bluuebunny/crossref_metadata_2025 huggingface dataset:
φ-MESON PHOTOPRODUCTION AT THRESHOLD AND φ – N SCATTERING LENGTH
Authors: TITOV A. I. , NAKANO T. , DATÉ S. , OHASHI Y.
Published: October 2008

We show that the differential cross section dσ/dt of γp → φp reaction at the threshold has a finite value and it is crucial to the mechanism of the φ meson photoproduction and for the models of φN interaction.
PRODUCTION OF TWO PIONS INDUCED BY NEUTRINOS
Authors: VALVERDE M. , NIEVES J. , HERNÁNDEZ E. , SINGH S. K. , VACAS M. J. VICENTE
Published: October 2008

We study the threshold production of two pions induced by neutrinos in nucleon targets. The contribution of nucleon pole, pion and contact terms is calculated using a chiral Lagrangian. The contribution of the Roper resonance, neglected in earlier studies, has also been taken into account.
DOUBLE PION PHOTOPRODUCTION EXPERIMENT AT LNS–TOHOKU
Authors:   THE NKS/NKS2 COLLABORATIONS, KANDA H. , CHIGA N. , FUJII Y. , FUTATSUKAWA K. , HAN Y. C. , HASHIMOTO O. , HIROSE K. , HOSOMI K. , IGUCHI A. , ISHIKAWA T. , KANETA M. , KAWAI M. , KAWAMA D. , KAWASAKI T. , KIYOKAWA S. , KOIKE T. , KONNO O. , MA Y. , MAEDA K. , MATSUMURA A. , MIMORI M. , MIWA K. , MIYAHARA F. , NAKAMURA S. N. , OKAYASU Y. , OTANI T. , SASAKI A. , SHIMIZU H. , SHIROTORI K. , SUZUKI K. , TAKAHASHI T. , TAMAE T. , TAMURA H , TERADA N. , TSUKADA K. , UKAI M. , WANG T. , WATANABE T. , YAMAZAKI H.
Published: October 2008

The total cross sections for the π+π− photoproduction on the deuteron were measured in an energy range of 0.8 to 1.1 GeV. The obtained total cross section for the quasi-free π+π− photoproduction on the deuteron was about 60 % of those on the free proton. The cross section for Δ++Δ− photoproduction was derived from the non-quasi-free π+π− photoproduction events. It was smaller than the previous data.
THE ROLE OF THE QCD ANOMALY IN KAON PHOTOPRODUCTION
Authors: OZAKI SHO , NAGAHIRO HIDEKO , HOSAKA ATSUSHI
Published: October 2008

We study the kaon photoproduction associated with the production of the ground state Λ. We investigate the role of K and K* exchange in the t -channel, which can be tested by the photon asymmetry in comparison with experimental data. We find a significant amount of contribution from the one-loop diagram induced by the gauged Wess-Zumino-Witten term for QCD anomaly. This enable us to use coupling constants which are determined in a microscopic way, unlike the previous phenomenological studies where the K* coupling strengths were treated as a free parameter.
INTER-QUARK POTENTIALS IN BARYONS AND MULTI-QUARK SYSTEMS IN QCD
Authors: SUGANUMA HIDEO , YAMAMOTO ARATA , SAKUMICHI NAOYUKI , TAKAHASHI TORU T. , IIDA HIDEAKI , OKIHARU FUMIKO
Published: October 2008

We perform the first studies of various inter-quark potentials in SU(3)c lattice QCD. From the accurate lattice calculation for more than 300 different patterns of three-quark (3Q) systems, we find that the static 3Q potential V3Q is well described by Y-Ansatz, i.e., the Coulomb plus Y-type linear potential. Quark confinement mechanism in baryons is also investigated in maximally-Abelian projected QCD. We next study the multi-quark potentials VnQ (n = 4,5) in SU(3)c lattice QCD, and find that they are well described by the one-gluon-exchange Coulomb plus multi-Y type linear potential, which supports the flux-tube picture even for the multi-quarks. Finally, we study the heavy-heavy-light quark (QQq) potential both in lattice QCD and in a lattice-QCD-based quark model.
THE COULOMB GAUGE CONFINEMENT SCENARIO AND THE COLOR-DEPENDENT QUARK POTENTIALS IN LATTICE QCD SIMULATIONS
Authors: NAKAGAWA Y. , NAKAMURA A. , SAITO T. , TOKI T.
Published: October 2008

We study the color confinement of QCD with the Coulomb gauge in lattice simulations. The color-Coulomb instantaneous interaction in color-singlet channel causes a linearly rising potential at large distances. We also estimate the other color-channel forces for two-quark states, i.e. color-octet, color-sextet and color-antitriplet channels. Moreover we investigate the volume dependence of color-nonsinglet potentials on finite lattices.
CONFINING TIME-LIKE GLUON AND CONFINED SPATIAL GLUONS IN COULOMB GAUGE QCD
Authors: NAKAGAWA Y. , NAKAMURA A. , SAITO T. , TOKI H.
Published: October 2008

We investigate the Gribov-Zwanziger scenario in Coulomb gauge QCD using a SU(3) quenched lattice gauge simulation. The ghost propagator diverges in the infrared limit stronger than the free ghost propagator, and the ghost degree of freedom plays a central role in the confinement mechanism in the Coulomb gauge. The infrared divergent ghost dressing function results in the confining color-Coulomb instantaneous interaction. The equal-time transverse gluon propagator is suppressed in the infrared region. Therefore, in the Coulomb gauge, the instantaneous interaction mediated by time-like gluons is responsible for the confining force, and the would-be physical gluons are confined in hadrons.
MONOPOLES FROM QUARK CONDENSATES IN QCD
Authors: CHERNODUB M. N.
Published: October 2008

