Is the (hfac)Cu(I)–(tmvs) bond intrinsically weak?

Density functional theory studies were performed to study the structure and bonding of (hexafluoroacetylacetonate)-copper(I)-(trimethylvinylsilane) [Cu(hfac)(tmvs)], an ideal and important Cu(I)-CVD compound. A popular three-parameter hybrid density functional (B3LYP) with 6-311+G(d,p) and an effective core potential included LanL2DZ basis set was utilized for this purpose. The (hfac)Cu–(tmvs) bond energy of approximately 30?kcal?mol^?1 obtained at the B3LYP/6-311+G(d,p) level of theory reveals that the Cu–olefin bond in Cu(hfac)(tmvs) is not as weak as previously estimated/assumed and, hence, that the substrate plays a vital role in copper film formation from Cu(hfac)(tmvs). Bonding analysis reveals that fairly strong (hfac)Cu–(tmvs) bonding is the result of DCD-model σ-donation and π-back-bonding between the copper and tmvs in Cu(hfac)(tmvs).     

How to Determine the Spin of the ξ(2230)

The possibility for increasing the statistics by summing up the events of decaying into two pseudo scalar mesons from the existing data samples is discussed.     

Hyperons Analogous to the Λ(1405)

The low mass of the Λ(1405) hyperon with j ^P =  1/2^?, which is higher than the ground state Λ(1116) mass by 290 MeV, is difficult to understand in quark models. We analyze the hyperon spectrum in the bound state approach of the Skyrme model that successfully describes both the Λ(1116) and the Λ(1405). This model predicts that several hyperon resonances of the same spin but with opposite parity form parity doublets that have a mass difference of around 300 MeV, which is indeed realized in the observed hyperon spectrum. Furthermore, the existence of the ${\Xi(1620)}$ and the ${\Xi(1690)}$ of j ^P  = 1/2^? is predicted by this model. Comments on the Ω baryons and heavy quark baryons are made as well.     

Interpretation of Z_b(10610)and Z_b(10650)in the ISPE mechanism and the Charmonium Counterpart~

The initial single pion emission(ISPE) mechanism is applied to the processes γ(55)→πB~((*))B~((*)),whose details have been recently reported at ICHEP2012,and we obtain reasonable agreement with Bell's measurements;that is,we succeed in reproducing the enhancement structures of Zb(10610) and Zb(10650).Inspired by this success,we also predict the corresponding enhancement structures in open charm one-pion decays of higher charmonia near the thresholds of D*D and D*D*.     

On the role of the Δ(1232) on the transverse nuclear response in the (e,e′) reaction

The transverse nuclear response to an electromagnetic probe which is limited to create (or destroy) a particle-hole (ph) or delta-hole (Δh) pair is analyzed. Correlations of the random phase approximation (RPA) type and self-energy insertions are considered. For RPA correlations we have developed a scheme which includes explicitly the Δ and the exchange terms. Self-energy insertions over ph and Δh bubbles are studied. Several residual interactions based on a contact plus a (π + ϱ)-meson exchange potential are used. All calculations are performed in non-relativistic nuclear matter. The main effect of the Δ is to reduce the intensity over the nuclear quasi-elastic peak. Exchange RPA terms are very important, while the terms with self-energy insertions depend strongly on the residual interaction employed. Our results are compared with data for ⁴⁰Ca at momentum transfer q = 410 and q = 550 MeV/c, where the longitudinal response is also briefly discussed.     

Violation of the Okubo-Zweig-Iizuka rule in the decay mode B(1235) →φ(1020) +π

The Okubo-Zweig-Iizuka rule forbids the transitionB(1235)→φπ. Unitarity, however, induces a non-vanishing amplitude forB→φπ. We estimate the amplitude using dispersion relation. The absorptive part is shown to be small contributing less than 100 keV to the partial width Γ (B→φπ). For the dispersive part we evaluate the contributions of the and intermediate states and point out that the state does not contribute significantly. The dispersive part contributes about 300 keV to the partial width. Thus unitarity correction to the Okubo-Zweig-Iizuka rule gives the partial width Γ(B→φπ) to be around 300–400 keV compared with the present experimental upper limit of 1·9 MeV.     

Estimate of the Δ(1232) component in the 12C nucleus

The cross section for the ¹²C(γ, π⁺ p) reaction was measured in the range of the Δ(1232) isobar. The data were analyzed using the models taking into account the nucleon and isobaric degrees of freedom of the ¹²C nucleus. The conclusion is drawn that in the large-momentum transfer range the π⁺ p pairs are produced in the course of the direct knocking-out of Δ⁺⁺ isobar from the nucleus. The probability of finding the Δ isobar in the ground-state ¹²C nucleus is estimated at 0.018±0.005 Δ isobars per nucleon.     

