Two-pion-exchange parity-violating potential and n⃗p→dγ\vec{n} p \to d \gamma

We calculate the parity-violating nucleon-nucleon potential in heavy-baryon chiral perturbation theory up to the next-to-next-to-leading order. The one-pion exchange comes in the leading order and the next-to-next-to-leading order consists of two-pion-exchange and the two-nucleon contact terms. In order to investigate the effect of the higher order contributions, we calculate the parity-violating asymmetry in $\vec{n} p \to d \gamma$ at the threshold. The one-pion dominates the physical observable and the two-pion contribution is about or less than 10% of the one-pion contribution.Comment: 3 pages, contribution to the workshop PAVI06 held in Milos island, Greece, May 16-20, 200

Sixteen-fermion and related terms in M-theory on T**2

Certain one-loop processes in eleven-dimensional supergravity compactified on T**2 determine exact, non-perturbative, terms in the effective action of type II string theories compactified on a circle. One example is the modular invariant U(1)-violating interaction of sixteen complex spin-1/2 fermions of ten-dimensional type IIB theory. This term, together with the (curvature)**4 term, and many other terms of the same dimension are all explicitly related by supersymmetry.Comment: 14 Pages, Latex, no figures, Minor changes, version to appear in PL

Parity violation in pppp scattering and vector-meson weak-coupling constants

We calculate the parity-nonconserving longitudinal asymmetry in the elastic $\vec{p} p$ scattering at the energies where experimental data are available. In addition to the standard one-meson exchange weak potential, the variation of the strong-coupling constants and the non-standard effects such as form factors and $2 \pi$-exchange description of the $\rho$-exchange potential are taken into account. With the extra effects, we investigate the compatibility of the experimental data and the presently-known range of the vector-meson weak-coupling constants.Comment: Contribution to the proceedings of the 3rd Asia-Pacific conference on few-body problems in physics, Suranaree Univ. of Technology, Nakhon Ratchasima, Thailand, July 26 - 30, 200

Deuteron Anapole Moment with Heavy Mesons

Parity-nonconserving two-body currents due to vector meson exchange are considered with the aim to determine the related contributions to the anapole moment. A particular attention is given to the requirement of current conservation which is essential for a reliable estimate of this quantity. An application is made for the deuteron case.Comment: 23 pages, 5 EPS figures, uses REVTeX 4, v2: fixes layout problem

Effect of ferromagnetic contacts on spin accumulation in an all-metallic lateral spin-valve system: Semiclassical spin drift-diffusion equations

We study the effect of the ferromagnetic (FM) contacts on the spin accumulation in the lateral spin valve system for the collinear magnetization configurations. When an additional FM electrode is introduced in the all-metallic lateral spin-valve system, we find that the transresistance can be fractionally suppressed or very weakly influenced depending on the position of the additional FM electrode, and relative magnitudes of contact resistance and the bulk resistance defined over the spin diffusion length. Nonlocal spin signals such as nonlocal voltage drop and leakage spin currents are independent of the magnetization orientation of the additional FM electrode. Even when the additional contact is nonmagnetic, nonlocal spin signals can be changed by the spin current leaking into the nonmagnetic electrode.Comment: 13 pages, 1 figure, revised versio

Eleven-dimensional massless superparticles and matrix theory spin-orbit couplings revisited

The classical probe dynamics of the eleven-dimensional massless superparticles in the background geometry produced by N source M-momenta is investigated in the framework of N-sector DLCQ supergravity. We expand the probe action up to the two fermion terms and find that the fermionic contributions are the spin-orbit couplings, which precisely agree with the matrix theory calculations. We comment on the lack of non-perturbative corrections in the one-loop matrix quantum mechanics effective action and its compatibility with the supergravity analysis.Comment: 11 pages, Latex, no figure

Antiferromagnetic and structural transitions in the superoxide KO2 from first principles: A 2p-electron system with spin-orbital-lattice coupling

KO2 exhibits concomitant antiferromagnetic (AFM) and structural transitions, both of which originate from the open-shell 2p electrons of O$_{2}^{-}$ molecules. The structural transition is accompanied by the coherent tilting of O$_{2}^{-}$ molecular axes. The interplay among the spin-orbital-lattice degrees of freedom in KO2 is investigated by employing the first-principles electronic structure theory and the kinetic-exchange interaction scheme. We have shown that the insulating nature of the high symmetry phase of KO2 at high temperature (T) arises from the combined effect of the spin-orbit coupling and the strong Coulomb correlation of O 2p electrons. In contrast, for the low symmetry phase of KO2 at low T with the tilted O$_{2}^{-}$ molecular axes, the band gap and the orbital ordering are driven by the combined effects of the crystal-field and the strong Coulomb correlation. We have verified that the emergence of the O 2p ferro-orbital ordering is essential to achieve the observed AFM structure for KO2

Hearing Conservation Program For Marching Band Members: A Risk For Noise-Induced Hearing Loss?

Purpose: To examine the risk for noise-induced hearing loss (NIHL) in university marching band members and to provide an overview of a hearing conservation program for a marching band. Method: Sound levels during band rehearsals were recorded and audiometric hearing thresholds and transient otoacoustic emission were measured over a 3-year period. Musician's earplugs and information about hearing loss were provided to the students. The hearing thresholds of other college students were tested as a partial control. Results: There were no significant differences in hearing thresholds between the two groups. During initial testing, more marching band members showed apparent high-frequency notches than control students. Follow-up hearing tests in a subsequent year for the marching band members showed that almost all notches disappeared. Persistent standard threshold shift (STS) across tests was not observed in the band members. Conclusion: Band members showed no evidence of STS or persistent notched audiograms. Because accepted procedures for measuring hearing showed a lack of precision in reliably detecting early NIHL in marching band members, it is recommended that signs of NIHL be sought in repeated measurements compared to baseline audiograms rather than in a single measure (a single notch). A hearing conservation program for this population is still recommended because of lengthy rehearsal times with high sound-level exposure during rehearsals.Communication Sciences and Disorder