188 research outputs found

    Calculation of nuclear spin-dependent parity-nonconserving amplitude for (7s,F=4) --> (7s,F=5) transition in Fr

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    Many-body calculation of nuclear spin-dependent parity-nonconserving amplitude for (7s,F=4) --> (7s,F=5) transition between hyperfine sublevels of the ground state of 211^{211}Fr is carried out. The final result is <7s,F=5 ||d_PNC|| 7s,F=4> = -0.49 10^{-10} i kappa a.u., where kappa is the dimensionless coupling constant. This is approximately an order of magnitude larger than similar amplitude in Cs. The dominant contribution to kappa is associated with the anapole moment of the nucleus.Comment: 4 pages, submitted to Phys.Rev.

    E1 amplitudes, lifetimes, and polarizabilities of the low-lying levels of atomic ytterbium

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    The results of ab initio calculation of E1 amplitudes, lifetimes,and polarizabilities for several low-lying levels of ytterbium are reported. The effective Hamiltonian for the valence electrons has been constructed in the frame of CI+MBPT method and solutions of many electron equation are found.Comment: 11 pages, submitted to Phys.Rev.

    Limits on the monopole magnetic field from measurements of the electric dipole moments of atoms, molecules and the neutron

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    A radial magnetic field can induce a time invariance violating electric dipole moment (EDM) in quantum systems. The EDMs of the Tl, Cs, Xe and Hg atoms and the neutron that are produced by such a field are estimated. The contributions of such a field to the constants, χ\chi of the T,P-odd interactions χeN⋅s/s\chi_e {\bf N} \cdot {\bf s}/s and χNN⋅I/I\chi_N {\bf N} \cdot {\bf I}/I are also estimated for the TlF, HgF and YbF molecules (where s{\bf s} (I{\bf I}) is the electron (nuclear) spin and N{\bf N} is the molecular axis). The best limit on the contact monopole field can be obtained from the measured value of the Tl EDM. The possibility of such a field being produced from polarization of the vacuum of electrically charged magnetic monopoles (dyons) by a Coulomb field is discussed, as well as the limit on these dyons. An alternative mechanism involves chromomagnetic and chromoelectric fields in QCD.Comment: Uses RevTex, 16 pages, 4 postscript figures. An explanation of why there is no orbital contribution to the EDM has been added, and the presentation has been improved in genera

    Stringent bounds to spatial variations of the electron-to-proton mass ratio in the Milky Way

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    The ammonia method to probe variations of the electron-to-proton mass ratio, Delta_mu/mu, is applied for the first time to dense prestellar molecular clouds in the Milky Way. Carefully selected sample of 21 NH_3/CCS pairs observed in the Perseus molecular cloud provide the offset Delta V (CCS-NH_3)= 36+/-7_{stat}+/-13.5_{sys} m/s . A similar offset of Delta V = 40.8 +/- 12.9_{stat} m/s between NH_3 (J,K) = (1,1) and N_2H+ J = 1-0 has been found in an isolated dense core L183 by Pagani et al. (2009). Overall these observations provide a safe bound of a maximum offset between ammonia and the other molecules at the level of Delta V < 100 m/s. This bound corresponds to Delta_mu/mu < 1E-7, which is an order of magnitude more sensitive than available extragalactic constraints. Taken at face value the measured Delta V shows positive shifts between the line centers of NH_3 and these two other molecules and suggest a real offset, which would imply a Delta_mu/mu about 4E-8. If Delta_mu/mu follows the gradient of the local gravitational potential, then the obtained results are in conflict with laboratory atomic clock experiments in the solar system by 5 orders of magnitude, thus requiring a chameleon-type scalar field model. New measurements involving other molecules and a wider range of objects along with verification of molecular rest frequencies are currently planned to confirm these first indications.Comment: 7 pages +2 figures. Galileo Galilei Institute Conferences on Dark Matter and Dark Energ

    Reevaluation of the role of nuclear uncertainties in experiments on atomic parity violation with isotopic chains

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    In light of new data on neutron distributions from experiments with antiprotonic atoms [ Trzcinska {\it et al.}, Phys. Rev. Lett. 87, 082501 (2001)], we reexamine the role of nuclear-structure uncertainties in the interpretation of measurements of parity violation in atoms using chains of isotopes of the same element. With these new nuclear data, we find an improvement in the sensitivity of isotopic chain measurements to ``new physics'' beyond the standard model. We compare possible constraints on ``new physics'' with the most accurate to date single-isotope probe of parity violation in the Cs atom. We conclude that presently isotopic chain experiments employing atoms with nuclear charges Z < 50 may result in more accurate tests of the weak interaction.Comment: 6 pages, 1 fig., submitted to Phys. Rev.