Isolating the Λ(1405) in lattice QCD

The odd-parity ground state of the Λ baryon lies surprisingly low in mass. At 1405 MeV, it lies lower than the odd-parity ground-state nucleon, even though it has a valence strange quark. Using the PACS-CS (2+1)-flavor full-QCD ensembles, we employ a variational analysis using source and sink smearing to isolate this elusive state. For the first time we reproduce the correct level ordering with respect to nearby scattering thresholds. With a partially quenched strange quark to produce the appropriate kaon mass, we find a low-lying, odd-parity mass trend consistent with the experimental value.     

Critical phenomena in the β-(2×4) → α-(2×4) reconstruction transition on the (001) GaAs surface

The critical exponents of the β-(2×4) → α-(2×4) reconstruction phase transition on the (001) GaAs surface are determined experimentally. It is found that the phase transition is analogous to a van der Waals transition. The critical parameters T _c , P _c , and Θ_c have been measured experimentally. The mean field theory is applied, and three-parameter isotherms are obtained that agree with the experimental results at the following values of the parameters: E_st = 0.36 eV, ΔE = 0.18 eV, and E _i = 0.134 eV. Precision measurements of the critical exponents β and δ are carried out. Their values β = 1/8 and δ = 15 indicate that the phase transition is truly two-dimensional.     

Photo-induced effect in the layered perovskite manganite La_(1.2)Sr_(1.8)Mn_(1.8)Co_(0.2)O_7

1IntroductionWiththediscoveryofcolossalmagnetoresistance(CMR)effectinmanganites,hole-dopingperovskitemanganiteswithunusualelectronictransportandmagneticpropertieshaveattractedconsiderableattention.Thesepropertiesresultfromanintrinsicinteractionbetweencharge,spin,orbitalandlatticedegreesoffreedomthatarestronglycoupledtoeachother[1—6].DoubleexchangemodelcombinedwithJohn-Tellereffectwasusedtoexplainthesepropertiespartly[7—9].InordertogetbetterunderstandingofthemechanismofCMReffect,externals…     

Spontaneous SU(2) symmetry violation in the SU(2) L × SU(2) R × SU(4) electroweak model

A new approach to electroweak (EW) composite scalars is developed starting from the fundamental gauge interaction on high scale. The latter is assumed to have the group structure SU(2) _L × SU(2) _R × SU(4), where SU(4) is the Pati-Salam color-lepton group. The topological EW vacuum filled by instantons is explicitly constructed and the resulting equations for fermion masses exhibit spontaneous SU(2) flavor symmetry violation with possibility of very large mass ratios.     

Coherent pion electroproduction on the deuteron in the Δ(1232) resonance region

Coherent pion electroproduction on the deuteron is studied in the ((1232) resonance region in the impulse approximation, i.e., neglecting pion rescattering and two-body effects. The elementary reaction on the nucleon is described in the framework of an effective Lagrangian approach including the dominant P₃₃(1232) resonance and the usual background terms of the Born contributions for ?⁰ production. We have studied the influence of these different contributions on the various structure functions which determine the unpolarized exclusive differential cross section in a variety of kinematic regions.     

Measurement of the LT-asymmetry in πelectroproduction at the energy of the Δ(1232)-resonance

The reaction p(e, e'p)π⁰ has been studied at Q² = 0.2 (GeV/c)² in the region of W = 1232MeV. From measurements left and right of , cross-section asymmetries ρ_LT have been obtained in forward kinematics ρ_LT( = 20^°) = (- 11.68±2.36_stat±2.36_sys) and backward kinematics ρ_LT( = 160^°) = (12.18±0.27_stat±0.82_sys) π⁰. Multipole ratios {S₁₊ ^* M₁₊}/| M₁₊|² and {S₀₊ ^* M₁₊}/| M₁₊|² were determined in the framework of the MAID2003 model. The results are in agreement with older data. The unusally strong negative {S₀₊ ^* M₁₊}/| M₁₊|² required to bring also the result of Kalleicher et al. in accordance with the rest of the data is almost excluded.     

First observation of the decays B(0) → D(+)K(-)π(+)π(-) and B(-) → D(0)K(-)π(+)π(-)

First observations of the Cabibbo-suppressed decays B(0) → D(+)K(-)π(+)π(-) and B(-) → D(0)K(-)π(+)π(-) are reported using 35 pb(-1) of data collected with the LHCb detector. Their branching fractions are measured with respect to the corresponding Cabibbo-favored decays, from which we obtain B(B(0) → D(+)K(-)π(+)π(-))/B(B(0) → D(+)π(-)π(+)π(-))=(5.9±1.1±0.5)×10(-2) and B(B(-) → D(0)K(-)π(+)π(-))/B(B(-) → D(0)π(-)π(+)π(-))=(9.4±1.3±0.9)×10(-2), where the uncertainties are statistical and systematic, respectively. The B(-) → D(0)K(-)π(+)π(-) decay is particularly interesting, as it can be used in a similar way to B(-) → D(0)K(-) to measure the Cabibbo-Kobayashi-Maskawa phase γ.     

