Gluon Fragmentation into Heavy Quarkonium

The dominant production mechanism for heavy quark-antiquark bound states in very high energy processes is fragmentation, the splitting of a high energy parton into a quarkonium state and other partons. We show that the fragmentation functions $D(z,\mu)$ describing these processes can be calculated using perturbative QCD. We calculate the fragmentation functions for a gluon to split into S-wave quarkonium states to leading order in the QCD coupling constant. The leading logarithms of $\mu/m_Q$, where $\mu$ is the factorization scale and $m_Q$ is the heavy quark mass, are summed up using Altarelli-Parisi evolution equations.Comment: LateX 11 pages (3 figures available upon request). NUHEP-TH-92-2

Perturbative QCD Fragmentation Functions for BcB_c and Bc∗B_c^* Production

The dominant production mechanism for ${\bar b} c$ bound states in high energy processes is the production of a high energy ${\bar b}$ or $c$ quark, followed by its fragmentation into the ${\bar b} c$ state. We calculate the fragmentation functions for the production of the S-wave states $B_c$ and $B_c^*$ to leading order in the QCD coupling constant. The fragmentation probabilities for ${\bar b} \rightarrow B_c$ and ${\bar b} \rightarrow B_c^*$ are approximately $2.2 \times 10^{-4}$ and $3.1 \times 10^{-4}$, while those for $c \rightarrow B_c$ and $c \rightarrow B_c^*$ are smaller by almost two orders of magnitude.Comment: Latex, 12 pages, 3 figures available upon request, NUHEP-TH-93-

Recent progress on the chiral unitary approach to meson meson and meson baryon interactions

We report on recent progress on the chiral unitary approach, analogous to the effective range expansion in Quantum Mechanics, which is shown to have a much larger convergence radius than ordinary chiral perturbation theory, allowing one to reproduce data for meson meson interaction up to 1.2 GeV. Applications to physical processes so far unsuited for a standard chiral perturbative approach are presented. Results for the extension of these ideas to the meson baryon sector are discussed, together with applications to kaons in a nuclear medium and $K^-$ atoms.Comment: Contribution to the KEK Tanashi Symposium on Physics of Hadrons and Nuclei, Tokyo, December 1998, 10 pages, 3 postscript figures. To be published as a special issue of Nuclear Physics

Chiral Unitary Approach To The N*N*pi, N*N*eta Couplings For The N*(1535) Resonance

Using a chiral unitary model in which the negative parity nucleon resonance $N^\ast \equiv N^\ast(1535)$ is generated dynamically by means of the Bethe Salpeter equation with coupled meson baryon channels in the $S = 0$ sector, we have obtained the $\pi^0 N^\ast N^\ast$ and $\eta N^\ast N^\ast$ couplings. The $\pi^0 N^\ast N^\ast$ coupling has smaller strength and the same sign as the $\pi^0 N N$ coupling. This rules out the mirror assignment of chiral symmetry where the ground state nucleon $N$ and the negative parity resonance $N^\ast$ are envisaged as chiral partners in the baryon sector.Comment: 30 pages, 15 figures (ps files). The new version discusses pi-N scattering around the N*(1535) resonanc

Can residuals of the Solar system foreground explain low multipole anomalies of the CMB ?

The low multipole anomalies of the Cosmic Microwave Background has received much attention during the last few years. It is still not ascertained whether these anomalies are indeed primordial or the result of systematics or foregrounds. An example of a foreground, which could generate some non-Gaussian and statistically anisotropic features at low multipole range, is the very symmetric Kuiper Belt in the outer solar system. In this paper, expanding upon the methods presented by Maris et al. (2011), we investigate the contributions from the Kuiper Belt objects (KBO) to the WMAP ILC 7 map, whereby we can minimize the contrast in power between even and odd multipoles in the CMB, discussed discussed by Kim & Naselsky (2010). We submit our KBO de-correlated CMB signal to several tests, to analyze its validity, and find that incorporation of the KBO emission can decrease the quadrupole-octupole alignment and parity asymmetry problems, provided that the KBO signals has a non-cosmological dipole modulation, associated with the statistical anisotropy of the ILC 7 map. Additionally, we show that the amplitude of the dipole modulation, within a 2 sigma interval, is in agreement with the corresponding amplitudes, discussed by Lew (2008).Comment: 24 pages, 9 figures, 5 tables. Matches version in JCA