Chiral monopoles are hedgehoglike structures in local chiral condensates in QCD. These monopoles are (i) made of quark and gluon fields; (ii) explicitly gauge-invariant; (iii) they carry quantized and conserved chromomagnetic charge. We argue that the chiral condensate vanishes in a core of the chiral monopole while the density of these monopoles increases with temperature wiping out the quark condensate in quark-gluon plasma. We suggest that the chiral monopoles are responsible for the chiral symmetry restoration in QCD. We also argue that the chiral monopoles are unlikely to be responsible for confinement of color. Thus, phenomena of the chiral symmetry restoration and the color deconfinement in QCD are not necessarily related to each other and the corresponding transitions may happen at different temperatures.
MAGNETIC SUSCEPTIBILITY OF THE QCD VACUUM AT FINITE DENSITY
Authors: NAM SEUNG-IL , KIM HYUN-CHUL
Published: October 2008

We present in this talk a recent investigation on the magnetic susceptibility (χ) of the QCD vacuum at finite density, utilizing the nonlocal chiral quark model from the instanton vacuum. We take into account the nonzero current-quark mass (mq) explicitly to consider the effect of explicit flavor SU(3) symmetry breaking. It turns out that, when we turn on the current-quark mass (mq ≠ 0), χ becomes smaller, indicating less response to the externally induced electromagnetic field, in comparison to that for mq = 0.
BARYONS WITH HOLOGRAPHY
Authors: NAWA KANABU , SUGANUMA HIDEO , KOJO TORU
Published: October 2008

We perform the first study of baryons in holographic QCD with [Formula: see text] multi-D-brane system in type IIA superstring theory. The baryon is described as a chiral soliton solution in the four-dimensional meson effective action derived from holographic QCD. We also present a brief review of the holographic model from the viewpoints of recent hadron physics and QCD phenomenologies.
CHIRAL PROPERTIES OF BARYON INTERPOLATING FIELDS
Authors: DMITRAŠINOVIĆ V. , NAGATA KEITARO , HOSAKA ATSUSHI
Published: October 2008

We study the chiral transformation properties of all possible local (non-derivative) interpolating field operators for baryons consisting of three quarks with two flavors, assuming good isospin symmetry. We derive and use the relations/identities among the baryon operators with identical quantum numbers that follow from the combined color, Dirac and isospin Fierz transformations. These relations reduce the number of independent baryon operators with any given spin and isospin. The Fierz identities also effectively restrict allowed baryon chiral multiplets. It turns out that the chiral multiplets of the baryons are equivalent to their Lorentz representation.
Λ(1405) IN CHIRAL SU(3) DYNAMICS
Authors: HYODO TETSUO , WEISE WOLFRAM , JIDO DAISUKE , ROCA LUIS , HOSAKA ATSUSHI
Published: October 2008

We discuss several aspects of the Λ(1405) resonance in relation to the recent theoretical developments in chiral dynamics. We derive an effective single-channel [Formula: see text] interaction based on chiral SU(3) coupled-channel approach, emphasizing the important role of the πΣ channel and the structure of the Λ(1405) in [Formula: see text] phenomenology. In order to clarify the structure of the resonance, we study the behavior with the number of colors (Nc) of the poles associated with the Λ(1405), and argue the physical meaning of the renormalization procedure.
PARTIAL DECAY WIDTHS OF THE ϕ INTO e+e− AND K+K− PAIRS IN 12 GeV p + A REACTIONS AT KEK-PS E325
Authors: SAKUMA F. , CHIBA J. , EN'YO H. , FUKAO Y. , FUNAHASHI H. , HAMAGAKI H. , IEIRI M. , ISHINO M. , KANDA H. , KITAGUCHI M. , MIHARA S. , MIWA K. , MIYASHITA T. , MURAKAMI T. , MUTO R. , NAKURA T. , NARUKI M. , OZAWA K. , SASAKI O. , SEKIMOTO M. , TABARU T. , TANAKA K. H. , TOGAWA M. , YAMADA S. , YOKKAICHI S. , YOSHIMURA Y.
Published: October 2008

The experiment KEK-PS E325 measured e+e− and K+K− pairs produced in 12 GeV p + A reactions, in order to search for in-medium modification of vector mesons. In the e+e− spectra, a significant excess on the low-mass side of the ϕ-meson peak is observed in the very low βγ (= p/m) region of the copper target data. On the other hand when the velocity of ϕ mesons is higher or a smaller target, carbon, is employed, the observed ϕ-meson shapes are consistent with the expected shape in vacuum, both in the e+e− and K+K− spectra. We have also compared the nuclear mass number dependence of ϕ-meson production between the e+e− and K+K− decay channels. Using these results, the first experimental limits are obtained for in-medium broadening of the partial decay widths.
VECTOR MESON MODIFICATION IN NUCLEAR MATTER AT CLAS
Authors: DJALALI CHADEN , WOOD MIKE , NASSERIPOUR RAKHSHA , WEYGAND DENNIS , The CLAS COLLABORATION
Published: October 2008

Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The properties of the ρ vector mesons were investigated via their rare leptonic decay to e+e−. After subtracting the combinatorial background, the ρ meson mass distributions were extracted for each of the targets. We observe no effects on the mass of the ρ meson, some widening in titanium and iron is observed consistent with the collisional broadening.
ELECTRIC MEAN SQUARED RADII OF Λ(1405) IN CHIRAL DYNAMICS
Authors: SEKIHARA T. , HYODO T. , JIDO D.
Published: October 2008

The electric mean squared radii 〈r2〉E of Λ(1405) are calculated in the chiral unitary model. We describe the Λ(1405) as a dynamically generated resonance fully in the octet meson and octet baryon scattering. We also consider “Λ(1405)” as a bound state of [Formula: see text]. For the later “Λ(1405),” we obtain negative and larger absolute value of electric mean squared radius than that of ordinary baryons, which implies that Λ(1405) have structure of widely spread K− around p.
GRAVITATIONAL COLLAPSE OF MASSIVE STARS AS A PROBE INTO HOT DENSE MATTER
Authors: YAMADA SHOICHI
Published: October 2008

