Distinctive signatures for new particles in e+ e− annihilation and z-decay

New particles and new interactions reveal themselves most clearly where standard model contributions are negligibly small. A prominent example with this advantage is the one-lepton inclusive longitudinal structure function (W_L) in e⁺ e^? annihilation and Z-decay. We discuss general features of this approach and present structure functions for two types of new particles (heavy charged fermion, e.g. new sequential lepton or top quark; and supersymmetric scalar lepton, i.e. slepton), along with the (small) standard model “background”. The x-dependence of W_L provides a distinct signature of the identity of the new particle. Extensions of this approach are discussed.     

Electrochemical immobilization of Cs in single-crystalline SYNROC

The development of a disposal technique for the radiotoxic ¹³⁷Cs in nuclear wastes is one of the most urgent issues in nuclear fuel technology. An effective disposal method of ¹³⁷Cs is to immobilize it in a synthetic rock (SYNROC) material: cesium titanate hollandite, ¹³⁷Cs_xTi₈O₁₆ (I4/m, , ). Practical applications of ¹³⁷Cs_xTi₈O₁₆ have been restricted so far because the conventional synthetic method requires strong chemical reducers and reaction temperatures higher than 1250 °C. In this report, we present a milder preparation method of Cs_xTi₈O₁₆ by electrolysis of a mixture of Cs₂MoO₄ and TiO₂ in ambient atmosphere at 900 °C. The Cs content in the resultant single-crystalline Cs_1.35Ti₈O₁₆ is competitive with the highest value in polycrystalline Cs_1.36±0.03Ti₈O₁₆ prepared by the conventional synthetic method. The electrochemical preparation of Cs_1.35Ti₈O₁₆ is a promising way to immobilize a high quantity of ¹³⁷Cs ions in a stable form of single-crystalline SYNROC.     

Electromagnetic radiation in a semi-compact space

In this note, we investigate the electromagnetic radiation emitted from a revolving point charge in a compact space. If the point charge is circulating with an angular frequency ${\omega }_0$ on the $(x,y)$-plane at $z=0$ with boundary conditions, $x～x+2\pi R$ and $y～y+2\pi R$, it emits radiation into the z-direction of $z\in [?\infty ,+\infty ]$. We find that the radiation shows discontinuities as a function of ${\omega }_{0}R$ at which a new propagating mode with a different Fourier component appears. For a small radius limit ${\omega }_{0}R?1$, all the Fourier modes except the zero mode on $(x,y)$-plane are killed, but an effect of squeezing the electric field totally enhances the radiation. In the large volume limit ${\omega }_{0}R\to \infty$, the energy flux of the radiation reduces to the expected Larmor formula.     

Photoreversible Gelation of a Triblock Copolymer in an Ionic Liquid

The reversible micellization and sol–gel transition of block copolymer solutions in an ionic liquid (IL) triggered by a photostimulus is described. The ABA triblock copolymer employed, denoted P(AzoMA‐r‐NIPAm)‐b‐PEO‐b‐P(AzoMA‐r‐NIPAm)), has a B block composed of an IL‐soluble poly(ethylene oxide) (PEO). The A block consists of a random copolymer including thermosensitive N‐isopropylacrylamide (NIPAm) units and a methacrylate with an azobenzene chromophore in the side chain (AzoMA). A phototriggered reversible unimer‐to‐micelle transition of a dilute ABA triblock copolymer (1 wt %) was observed in an IL, 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C₄mim]PF₆), at an intermediate “bistable” temperature (50 °C). The system underwent a reversible sol–gel transition cycle at the bistable temperature (53 °C), with reversible association/fragmentation of the polymer network resulting from the phototriggered self‐assembly of the ABA triblock copolymer (20 wt %) in [C₄mim]PF₆.     

“Dumbbell”‐ and “Clackers”‐Shaped Dimeric Derivatives of Monocarba‐closo‐dodecaborate

We designed, synthesized, and characterized two types of dimeric forms of monocarba‐closo‐dodecaborate, namely, a “dumbbell”‐shaped dianion having a C?C bond and a “clackers”‐shaped monoanion having an iodonium linker. The unique architectures of these anionic molecules were established by X‐ray analysis. Spectroscopic analysis, DFT calculations, and reactivity experiments revealed high anionic and chemical stability of both anions, which are crucial properties for weakly coordinating anions.     

Electronic interactions in a new fullerene dimer: C(122)H(4), with two methylene bridges

The isolation of a new fullerene dimer, C(122)H(4), and its structural characterization by (13)C NMR and (1)H NMR spectroscopy and by UV/vis and IR spectroscopy are reported. The structure of this dimer consists of two fullerene cages, which are directly connected through two C-C bonds and two methylene bridges. Consequently, adjacent hexagonal faces of the two fullerene cages are arranged in a face to face manner. Molecular orbital calculations indicate that the proximity of the fullerene cages results in significant through space overlap in both the HOMO and LUMO. As a consequence of this overlap, the electrochemistry of the dimer shows electronic communication with stepwise reduction of each cage.     

Effective mass of electrons in BaPb1−xBixO3

The reflectivity spectra of BaPb_1?xBi_xO₃ were measured in near-infrared region in several samples. The effective masses for the metallic samples of compositions from x = 0 to 0.25 were estimated from the observed plasma edges to be 0.5–0.8 m_e. These values are rather small comparing with those in other typical high T_c superconductors.