Right-Handed New Physics Remains Strangely Beautiful

Current data on CP violation in B_d -> eta' K_S and B_d -> phi K_S, taken literally, suggest new physics contributions in b -> s transitions. Despite a claim to the contrary, we point out that right-handed operators with a single weak phase can account for both deviations thanks to the two-fold ambiguity in the extraction of the weak phase from the corresponding CP-asymmetry. This observation is welcome since large mixing in the right-handed sector is favored by many GUT models and frameworks which address the flavor puzzle. There are also interesting correlations with the B_s system which provide a way to test this scenario in the near future.Comment: 7 pages, 9 figures; published version: added 1 reference and 1 clarificatio

Mapping Class Group Actions on Quantum Doubles

We study representations of the mapping class group of the punctured torus on the double of a finite dimensional possibly non-semisimple Hopf algebra that arise in the construction of universal, extended topological field theories. We discuss how for doubles the degeneracy problem of TQFT's is circumvented. We find compact formulae for the ${\cal S}^{\pm 1}$-matrices using the canonical, non degenerate forms of Hopf algebras and the bicrossed structure of doubles rather than monodromy matrices. A rigorous proof of the modular relations and the computation of the projective phases is supplied using Radford's relations between the canonical forms and the moduli of integrals. We analyze the projective $SL(2, Z)$-action on the center of $U_q(sl_2)$ for $q$ an $l=2m+1$-st root of unity. It appears that the $3m+1$-dimensional representation decomposes into an $m+1$-dimensional finite representation and a $2m$-dimensional, irreducible representation. The latter is the tensor product of the two dimensional, standard representation of $SL(2, Z)$ and the finite, $m$-dimensional representation, obtained from the truncated TQFT of the semisimplified representation category of $U_q(sl_2)\,$.Comment: 45 page

Spin interactions of interstitial Mn ions in ferromagnetic GaMnAs

The recently reported Rutherford backscattering and particle-induced X-ray emission experiments have revealed that in low-temperature MBE grown GaMnAs a significant part of the incorporated Mn atoms occupies tetrahedral interstitial sites in the lattice. Here we study the magnetic properties of these interstitial ions. We show that they do not participate in the hole-induced ferromagnetism. Moreover, Mn interstitial double donors may form pairs with the nearest substitutional Mn acceptors - our calculations evidence that the spins in such pairs are antiferromagnetically coupled by the superexchange. We also show that for the Mn ion in the other, hexagonal, interstitial position (which seems to be the case in the GaMnBeAs samples) the p-d interactions with the holes, responsible for the ferromagnetism, are very much suppressed.Comment: 4 pages, 3 figures, submitted to PR

New limits on the ordered moments in alpha-Pu and Ga-stabilized delta-Pu

We present the first muon spin relaxation measurements ever performed on elemental Pu, and set the most stringent upper limits to date on the magnitude of the ordered moment in alpha-Pu and delta-stabilized Pu (alloyed with 4.3 at. % Ga). Assuming a nominal hyperfine coupling field of 1 kOe per Bohr magneton we set an upper limit of 0.001 Bohr magnetons for both materials at T = 4 K.Comment: 4 pages, 3 figures. Submitted to 10th International Conference on Muon Spin Rotation, Relaxation and Resonance, Oxford, UK, August 200

The Grad-Shafranov Reconstruction of Toroidal Magnetic Flux Ropes: Method Development and Benchmark Studies