Nuclear physics is an indispensable input for the investigation of high energy astrophysical phenomena involving compact objects. In this paper I take a gravitational collapse of massive stars as an example and show how the macroscopic dynamics is influenced by the properties of nuclei and nuclear matter. I will discuss two topics that are rather independent of each other. The first one is the interplay of neutrino-nuclei inelastic scatterings and the standing accretion shock instability in the core of core collapse supernovae and the second is concerning the neutrino emissions from black hole formations and their dependence on the equation of state at very high densities. In the latter, I will also demonstrate that future astronomical observations might provide us with valuable information on the equation of state of hot dense matter.
TOPOLOGICAL SUSCEPTIBILITY AT FINITE TEMPERATURE IN A RANDOM MATRIX MODEL
Authors: OHTANI MUNEHISA , LEHNER CHRISTOPH , WETTIG TILO , HATSUDA TETSUO
Published: October 2008

The temperature and quark mass dependence of the topological susceptibility is analyzed in a random matrix model. A model combining random matrices and the lowest Matsubara frequency is known to describe the chiral phase transition of QCD qualitatively, but at finite temperature it suppresses the topological susceptibility in the thermodynamic limit by the inverse of the volume. We propose a modified model in which the topological susceptibility at finite temperature behaves reasonably. The modified model reproduces the chiral condensate and the zero-temperature result for the topological susceptibility of the conventional model, and it leads to a topological susceptibility at finite temperature in qualitative agreement with lattice QCD results.
DENSITY FLUCTUATIONS AND A FIRST-ORDER CHIRAL PHASE TRANSITION IN NON-EQUILIBRIUM
Authors: SASAKI CHIHIRO , FRIMAN BENGT , REDLICH KRZYSZTOF
Published: October 2008

The thermodynamics of a first-order chiral phase transition is considered in the presence of spinodal phase separation using the Nambu-Jona-Lasinio model in the mean field approximation. We focus on the behavior of conserved charge fluctuations. We show that in non-equilibrium the specific heat and charge susceptibilities diverge as the system crosses the isothermal spinodal lines.
ΛΣ− PAIRING IN “BUBBLE FERMI SHELL” SCHEME
Authors: TAKATSUKA TATSUYUKI , TAMAGAKI RYOZO
Published: October 2008

In neutron star cores, superfluid state of hyperons such as lambda (Λ) and sigma-minus (Σ−) has been shown to realize by a realistic approach. This result importantly supports the idea of nonstandard fast “hyperon cooling” scenario to explain colder class neutron stars observed. However, a less attractive ΛΛ interaction suggested by a double Λ hypernucleus ([Formula: see text]; “NAGARA” event) leads to a disappearance of Λ superfluidity and thereby the breaking down of the scenario. In this connection, the revival of “Λ superfluidity” due to the ΛΣ− pairing, instead of ΛΛ one, is discussed in a new scheme of “bubble Fermi shell” hypothesis where the matching of two different Fermi surfaces is forced.
ON THE EQUATION OF STATE IN EFFECTIVE QUARK THEORIES
Authors: BENTZ W. , LAWLEY S. , THOMAS A. W.
Published: October 2008

We discuss the saturation mechanism for the nuclear matter equation of state in a chiral effective quark theory. The importance of the scalar polarizability of the nucleon is emphasized. The phase transition to color superconducting quark matter is also discussed.
HADRON-QUARK PHASE TRANSITION AND ANTIKAON CONDENSATION IN NEUTRON STARS
Authors: SHEN H. , YANG F. , YUE P.
Published: October 2008

We study the hadron-quark phase transition and antikaon condensation which may occur in the core of massive neutron stars. The relativistic mean field theory is used to describe the hadronic phase, while the Nambu-Jona-Lasinio model is adopted for the quark phase. We find that the hadron-quark phase transition is very sensitive to the models used. The appearance of deconfined quark matter and antikaon condensation can soften the equation of state at high density and lower the maximum mass of neutron stars.
THE MASSLESS LINEAR SIGMA MODEL WITH LOOP CORRECTIONS
Authors: TAMENAGA S. , TOKI H. , HAGA A. , OGAWA Y.
Published: October 2008

We study the effect of one-loop corrections from nucleon together with those from meson in the massless linear sigma model, where we perform the Coleman-Weinberg (CW) renormalization procedure in order to obtain the stable effective potential. We also study the non-perturbative and higher loop corrections with fermions and bosons in the Cornwall, Jackiw and Tomboulis (CJT) method.
MESIC ATOMS AND MESIC NUCLEI
Authors: HIRENZAKI SATORU
Published: October 2008

We briefly summarize the interests in mesic atoms and mesic nuclei in the contemporary hadron-nucleus physics and give a short report on the recent research activities for several meson-nucleus systems.
STUDY OF IN-MEDIUM PROPERTIES OF N*(1535) AND CHIRAL SYMMETRY FOR BARYONS THROUGH THE η-MESIC NUCLEI FORMATION AT J-PARC
Authors: NAGAHIRO HIDEKO , JIDO DAISUKE , HIRENZAKI SATORU
Published: October 2008

We investigate the properties of η-nucleus interaction by postulating the N*(1535) dominance for η-N system. We evaluate the N*(1535) properties in the nuclear medium using two kinds of chiral models, and find that these two models provide qualitatively different η-nucleus optical potentials reflecting the quite distinct properties of N*(1535) in these chiral models. Especially, in the chiral doublet model, we can expect to have the level crossing between η and N*(1535)-hole which is expected to provide the characteristic features for the optical potential and the formation spectra. We find also that the difference of these models can be seen in the formation cross sections of the η mesic nuclei with (π+, p ) reaction expected to be performed at J-PARC project.
KAONIC NUCLEI AS DECAYING STATES
Authors: AKAISHI YOSHINORI
Published: October 2008

