second dipole moment, a decisive experimental proof would be most welcome. How to construct such a proof is not obvious. The phenomenon to be shown and measured is the second spin-flip of an electron under influence of a vector potential. A first option is the use of electron spin resonance spectrography (ESR), [14]. Unfortunately, the spectral split due to the anomalous electric dipole moment is masked by the electron’s orbital motion in atoms, because the orbital motion cancels symmetric contributions. As a second option one might consider the hyperfine split effect due to the spin-spin interaction of the electron with the atomic nucleus, which gives rise to the well-known 21 cm line in the cosmological electromagnetic spectrum of atomic hydrogen [15]. Unfortunately, the interaction energy between the spins due to the anomalous electric dipole moments is just equal to the interaction energy due to the anomalous magnetic dipole moments. This can be seen as follows. According to Griffiths [5,16], the interaction energy Δ E between the magnetic dipoles e
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Electric Dipole Moment Results from lattice QCD

Electric Dipole Moment Results from lattice QCD

Abstract. We utilize the gradient flow to define and calculate electric dipole moments induced by the strong QCD θ-term and the dimension-6 Weinberg operator. The gradient flow is a promising tool to simplify the renormalization pattern of local operators. The results of the nucleon electric dipole moments are calculated on PACS-CS gauge fields (available from the ILDG) using N f = 2+1, of discrete size 32 3 × 64 and spacing a 0.09 fm. These gauge fields use a renormalization-group improved gauge action and a non- perturbatively O(a) improved clover quark action at β = 1.90, with c S W = 1.715. The
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A Thermochemical Cryogenic Buffer Gas Beam Source of ThO for Measuring the Electric Dipole Moment of the Electron

A Thermochemical Cryogenic Buffer Gas Beam Source of ThO for Measuring the Electric Dipole Moment of the Electron

Permanent electric dipole moments (EDMs), or lopsided charge distributions, are another experimentally accessible property of ordinary particles with potentially profound impli- cations. To date, no nonzero EDM of a fundamental particle has been observed, though physicists have been searching for over 60 years. As discussed in Section 1.2, the reason for this failure is a sound one: the Standard Model of particle physics (SM), a fantastically suc- cessful theory describing all known particles and interactions, has symmetries that strongly suppress EDMs, leading to EDM predictions that are in some cases ten orders of magnitude below the reach of current experiments [115, 154]. Despite this fact, and the decades of null results, the reason for continuing the search is also an excellent one: namely, that the SM is widely held to be incomplete. Among other shortcomings, it does not appear to account for the observation of dark matter, the invisible source of mass comprising for most of the bulk of galaxies; dark energy, believed to be responsible for the accelerating expansion of the universe; or the preponderance of matter over antimatter in the observable universe. A variety of unconfirmed theories beyond the SM purport to explain such phenomena—and as a side effect, they also tend to predict EDMs that are within or near the reach of current experimental methods. These theories and their implications for EDMs, especially that of the electron, are briefly discussed in Section 1.2.2.
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Numerical Experiment for Dipole Dipole Interaction in Electro Magnetism with Help of a Regular Tetrahedron

Numerical Experiment for Dipole Dipole Interaction in Electro Magnetism with Help of a Regular Tetrahedron

DOI: 10.4236/ojpc.2019.91002 17 Open Journal of Physical Chemistry Figure 2. (a) A straight Conductor with cross-section area A and length  . (b) Free Electrons Cloud is displaced to right, by a distance + x , where x   . A positive electric charge + q is formed at left end of the Conductor and a negative charge – q at right end. The Coulomb electrostatic attractive force F , between the two opposite charges ± q , at ends of Conductor, is acting on Free Electrons Cloud, directed to left. (c) The Free Elec- trons Cloud is displaced to left by a distance – x , where x   . Now, a positive electric charge + q is formed at right end of Conductor and a negative charge – q at left end. The Coulomb electrostatic attractive force F , between the two opposite charges ± q , at ends of Conductor, is acting on Free Electrons Cloud, directed, now, to right.
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Paddlefish strike at artificial dipoles simulating the weak electric fields of planktonic prey

Paddlefish strike at artificial dipoles simulating the weak electric fields of planktonic prey

