Peculiarities of the electronic structure of Yb, In, Ag, and Cu in the heavy-fermion system YbIn1−x AgxCu4

The method of x-ray spectral line displacement is used for studying the electronic structure, i.e., the population of the 4f shell of Yb, 5s shells of In and Ag, and 4s shell of Cu, in the YbIn_1?x Ag_xCu₄ heavy-fermion system (0≤x≤1, T=300 K; T=77, 300, and 1000 K for YbIn_0.7Ag_0.3Cu₄). It is shown that Yb is in a state with fractional valence whose value is independent of x (or on the type of the partner, i.e., In and Ag) in the entire range of compositions and is equal to $\bar m = 2.91 \pm 0.01$ at T=300 K. An increase in the population of the In s states of In, Ag, and Cu (as compared to metals) is observed: $\overline {\Delta n_s } (In) = 0.65 \pm 0.05 el/at$ , $\overline {\Delta n_s } (Ag) = 0.71 \pm 0.09 el/at$ , and $\overline {\Delta n_s } (Cu) = 0.08 \pm 0.02 el/at$ . A practically linear decrease in the valence of Yb to the value m(T=1000 K)=2.81±0.02 is observed in YbIn_0.7Ag_0.3Cu₄ upon an increase in temperature from T=77 to 1000 K.     

Resonant phonon scattering due to crystal-field-split paramagnetic levels of Pr ions in PrTe1.46

The lattice heat conductivity κ_ph of PrTe_1.46 and LaTe_1.46 has been measured within the 2-to 100-K interval. The quantity ?Δκ_res(T), the decrease in the heat conductivity caused by resonant phonon scattering due to crystal-field-split paramagnetic levels of Pr, was derived from experimental data using the relation $ - \Delta \kappa _{res} (T) = \kappa _{ph(PrTe_{1.46} )} (T) - \kappa _{ph(LaTe_{1.46} )} (T)$ . The energy of the first split paramagnetic level of Pr, Δ₁ was calculated from the Δκ_res(T) relation for T<T _res. It was found that Δ₁ depends on the nature of the nearest neighbor environment of Pr ions in the lattice. The temperature dependence Δκ_res(T) has been determined to be Δκ_res(T) (Δκ_res～T ^?0.5) for T>T _res.     

Influence of cone algorithm parameters on efficiency and characteristics of reconstructed jets in p-p interactions at \sqrt s = 200 GeV

The influence of the cone algorithm parameters (E _cut, E _seed, R) on efficiency and characteristics of reconstructed jets in p-p collisions at the energy $\sqrt s $ = 200 GeV is studied. Event generation was carried out using the Monte Carlo code PYTHIA. The fraction of dijet event production as a function of transverse momentum of the hard process $\hat p_ \bot $ for different algorithm parameters is studied. The dependence of energy and parton direction reconstruction accuracy for dijet events and two leading jets in N-jet (N _Jet ≥ 2) events on the algorithm parameters is found. The results of jet modeling are compared with predictions obtained in the framework of z-scaling and experimental data obtained at RHIC. It is proved that the slope parameter of the scaling function is independent of the algorithm parameters in the transverse jet energy range E _T ^Jet = 25–60 GeV. It is shown that in the region E _T ^Jet < 25 GeV, strong dependence of invariant cross sections and the slope of the scaling function on the algorithm parameters is observed, and this dependence is enhanced with decreasing E _T ^Jet .     

Energy splitting betweenT > andT < single particle states in91Nb

The isobaric energy splitting ΔE(n, l, j) betweenT _>- andT _<-single particle states in the shell (2d _5/2, 2d _3/2, 1g _7/2, 3S _1/2) has been experimentally determined for⁹¹Nb from a study of the reaction⁹⁰Zr(³He,d)⁹¹Nb. The splitting of the 1g _7/2-states is found to be about 25% larger than that of the³ s _1/2-states. The observed dependence of the energy splitting ΔE(n, l, j) on the shell model quantum numbers (n, l, j) of the states is reproduced by the expression \(\Delta {\rm E}(n, l, j) = \frac{1}{2}(2T + 1) \left\langle {\phi _ > ^{n l j} | U_1 (r)|\phi _ > ^{n l j} } \right\rangle\) , which is based on approximate solutions of Lane's equations.φ _> ^nlj is the wave function of the parent state in the (nC) system. There is evidence, that only a Lane potentialU ₁(r) of surface type can reproduce the observed strong dependence of ΔE(n, l, j) on the quantum numbers. The depthū ₁ of Lane's potential is found to be 2.0 MeV.     