Evidence of Vibrational-Induced Rotational Axis Switching for HD(12)C(16)O: New High-Resolution Analysis of the nu(5) and nu(6) Bands and First Analysis of the nu(4) Band (10-µm Region)

Using new high-resolution Fourier transform spectra recorded in Giessen in the 8-12 μm region, a more extended analysis of the nu(5) and nu(6) bands and the first high-resolution study of the nu(4) band of HDCO were performed. As pointed out previously [M. Allegrini, J. W. C. Johns, and A. R. W. McKellar, Can. J. Phys. 56, 859-864 (1978)], the energy levels of the 5(1) and 6(1) states are strongly coupled by A- and B-type Coriolis interactions. On the other hand, it appeared that weaker resonances involving the energy levels of the 4(1) state with those of the 5(1) and 6(1) states also had to be accounted for. Consequently, the calculation of the energy levels was performed taking into account the Coriolis-type resonances linking the energy levels of the {6(1), 5(1), 4(1)} resonating states. Because of the unusually strong Coriolis interaction between nu(5) and nu(6), a nonclassical behavior of the rotational levels of the 5(1) and 6(1) states was observed and it was necessary to use a new Hamiltonian matrix which possesses, as usual, both A- and B-type Coriolis operators in the 5(1) if 6(1) and 6(1) if 4(1) off diagonal blocks but differs from the classical reduced Hamiltonian which is used commonly for planar C(s)-type molecules. More precisely, it proved necessary to include non-orthorhombic terms in the expansion of the rotational Hamiltonian of the 5(1) and 6(1) states. According to the considerations developed by Watson [J. K. G. Watson, in "Vibrational Spectra and Structure," (J. Durig, Ed.), Chap. 1, Elsevier, Amsterdam, 1977], these non-orthorhombic operators which are not symmetry forbidden are usually removed for semirigid C(s)-type molecules by rotational contact transformations. In the present study, the occurrence of terms in {J(x), J(z)} in the expansions of the rotational Hamiltonians for the 5(1) and 6(1) states indicates that the inertial system of HDCO differs for each of the three {6(1), 5(1), 4(1)} resonating states. Therefore, HDCO becomes a good example of vibrational-induced rotational axis switching (VIRAS) which was already suggested as the mechanism responsible for the enhanced densities of coupled states observed in 2-fluoroethanol [H. Li, S. Erza, and L. A. Philips, J. Chem. Phys. 97, 5956-5963 (1992)]. Copyright 2000 Academic Press.     

O(5)×U(1) Electroweak gauge theory and the triggering of the neutrino oscillations by 't Hooft-polyakov monopole

TheO(5)×U(1) electroweak gauge theory with two particle generations of quarks and leptons is considered. With spontaneous symmetry breaking down to theO(3) level, the 't Hooft-PolyakovSO(3) monopole theory along with its triplet of scalar fields is reproduced and developed to the extent necessary to establish the results. It is shown that the existence of the monopole triggers the Cabibbo rotation ofd ands along with the _e and _µ flavors, which in turn results in the neutrino oscillations. The neutrino oscillation angle turns out to be the Cabibbo angle. Using the experimental data of Bakeret al., an upper limit is set on m ²1.3 eV² (m ² _µ ² –m _e ² ). Furthermore, it is exactly the Cabibbo angle in which the isovector has to be rotated so as to spontaneously break the symmetry down to theO(3) level, together with, on theSO(3) sector, to theU(1) level. It turns out that the Weinberg angle is twice the Cabibbo angle, a result already noted elsewhere.     

O(5)×U(1) electroweak gauge theory and the relevance of the Cabibbo angle inCP violation inK decays

Some of the relevant mathematics ofO(5)×U(1) electroweak gauge theory is briefly sketched. TheO(5)×U(1) model is presented. To facilitate the discussion ofCP violation inK decays, the relevant Lagrangian is given in several alternative forms. It is shown that in theCP-violating part of the Lagrangian, by a redefinition of quark phases, the coupling of theCP eigenstatesK ₁ andK ₂ cannot be broken. However, if the Cabibbo angle were not present, the statesK ₁ andK ₂ would decouple and the theory would becomeCP-invariant. Such a result was also reported by Deshpandeet al., working with a different formalism. Relating the mixing parameters and to the parameters ₁ and ₂, it is shown that when ₁= ₂=, reduces to the usualCP-violating andCPT-conserving parameter.     

Band-mapping of InP (100) along the ΓX-line

We have prepared InP (100) surfaces from wafer-material by cycles of argon ion sputtering and gentle annealing. From these samples normal-emission photoelectron spectra were recorded using photons in the energy range 10eV<h<75eV. From the results we derive the initial-state band disperison along the X-line of the 3-dimensional Brillouin zone. Our results are fully consistent with initial-state bands mapped by other authors along the KX-line. From the good agreement we conclude that the quality of the (100)-surfaces as used in our work is at least adequate for bulk band investigations.