In the Midwestern rivers of the United Sates, paddlefish encounter waters of different conductivity. For example, water conductivity in the Missouri River varies dramatically, both seasonally and daily, depending on residence time in reservoirs and local precipitation. Local values (P. Keck, personal communication, St Louis County Water Co.) vary from 175 to 600 µS cm −2 , with readings up to 843 µS cm −2 elsewhere in Missouri (J. Grady; US Fish and Wildlife Service). The strength of an electrical signal will vary in intensity with the conductivity of the water and will be greater at lower conductivities. Our experiments showed higher strike activity in water with lower conductivity, suggesting the likelihood that the detection of planktonic electric fields by paddlefish would vary accordingly. As a result, feeding efficiency may vary with natural changes in environmental water quality. This may be a critical feature for newly hatched paddlefish. After depletion of the yolk sac, small paddlefish must feed continuously as a result of their high ram-ventilating activity levels. Paddlefish spawning is triggered by high spring waters (Russell, 1986), conditions that would provide low conductivity and maximum plankton detectability.
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The radiofrequency NMR spectra of lithium salts in

The radiofrequency NMR spectra of lithium salts in

after, precise lithium nuclei dipole moments were measured by the atomic beam magnetic 70.. resonance method [13].[r]

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The Field of an Electric Dipole and the Polarizability of a Conducting Object Embedded in the Interface Between Dielectric Materials

The Field of an Electric Dipole and the Polarizability of a Conducting Object Embedded in the Interface Between Dielectric Materials

embedded dipole, depending on its orientation. The concepts learned from the study of the dipole moments were then used to provide a clear definition for the electric polarizability of a scatterer embedded in an interface. Our general result was illustrated for the case of a perfectly conducting spherical scatterer. Other authors [14, 25] have treated very similar problems, but have reached somewhat different conclusions. We believe that our approach provides an unambiguous way of accounting for the scattering by small particles at an interface, and will enable the proper treatment of arrays of such particles at an interface, extending our previous work in [1–4]. A study of the magnetic moment of a dipole, along with the magnetic polarizability of a superconducting sphere, in the interface between two magnetic media is currently underway, as is the derivation of sheet transition conditions for a metafilm embedded in a material interface. The results of the work in this paper and corresponding ones for magnetic dipoles in an interface will have important implications for the modeling of nanostructures in multilayered circuit technology.
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Use of a Genetic Algorithm in Modelling Small Structures in Airframes : Characterising and modelling joints, seams, and apertures

Use of a Genetic Algorithm in Modelling Small Structures in Airframes : Characterising and modelling joints, seams, and apertures

A magnetic field probe loop was fabricated on a microwave PCB laminate (Fig. 4). An outer loop with a gap acts as a shield against electric field pickup. Two rectangular copper plates are placed to provide further shielding against electric field on the loop side whilst a slotted ground-plane is used below the loop. The probe is terminated through two semi-rigid cables. One of those is mounted to an SMA connector, and another terminated by a 50 ohms load, which is formed by two 100 ohms surface-mount resistors, connected in parallel to reduce stray inductance.
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Some structural studies by deuterium magnetic resonance

Some structural studies by deuterium magnetic resonance

nuclear magnetic dipole and nuclear electric quadrupole moment effects on which one and the other are based: while the magnetic dipole interacts with a magnetic field and in this connect[r]

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Radiative τ leptonic decays and the possibility to determine the τ dipole moments

Radiative τ leptonic decays and the possibility to determine the τ dipole moments

The electric dipole moment (EDM) and the anomalous magnetic moment (g −2) of a lepton are physical observ- ables sensitive to quantum corrections induced by virtual particles that populate the vacuum. For this reason they are very well suited to test the Standard Model (SM) of parti- cle physics and to unveil unknown new physics hidden at high energy. The electron and muon g −2 have been mea- sured with the wonderful precision of 0.24 ppb [1] and 540 ppb [2], and they agree with the SM predictions at the level of ∼ 1.4 and ∼ 3.8 standard deviations, respectively [3]. In contrast, the short lifetime of the τ lepton (2.9 × 10 − 13 s)
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Planar Endfire Circularly Polarized Quasi-Yagi Antenna with Enhanced Bandwidth and Reduced Size for Wideband Wireless Applications

Planar Endfire Circularly Polarized Quasi-Yagi Antenna with Enhanced Bandwidth and Reduced Size for Wideband Wireless Applications

