A possible interpretation of CDF dijet mass anomaly and its realization in supersymmetry

Recently, the CDF Collaboration reports an anomaly in dijet mass distribution in association with a lepton and missing energy. We discuss a possibility that the origin of the lepton and missing energy comes not from a W boson but a new boson particle, which is also responsible for the dijet mass peak. We show that such a situation can be realized in the framework of the minimal supersymmetric standard model and the dijet anomaly can be explained.     

Calorimetric study of the cubic mesogen, ACBC(6)

The heat capacity of the cubic mesogen ACBC(16) was measured between 16 and 500 K by adiabatic calorimetry. As well as the known condensed phases, a new crystalline phase was found to undergo a glass transition at around 165 K. Phase transitions between crystal, SmC, cubic, and isotropic liquid phases took place at 399.16, 431.15, and 474.30 K, respectively. As in the case of ANBC, a broad hump was observed in the heat capacity of the isotropic liquid phase. The first order nature of the SmC-cubic phase transition was confirmed for the first time by the observation of supercooling of the cubic phase. The broad hump in the isotropic liquid phase was shown to extend to a low temperature side if the isotropic liquid was supercooled, suggesting that the event occurring at the hump is not directly related to the cubic-isotropic liquid phase transition.     

Lognormal Modes of Dielectric Optical Waveguides

It is shown that, at a critical point where the effective refractive index of a mode coincides with the bulk index of a cladding region, optical waveguide modes exhibiting a lognormal feature are supportable for a hyperlongrange refractive-index profile. As a typical example of waveguides that support lognormal modes a parabolic-index core surrounded by a depressed-index cladding is presented.     

Asymmetric Total Synthesis of ent‐Pyripyropene A

An asymmetric total synthesis of ent‐pyripyropene A was achieved by a convergent synthetic route. We used our originally developed Ti^III‐catalyzed radical cyclization to construct an AB‐ring portion that consisted of a trans‐decalin skeleton with five contiguous stereogenic centers. The coupling between the AB‐ring and the DE‐ring portions, and a subsequent C‐ring cyclization, led to the total synthesis of ent‐pyripyropene A. An evaluation of the insecticidal activity of ent‐pyripyropene A against two aphid species revealed that ent‐pyripyropene A was 35–175 times less active than naturally occurring pyripyropene A. This result indicated that the biological target of pyripyropene A recognizes the absolute configuration of pyripyropene A.     

Highly photoluminescent nanocrystals based on a gold(I) complex and their electrophoretic patterning

The fabrication of nanocrystals (NCs) composed of the cationic Au(I) complex was demonstrated by the reprecipitation method in which the colloidal solution of the NCs showed brilliant green phosphorescence with a quantum yield of 83% in n-hexane. Characterization of the prepared NCs was performed by transmission electron microscopy observation and elemental analysis with energy-dispersive X-ray spectroscopy. The obtained Au(I) NCs were particles of random shapes with a diameter of 200-400 nm. The selected-area electron diffraction and X-ray diffraction measurements showed the characteristic diffraction patterns attributable to the crystal structure of the bulk crystal of the Au(I) complex. A similar method was performed with a different counteranion, leading to a colloidal solution of the microcrystals (MCs) with brilliant yellow phosphorescence and a quantum yield of 26% in n-hexane. Luminescence patterning of the NCs and MCs was also achieved successfully by electrophoretic deposition onto an indium tin oxide (ITO)-coated glass substrate, resulting in characteristic luminescence patterns on the ITO substrates with relatively high photoluminescence quantum yields.     

Cyanide-bridged [Fe8M6] clusters displaying single-molecule magnetism (M=Ni) and electron-transfer-coupled spin transitions (M=Co)

