Publisher's Note: Axial charges of octet and decuplet baryons [Phys. Rev. D 82, 014007 (2010)]
No abstract prepared.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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Lowest-lying baryon masses in covariant SU(3)-flavor chiral perturbation theory
We present an analysis of the baryon-octet and -decuplet masses using covariant SU(3)-flavor chiral perturbation theory up to next-to-leading order. Besides the description of the physical masses we address the problem of the lattice QCD extrapolation. Using the PACS-CS Collaboration data we show that a good description of the lattice points can be achieved at next-to-leading order with the covariant loop amplitudes and phenomenologically determined values for the meson-baryon couplings. Moreover, the extrapolation to the physical point up to this order is found to be better than the linear one given at leading-order by the Gell-Mann-Okubo approach. The importance that a reliable combination of lattice QCD and chiral perturbation theory may have for hadron phenomenology is emphasized with the prediction of the pion-baryon and strange-baryon sigma terms.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Large-N{sub c} operator analysis of 2-body meson-baryon counterterms in the chiral Lagrangian
The chiral SU(3) Lagrangian with the baryon octet and decuplet fields is considered. The Q{sup 2} counterterms involving the decuplet fields are constructed. We derive the correlation of the chiral parameters implied by the 1/N{sub c} expansion at leading order in QCD.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Color Sextet Scalars in Early LHC Experiments
We explore the potential for discovery of an exotic color sextet scalar in same-sign top quark pair production in early running at the LHC. We present the first phenomenological analysis at colliders of color sextet scalars with full top quark spin correlations included. We demonstrate that one can measure the scalar mass, the top quark polarization, and confirm the scalar resonance with 1 fb{sup -1} of integrated luminosity. The top quark polarization can distinguish gauge triplet and singlet scalars.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Bosons, fermions and anyons in the plane, and supersymmetry
Universal vector wave equations allowing for a unified description of anyons, and also of usual bosons and fermions in the plane are proposed. The existence of two essentially different types of anyons, based on unitary and also on non-unitary infinite-dimensional half-bounded representations of the (2 + 1)D Lorentz algebra is revealed. Those associated with non-unitary representations interpolate between bosons and fermions. The extended formulation of the theory includes the previously known Jackiw-Nair (JN) and Majorana-Dirac (MD) descriptions of anyons as particular cases, and allows us to compose bosons and fermions from entangled anyons. The theory admits a simple supersymmetric generalization, in which the JN and MD systems are unified in N = 1 and N = 2 supermultiplets. Two different non-relativistic limits of the theory are investigated. The usual one generalizes Levy-Leblond's spin 1/2 theory to arbitrary spin, as well as to anyons. The second, 'Jackiw-Nair' limit (that corresponds to Inoenue-Wigner contraction with both anyon spin and light velocity going to infinity), is generalized to boson/fermion fields and interpolating anyons. The resulting exotic Galilei symmetry is studied in both the non-supersymmetric and supersymmetric cases.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Macroscopic properties of triplon Bose-Einstein condensates
Magnetic insulators can be characterized by a gap separating the singlet ground state from the lowest-energy triplet, S=1 excitation. If the gap can be closed by the Zeeman interaction in applied magnetic field, the resulting quasiparticles, triplons, can have concentrations sufficient to undergo the Bose-Einstein condensates transition. We consider macroscopic properties of the triplon Bose-Einstein condensates in the Hartree-Fock-Bogoliubov approximation taking into account the anomalous averages. We prove that these averages play the qualitative role in the condensate properties. As a result, we show that with the increase in the external magnetic field at a given temperature, the condensate demonstrates an instability related to the appearance of nonzero phonon damping and a change in the characteristic dependence of the speed of sound on the magnetic field. The calculated magnetic susceptibility diverges when the external magnetic field approaches this instability threshold, providing a tool for the experimental verification of this approach. - Highlights: > A consistent theory of the triplon BEC should consider the anomalous density terms. > These terms strongly modify the macroscopic properties of the BEC. > They lead to the instability of the BEC in strong enough magnetic fields. > The instability can be observed in neutron scattering and magnetization experiments.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Quantitative study of the f occupation in CeMIn5 and other cerium compounds with hard X-rays