Alternative technique for Standard Model estimation of the rare kaon decay branchings \left. {BR(K \to \pi \nu \bar \nu )} \right|_{SM}

We estimate $BR(K \to \pi \nu \bar \nu )$ in the context of the Standard Model by fitting for λ _t≡V _tdV _ts ^* of the “kaon unitarity triangle” relation. To find the vertex of this triangle, we fit data from |? _K|, the CP-violating parameter describing K mixing, and a _ψ,K , the CP-violating asymmetry in B _d ⁰ → J/ψK ⁰ decays, and obtain the values $\left. {BR(K \to \pi \nu \bar \nu )} \right|_{SM} = (7.07 \pm 1.03) \times 10^{ - 11} $ and $\left. {BR(K_L^0 \to \pi ^0 \nu \bar \nu )} \right|_{SM} = (2.60 \pm 0.52) \times 10^{ - 11} $ . Our estimate is independent of the CKM matrix element V _cb and of the ratio of B-mixing frequencies ${{\Delta m_{B_s } } \mathord{\left/ {\vphantom {{\Delta m_{B_s } } {\Delta m_{B_d } }}} \right. \kern-0em} {\Delta m_{B_d } }}$ . We also use the constraint estimation of λ _t with additional data from $\Delta m_{B_d } $ and |V _ub|. This combined analysis slightly increases the precision of the rate estimation of $K^ + \to \pi ^ + \nu \bar \nu $ and $K_L^0 \to \pi ^0 \nu \bar \nu $ (by ?10 and ?20%, respectively). The measured value of $BR(K^ + \to \pi ^ + \nu \bar \nu )$ can be compared both to this estimate and to predictions made from ${{\Delta m_{B_s } } \mathord{\left/ {\vphantom {{\Delta m_{B_s } } {\Delta m_{B_d } }}} \right. \kern-0em} {\Delta m_{B_d } }}$ .     

p¯p Annihilation into two mesons in the quark rearrangement model and the quark annihilation model

The relativistic³ P ₀ model is applied to the \(p\bar p\) annihilation into twoS-wave mesons. We calculate the branching ratios of the \(p\bar p\) annihilation at rest into two mesons in the quark rearrangement model and in the quark annihilation model. In the annihilation model, we project the intermediate \(cq\bar q\) state to eigenstates ofSU (4) with the relative angular momentum of \(cq\bar q\) equals orp. In the rearrangement model, no annihilation occurs from theS-wave \(p\bar p\) and certain branching ratios conflict with the experimental data. Detailed comparison with the experiment needs inclusion ofP-wave mesons in the final state, nevertheless we find that the annihilation model gives qualitatively better results than the rearrangement model. The effect of initial state interaction through \(N\bar \Delta \pm \Delta \bar {\rm N}\) or \(\Delta \bar \Delta \) channels is discussed.     