Formation spectra of model [Formula: see text] systems excited by [Formula: see text] reaction are investigated in order to get a theoretical basis for proper interpretation of experimental data concerning kaonic nuclear quasi-bound states. It is argued that experimentally observable kaonic nuclear peak should be regarded as the decaying state introduced by Kapur-Peierls.
YN CORRELATIONS FROM THE STOPPED K− REACTION ON 4He
Authors: SUZUKI T. , IIO M. , ITAHASHI K. , IWASAKI M. , MATSUDA Y. , OHNISHI H. , OKADA S. , OUTA H. , TOMONO D. , YAMAZAKI T. , BHANG H. , CHOI S. , KIM J. H. , YIM H. , CHIBA J. , HANAKI T. , FUKUDA Y. , SATO M. , HAYANO R. S. , ISHIKAWA T. , ISHIMOTO S. , IWAI M. , SUZUKI S. , ISHIWATARI T. , KIENLE P. , WIDMANN E.
Published: October 2008

We have investigated non-mesonic reactions of the stopped K− on 4 He in terms of correlations of coincident ΛN pairs. As the result, Λp and Λn branches of the two-nucleon absorption process were clearly observed in the ΛN invariant mass spectra. The spin-isospin dependence of the process was observed for the first time.
THE ppK− SYSTEM STUDIED WITH A CHIRAL SU(3) BASED $\bar{K}N$ POTENTIAL
Authors: DOTÉ AKINOBU , HYODO TETSUO , WEISE WOLFRAM
Published: October 2008

We have investigated the prototype of [Formula: see text]-nuclear systems, ppK−, with a realistic NN potential and effective local [Formula: see text] potentials based on chiral SU (3) dynamics. Including estimates of theoretical uncertainties, we find that ppK− is not deeply bound, with a total binding energy = 19 ± 3 MeV and mesonic decay width between about 40 and 70 MeV. The [Formula: see text] component in the ppK− compound is of a similar structure as the [Formula: see text] two-body quasibound state embedded in the πΣ continuum.
STRUCTURE OF MULTI-ANTIKAONIC NUCLEI IN THE RELATIVISTIC MEAN-FIELD MODEL
Authors: MUTO TAKUMI , MARUYAMA TOSHIKI , TATSUMI TOSHITAKA
Published: October 2008

The structure of multi-antikaonic nuclei (MKN), where several K− mesons are bound in the nucleus, is studied in the relativistic mean-field model. A kaonic part of the thermodynamic potential including kaon-nucleon interactions is derived on the basis of chiral symmetry (abbreviated as a chiral model). It is shown that nonperturbative effects from kaons in the chiral model on the properties of the MKN such as the density distributions of nucleons and K− mesons and the binding energy become important since the number of the embedded K− increases.
SEARCH FOR K−pn AND K−pp BOUND STATES AT SPRING-8/LEPS
Authors:   FOR THE LEPS COLLABORATION, PARKER J. D.
Published: October 2008

K−pn and K−pp bound states are searched for at SPring-8/LEPS in the d(γ, K+) and d(γ, K+π−) reactions with photon energies from 1.5 to 2.4 GeV. The data was collected during the 2002-2003 run period utilizing liquid hydrogen and liquid deuterium targets. Using the K+ and K+π− missing mass spectra from the deuteron, we hope to determine upper limits for K−pn and K−pp bound state production.
CHIRAL SYMMETRY IN NUCLEAR MANY BODY SYSTEM
Authors: TOKI HIROSHI , OGAWA YOKO , MYO TAKAYUKI , TAMENAGA SETSUO , IKEDA KIYOMI
Published: October 2008

The pion was introduced by Yukawa as the mediator of nucleon-nucleon interaction to bind nucleons in nucleus. Due to its characteristic properties, however, the pion had not be used until recent years for description of nuclei. We present here a newly developed method to treat the pion exchange interaction in nuclei. We study nuclear structure by using the chiral sigma model lagrangian in the relativistic chiral mean field model with projection. The pion develops mean field and provides a magic number effect. We demonstrate also the ability of treating tensor interaction due to pion exchange in terms of tensor optimized shell model.
DELTA-HOLE EFFECTS ON THE SHELL EVOLUTION OF NEUTRON-RICH EXOTIC NUCLEI
Authors: OTSUKA TAKAHARU , SUZUKI TOSHIO , AKAISHI YOSHINARI
Published: October 2008

We suggest that the three-body force due to the Delta-hole excitation plays a crucial role in determining the neutron drip line of oxygen isotopes. This is one of the consequences of the repulsive effective T=1 force produced by the Delta-hole excitation on the shell evolution. The same mechanism makes effective T=1 interaction more repulsive in general.
STUDIES AT RCNP CYCLOTRON RELATED TO CHIRAL SYMMETRY IN NUCLEAR PHYSICS
Authors: OKAMURA H.
Published: October 2008

Nuclear physics programs recently carried out at the RCNP cyclotron facility have been discussed with emphasis on the two subjects in relation to the chiral symmetry. One is the three-nucleon reactions at intermediate energies and effects of the three-nucleon force, which may be consistently understood in the chiral effective field theory. Another is the high-resolution measurements of spin-isospin excitations and a possibility for explaining the fine-structures in giant resonances by the chiral mean field model.
A SYSTEMATIC STUDY OF THE TENSOR CORRELATION IN He AND Li ISOTOPES
Authors: MYO TAKAYUKI , TOKI HIROSHI , SUGIMOTO SATORU , KATŌ KIYOSHI , KIKUCHI YUMA , IKEDA KIYOMI
Published: October 2008

We investigate the tensor correlations in He and Li isotopes systematically. We propose the tensor-optimized shell model (TOSM) to describe the strong tensor correlation arising from the bare nuclear force in nuclei. Using TOSM for Li isotopes, we investigate the anomalous structures of 9,10,11 Li based on the 9 Li +n+n model where the 9 Li cluster is described by TOSM. As a result, the couplings between the tensor correlation in 9 Li and the extra two neutrons emerge Pauli-blocking, which naturally increases the s2 component to develop the halo structure in 11 Li . We further describe the short-range correlation arising from the repulsive core in the bare nuclear force by the unitary correlation operator method (UCOM). We propose the new framework of TOSM+UCOM for the nuclear structure study starting from the bare nuclear force.
STUDY OF THE TENSOR CORRELATION IN A NEUTRON-RICH SD-SHELL REGION WITH MEAN-FIELD AND BEYOND-MEAN-FIELD METHODS
Authors: SUGIMOTO SATORU , TOKI HIROSHI , IKEDA KIYOMI
Published: October 2008