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Crystal structures and luminescent properties of lanthanide nitrate coordination polymers with structurally related amide type bridging podands
A one-dimensional linear chain coordination polymer [ErL{sup I}(NO{sub 3}){sub 3}(CH{sub 3}CO{sub 2}Et)]{sub n} (L{sup I}=1,2-bis{l_brace}[(2'-furfurylaminoformyl)phenoxyl]methyl{r_brace}benzene) and a one-dimensional zig-zag coordination polymer {l_brace}[TbL{sup II}(NO{sub 3}){sub 3}(H{sub 2}O)].(H{sub 2}O){r_brace}{sub n} (L{sup II}=1,2-bis{l_brace}[2'-(2-pyridylmethylaminoformyl)phenoxyl]methyl{r_brace}benzene) were assembled by two structurally related bridging podands L{sup I} and L{sup II} which have uniform skeleton and different terminal groups. In {l_brace}[TbL{sup II}(NO{sub 3}){sub 3}(H{sub 2}O)].(H{sub 2}O){r_brace}{sub n}, the neutral chains were linked by the hydrogen bonding interactions between the free and coordinated water molecules from two different directions to interpenetrate into a 3D supramolecular structure. At the same time, the luminescent properties of the solid Tb(III) nitrate complexes of these podands were investigated at room temperature. The lowest triplet state energy levels T{sub 1} of the podands L{sup I} and L{sup II} indicate that the triplet state energy levels of the antennae are both above the lowest excited resonance level of {sup 5}D{sub 4} of Tb{sup 3+} ion. Thus the absorbed energy could be transferred from ligands to the central Tb{sup 3+} ions. And the influence of the hydrogen bonding on the luminescence efficiencies of the coordination polymers was also discussed. -- Graphical Abstract: Two one-dimensional lanthanide coordination polymers were assembled by two structurally related bridging podands, and the effects of the structures on luminescent properties of the solid Tb(III) nitrate complexes were investigated. Display Omitted Research highlights: > Two structurally related amide type bridging ligands were designed and synthesized. > Two one dimensional lanthanide nitrate coordination polymers were obtained. > The structure effects on luminescent properties of the terbium complexes were discussed.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates
The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe 2+ ) and ferric (Fe 3+ ) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe 3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic C=C, ester, phenol and anomeric C (R-O-C-O-R), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. In conclusion, our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Minimal unitary representation of SU(2,2) and its deformations as massless conformal fields and their supersymmetric extensions
We study the minimal unitary representation (minrep) of SO(4,2) over a Hilbert space of functions of three variables, obtained by quantizing its quasiconformal action on a five dimensional space. The minrep of SO(4,2), which coincides with the minrep of SU(2,2) similarly constructed, corresponds to a massless conformal scalar in four space-time dimensions. There exists a one-parameter family of deformations of the minrep of SU(2,2). For positive (negative) integer values of the deformation parameter {zeta}, one obtains positive energy unitary irreducible representations corresponding to massless conformal fields transforming in (0,{zeta}/2)((-{zeta}/2,0)) representation of the SL(2,C) subgroup. We construct the supersymmetric extensions of the minrep of SU(2,2) and its deformations to those of SU(2,2|N). The minimal unitary supermultiplet of SU(2,2|4), in the undeformed case, simply corresponds to the massless N=4 Yang-Mills supermultiplet in four dimensions. For each given nonzero integer value of {zeta}, one obtains a unique supermultiplet of massless conformal fields of higher spin. For SU(2,2|4), these supermultiplets are simply the doubleton supermultiplets studied in the work of Gunaydin et al. [Nucl. Phys. B 534, 96 (1998); e-print arXiv:hep-th/9806042].
