We perform an analysis of QCD lattice data on charmed meson masses. The quark-mass dependence of the data set is used to gain information on the size of counter terms of the chiralLagrangian formulated with open-charm states with J P = 0 − and J P = 1 − quantum numbers. Of particular interest are those counter terms that are active in the exotic flavour sextet channel. A chiral expansion scheme where physical masses enter the extrapolation formulae is developed and applied to the lattice data set. Good convergence properties are demonstrated and an accurate reproduction of the lattice data based on ensembles of PACS-CS, MILC, ETMC and HSC with pion and kaon masses smaller than 600 MeV is achieved. It is argued that a unique set of low-energy parameters is obtainable only if additional information from HSC on some scattering observables is included in our global fits. The elastic and inelastic s-wave πD and ηD scattering as considered by HSC is reproduced faithfully. Based on such low-energy parameters we predict 15 phase shifts and in-elasticities at physical quark masses but also for an additional HSC ensemble at smaller pion mass. In addition we find a clear signal for a member of the exotic flavour sextet states in the ηD channel, below theKD s threshold. For the isospin violating strong decay width of the D * s0 (2317) we obtain the range (104 − 116) keV.
We study the chiral expansion of the baryon octet and decuplet masses in the isospin limit. It is illustrated that a chiral expansion of the one-loop contributions is rapidly converging up to quark masses that generously encompasses the mass of the physical strange quark. We express the successive orders in terms of physical meson and baryon masses. In addition, owing to specific correlations amongst the chiral moments, we suggest a reordering of terms that make the convergence properties more manifest. Explicit expressions up to chiral order five are derived for all baryon masses at the one-loop level. The baryon masses obtained do not depend on the renormalization scale. Our scheme is tested against QCD lattice data, where the low-energy parameters are systematically correlated by large-N c sum rules. A reproduction of the baryon masses from PACS-CS, LHPC, HSC, NPLQCD, QCDSF-UKQCD and ETMC is achieved for ensembles with pion and kaon masses smaller than 600 MeV. Predictions for baryon masses on ensembles from CLS as well as all low-energy constants that enter the baryon masses at N 3 LO are made.
A new family of axially unfixed biaryl-based water-compatible bifuctional organocatalysts were designed and synthesized for the asymmetric direct Michael reaction of cyclohexanone with various nitroolefins in water. One of the organocatalysts incorporates pyrrolidine and arylsulfonamide motifs as active organocatalytic sites, and axially unfixed biaryl as a skeleton; with this organocatalyst, the direct Michael reactions proceeded readily, furnishing the desired Michael adducts in high yields (up to 99% yield) with high levels of stereocontrol (up to >99:1 dr and 94% ee).The asymmetric organocatalytic direct Michael reaction represents one of the most efficient and powerful methods for the formation of C-C or C-heteroatom bonds, and has been widely used to generate enantioenriched organic compounds in the context of drug discovery and organic synthesis of natural products and heterocycles. 1 Since the seminal works of List and Barbas, many efficient and highly stereoselective organocatalysts have been developed for the asymmetric direct Michael reactions. 2 To the best of our knowledge, most of the reports deal with such reactions in organic solvents. In view of the clear advantages of performing organocatalytic direct Michael reactions in water, many recent efforts have been devoted to the development of highly efficient water-compatible organocatalysts. 3 The main challenges with the development of such catalysts stem from interference in the transition state by water, which reduces the reactivity and level of stereocontrol of the organocatalysts. 4 Encouraged by the pioneering findings of Barbas, a number of watercompatible organocatalysts has been devised for the direct Michael additions of ketones or aldehydes to nitroolefins in water with high yields and levels of stereocontrol. 5 It has been demonstrated that the success of these watercompatible organocatalysts in the direct Michael reactions in water depends significantly on the fact that they can assemble with the Michael donors and acceptors, and sequester water from the transition states of the direct Michael reactions in water efficiently through hydrophobic interactions. Evidently, sufficient hydrophobicity of the water-compatible organocatalysts is necessary to achieve high levels of stereocontrol in direct Michael reactions in water. The appropriate hydrophobicity of the water-compatible organocatalysts can be afforded by the introduction of a bulky hydrophobic group into the architecture of the organocatalysts. To date, through the choice of different bulky hydrophobic scaffolds, 6 several tens of highly efficient water-compatible organocatalysts have already been developed to perform direct Michael reactions in water. However, so far, there have been no reports on the development of hydrophobic axially unfixed chiral biphenyl-or bipyridyl-based water-compatible organocatalysts for the direct Michael reactions in water. Accordingly, the development of novel water-compatible organocatalysts that catalyze such reactions efficiently through the use o...
We study the chiral expansion of meson masses and decay constants using a chiral Lagrangian that was constructed previously based on the hadrogenesis conjecture. The one-loop self energies of the Goldstone bosons and vector mesons are evaluated. It is illustrated that a renormalizeable effective field theory arises once specific conditions on the low-energy constants are imposed. For the case where the hadrogenesis mass gap scale Λ HG is substantially larger than the chiral symmetry breaking scale Λ χ a partial summation scheme is required. All terms proportional to (M/Λ χ ) n can be summed by a suitable renormalization, where M is the chiral and large-N c limit of the vector meson masses in QCD. The size of loop effects from vector meson degrees of freedom is illustrated for physical quarks masses. Naturally sized effects are observed that have significant impact on the chiral structure of low-energy QCD with three light flavours.
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