We study the effect of the tensor force on nuclear structure with mean-field and beyond-mean-field methods. An important correlation induced by the tensor force is two-particle–two-hole (2p2h) correlation, which cannot be treated with a usual mean-field method. To treat the 2p2h tensor correlation, we develop a new framework (charge- and parity-projected Hartree-Fock (CPPHF) method), which is a beyond-mean-field method. We apply the CPPHF method to oxygen isotopes including neutron-rich ones. The potential energy from the tensor force has the same order of magnitude as that from the LS force and becomes smaller with neutron number, which indicates that excess neutrons do not contribute to the 2p2h tensor correlation significantly. We also study the effect of the tensor force on spin-orbit-splitting (ls-splitting) in a neutron-rich fluorine isotope 23 F . The tensor force reduces the ls-splitting for the proton d-orbits by about 3MeV. This effect is important to reproduce the experimental value.
WEAKLY BOUND STRUCTURES, HALOS AND MAGICITY IN NEUTRON RICH NUCLEI
Authors: SAXENA G. , SINGH D. , YADAV H. L. , HAGA A. , TOKI H.
Published: October 2008

Inspired by recent measurements indicating proton magic number at Z =14 in the vicinity of 42 Si , we have employed our relativistic mean-field (RMF) plus state dependent BCS approach for the study of even-even nuclei to obtain magic numbers and to look for nuclei exhibiting weakly bound structures and even halo formation. In our RMF+BCS approach the single particle continuum corresponding to the RMF is replaced by a set of discrete positive energy states for the calculations of pairing energy. It is found that in several nuclei the filling in of low lying single particle resonant state with large angular momentum, even before it becomes a bound state, helps to accommodate more neutrons but with extremely small increase in the binding energy. This gives rise to the occurrence of weakly bound system of neutron rich nuclei.
APPROXIMATE ENERGY EXPRESSION FOR NUCLEAR MATTER WITH NECESSARY CONDITIONS ON TENSOR STRUCTURE FUNCTIONS
Authors: TANAKA KAZUNORI , TAKANO MASATOSHI
Published: October 2008

The approximate energy expression for neutron matter is refined with respect to the tensor forces. The refined energy expression includes the main part of the three-body-cluster kinetic-energy terms caused by tensor correlations appropriately. Furthermore, the new energy expression guarantees necessary conditions on tensor structure functions. Significant improvement is seen in the numerical results of the variational calculation with the refined energy expression for neutron matter.
THEORETICAL CALCULATIONS ON α-DECAY HALF-LIVES BY THE DENSITY-DEPENDENT CLUSTER MODEL
Authors: REN ZHONGZHOU , XU CHANG
Published: October 2008

The theoretical calculations of α-decay half-lives for three kinds of α-emitters (even-even, even-odd, odd-odd nuclei) are systematically reviewed within the framework of the density-dependent cluster model (DDCM). The half-lives of three typical α-emitters (8 Be , 212 Po , and 270 Ds ) are discussed in detail. The good agreement between experimental and theoretical results shows that DDCM is applicable in the whole mass table from very light nuclei to heavy and superheavy ones.
Cell Polarity Signaling in Arabidopsis
Authors: Yang Zhenbiao
Published: October 2008

Cell polarization is intimately linked to plant development, growth, and responses to the environment. Major advances have been made in our understanding of the signaling pathways and networks that regulate cell polarity in plants owing to recent studies on several model systems, e.g., tip growth in pollen tubes, cell morphogenesis in the leaf epidermis, and polar localization of PINs. From these studies we have learned that plant cells use conserved mechanisms such as Rho family GTPases to integrate both plant-specific and conserved polarity cues and to coordinate the cytoskeketon dynamics/reorganization and vesicular trafficking required for polarity establishment and maintenance. This review focuses upon signaling mechanisms for cell polarity formation in Arabidopsis, with an emphasis on Rho GTPase signaling in polarized cell growth and how these mechanisms compare with those for cell polarity signaling in yeast and animal systems.
Polar Targeting and Endocytic Recycling in Auxin-Dependent Plant Development
Authors: Kleine-Vehn Jürgen , Friml Jiří
Published: October 2008

Plant development is characterized by a profound phenotypic plasticity that often involves redefining of the developmental fate and polarity of cells within differentiated tissues. The plant hormone auxin and its directional intercellular transport play a major role in these processes because they provide positional information and link cell polarity with tissue patterning. This plant-specific mechanism of transport-dependent auxin gradients depends on subcellular dynamics of auxin transport components, in particular on endocytic recycling and polar targeting. Recent insights into these cellular processes in plants have revealed important parallels to yeast and animal systems, including clathrin-dependent endocytosis, retromer function, and transcytosis, but have also emphasized unique features of plant cells such as diversity of polar targeting pathways; integration of environmental signals into subcellular trafficking; and the link between endocytosis, cell polarity, and cell fate specification. We review these advances and focus on the translation of the subcellular dynamics to the regulation of whole-plant development.
Deposition of Organic- Inorganic Hybrid Materials by Atomic Layer Deposition
Authors: Nilsen Ola , Klepper Karina , Nielsen Heidi , Fjellvaåg Helmer
Published: October 2008

The atomic layer deposition (ALD) technique has proved to be very suitable for deposition of thin films of organic- inorganic hybrid type of materials. This class of materials combines the rigid structures and physical properties of inorganic materials with the flexibility and physicochemical properties of organic compounds. The ALD growth of these nanostructured hybrid films is enabled by the use of highly reactive inorganic precursors and particular organic building units that can bond to the inorganic component via functional groups such as alcohols, carboxylic acids, amines, etc. The ALD technique enables design of such materials, constructed from a variety of inorganic and organic building units, at a resolution of one monolayer. This represents a major step forward with respect to nanostructured hybrid materials. Compared to the growth rate of purely inorganic materials by ALD, the growth rates for hybrid materials are much larger, and deposition rates as high as 4.4 nm/cycle has been demonstrated, thus enabling rapid depositions.
Leading Edge Atomic Layer Deposition Applications
Authors: Sundaram Ganesh , Monsma Douwe , Becker Jill
Published: October 2008