Figure 1 shows the geometry of the proposed planar endfire circularly polarized quasi-Yagi antenna. The substrate has a relative dielectric constant of 2.2, loss tangent of 0.0009, surface area size of 60 . 9 mm × 57 . 7 mm and height of 2.54 mm (100 mil). The common driver can be divided into three parts, namely magnetic dipole, electric dipole and phase shift line. The magnetic dipole element is realized by a microstrip patch with one long edge opened and the other three edges shorted. For fabrication convenience, several rows of closely-spaced shorting pins penetrating through the proposed antenna are employed to replace the ideal shorting walls. The shorting pins have a radius of 0.33 mm and a distances of 1.78 mm. The magnetic dipole is 60 . 9 mm × 10 . 3 mm in size. And two rectangular slots with sizes of 5 . 5 mm × 0 . 4 mm are symmetrically loaded on the metal ground of the magnetic dipole. The electric dipole’s two arms are printed on the front and back sides of the substrate complementarily. Each arm has a size of 12 . 9 mm × 4 . 4 mm, and a meandered slot composed of three identical arc-shaped slots is loaded on it. The radius of two arc-shaped slots is 1.2 mm. Meanwhile, the sizes of the two-stage stepped balanced phase shift line are 9 . 3 mm × 1 . 25 mm and 5 mm × 0 . 85 mm, respectively. The feeding
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An In-Tube Radar for  Detecting Defects in Thin-Walled Metal Tubes

An In-Tube Radar for Detecting Defects in Thin-Walled Metal Tubes

The configuration for a loop transmitter and receive monopole was analyzed using the finite element method both with and without a defect. The received electric field as a function of position inside the tube is plotted in Fig. 8. The solid curve is proportional to the received voltage for a perfect tube; the dashed curve is the response when a defect is present. The increase in on axis field represents the presence of a defect. By transmitting with one, then the other loop antenna, the azi- muthal position of the defect can be determined.

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Cryogenic Design for the Neutron Electric Dipole Moment Experiment.

Cryogenic Design for the Neutron Electric Dipole Moment Experiment.

The quantity of helium-3 must be controlled carefully because helium-3 atoms absorb neutrons. The amount needs to be quite small to keep the neutron storage time long, about one helium-3 atom for every 10 10 helium-4 atoms. However, the helium-3 absorption is highly spin-dependent and provides for the method of measurement. If both the neutrons and the helium-3 atoms are polarized (that is, the spins of each species are separately aligned), the neutrons are absorbed only when the spins of the neutron and helium-3 are pointing opposite to each other. As the magnetic moments of the two species differ by 10 percent, they oscillate between being aligned and antialigned. Thus, the neutron absorp- tion rate is proportional to the beat frequency of the two rates of preces- sion. When the neutrons are absorbed into a helium-3 nucleus, the positively charged reaction products (a tritium nucleus and a proton) scintillate in the liquid helium, emitting light in the hard ultraviolet. That light can be observed with a photosensitive detec- tor if it is wavelength-shifted into the visible spectrum by scattering from an
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Electric-dipole-induced universality for Dirac fermions in graphene

Electric-dipole-induced universality for Dirac fermions in graphene

developed, but the observed spectrum shows the emergence of new bound state towers as the dipole moment increases. Figure 3 also clarifies the fate of bound states upon increasing the dipole moment. First, we find that bound states do not dive into the continuum. This agrees with our analytical results, which are exact close to the gap edges, and indicates that supercriticality is unlikely to occur.

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An Overview of Magneto-Electric Dipole Antenna Feed Design

An Overview of Magneto-Electric Dipole Antenna Feed Design

The concept of exciting electric and magnetic dipole simultaneously to produce equal E and H plane radiation pattern was first introduced by Clavin [11] in 1954 and since then many researches have been proposed on said complimentary antenna. A wideband complimentary antenna has been redesignated as Magneto Electric Dipole antenna by K.M.Luk in 2006. This section will give a brief overview of the some of the feed line structures that have been used for the design and development of magneto electric dipole antenna.
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Neutron Electric Dipole Moment from colored scalars

Neutron Electric Dipole Moment from colored scalars

Abstract. We present new contributions to the neutron electric dipole moment induced by a color octet, weak doublet scalar, accommodated within a modified Minimal Flavor Violating framework. These flavor non-diagonal couplings of the color octet scalar might account for an assymmetry of order 3 × 10 −3 for a CP (D 0 → K − K + ) − a CP (D 0 → π + π − )

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The PanEDM neutron electric dipole moment experiment at the ILL

The PanEDM neutron electric dipole moment experiment at the ILL

The planned configuration of UCN storage cells is shown in Fig. 1 without the valves, filling guides, and vacuum chamber. A common central electrode applies high-voltage (HV) of either polarity to both cells at once, producing equal and antiparallel electric fields. The two identical cylindrical cells have quartz insulator rings (480mm × 94mm) coated with deuterated polyethylene (dPe) [8,9], and flat electrode end-caps coated with copper or diamond- like carbon. Visibility parameters α(T = 200 s) > 0.8 were demonstrated in storage experiments with test cells at PF2 [10].

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