B Meson Transitions into Higher Mass Charmed Resonances

We use QCD sum rules to estimate the universal form factors describing the semileptonic B decays into excited charmed resonances, such as the $1^-$ and $2^-$ states $D_1^{*}$ and $D_2^{*}$ belonging to the $s_\ell^P={3/2}^-$ heavy quark doublet, and the $2^-$ and $3^-$ states $D_2^{*\prime}$ and $D_3$ belonging to the s_\ell^P={5\2}^- doublet.Comment: LaTex, 14 pages, 1 figur

Blocked All-Pairs Shortest Paths Algorithm on Intel Xeon Phi KNL Processor: A Case Study

Manycores are consolidating in HPC community as a way of improving performance while keeping power efficiency. Knights Landing is the recently released second generation of Intel Xeon Phi architecture. While optimizing applications on CPUs, GPUs and first Xeon Phi's has been largely studied in the last years, the new features in Knights Landing processors require the revision of programming and optimization techniques for these devices. In this work, we selected the Floyd-Warshall algorithm as a representative case study of graph and memory-bound applications. Starting from the default serial version, we show how data, thread and compiler level optimizations help the parallel implementation to reach 338 GFLOPS.Comment: Computer Science - CACIC 2017. Springer Communications in Computer and Information Science, vol 79

Critical Behavior of J/psi across the Phase Transition from QCD sum rules

We study behavior of J/psi in hot gluonic matter using QCD sum rules. Taking into account temperature dependences of the gluon condensates extracted from lattice thermodynamics for the pure SU(3) system, we find that the mass and width of J/psi exhibit rapid change across the critical temperature.Comment: 5 pages, 3 figures. Poster contribution for Quark Matter 2008. To be published in the proceeding

Constraints on QCD Sum-rules from the H\"older Inequalities

A new technique based on H\"older's integral inequality is applied to QCD sum-rules to provide fundamental constraints on the sum-rule parameters. These constraints must be satisfied if the sum-rules are to consistently describe integrated physical cross-sections, but these constraints do not require any experimental data and therefore can be applied to any hadronic spectral function. As an illustration of this technique the Laplace sum-rules of the light-quark correlation function for the vector and the axial-vector currents are examined in detail. We find examples of inconsistency between the inequalities and sum-rule parameters used in some previous analyses of the vector and axial-vector channels.Comment: 13 pages, RevTeX, 4 figures available upon request, to appear in Phys. Lett

Light-Quark Mesons and Four-Quark Condensates at Finite Temperature

We propose an analog of the familiar gap equation for the case of four-quark condensates at finite temperature. The condensates of interest correspond to scalar, vector, psudoscalar, axial vector, and tensor Dirac structures. Working with correlators at zero chemical potential without factorization, we arrive at coupled equations for these four-quark condensates and the masses of certain light-quark mesons. We study the temperature dependence of the four-quark condensates and masses; in one of our models, factorization of the four-quark condensates is shown to be increasingly violated as the temperature is increased toward $T_c$. The 2$^{++}$ tensor mesons a$_2$(1320)-f$_2$(1270) are identified as especially sensitive probes of the four-quark condensates.Comment: Latex file, 6 Fig

Quark condensate in nuclear matter based on Nuclear Schwinger-Dyson formalism

The effects of higher order corrections of ring diagrams for the quark condensate are studied by using the bare vertex Nuclear Schwinger Dyson formalism based on $\sigma$-$\omega$ model. At the high density the quark condensate is reduced by the higher order contribution of ring diagrams more than the mean field theory or the Hartree-Fock

Uncertainties in the MSbar bottom quark mass from relativistic sum rules

A detailed compilation of uncertainties in the MSbar bottom quark mass m_b(m_b) obtained from low-n spectral sum rules at order alpha_s^2 is given including charm mass effects and secondary b production. The experimental continuum region above 11.1 GeV is treated conservatively. An inconsistency of the PDG averages for the electronic partial widths of Upsilon(4S) and Upsilon(5S) is pointed out. From our analysis we obtain m_b(m_b)=4.20\pm 0.09 GeV. The impact of future CLEO data is discussed.Comment: 11 pages, late

Gaussian Sum-Rules and Prediction of Resonance Properties

Techniques for using Gaussian QCD sum-rules to predict hadronic resonance properties are developed for single-resonance and two-resonance phenomenological models, and criteria are developed for determining which of these models is required for analyzing a particular hadronic channel. The vector current sum-rule coupled to the $\rho$ meson is shown to be consistent with a single resonance model, and the Gaussian sum-rule analysis results in an accurate $\rho$ mass prediction which exhibits excellent agreement between the theoretical prediction of the Gaussian sum-rule and the phenomenological model. A two-resonance model is shown to be necessary for the Gaussian sum-rule for the non-strange quark scalar ($\bar n n$) currents. The two-resonance Gaussian sum-rule analysis of the isoscalar and isovector ($I=0,1$) $\bar n n$ scalar mesons exhibits excellent agreement between the theoretical prediction and phenomenological model. The prediction of the resonance properties of the $I=0,1$ $\bar n n$ scalar mesons in this two-resonance model provides valuable information for the interpretation of the scalar mesons, including the X(1775).Comment: latex2e, 29 pages, 10 eps figures embedded in latex2e. Revised version includes additions to reference [28] and correction to equation (56

QCD sum rules for the pseudoscalar decay constants - To constrain the strange quark mass

We study the higher order corrections of quark masses to the Gell-Mann$-$Oakes$-$Renner (GOR) relation by constructing QCD sum rules exclusively for pseudoscalar mesons from the axial-vector correlation function, $i \int d^4x~ e^{ip\cdot x}$. To project out the pseudoscalar meson contributions, we apply $-p^\mu p^\nu/p^2$ to this correlation function and construct sum rules for the decay constants of pseudoscalar mesons, $f_\pi, f_k$ and $f_{\eta_8}$. The OPE is proportional to quark masses due to PCAC. To leading order in quark mass, each sum rule reproduces the corresponding GOR relation. For kaon and $\eta_8$, the deviation from the GOR relation due to higher orders in quark mass is found to be substantial. But the deviation gives better agreements with the phenomenology. Our sum rule provides a sensitive relation between $f_K$ and $m_s$, which stringently constrain the value for $m_s$. To reproduce the experimental value for $f_K$, $m_s$ is found to be 186 MeV at 1 GeV scale. The $f_{\eta_8}$ sum rule also supports this finding.Comment: 14 pages including 3 figures. slightly revised. Accepted for publication in Physical Review

Isospin Breaking in the Pion-Nucleon Coupling from QCD Sum Rules

We use QCD sum rules for the three point function of a pseudoscalar and two nucleonic currents in order to estimate the charge dependence of the pion nucleon coupling constant $g_{NN\pi}$ coming from isospin violation in the strong interaction. The effect can be attributed primarily to the difference of the quark condensates $$and$$. For the splitting $(g_{pp\pi_0} - g_{nn\pi_0}) / g_{NN\pi}$ we obtain an interval of $1.2 * 10^{-2}$ to $3.7 * 10^{-2}$, the uncertainties coming mainly from the input parameters. The charged pion nucleon coupling is found to be the average of $g_{pp\pi_0}$ and $g_{nn\pi_0}$. Electromagnetic effects are not included.Comment: 18 pages (REVTeX) + 2 figures (as PostScript), to be published in PRC, replaced with final version: inclusion of pi-eta mixing and N -> N* transition