The growing adoption of Atomic Layer Deposition (ALD), as a means of producing highly uniform, and conformal thin films, has paved the way for its use in an array of extremely important emergent technologies. This in turn has influenced the design and capabilities of commercially available ALD systems. In this paper we will discuss aspects of the ALD system design, and explore a few select applications developed by the Savannah ALD users. Examples of these include the use of ALD for graphene-based devices with specific emphasis on different functionalization methods (NO2, and ozone) which result in the uniform deposition of ALD gate oxide material on Graphene, and the use of low vapor pressure precursors for the growth of solid oxide fuel cells (SOFC).
Fabrication and Characterization of Lead Sulfide Thin Films by Atomic Layer Deposition
Authors: Dasgupta Neil P. , Walch Stephen P. , Prinz Friedrich
Published: October 2008

We present a study of the deposition of lead sulfide (PbS) thin films by atomic layer deposition (ALD). PbS films were deposited from Pb(tmhd)2 and H2S precursors at precursor sublimation temperatures of 165-175 C. The film growth rate was 1.3-1.8 Aå/cycle, which is higher than previously published values. A linear growth rate characteristic of ALD was observed, with no chemical contamination. Film properties are studied using XPS, XRD, SEM and AFM measurements. AFM images show that the films are polycrystalline with grain size increasing with film thickness. Calculations have been performed using Density Functional Theory (DFT) to model the reaction mechanism.
Comparison of Gate Sensitivity for Spin Interference Effect between Al2O3 and SiO2 Gate Insulators on InGaAs Based Mesoscopic Ring Arrays
Authors: Kohda Makoto , Takagi Jun , Nitta Junsaku
Published: October 2008

We demonstrated gate voltage control of spin precession in InGaAs mesoscopic ring arrays based on the Rashba spin orbit interaction (SOI). We employed ALD 100 nm Al2O3 and suputtered 150 nm SiO2 gate insulators combined with large and small ring arrays to compare the gate sensitivity for the spin precession. Al'tshuler-Aronov-Spivak (AAS) oscillations were clearly observed and the oscillation phases at B = 0 switched between negative and positive by changing the gate bias voltages Vg. It corresponds to the electrical manifestation of spin rotation due to the Rashba SOI. The spin precession angle of 2π is achieved by changing Vg for 0.6 V in large ring array with Al2O3 gate whereas Vg for 5.4 V in small ring array with SiO2 gate. We can explain enhancement of the gate sensitivity in Al2O3 gate by taking the gate control of Rashba SOI parameter α and the different ring diameter into account.
Electrical Properties of High-k ALD HfO2 Deposited on Strained Si Layers Epitaxially Grown on Si0.8Ge0.2/Si Substrates
Authors: Shrestha Pragya R. , Gu Diefeng , Tapily Kandabara , Baumgart H.
Published: October 2008

MOS capacitors were fabricated on strained Si layers epitaxially grown on Si0.8Ge0.2/Si substrates and bulk Si with HfO2 as high-k material to investigate electrical properties and oxide/sSi interface quality. The performance of high-k dielectric material significantly depends on the interface quality between the ALD dielectric and the strained silicon substrate due to oxygen diffusion from HfO2 and Ge diffusion from the SiGe buffer layer. The electrical and structural properties were investigated by performing C-V and I-V measurements, surface roughness measurements by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Samples were tested with varying film thickness of strained Si capping layers (232, 928 and 1982 Aå). To investigate interface quality, samples were nitrided in a rapid thermal annealing (RTA). It was found that the interface quality of strained Si and ALD dielectric improves by nitridation, which prevents oxygen diffusion and acts as a diffusion barrier layer between the HfO2 and the out-diffused Ge. In contrast to sSi this is not the case for non strained relaxed bulk Si. The results show that the performance of device depends on the type of substrate used and the type of surface treatment performed before ALD deposition of HfO2.
Application of Advanced Atomic Layer Deposition for Understanding and Control of VTH and EOT in Metal/High-k Gate Stacks
Authors: Toriumi Akira , Nabatame Toshihide , Ota Hiroyuki
Published: October 2008

This paper discusses applications of atomic layer deposition (ALD) for both understanding and control of various challenges in metal/high-k gate stacks for advanced CMOS. Though ALD is generally used for high-k film deposition, this work focuses on understanding and controlling both anomalous VTH behaviors observed in high-k gate stacks and EOT scalability down to 0.5 nm.
Novel Zirconium Precursors for Atomic Layer Deposition of ZrO2 films
Authors: Chen Tianniu , Cameron Thomas M. , Nguyen Shawn D. , Stauf Gregory T. , Peters David W. , Maylott Leah , Li Weimin , Xu Chongying , Roeder Jeffrey F. , Hendrix Bryan C. , Hilgarth Monica , Niinisto Jaakko , Kukli Kaupo , Ritala Mikko , Leskela Markku
Published: October 2008