    Possibility of an ultra-precise optical clock using the 61S0→63P0o6 ^1S_0 \to 6 ^3P^o_0 transition in 171,173^{171, 173}Yb atoms held in an optical lattice

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    We report calculations designed to assess the ultimate precision of an atomic clock based on the 578 nm 61S0−−>63P0o6 ^1S_0 --> 6 ^3P^o_0 transition in Yb atoms confined in an optical lattice trap. We find that this transition has a natural linewidth less than 10 mHz in the odd Yb isotopes, caused by hyperfine coupling. The shift in this transition due to the trapping light acting through the lowest order AC polarizability is found to become zero at the magic trap wavelength of about 752 nm. The effects of Rayleigh scattering, higher-order polarizabilities, vector polarizability, and hyperfine induced electronic magnetic moments can all be held below a mHz (about a part in 10^{18}), except in the case of the hyperpolarizability larger shifts due to nearly resonant terms cannot be ruled out without an accurate measurement of the magic wavelength.Comment: 4 pages, 1 figur

    Proof of the multi-Regge form of QCD amplitudes with gluon exchanges in the NLA

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    The multi--Regge form of QCD amplitudes with gluon exchanges is proved in the next-to-leading approximation. The proof is based on the bootstrap relations, which are required for the compatibility of this form with the s-channel unitarity. We show that the fulfillment of all these relations ensures the Reggeized form of energy dependent radiative corrections order by order in perturbation theory. Then we prove that all these relations are fulfilled if several bootstrap conditions on the Reggeon vertices and trajectory hold true. Now all these conditions are checked and proved to be satisfied.Comment: 15 page

    Time-reversal violating rotation of polarization plane of light in gas placed in electric field

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    Rotation of polarization plane of light in gas placed in electric field is considered. Different factors causing this phenomenon are investigated. Angle of polarization plane rotation for transition 6S_{1/2} - 7S_{1/2} in cesium (lambda=539 nm) is estimated. The possibility to observe this effect experimentally is discussed.Comment: 10 pages, Late

    Electric dipole moments of Hg, Xe, Rn, Ra, Pu, and TlF induced by the nuclear Schiff moment and limits on time-reversal violating interactions

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    We have calculated the atomic electric dipole moments (EDMs) induced in ^{199}Hg, ^{129}Xe, ^{223}Rn, ^{225}Ra, and ^{239}Pu by their respective nuclear Schiff moments S. The results are (in units 10^{-17}S(e {fm}^{3})^{-1}e cm): d(^{199}Hg)=-2.8, d(^{129}Xe)=0.38, d(^{223}Rn)=3.3, d(^{225}Ra)=-8.5, d(^{239}Pu)=-11. We have also calculated corrections to the parity- and time-invariance-violating (P,T-odd) spin-axis interaction constant in TlF. These results are important for the interpretation of atomic and molecular experiments on EDMs in terms of fundamental P,T-odd parameters.Comment: 16 page

    Anomalous Neutrino Interaction, Muon g-2, and Atomic Parity Nonconservation

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    We propose a simple unified description of two recent precision measurements which suggest new physics beyond the Standard Model of particle interactions, i.e. the deviation of sin⁥2ΞW\sin^2 \theta_W in deep inelastic neutrino-nucleon scattering and that of the anomalous magnetic moment of the muon. Our proposal is also consistent with a third precision measurement, i.e. that of parity nonconservation in atomic Cesium, which agrees with the Standard Model.Comment: 9 pages, including 1 figure, latest muon g-2 information adde
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