Sample records for antimesons

  1. Two-Particle Correlations and Meson-Antimeson Mixing Effects


    Dass, G. V.; Grimus, W.


    We discuss 2-particle correlations which arise in the time evolution of C-odd and C-even meson--antimeson states of flavoured neutral mesons. In order to keep our discussion general, we do not use the Weisskopf -- Wigner approximation. Possible deviations from quantum-mechanical coherence effects are parameterized by a so-called decoherence parameter $\\zeta$. In particular, we study the $\\zeta$-dependence of the asymmetry of unlike and like-flavoured events which was recently observed experim...

  2. On unitarity relations and their application to meson–antimeson mixing

    Indian Academy of Sciences (India)

    G V Dass


    In view of the recent observation of nonexponential decay features for a certain quantummechanical system, we revisit our earlier study of the small-time behaviour of the meson–antimeson complex wherein the commonly employed Weisskopf–Wigner approximation could be tested, in principle. We find that the experiments for this testing are difficult because of (i) the smallness of the times required for this study, (ii) the high accuracy required for probing the nonleading terms (which distinguish this approximation from the general theory) in the small-time behaviour of the relevant probabilities and (iii) the crude knowledge of the required ‘flavour-tagging’ procedures, as available at present.

  3. Testing the Wigner - Weisskopf approximation by using neutral-meson - antimeson correlated states


    Dass, G. V.; Grimus, W.


    We phenomenologically decompose the Weisskopf--Wigner approximation, as applied to the neutral flavoured meson complexes, into three pieces and propose tests for these pieces. Our tests hold for general decay amplitudes and $M^0$--$\\bar M^0$ mixing parameters. We concentrate on C-odd $M^0 \\bar M^0$ states and stress the importance of such tests in view of the variety of physics extracted from measurements on such complexes. Studying the feasibility of the tests confines one to the $K^0 \\bar K...

  4. An Effective Field Theory study of heavy meson-heavy antimeson molecules based on Heavy Quark Symmetries


    Hidalgo Duque, Carlos


    El estudio de las interacciones hadrónicas en el régimen de energías bajas e intermedias ha experimentado grandes avances en los últimos años. La descripción de la dinámica de QCD a bajas energías por medio de teorías efectivas, en las que los grados de libertad son mesones y bariones, ha sido ampliamente explotada para explicar el complejo espectro experimental observado. En particular, la teoría quiral de perturbaciones y sus extensiones unitarias han permitido entender y clasificar multitu...

  5. Heavy Quark Symmetries: Molecular partners of the X(3872 and Zb(10610/Zb′(10650

    Directory of Open Access Journals (Sweden)

    Guo Feng-Kun


    Full Text Available In this work, we have made use of the identification of the X(3872 and Zb(10610/Zb′(10650 as heavy meson-heavy antimeson molecules to establish some consequences derived from the symmetries that these heavy meson-heavy antimeson systems must have. We show the most general effective lagrangian that respects these symmetries only depends on four undetermined low energy constants (LECs, which will be fitted to reproduce the experimental data about the resonances we are identifying as molecular states. Then, we obtain a whole new set of states in the spectrum that could also be thought as heavy meson-heavy antimeson molecules. Finally, using another different symmetry: Heavy Antiquark-Diquark Symmetry, we can also establish a set of pentaquark-like states taking advantage of the previous LEC calculation.

  6. Molecular Quarkonium


    Voloshin, M. B.


    I discuss topics related to four-quark states of the `molecular quarkonium' type, i.e. resonances that could be considered as (dominantly) made from a heavy meson and antimeson. Of the so far observed resonances such picture is very likely applicable to the state X(3872), and I also discuss its possible relevance to the peak near the $D^* {\\bar D}^*$ threshold in $e^+e^-$ annihilation.

  7. Heavy Meson Molecules in Effective Field Theory


    AlFiky, Mohammad T.; Gabbiani, Fabrizio; Petrov, Alexey A.


    We consider the implications from the possibility that the recently observed state X(3872) is a meson-antimeson molecule. We write an effective Lagrangian consistent with the heavy-quark and chiral symmetries needed to describe X(3872). We explore the consequences of the assumption that X(3872) is a molecular bound state of D^{*0} and anti-D^0 mesons for the existence of bound states in the D^0-anti-D^0 and D^{*0}-anti-D^{*0}.

  8. String breaking

    CERN Document Server

    Bali, G S; Lippert, T; Neff, H; Prkacin, Z; Schilling, K; Bali, Gunnar S; Dussel, Thomas; Lippert, Thomas; Neff, Hartmut; Prkacin, Zdravko; Schilling, Klaus


    We numerically investigate the transition of the static quark-antiquark string into a static-light meson-antimeson system. Improving noise reduction techniques, we are able to resolve the signature of string breaking dynamics for Nf=2 lattice QCD at zero temperature. We discuss the lattice techniques used and present results on energy levels and mixing angle of the static two-state system. We visualize the action density distribution in the region of string breaking as a function of the static colour source-antisource separation. The results can be related to properties of quarkonium systems.

  9. Unexpected Mesons X, Y, Z, ... (tetraquarks? hadron molecules? ...)

    CERN Document Server

    Azimov, Ya I


    This talk briefly discusses the set of meson resonances discovered in the latest decade. They are frequently treated in the literature as tetraquarks or hadron molecules. Our consideration (using the energy-time uncertainty relation) suggests, however, that the most reasonable description for each of them may be a two- (or more-) component Fock column, with one line being a conventional quark-antiquark pair, and the other line(s) corresponding to a charmed (or beauty) meson-antimeson pair near its threshold. Detailed investigation of decay properties might allow to reveal presence of several Fock components and separate their contributions.

