ηc\eta_c - glueball Mixing and Resonance X(1835)

The mixing of $\eta_c$ and the lowest mass pseudoscalar glueball is estimated within the framework of the instanton liquid model. It is demonstrated that the mixing is large and may explain the difference between the observed mass of the glueball candidate X(1835) and the theoretical prediction of QCD sum rule analysis.Comment: 5 pages, 1 figure, Late

Ultraviolet-Renormalon Reexamined

We consider large-order perturbative expansions in QED and QCD. The coefficients of the expansions are known to be dominated by the so called ultraviolet (UV) renormalons which arise from inserting a chain of vacuum-polarization graphs into photonic (gluonic) lines. In large orders the contribution is associated with virtual momenta $k^2$ of order $Q^2e^n$ where $Q$ is external momentum, $e$ is the base of natural logs and $n$ is the order of perturbation theory considered. To evaluate the UV renormalon we develop formalism of operator product expansion (OPE) which utilizes the observation that $k^2\gg Q^2$. When applied to the simplest graphs the formalism reproduces the known results in a compact form. In more generality, the formalism reveals the fact that the class of the renormalon-type graphs is not well defined. In particular, graphs with extra vacuum-polarization chains are not suppressed. The reason is that while inclusion of extra chains lowers the power of $\ln k^2$ their contribution is enhanced by combinatorial factors.Comment: LaTex, 18 pages, 5 figures. Some numerical coefficients are corrected once mor

QFT results for neutrino oscillations and New Physics

The CP asymmetry in neutrino oscillations, assuming new physics at production and/or detection processes, is analyzed. We compute this CP asymmetry using the standard quantum field theory within a general new physics scenario that may generate new sources of CP and flavor violation. Well known results for the CP asymmetry are reproduced in the case of V -A operators, and additional contributions from new physics operators are derived. We apply this formalism to SUSY extensions of the Standard Model where the contributions from new operators could produce a CP asymmetry observable in the next generation of neutrino experiments.Comment: 6 pages, 3 figures, version to be published in Phys.Rev.

Generalization of the Fierz-Pauli Action

We consider the Lagrangian of gravity covariantly amended by the mass and polynomial interaction terms with arbitrary coefficients, and reinvestigate the consistency of such a theory in the decoupling limit, up to the fifth order in the nonlinearities. We calculate explicitly the self-interactions of the helicity-0 mode, as well as the nonlinear mixing between the helicity-0 and -2 modes. We show that ghost-like pathologies in these interactions disappear for special choices of the polynomial interactions, and argue that this result remains true to all orders in the decoupling limit. Moreover, we show that the linear, and some of the nonlinear mixing terms between the helicity-0 and -2 modes can be absorbed by a local change of variables, which then naturally generates the cubic, quartic, and quintic Galileon interactions, introduced in a different context. We also point out that the mixing between the helicity-0 and 2 modes can be at most quartic in the decoupling limit. Finally, we discuss the implications of our findings for the consistency of the effective field theory away from the decoupling limit, and for the Boulware-Deser problem.Comment: 18 pages, no figure

New physics in \epsilon' from chromomagnetic contributions and limits on Left-Right symmetry

New physics in the chromomagnetic flavor changing transition s->dg* can avoid the strong GIM suppression of the Standard Model and lead to large contributions to CP-violating observables, in particular to the epsilon' parameter, that we address here. We discuss the case of the Left-Right symmetric models, where this contribution implies bounds on the phases of the right-handed quark mixing matrix, or in generic models with large phases a strong bound on the Left-Right symmetry scale. To the leading order, a numeric formula for epsilon' as a function of the short-distance coefficients for a wide class of models of new physics is given.Comment: 12 pages, Eq. 12 and related numerics amende

Masses and decay constants of bound states containing fourth family quarks from QCD sum rules

The heavy fourth generation of quarks that have sufficiently small mixing with the three known SM families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from fourth family and the other from known third family SM quarks in the framework of the QCD sum rules. In the calculations, we take into account two gluon condensate diagrams as nonperturbative contributions. The obtained results reduce to the known masses and decay constants of the $\bar b b$ and $\bar c c$ quarkonia when the fourth family quark is replaced by the bottom or charm quark.Comment: 15 Pages, 9 Figures and 6 Table

On the Motion of Heavy Quarks inside Hadrons: Universal Distributions and Inclusive Decays

In previous papers we have pointed out that there exists a QCD analog of the phenomenological concept of the so called Fermi motion for the heavy quark inside a hadron. Here we show in a more detailed way how this comes about and we analyze the limitations of this concept. Non-perturbative as well as perturbative aspects are included. We emphasize both the similarities and the differences to the well-known treatment of deep inelastic lepton-nucleon scattering. We derive a model-independent {\em lower} bound on the kinetic energy of the heavy quark inside the hadron.Comment: 34 pages, Latex, 4 figures. Some clarifying comments and postscript files of figures are adde

Sum Rules for Heavy Flavor Transitions in the SV Limit

We show how sum rules for the weak decays of heavy flavor hadrons can be derived as the moments of spectral distributions in the small velocity (SV) limit. This systematic approach allows us to determine corrections to these sum rules, to obtain new sum rules and it provides us with a transparent physical interpretation; it also opens a new perspective on the notion of the heavy quark mass. Applying these sum rules we derive a lower bound on the deviation of the exclusive form factor $F_{B->D^*}$ from unity at zero recoil; likewise we give a field-theoretical derivation of a previously formulated inequality between the expectation value for the kinetic energy operator of the heavy quark and for the chromomagnetic operator. We analyze how the known results on nonperturbative corrections must be understood when one takes into account the normalization point dependence of the low scale parameters. Relation between the field-theoretic derivation of the sum rules and the quantum-mechanical approach is elucidated.Comment: 72 pages, 5 figures (uuencoded ps files added using figures option), Revised version. Paper is considerably extended to include some new results. New section on quantum mechanical approach is adde

Loop-Less Electric Dipole Moment of the Nucleon in the Standard Model

We point out that the electric dipole moment of the neutron in the Standard Model is generated already at tree level to the second order in the weak interactions due to bound-state effects, without short-distance Penguin loops. The related contribution has a regular nonvanishing chiral limit and does not depend on the mass splitting between s and d quarks. We estimate it to be roughly 10^(-31)e*cm and expect a more accurate evaluation in the future. We comment on the connection between d_n and the direct CP-violation in D decays.Comment: 10 pages, 2 figure