Strange hadron production in d+Au collisions at RHIC

We report the centrality dependence of transverse mass (m _t ) spectra at mid-rapidity for the identified strange hadrons K _S ⁰ , ? $\Lambda + \bar \Lambda $ and $\Xi ^ - + \bar \Xi ^ + $ in d+Au collisions at RHIC. The measured transverse momentum (p _T ) covers 0.4<p _T <6.0 GeV/c for K _S ⁰ , ø, $\Lambda + \bar \Lambda $ and 0.6<p _T <5.0 GeV/c for $\Xi ^ - + \bar \Xi ^ + $ . The binary collision normalized nuclear modification factors R _CP of these hadrons indicate that the Cronin effect in d+Au collisions has a distinct particle-type dependence. the R _CP ratios show a distinct baryons versus mesons dependence: the R _CP for $\Xi ^ - + \bar \Xi ^ + $ follows that for $\Lambda + \bar \Lambda $ while the R _CP for the ? is close to that for the K _S ⁰ . Similar features have also been observed in Au+Au collisions. Initial parton scattering alone is not sufficient to explain this particle-type dependence. Hadronization processes are likely to be important for determining hadron properties in high-energy collisions as suggested by coalescence and recombination models.     

Dispersionskorrektur Δf′ für Nickel nahe derK-absorptionskante

Employing an X-ray interferometer the dispersion correction Δf′ of the forward atomic scattering amplitude \(f = z + \Delta f' + \Delta f''\) of Nickel is measured using CuK \(\bar \alpha \) -radiation. Since \(\lambda _{CuK\bar \alpha } /\lambda _{K - edge Ni} = 1.037 \approx 1\) a value of Δf′ close to theK-absorption edge is obtained. The result $$\Delta f\prime = - 1.45 \pm 7.6\% $$ is compared with experimental values by Doan, Kiessing and Lameris and Prins and also theoretical values by Hönl, Dauben and Templeton and Cromer. The present value is considerably smaller than all theoretical estimates. It is the most accurate value measured so far and-except for the value measured by Kiessing-aggrees with the other experimental values within their (comparatively large) error limits.     

On the behavior of the πN partial wave amplitudes ats=0

The behavior of theπN partial wave amplitudes in the limitss→+0 ands→? 0 is related to backward scattering in thes- andt-channel, respectively. Assuming Mandelstam analyticity we prove with the aid of the Phragmen-Lindelöf theorem that the amplitudes for high energy backward scattering inπN→πN andππ→N¯N are equal and therefore dominated by the same exchange mechanism, namely Reggeized Fermion exchange. The dominating Regge trajectory is the Δ_δ-trajectory, and it is shown that theπN partial wave amplitudes diverge fors→±0 as \(s^{ - \alpha \Delta _\delta (0) - {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-0em} 2}} \) . — Reduced amplitudes are defined which are regular ats=0. — Using recent results ofπN backward scattering real and imaginary part of thes-wave amplitudef ₀₊ ^(?) are calculated in the interval 0≦s≦7.     

Neutral strange particle production in proton-proton collisions at\sqrt s = 63 GeV

The inclusive cross section for the production ofK _s ⁰ mesons, Λ and \(\bar \Lambda\) particles in proton-proton interactions at \(\sqrt s = 63\) GeV is presented. The produced particles have been detected in the full phase space. Behaviour of the longitudinal and transversal depandences of the cross sections are discussed. The total production cross sections for _s ⁰ mesons and Λ particles was determined to \(\sigma _{{\rm K}_S^0 } = (25.5 \pm 1.4)\) mb andσ _Λ =(7.8±1.2) mb respectively. A strong energy dependence of the production cross sections is observed.     

Covariant partition temperature model ande + e − annihilation

The rapidity distributions of inclusive \(e^ + e^ - \to h\bar h + \cdot \cdot \cdot\) of PEP and DESY experiments are analyzed in terms of the covariant partition temperatureT _p model. The estimates ofT _p ^* in the fireball system are comparable to the conventional temperature, the energy dependence follows approximately Stefan's law, the radius of the specific volume ralative to the energy density being ～1.18 fm. In the c.m.s. of collision, \(T_p = AW^a (W = \sqrt s in GeV)\) witha=0.60±0.05 andA=0.256±0.006, it is found \(T_p \cong {W \mathord{\left/ {\vphantom {W {\tfrac{3}{2}\left\langle {n_ \pm } \right\rangle }}} \right. \kern-0em} {\tfrac{3}{2}\left\langle {n_ \pm } \right\rangle }}\) . These properties hold also for \(\bar pp\) collision, but not forpp→π^?+...     