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Imaging the radical channel in acetaldehyde photodissociation: Competing mechanisms at energies close to the triplet exit barrier
The photodissociation of acetaldehyde in the radical channel has been studied at wavelengths between 315 and 325 nm using the velocity-map imaging technique. Upon one-photon absorption at 315 nm, the molecule is excited to the first singlet excited state S{sub 1}, which, in turn, undergoes intersystem crossing to the first excited triplet state T{sub 1}. On the triplet surface, the molecule dissociates into CH{sub 3} and HCO radicals with large kinetic energy release (KER), in accordance with the well characterized exit barrier on T{sub 1}. However, at longer wavelengths (>320 nm), which correspond to excitation energies just below the triplet barrier, a sudden change in KER is observed. At these photolysis wavelengths, there is not enough energy to surpass the exit barrier on the triplet state, which leaves the possibility of unimolecular dissociation on S{sub 0} after internal conversion from S{sub 1}. We have characterized the fragments' KER at these wavelengths, as well as determined the energy partitioning for the radical fragments. A new accurate estimate of the barrier height on T{sub 1} is presented.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Reaction of C{sub 2}H{sub 2}{sup +} (n{center_dot}{nu}{sub 2}, m{center_dot}{nu}{sub 5}) with NO{sub 2}: Reaction on the singlet and triplet surfaces
Integral cross sections and product recoil velocity distributions were measured for reaction of C{sub 2}H{sub 2}{sup +} with NO{sub 2}, in which the C{sub 2}H{sub 2}{sup +} reactant was prepared in its ground state, and with mode-selective excitation in the cis-bend (2{nu}{sub 5}) and CC stretch (n{center_dot}{nu}{sub 2}, n = 1, 2). Because both reactants have one unpaired electron, collisions can occur with either singlet or triplet coupling of these unpaired electrons, and the contributions are separated based on distinct recoil dynamics. For singlet coupling, reaction efficiency is near unity, with significant branching to charge transfer (NO{sub 2}{sup +}), O{sup -} transfer (NO{sup +}), and O transfer (C{sub 2}H{sub 2}O{sup +}) products. For triplet coupling, reaction efficiency varies between 13% and 19%, depending on collision energy. The only significant triplet channel is NO{sup +}+ triplet ketene, generated predominantly by O{sup -} transfer, with a possible contribution from dissociative charge transfer at high collision energies. NO{sub 2}{sup +} formation (charge transfer) can only occur on the singlet surface, and appears to be mediated by a weakly bound complex at low energies. O transfer (C{sub 2}H{sub 2}O{sup +}) also appears to be dominated by reaction on the singlet surface, but is quite inefficient, suggesting a bottleneck limiting coupling to this product from the singlet reaction coordinate. The dominant channel is O{sup -} transfer, producing NO{sup +}, with roughly equal contributions from reaction on singlet and triplet surfaces. The effects of C{sub 2}H{sub 2}{sup +} vibration are modest, but mode specific. For all three product channels (i.e., charge, O{sup -}, and O transfer), excitation of the CC stretch fundamental ({nu}{sub 2}) has little effect, 2{center_dot}{nu}{sub 2} excitation results in {approx}50% reduction in reactivity, and excitation of the cis-bend overtone (2{center_dot}{nu}{sub 5}) results in {approx}50% enhancement. The fact that all channels have similar mode dependence suggests that the rate-limiting step, where vibrational excitation has its effect, is early on the reaction coordinate, and branching to the individual product channels occurs later.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
On nonminimal N=4 supermultiplets in 1D and their associated {sigma}-models
We construct the nonminimal linear representations of the N=4 extended supersymmetry in one-dimension. They act on eight bosonic and eight fermionic fields. Inequivalent representations are specified by the mass-dimension of the fields and the connectivity of the associated graphs. The oxidation to minimal N=5 linear representations is given. Two types of N=4{sigma}-models based on nonminimal representations are obtained: the resulting off-shell actions are either manifestly invariant or depend on a constrained prepotential. The connectivity properties of the graphs play a decisive role in discriminating inequivalent actions. These results find application in partial breaking of supersymmetric theories.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Effective interactions and long distance symmetries in the Nucleon-Nucleon system
Effective interactions, when defined in a coarse grained sense, such as V{sub lowk} at the scale {Lambda} = 450 MeV, display a remarkable symmetry pattern. Serber symmetry works with high accuracy for spin triplet states. Wigner SU(4) spin-isospin symmetry with nucleons in the fundamental representation works only for even partial waves exactly as predicted by large N{sub c} limit of QCD with accuracy O(1/N{sub c}{sup 2}). This suggests tailoring the very definition of effective interactions to provide a best possible fulfillment of long distance symmetries. With the V{sub lowk} definition Wigner symmetry requires that chiral potentials have low cut-offs {Lambda}{sub {chi}{approx}4}50 MeV. Perturbative saturation of exchanged heavy mesonic resonances does not faithfully display the Serber symmetry pattern.