Cyanide‐bridged metal complexes of [Fe₈M₆(μ‐CN)₁₄(CN)₁₀ (tp)₈(HL)₁₀(CH₃CN)₂][PF₆]₄?n CH₃CN?m H₂O (HL=3‐(2‐pyridyl)‐5‐[4‐(diphenylamino)phenyl]‐1H‐pyrazole), tp^?=hydrotris(pyrazolylborate), 1 : M=Ni with n=11 and m=7, and 2 : M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2₁/n. They have tetradecanuclear cores composed of eight low‐spin (LS) Fe^III and six high‐spin (HS) M^II ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown‐like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro‐ and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2 , respectively. Ac magnetic susceptibility measurements of 1 showed frequency‐dependent in‐ and out‐of‐phase signals, characteristic of single‐molecule magnetism (SMM), while desolvated samples of 2 showed thermal‐ and photoinduced intramolecular electron‐transfer‐coupled spin transition (ETCST) between the [(LS‐Fe^II)₃(LS‐Fe^III)₅(HS‐Co^II)₃(LS‐Co^III)₃] and the [(LS‐Fe^III)₈(HS‐Co^II)₆] states.     

Photochemical activation of ruthenium(II)-pyridylamine complexes having a pyridine-N-oxide pendant toward oxygenation of organic substrates

Ruthenium(II)-acetonitrile complexes having η(3)-tris(2-pyridylmethyl)amine (TPA) with an uncoordinated pyridine ring and diimine such as 2,2'-bipyridine (bpy) and 2,2'-bipyrimidine (bpm), [Ru(II)(η(3)-TPA)(diimine)(CH(3)CN)](2+), reacted with m-chloroperbenzoic acid to afford corresponding Ru(II)-acetonitrile complexes having an uncoordinated pyridine-N-oxide arm, [Ru(II)(η(3)-TPA-O)(diimine)(CH(3)CN)](2+), with retention of the coordination environment. Photoirradiation of the acetonitrile complexes having diimine and the η(3)-TPA with the uncoordinated pyridine-N-oxide arm afforded a mixture of [Ru(II)(TPA)(diimine)](2+), intermediate-spin (S = 1) Ru(IV)-oxo complex with uncoordinated pyridine arm, and intermediate-spin Ru(IV)-oxo complex with uncoordinated pyridine-N-oxide arm. A Ru(II) complex bearing an oxygen-bound pyridine-N-oxide as a ligand and bpm as a diimine ligand was also obtained, and its crystal structure was determined by X-ray crystallography. Femtosecond laser flash photolysis of the isolated O-coordinated Ru(II)-pyridine-N-oxide complex has been investigated to reveal the photodynamics. The Ru(IV)-oxo complex with an uncoordinated pyridine moiety was alternatively prepared by reaction of the corresponding acetonitrile complex with 2,6-dichloropyridine-N-oxide (Cl(2)py-O) to identify the Ru(IV)-oxo species. The formation of Ru(IV)-oxo complexes was concluded to proceed via intermolecular oxygen atom transfer from the uncoordinated pyridine-N-oxide to a Ru(II) center on the basis of the results of the reaction with Cl(2)py-O and the concentration dependence of the consumption of the starting Ru(II) complexes having the uncoordinated pyridine-N-oxide moiety. Oxygenation reactions of organic substrates by [Ru(II)(η(3)-TPA-O)(diimine)(CH(3)CN)](2+) were examined under irradiation (at 420 ± 5 nm) and showed selective allylic oxygenation of cyclohexene to give cyclohexen-1-ol and cyclohexen-1-one and cumene oxygenation to afford cumyl alcohol and acetophenone.     

Selective photoinduced energy transfer from a thiophene rotaxane to acceptor

An energy transfer process was investigated using cyclodextrin-oligothiophene rotaxanes (2T-[2]rotaxane). The excited energy of 2T-[2]rotaxane is transferred to the sexithiophene derivative which is included in the cavity of β-CD stoppers of 2T-[2]rotaxane.     

Experimental assessment of quasi-binary picture of thermotropics: induced smectic A phase in 7CB-n-heptane system

Quasi-binary (QB) picture of thermotropics, which regards a neat thermotropic liquid crystal as a binary system consisting of (semi)rigid core and molten alkyl chain, was assessed experimentally for the most famous (and representative) thermotropic mesogenic series nCB. By adding n-heptane as solvent, the smectic A phase was induced in 7CB-n-heptane system. Small angle x-ray diffraction showed that the QB picture holds not only in the phase behavior but also in the structure. It is suggested that the melting of 8CB and 9CB to isotropic liquid via smectic and nematic liquid crystals can be understood as a thermotropic-lyotropic crossover.