Critical properties of high-spin Ising models on anisotropic lattices

The coordinates of the critical points of spin-S Ising models with coupling constants J and J′ are calculated for 1/2 ≤ S ≤ 13/2. The calculations are performed for several values of S and Δ ≡ J′/J independently by using the phenomenological renormalization-group method or (approximate) self-duality. Numerical results combined with a mean-field analysis show that the critical coupling strength for Δ ～ 1 (weakly anisotropic lattice) is K _c ^(S) (Δ) = K _c ^(S) (1)[1 + a(1 ? Δ)], where a = (d ? 1)/d is independent of S (d is the space dimension). Both free energy and internal energy are determined at the critical points. An extremum of the critical internal energy is found at Δ* ∈ (0, 1). The parameter Δ* can be used as a criterion that separates quasi-isotropic and quasi-one-dimensional regimes (Δ* < Δ ≤ 1 and Δ < Δ*, respectively). The finite-size scaling amplitudes A _s and A _e of the inverse spin-spin and energy-energy correlation lengths are estimated. Calculations show that the amplitudes A _s and A _e are independent of S within the accuracy of the adopted approximations. Moreover, their ratio A _e/A _s is independent of the anisotropy parameter Δ. These results support the Ising universality hypothesis.     

Largep T double photon production in hadronic collisions-beyond leading logarithm QCD calculation

We calculateO(α _s ) corrections to largep _T double photon production in hadronic collisions. We find that these corrections to the basic \(q\bar q \to \gamma \gamma \) subprocess are important, preventing to describe double photon production on the basis of the leading logarithm approximation only. We give a phenomenological discussion of the results obtained at SPS, ISR and \(Sp\bar pS\) energies. In particular, we investigate how the effect of the intrinsic parton <K _T> may be disentangled from the perturbative contribution. We also calculate the aplanarity distribution characteristic of 3 jet events.     

The static multipole moments of Δ1236(3/2,3/2) from superconvergence inNγ → Δπ scattering

Saturating superconvergence sum rules inNγ→Δπ scattering byN andΔ, we are able to relate the (isoscalar) dipole magnetic moment \(\tilde \mu _\Delta\) and the quadrupole electric moment \(\tilde Q_\Delta\) of the isobarΔ to the electric charge \(\tilde Z_\Delta\) and the dipole magnetic momentμ _N of the nucleonN. The numerical results are: \(\tilde \mu _\Delta \equiv \mu _{\Delta ^ + } + \mu _{\Delta ^0 } = 3.26\) (in unitse/2M)=2.48 (in unitse/2m), and \(\tilde Q_\Delta \equiv Q_{\Delta ^ + } + Q_{\Delta ^0 } = 0.050\) (in unitse/M ²)=0.029 (in unitse/m ²), whereM(m) is the mass ofΔ(N). Neglecting the pion mass and takingM=m,μ _n /μ _p =?2/3, we get theSU ₆ result μ_Δ+=μ _p .     

Quark-diagram estimates ofCP violation in two-body baryonicB_d^0 - \bar B_d^0 decays

CP violation in partial-decay-rate asymmetries are examined for some two-body baryonic decays of \(B_d^0 - \bar B_d^0 \) system. We discuss two feasible experimental circumstances: the symmetrice ⁺ e ^? collisions (i) on theZ ⁰ resonance to produce incoherent \(B_d^0 \bar B_d^0 \) states, and (ii) just above the ?(4S) resonance to produceC=even \(B_d^0 \bar B_d^0 \) states. Using the quark-diagram scheme, we estimate the branching ratios of those decays, and the numbers ofb \(\bar b\) pairs needed for testing theCP-violating effects for 3σ signature. We find that the promising channels may beB _d ⁰ , \(\bar B_d^0 \to p\bar p\) , \(\Delta ^ + \bar \Delta ^ - \) , \(p\bar \Delta ^ - \) , \(\Delta ^ + \bar p\) , \(n\bar n\) , \(\Delta ^0 \bar \Delta ^0 \) , \(n\bar \Delta ^0 \) , \(\Delta ^0 \bar n\) , \(\Sigma _c^ + \bar \Sigma _c^ - \) , \(\Lambda _c^ + \bar \Lambda _c^ - \) , \(\Sigma _c^ + \bar \Lambda _c^ - \) , \(\Lambda _c^ + \bar \Sigma _c^ - \) , \(\Sigma _c^0 \bar \Sigma _c^0 \) , \(\Xi _c^0 \bar \Xi _c^0 \) , which should be interesting for experimental observation.     

