Observation of Upsilon(3S)-->tau+tau- and tests of lepton universality in Upsilon decays

Using data collected with the CLEO III detector at the CESR e+e- collider, we report on a first observation of the decay Upsilon(3S)-->tau+tau-, and precisely measure the ratio of branching fractions of Upsilon(nS), n=1, 2, 3, to tau+tau- and mu+mu- final states, finding agreement with expectations from lepton universality. We derive absolute branching fractions for these decays, and also set a limit on the influence of a low mass CP-odd Higgs boson in the decay of the Upsilon(1S).     

Nanosegregated polymeric domains on the surface of Fe3O4@SiO2 particles

Multifunctional, biocompatible, and brush‐grafted poly(ethylene glycol)/poly(ε‐caprolactone) (PEG/PCL) nanoparticles have been synthesized, characterized, and used as vehicles for transporting hydrophobic substances in water. For anchoring the polymer mixed brushes, we used magnetic‐silica particles of 40 nm diameter produced by the reverse microemulsion method. The surface of the silica particle was functionalized with biocompatible polymer brushes, which were synthesized by the combination of “grafting to” and “grafting from” techniques. PEG was immobilized on the particles surface, by “grafting to,” whereas PCL was growth by ROP using the “grafting from” approach. By varying the synthetic conditions, it was possible to control the amount of PCL anchored on the surface of the nanoparticles and consequently the PEG/PCL ratio, which is a vital parameter connected with the arrangement of the polymer brushes as well as the hydrophobic/hydrophilic balance of the particles. Thus, adjusting the PEG/PCL ratio, it was possible to obtain a system formed by PEG and PCL chains grafted on the particle's surface that collapsed in segregated domains depending on the solvent used. For instance, the nanoparticles are colloidally stable in water due to the PEG domains and at the same time are able to transport, entrapped within the PCL portion, highly water‐insoluble drugs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2966–2975     

Far infrared impurity absorption in a quantum well

We have calculated the energy and lineshape of the 1s → 2p_x,y transition for a hydrogenic impurity located in a quantum well. Due to the dependence of the transition energy on the impurity location, the absorption lineshape is very sensitive to the doping profile. The spectrum, in general, exhibits two peaks, arising from impurities located near the center and the edges of the well.     

SO(10) v ×SO(10) H grand unified-extended technicolour models

We discuss a recently proposedSO(10) _v ×SO(10) _H grand unified-extended technicolour model. Because proton decay is probably too fast in this model, we study the other possible models based onSO(10) _v ×SO(10) _H . As a result of this analysis only a few of these models could possibly be realistic, they would be slight modifications of that previously proposed. None of them predicts the expected value forΛ _TC, it must be adjusted by introducing another mass scale. In these models ordinary fermion masses tend to be too small.     

Determination of hexacyanoferrate(II) with electrolytically generated octacyanomolybdate(V)

The determination of hexacyanoferrate(II) with electrolytically generated octacyanomolybdate(V) at a platinum anode over a wide pH range is described. From 1 to 20 muequiv are determined with a relative standard deviation of 0.3%.     

Stacking faults and partial dislocations in graphene

We investigate two mechanisms of crystallographic slip in graphene, corresponding to glide and shuffle generalized stacking faults (GSF), and compute their γ-curves using Sandia National Laboratories Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). We find evidence of metastable partial dislocations for the glide GSF only. The computed values of the stable and unstable stacking-fault energies are suggestive of a high stability of full dislocations against dissociation and of dislocation dipoles against annihilation.     

Solute-Solvent Interactions in Solutions of Solvatochromic Phenoxides: A Dynamics Simulation Study

Solute-solvent interactions in protic (water, methanol and 2-propanol) and aprotic (DMSO) solvents of four solvatochromic phenoxides, the 4- and 2-pyridiniophenoxides, Brooker’s merocyanine and the N-methyloxyquinolinium betaine, were investigated with the aid of molecular dynamics simulations. Although the size of the first solvation shell of the phenoxide oxygen of all betaines remains constant in the three protic solvents, it comprises increasingly fewer solvent molecules as the volume of the hydroxylic solvent increases. In DMSO, the donor phenoxide group of the 4-pyridiniophenoxide betaine is loosely solvated, leading to an internal charge-transfer with smaller transition energies than in protic media.     

Precision measurements of the timelike electromagnetic form factors of pion, kaon, and proton

Using 20.7 pb(-1) of e(+)e(-) annihilation data taken at sq.rt(r) = 3.671 GeV with the CLEO-c detector, precision measurements of the electromagnetic form factors of the charged pion, charged kaon, and proton have been made for timelike momentum transfer of |Q(2)| = 13.48 GeV(2) by the reaction e(+)e(-) --> h(+)h(-). The measurements are the first ever with identified pions and kaons of |Q(2)| > 4 GeV(2), with the results F(13.48 GeV(2)) = 0.075 +/- 0.008(stat) +/- 0.005(syst) and F(K)(13.48 GeV(2)) = 0.063 +/- 0.004(stat) +/- 0.001(syst). The result for the proton, assuming G(p)(E) = G(p)(M), is G(p)(M)(13.48 GeV(2)) = 0.014 +/- 0.002(stat) +/- 0.001(syst), which is in agreement with earlier results.