Microstructure and kinetics of hot corrosion for a nickel alloy in molten salt

Metallography, analytical SEM, and XRD were used to measure kinetics and characterize the microstructure of hot corrosion of the Ni-Cr-Fe alloy INCONEL 600 after 500 h immersion in molten Na{sub 2}CO{sub 3}- NaCl salt at 900-950 C in an oxidizing atmosphere. This was done to assess the alloy as a reaction vessel material for a waste treatment process known as Molten Salt Oxidation. The alloy was found to hot corrode by surface oxidation and intergranular attack. Combined rate for loss of load-bearing cross-section metal was comparable to corrosion rates for analogous salts. About 5% of the oxide scale was a continuous, dense, protective layer of Cr{sub 2}O{sub 3} at the metal/oxide interface. A middle portion comprised about 55% of the scale and was a porous, mixed oxide of NiO>Cr{sub 2}O{sub 3}>Fe{sub 2}O{sub 3}. The outer 40% was nearly all NiO with dense grains and cavitated grain boundaries. Overall, the NiO was dominant and the lesser amounts of Cr{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} were roughly equivalent. No direct invasion of salt through the oxide to the metal was observed

Final-State Phases in B→Dπ,D∗πB \to D \pi, D^* \pi, and DρD \rho Decays

The final-state phases in $\bar{B} \to D \pi, D^* \pi$, and $D \rho$ decays appear to follow a pattern similar to those in $D \to \bar{K} \pi$, $\bar{K}^* \pi$, and $\bar{K} \rho$ decays. Each set of processes is characterized by three charge states but only two independent amplitudes, so the amplitudes form triangles in the complex plane. For the first two sets the triangles appear to have non-zero area, while for the $D \rho$ or $\bar{K} \rho$ decays the areas of the triangles are consistent with zero. Following an earlier discussion of this behavior for $D$ decays, a similar analysis is performed for B decays, and the relative phases and magnitudes of contributing amplitudes are determined. The significance of recent results on \ob \to D^{(*)0} \bar{K}^{(*)0} is noted. Open theoretical and experimental questions are indicated.Comment: 16 pages, LaTeX, 3 figures, to be submitted to Phys. Rev. D. References added; comments on new experimental results and analysi

Antimatter from the cosmological baryogenesis and the anisotropies and polarization of the CMB radiation

We discuss the hypotheses that cosmological baryon asymmetry and entropy were produced in the early Universe by phase transition of the scalar fields in the framework of spontaneous baryogenesis scenario. We show that annihilation of the matter-antimatter clouds during the cosmological hydrogen recombination could distort of the CMB anisotropies and polarization by delay of the recombination. After recombination the annihilation of the antibaryonic clouds (ABC) and baryonic matter can produce peak-like reionization at the high redshifts before formation of quasars and early galaxy formation. We discuss the constraints on the parameters of spontaneous baryogenesis scenario by the recent WMAP CMB anisotropy and polarization data and on possible manifestation of the antimatter clouds in the upcoming PLANCK data.Comment: PRD in press with minor change

Hadronic Charmed Meson Decays Involving Axial Vector Mesons

Cabibbo-allowed charmed meson decays into a pseudoscalar meson and an axial-vector meson are studied. The charm to axial-vector meson transition form factors are evaluated in the Isgur-Scora-Grinstein-Wise quark model. The dipole momentum dependence of the $D\to K$ transition form factor and the presence of a sizable long-distance $W$-exchange are the two key ingredients for understanding the data of $D\to \bar Ka_1$. The $K_{1A}-K_{1B}$ mixing angle of the strange axial-vector mesons is found to be $\approx \pm37^\circ$ or $\pm58^\circ$ from $\tau\to K_1\nu_\tau$ decays. The study of $D\to K_1(1270)\pi, K_1(1400)\pi$ decays excludes the positive mixing-angle solutions. It is pointed out that an observation of the decay $D^0\to K_1^-(1400)\pi^+$ at the level of $5\times 10^{-4}$ will rule out $\theta\approx -37^\circ$ and favor the solution $\theta\approx -58^\circ$. Though the decays $D^0\to \bar K_1^0\pi^0$ are color suppressed, they are comparable to and even larger than the color-allowed counterparts: $\bar K_1^0(1270)\pi^0\sim K_1^-(1270)\pi^+$ and $\bar K_1^0(1400)\pi^0> K_1^-(1400)\pi^+$. The finite width effect of the axial-vector resonance is examined. It becomes important for $a_1(1260)$ in particular when its width is near 600 MeV.Comment: 19 page

Influence of typical environments on quantum processes

We present the results of studying the influence of different environmental states on the coherence of quantum processes. We choose to discuss a simple model which describe two electronic reservoirs connected through tunneling via a resonant state. The model could, e.g., serve as an idealization of inelastic resonant tunneling through a double barrier structure. We develop Schwinger's closed time path formulation of non-equilibrium quantum statistical mechanics, and show that the influence of the environment on a coherent quantum process can be described by the value of a generating functional at a specific force value, thereby allowing for a unified discussion of destruction of phase coherence by various environmental states: thermal state, classical noise, time dependent classical field, and a coherent state. The model allows an extensive discussion of the influence of dissipation on the coherent quantum process, and expressions for the transmission coefficient are obtained in the possible limits.Comment: 46 pages, 11 post script figures. Accepted for publication in Physical Review