We develop an approach of Grad-Shafranov (GS) reconstruction for toroidal structures in space plasmas, based on in-situ spacecraft measurements. The underlying theory is the GS equation that describes two-dimensional magnetohydrostatic equilibrium as widely applied in fusion plasmas. The geometry is such that the arbitrary cross section of the torus has rotational symmetry about the rotation axis $Z$, with a major radius $r_0$. The magnetic field configuration is thus determined by a scalar flux function $\Psi$ and a functional $F$ that is a single-variable function of $\Psi$. The algorithm is implemented through a two-step approach: i) a trial-and-error process by minimizing the residue of the functional $F(\Psi)$ to determine an optimal $Z$ axis orientation, and ii) for the chosen $Z$, a $\chi^2$ minimization process resulting in the range of $r_0$. Benchmark studies of known analytic solutions to the toroidal GS equation with noise additions are presented to illustrate the two-step procedures and to demonstrate the performance of the numerical GS solver, separately. For the cases presented, the errors in $Z$ and $r_0$ are 9$^\circ$ and 22\%, respectively, and the relative percent error in the numerical GS solutions is less than 10\%. We also make public the computer codes for these implementations and benchmark studies.Comment: submitted to Sol. Phys. late Dec 2016; under review; code will be made public once review is ove

Dynamic Evolution of a Quasi-Spherical General Polytropic Magnetofluid with Self-Gravity

In various astrophysical contexts, we analyze self-similar behaviours of magnetohydrodynamic (MHD) evolution of a quasi-spherical polytropic magnetized gas under self-gravity with the specific entropy conserved along streamlines. In particular, this MHD model analysis frees the scaling parameter $n$ in the conventional polytropic self-similar transformation from the constraint of $n+\gamma=2$ with $\gamma$ being the polytropic index and therefore substantially generalizes earlier analysis results on polytropic gas dynamics that has a constant specific entropy everywhere in space at all time. On the basis of the self-similar nonlinear MHD ordinary differential equations, we examine behaviours of the magnetosonic critical curves, the MHD shock conditions, and various asymptotic solutions. We then construct global semi-complete self-similar MHD solutions using a combination of analytical and numerical means and indicate plausible astrophysical applications of these magnetized flow solutions with or without MHD shocks.Comment: 21 pages, 7 figures, accepted for publication in APS

A supernova constraint on bulk majorons

In models with large extra dimensions all gauge singlet fields can in principle propagate in the extra dimensional space. We have investigated possible constraints on majoron models of neutrino masses in which the majorons propagate in extra dimensions. It is found that astrophysical constraints from supernovae are many orders of magnitude stronger than previous accelerator bounds. Our findings suggest that unnatural types of the "see-saw" mechanism for neutrino masses are unlikely to occur in nature, even in the presence of extra dimensions.Comment: Minor changes, matches the version to appear in PR

The Minimal Supersymmetric Fat Higgs Model

We present a calculable supersymmetric theory of a composite ``fat'' Higgs boson. Electroweak symmetry is broken dynamically through a new gauge interaction that becomes strong at an intermediate scale. The Higgs mass can easily be 200-450 GeV along with the superpartner masses, solving the supersymmetric little hierarchy problem. We explicitly verify that the model is consistent with precision electroweak data without fine-tuning. Gauge coupling unification can be maintained despite the inherently strong dynamics involved in electroweak symmetry breaking. Supersymmetrizing the Standard Model therefore does not imply a light Higgs mass, contrary to the lore in the literature. The Higgs sector of the minimal Fat Higgs model has a mass spectrum that is distinctly different from the Minimal Supersymmetric Standard Model.Comment: 13 pages, 5 figures, REVTe

Origin and Properties of the Gap in the Half-Ferromagnetic Heusler Alloys

We study the origin of the gap and the role of chemical composition in the half-ferromagnetic Heusler alloys using the full-potential screened KKR method. In the paramagnetic phase the C1_b compounds, like NiMnSb, present a gap. Systems with 18 valence electrons, Z_t, per unit cell, like CoTiSb, are semiconductors, but when Z_t > 18 antibonding states are also populated, thus the paramagnetic phase becomes unstable and the half-ferromagnetic one is stabilized. The minority occupied bands accommodate a total of nine electrons and the total magnetic moment per unit cell in mu_B is just the difference between Z_t and $2 \times 9$. While the substitution of the transition metal atoms may preserve the half-ferromagnetic character, substituting the $sp$ atom results in a practically rigid shift of the bands and the loss of half-metallicity. Finally we show that expanding or contracting the lattice parameter by 2% preserves the minority-spin gap.Comment: 11 pages, 7 figures New figures, revised tex