Five novel zirconium precursors - bis(N,N'-diisopropyl-1,3-propanediamide) zirconium (TCZR 1), tris(ethylmethylamide)(N,N,N'-trimethyl-1,2-ethaneamide-amine zirconium (TCZR 3), tris(dimethylamide)(N-ethyl-N',N'-dimethyl-1,2-ethaneamide-amine) zirconium (TCZR 4), mono-(N,N'-dimethyl-1,2-ethanediamide)-bis(cyclopentadienyl) zirconium (TCZR 5) and tris(ethylmethylamide)(N-ethyl-N',N'-dimethyl-1,2-ethaneamide-amine) zirconium (TCZR 6) have been synthesized and characterized by NMR, TGA, DSC and EA. The volatility of three precursors was measured by a Knudsen cell technique. The deposition behavior of these materials was evaluated in an ASM EmerAldTM ALD reactor or an ASM F-120 cross­flow reactor. Self-limiting deposition of ZrO2 films was observed with temperatures up to 300 {degree sign}C when used with oxygen plasma or ozone as the oxidant, as compared to more CVD-like behavior using bis(N, N'-di-tert-butyl-1,2-ethanediamide) zirconium (TCZR 2) and tetrakis(ethylmethylamide) zirconium (TEMAZ) under the same conditions. The resulting ZrO2 films from these novel precursors showed good step coverage (> 80%) on high aspect ratio structures, low carbon incorporation (< 2 atom%), high permittivity cubic/tetragonal phase, and growth rates comparable to TEMAZ based on analysis using X-ray diffraction, SIMS, and sputter depth profile AES. These results make the novel precursors promising candidates for ALD of high-k materials as storage capacitors in DRAM applications.
Batch Atomic Layer Deposition of HfO2 and ZrO2 Films Using Cyclopentadienyl Precursors
Authors: Fischer Pamela R. , Pierreux Dieter , Rouault Olivier , Sirugue Jacky , Zagwijn Peter M. , Tois Eva , Haukka Suvi
Published: October 2008

Thermal ALD deposition of ZrO2 and HfO2 films has been performed in the ASM A412(TM) 300mm vertical furnace using bis-cyclopentadienyl precursors. Due to the long precursor residence time and high surface area to be covered in a batch reactor, the thermal stability and volatility of the precursor is of critical importance. Evaluation of the thermal stability of the precursor was done by depositing on high surface area silica powder and then NMR studies were employed to evaluate precursor reactivity. The first deposition studies were in single wafer reactors to assess the viability for scale-up to batch processing. The deposition studies performed have shown that the family of bis-cyclopentadienyl precursors has demonstrated sufficient thermal stability to successfully achieve ALD films which meet deposition requirements in batch reactors for capacitor dielectrics in memory devices.
Remote Plasma and Thermal ALD of Platinum and Platinum Oxide Films
Authors: Knoops Harm C. , Mackus Adrie , Donders Merijn , Van de Sanden M. C. , Notten Peter , Kessels W. M.
Published: October 2008

Platinum and platinum oxide films were deposited using thermal and remote plasma ALD. The combination of MeCpPtMe3 precursor and O2 gas or a short (0.5 s) O2 plasma exposure resulted in high purity, low-resistivity (15 microOhm cm), high-density (21 g/cm3), cubic platinum films. The combination of MeCpPtMe3 precursor with a longer (5 s) O2 plasma exposure resulted in semi-conductive PtO2 films with a band gap of ~1.5 eV. The long nucleation delay observed with the thermal process could be overcome by using the remote plasma process where atomic oxygen is provided from the gas phase. The ALD process dependence on substrate temperature was investigated, where both the thermal and the remote plasma Pt process revealed a temperature window from 200 C to 300 C and the remote plasma PtO2 process had a temperature window from 100 C to 300 C.
HfO2 Atomic Layer Deposition Using HfCl4/H2O: The First Reaction Cycle
Authors: Nyns Laura , Delabie Annelies , Caymax Matty , Heyns Marc M. , Van Elshocht S. , Vinckier Chris , De Gendt S.
Published: October 2008

The growth behavior and film quality of HfO2 deposited by Atomic Layer Deposition (ALD) using HfCl4/H2O depends on the hydroxylation of the exposed surface. In this work, we investigate the dependence of the first HfCl4 chemisorption reaction at 300{degree sign}C on the OH density of the silicon surface. We observe that the hydroxyl density, and hence the Hf deposition, on O3/H2O wet oxides depends on the initial preparation as well as on the stabilization time in the ALD reactor. A good understanding of the initial nucleation behavior is necessary since wet oxides are used in CMOS transistors as surface pre-treatment for aggressively scaled HfO2 gate dielectrics. Moreover, the HfCl4 chemisorption reaction is used to estimate the hydroxylated fraction of these surfaces by means of theoretical models. Finally, the temperature dependence of the OH density, as available in literature, is applied to gain insight in the stoichiometry of the HfCl4 chemisorption reaction.
Carboxylic Acids as Oxygen Supplying Agents for Atomic Layer Deposition of High-k Thin Films
Authors: Rauwel Erwan , Ducroquet Frédérique , Rauwel Protima , Willinger Marc-Georg , Matko Igor , Kiselev Dmitry , Pinna Nicola
Published: October 2008

Atomic layer deposition (ALD) is known to be a good candidate for the growth of high-k thin films for microelectronic applications. Contrary to standard methods, in this work no common oxygen source such as water, oxygen or ozone is used. Titania and hafnia thin films were deposited on Si(100) and Si(111) substrates using metal alkoxides and carboxylic acids as oxygen source at temperatures ranging from 50 to 350ºC. The as-deposited films demonstrate good permittivity (k) and low leakage current densities due to their purity and amorphous character. Nevertheless, post deposition annealing under nitrogen leads to a densification of the films and further improves the electrical properties. An interesting aspect of the present approach is that the applied chemical approach which was adapted from non-aqueous sol-gel chemistry has the potential to grow oxides on silicon whilst minimizing the formation of a low-κ interfacial layer.
Two Step Annealing of Iridium Thin Films prepared by Plasma-Enhanced Atomic Layer Deposition
Authors: Kim Sung-Wook , Kwon Se-Hun , Kang Sang-Won
Published: October 2008

Plasma-enhanced atomic layer deposition of iridium thin film was investigated using (ethylcyclopentadienyl)(1,5-cyclooctadiene) iridium and ammonia plasma. The deposited Ir thin films had smooth surface and (111) preferred orientation due to atomic rearrangement by high energy of ammonia plasma. As a capacitor electrode material in dynamic random access memory applications, Ir thin films showed excellent thermal and morphological stability in ambient oxygen at 850 oC by adopting 2-step annealing process, which is consisted of the temperature rising step in ambient argon and the temperature maintenance step in ambient oxygen.
Enhanced Band Gap and Defect Structure of Low Dielectric Photonic Crystals Using ALD Coatings
Authors: Thitsa Makhin , Albin Sacharia
Published: October 2008