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Photoelectron angular distributions from autoionizing 4s{sup 1}4p{sup 6}6p{sup 1} states in atomic krypton probed with femtosecond time resolution
Photoelectron angular distributions (PADs) are obtained for a pair of 4s{sup 1}4p{sup 6}6p{sup 1} (a singlet and a triplet) autoionizing states in atomic krypton. A high-order harmonic pulse is used to excite the pair of states and a time-delayed 801 nm ionization pulse probes the PADs to the final 4s{sup 1}4p{sup 6} continuum with femtosecond time resolution. The ejected electrons are detected with velocity map imaging to retrieve the time-resolved photoelectron spectrum and PADs. The PAD for the triplet state is inherently separable by virtue of its longer autoionization lifetime. Measuring the total signal over time allows for the PADs to be extracted for both the singlet state and the triplet state. Anisotropy parameters for the triplet state are measured to be {beta}{sub 2}= 0.55 {+-} 0.17 and {beta}{sub 4}=-0.01 {+-} 0.10, while the singlet state yields {beta}{sub 2}= 2.19 {+-} 0.18 and {beta}{sub 4}= 1.84 {+-} 0.14. For the singlet state, the ratio of radial transition dipole matrix elements, X, of outgoing S to D partial waves and total phase shift difference between these waves, {Delta}, are determined to be X= 0.56 {+-} 0.08 and {Delta}= 2.19 {+-} 0.11 rad. The continuum quantum defect difference between the S and D electron partial waves is determined to be -0.15 {+-} 0.03 for the singlet state. Based on previous analyses, the triplet state is expected to have anisotropy parameters independent of electron kinetic energy and equal to {beta}{sub 2}= 5/7 and {beta}{sub 4}=-12/7. Deviations from the predicted values are thought to be a result of state mixing by spin-orbit and configuration interactions in the intermediate and final states; theoretical calculations are required to quantify these effects.
74 ATOMIC AND MOLECULAR PHYSICS↗
An infinite-dimensional calculus for generalized connections on hypercubic lattices
A space for gauge theories is defined, using projective limits as subsets of Cartesian products of homomorphisms from a lattice on the structure group. In this space, non-interacting and interacting measures are defined as well as functions and operators. From projective limits of test functions and distributions on products of compact groups, a projective gauge triplet is obtained, which provides a framework for the infinite-dimensional calculus in gauge theories. The gauge measure behavior on non-generic strata is also obtained.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Lambda-Nucleon Potential Calculated from Lattice QCD
We present our studies of Lambda-Nucleon ({Lambda}N) interaction by using lattice QCD. The equal-time Nambu-Bethe-Salpeter (NBS) amplitude of the lowest energy scattering state of a proton-{Lambda} system is calculated from lattice QCD. In this report, two different types of gauge configurations are employed: (i) Quenched QCD configurations at {beta} = 5.7 (a = 0.1416(9) fm) on a 32{sup 3}x48 lattice, whose spatial volume is (4.5 fm){sup 3}.(ii)2+1 flavor full QCD configurations generated by the PACS-CS collaboration at {beta} = 1.9 (a = 0.0907(13) fm) on a 32{sup 3}x64 lattice, whose spatial volume is (2.90 fm){sup 3}. The spin-singlet central potential is calculated from the NBS wave function for the spin J = 0 state, whereas the spin-triplet central potential as well as the tensor potential are deduced simultaneously from the NBS wave function for the spin J = 1 state by dividing it into the S-wave and the D-wave components.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Dephasing of strong coupling in the non-linear regime
We study the effect of pure dephasing on the strong-coupling of a two-level system (typically, a quantum dot) with the single mode of a microcavity. Whereas dephasing merely broadens the line in the linear regime, it results in a new spectral shape when transitions between higher manifolds of the Jaynes-Cummings ladder are involved, namely, a triplet, that we show does not imply weak-coupling. Higher excitation brings the system into lasing. Description of this intermediate triplet allows to demonstrate quantum nonlinearities even in noisy systems and to measure the magnitude of dephasing.
77 NANOSCIENCE AND NANOTECHNOLOGY↗