Spectrum of the Lichnerowicz Laplacian on Asymptotically Hyperbolic Surfaces

We show that, on any asymptotically hyperbolic surface, the essential spectrum of the Lichnerowicz Laplacian Δ _L contains the ray $\big[\frac{1}{4},+\infty\big[$ . If moreover the scalar curvature is constant then ??2 and 0 are infinite dimensional eigenvalues. If, in addition, the inequality $\langle \Delta u, u\rangle_{L^2}\geqslant \frac{1}{4}||u||^2_{L^2}$ holds for all smooth compactly supported function u, then there is no other value in the spectrum.     

The Dynamics of the 3D Radial NLS with the Combined Terms

In this paper, we show the scattering and blow-up result of the radial solution with the energy below the threshold for the nonlinear Schrödinger equation (NLS) with the combined terms $$iu_{t} + \Delta{u} = -|u|^{4}u + |u|^{2}u \qquad \qquad \qquad \qquad {\rm (CNLS)}$$ in the energy space ${{H^{1}(\mathbb{R}^{3})}}$ . The threshold is given by the ground state W for the energy-critical NLS: iu _t +  Δu =  ?|u|⁴ u. This problem was proposed by Tao, Visan and Zhang in (Comm PDEs 32:1281–1343, 2007). The main difficulty is lack of the scaling invariance. Illuminated by (Ibrahim et al., in Analysis & PDE 4(3):405–460, 2011), we need to give the new radial profile decomposition with the scaling parameter, then apply it to the scattering theory. Our result shows that the defocusing, ${{\dot{H}^{1}}}$ -subcritical perturbation |u|² u does not affect the determination of the threshold of the scattering solution of (CNLS) in the energy space.     

Exclusive measurement of the pp → nnπ+π+ reaction at 1.1 GeV

First exclusive data for the $\ensuremath{pp \to nn\pi^+\pi^+}$ reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of T_p = 1.1 GeV. Total and differential cross-sections disagree with theoretical calculations, which predict the $ \Delta$ $ \Delta$ excitation to be the dominant process at this beam energy. Instead, the data require the excitation of one of the nucleons to a higher-lying $ \Delta$ state, preferably the $\ensuremath{\Delta(1600)P_{33}}$ , to be the leading process.     

K S 0 , Λ and ≡ production at intermediate to high pT from Au+Au collisions at \sqrt {s_{NN} } = 39, 11.5 and 7.7 GeV

We report on the p _T dependence of nuclear modification factors (R _CP) for K _S ⁰ , ??, ?? and the $\bar NK_S^0 $ ratios at mid-rapidity from Au+Au collisions at $\sqrt {s_{NN} } $ = 39, 11.5 and 7.7 GeV. At $\sqrt {s_{NN} } $ = 39 GeV, the R _CP data show a baryon/meson separation at intermediate p _T and a suppression for K _S ⁰ for p _T up to 4.5 GeV/c; the $\bar \Lambda K_S^0 $ shows baryon enhancement in the most central collisions. However, at $\sqrt {s_{NN} } $ = 11.5 and 7.7 GeV, R _CP shows less baryon/meson separation and $\bar NK_S^0 $ shows almost no baryon enhancement. These observations indicate that the matter created in Au+Au collisions at $\sqrt {s_{NN} } $ = 11.5 or 7.7 GeV might be distinct from that created at $\sqrt {s_{NN} } $ = 39 GeV.