We propose a method for enhancing the photonic band gap and maximizing the gap to mid-gap ratio of photonic crystals fabricated on low dielectric substrates. By depositing materials of higher dielectric constants around the air holes of two dimensional photonic crystals TE band gap can be increased, and the gap position can be shifted to lower frequencies. Two examples using TiO2 interfacial layers in AAO and SiO2 substrates are presented. In the case of AAO/TiO2 the gap to mid-gap ratio can be increased from 10.4% to 25.2% whereas SiO2/TiO2 structure has a larger enhancement, from 1.9% to 23.4%. It is also demonstrated that in SiO2/TiO2 structure defect states can be brought into the band gap by introducing a single defect.
Effects of Film Thickness and Preferred Orientation on the Dieletric Constants of Hf-Aluminate Films Deposited by PEALD
Authors: Moon Hyoung-Seok , Joo Daekwon , Park Pan-Kwi , Kang Sang-Won
Published: October 2008

The thickness changes in Hf aluminate films deposited by PEALD were investigated by modifying the process sequence. The conventional supercycle of Hf aluminate film is composed of two groups of subcycles allocated to deposit Al2O3 and HfO2 films. The dielectric constants of these thin films decrease with decreasing film thickness. This decrease originates to a changing preferred orientation from (200) to (111). Using the modified supercycle which has a periodically addition of small dose of Al2O3 in HfO2 thin film, the HfO2 film was transformed from (111) preferred orientation to (200) preferred orientation. As a result of preferred orientation change, the dielectric constant of films increased up to 22.5
In-Situ Probing of Atomic Layer Deposition Processes using Infrared and Near Infrared Spectroscopy
Authors: O'Mahony Aileen , Povey Ian M. , Pemble Martyn E.
Published: October 2008

The monitoring of chemical vapour deposition, and its variant atomic layer deposition, by in-situ spectroscopic methods is well established and has been used to elucidate many important details of the dynamics, kinetics and mechanisms of these complex processes. Here we examine two in-situ gas phase probes that we have been employing, firstly, Fourier transform mid and near-infrared spectroscopy to elucidate the nature of the gas phase products, and secondly, the use of near infrared tunable diode laser spectroscopy to spatially and temporally resolve the spectral features due to either reactants or products. Data is presented for the i) Al2O3 from Al(CH3)3 and H2O and; ii) HfO2 from Hf(N(CH3)2)4 and H2O growth systems.
Atomic Vapor Deposited Tantalum Carbo-Nitride Film using TBTDET and Hydrogen
Authors: Kim Sukhoon , Song Moonkyun , Rhee Shiwoo
Published: October 2008

TaCN films have been deposited by atomic vapor deposition (AVD) using tert-butylimido tris-diethylamido tantalum (TBTDET, tBu-N=Ta-(NEt2)3, Et=C2H5, tBu=C(CH3)3) and hydrogen. The growth rate was 0.72~2.70nm/min depending on the TBTDET injection time and the deposition temperature. It was confirmed that the film was a mixture of TaC, Ta3N5, TaN, and Ta2O5 phases. Oxide phase was formed from the post deposition oxygen uptake. The film composition and phase composition were dependent on the deposition temperature. With the increase of deposition temperature, the resistivity was decreased because the conducting TaC and TaN phases were increased over the insulating Ta3N5 and Ta2O5 phases. The work function and the minimum resistivity of film deposited at 430åC were 4.28{plus minus}0.01eV and 1.63×104μΩcm. Therefore, the TaCN film deposited by AVD can be used for the nMOS gate electrode.
450 mm Silicon Wafers Challenges - Wafer Thickness Scaling
Authors: Goldstein Michael , Watanabe Masaharu
Published: October 2008

Pilot line using 450 mm wafer will start in 2012 according to ITRS. One of the most important discussions is wafer thickness scaling from 300 mm wafer to 450 mm wafer. It is discussed in terms of empirical scaling, gravitational sag, thermal stress and fracture strength.
Uphill Drift of Vacancies and Self-Interstitials in Silicon Crystal Growth
Authors: Voronkov Vladimir , Falster Robert
Published: October 2008

Point defects, in a growing crystal, drift along the temperature gradient, G, at a velocity α G. The reported microdefect patterns in crystals grown in the vacancy mode, with a temporary halt, include an interstitial region located around the halted interface. The features of this region provide a clear evidence in favour of a strong uphill drift of both kinds of intrinsic point defects. The drift coefficient αV (for vacancies) and αI (for self-interstitials) have been deduced, by fitting the simulated defect profiles to the reported patterns, to be around 1.6x10-5 cm2/sK. The drift phenomenon is essential in establishing the point defect spatial distribution.
The Development of Semi-insulating Silicon Substrates for Microwave Devices
Authors: Jordan Douglas M. , Haslam Henry , Mallik Kanad , Wilshaw Peter R.
Published: October 2008

The concept of fully encapsulated, semi-insulating silicon (SI-Si) Cz-SOI substrates for silicon microwave devices is presented. Results show that, using gold as a compensating impurity, a silicon resistivity of 180 kΩcm can be achieved. Sufficiently high resistivity substrates for microwave applications are obtained by depositing gold on silicon and annealing for one hour at 1000C. Silicon oxide and silicon nitride are considered as diffusion barriers for use in the new technology. At 1000C the diffusivity of gold in PECVD silicon nitride is found to be ~ 3.7x10-13cm2s-1, whilst for silicon oxide it is less than 6x10-14cm2s-1. These results imply that silicon nitride would be ineffective as a diffusion barrier in the SI-Si technology but that a silicon oxide BOX 600nm thick might allow devices to be processed with a thermal budget of up to 15 hours at 1000C without impurity contamination.