  10. Quark mixing in the discrete dark matter model

    CERN Document Server

    Toorop, Reinier de Adelhart; Morisi, Stefano


    We consider a model in which dark matter is stable as it is charged under a Z2 symmetry that is residual after an A4 flavour symmetry is broken. We consider the possibility to generate the quark masses by charging the quarks appropriately under A4. We find that it is possible to generate the CKM mixing matrix by an interplay of renormalisable and dimension-six operators. In this set-up, we predict the third neutrino mixing angle to be large and the dark matter relic density to be in the correct range. However, low energy observables - in particular meson-antimeson oscillations - strongly limit the available parameter space.

  11. Quantum correlations in B and K meson systems

    CERN Document Server

    Banerjee, Subhashish; MacKenzie, Richard


    We study quantum correlations in meson-antimeson systems, as provided for example in meson factories used mainly to probe physics beyond the Standard Model of particle physics. We use a semigroup formalism to compute a trace-preserving density matrix for these systems, in spite of the fact that the particles are unstable. This is used to compute the time evolution of several measures of quantum correlations for three meson systems (KKbar, BdBdbar and BsBsbar). We find that the quantum correlations for these systems can be non-trivially different from their stable counterparts.

  12. Quantum correlations in B and K meson systems (United States)

    Banerjee, Subhashish; Alok, Ashutosh Kumar; MacKenzie, Richard


    The interplay between the various measures of quantum correlations is well known in stable optical and electronic systems. Here we study such foundational issues in unstable quantum systems. Specifically we study meson-antimeson systems ( Kbar{K}, Bd bar{B}d and Bsbar{B}s, which are produced copiously in meson factories. In particular, the nonclassicality of quantum correlations which can be characterized in terms of nonlocality (which is the strongest condition), entanglement, teleportation fidelity or weaker nonclassicality measures like quantum discord are analyzed. We also study the impact of decoherence on these measures of quantum correlations, using the semigroup formalism. A comparison of these measures brings out the fact that the relations between them can be nontrivially different from those of their stable counterparts such as neutrinos.

  13. Molecular-like states in the bottomonium sector

    International Nuclear Information System (INIS)

    The molecular interpretation of the bottomonium like states have been proposed and studied since long time. Recently, the BELLE collaboration reported the charge narrow states Zb (10650) and Zb (10610) in the Υ(5 S) decay, which do not t in bb¯ scheme. The molecular interpretation of the states have been proposed by authors in various approaches like local hidden gauge approach, potential model, QCD sum rule. Here, we studied the dimesonic states which is assumed to be as a bound state of meson-antimeson, just like deuteron, in the potential model framework. We have used the Yuwka like potential with One Pion Exhange Potential for the mass calculation of the dimesonic systems

  14. Probing the perturbative dynamics of exclusive meson pair production

    Energy Technology Data Exchange (ETDEWEB)

    Harland-Lang, L.A., E-mail: [Department of Physics and Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE (United Kingdom); Khoze, V.A. [Department of Physics and Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE (United Kingdom); Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, St. Petersburg, 188300 (Russian Federation); Ryskin, M.G. [Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, St. Petersburg, 188300 (Russian Federation); Stirling, W.J. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE (United Kingdom)


    We present the results of a recent novel application of the ‘hard exclusive’ perturbative formalism to the process gg→MM{sup ¯} at large angles, where M (M{sup ¯}) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg→qq{sup ¯}(gg)qq{sup ¯}(gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k{sub ⊥}, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the η{sup ′} and η mesons display significant sensitivity to any valence gg component of the meson wavefunctions.

  15. Probing the perturbative dynamics of exclusive meson pair production

    CERN Document Server

    Harland-Lang, L A; Ryskin, M G; Stirling, W J


    We present the results of a recent novel application of the `hard exclusive' perturbative formalism to the process gg --> MMbar at large angles, where M (Mbar) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg --> qqbar(gg) qqbar(gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k_t, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the eta' and eta mesons display significant sensitivity to any valence gg component of the meson wavefunctions.

  16. Probing the perturbative dynamics of exclusive meson pair production (United States)

    Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.; Stirling, W. J.


    We present the results of a recent novel application of the 'hard exclusive' perturbative formalism to the process gg → MMbar at large angles, where M (Mbar) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg → qqbar (gg) qqbar (gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k⊥, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the η‧ and η mesons display significant sensitivity to any valence gg component of the meson wavefunctions.

  17. Production of the bottom analogs and the spin partner of the X(3872) at hadron colliders

    International Nuclear Information System (INIS)

    Using the Monte Carlo event generator tools Pythia and Herwig, we simulate the production of bottom/charm meson and antimeson pairs at hadron colliders in proton-proton/antiproton collisions. With these results, we derive an order-of-magnitude estimate for the production rates of the bottom analogs and the spin partner of the X(3872) as hadronic molecules at the LHC and Tevatron experiments. We find that the cross sections for these processes are at the nb level, so that the current and future data sets from the Tevatron and LHC experiments offer a significant discovery potential. We further point out that the Xb/Xb2 should be reconstructed in the γΥ(nS)(n = 1, 2, 3), Υ(1S)π+π-π0, or χbJπ+π- instead of the Υ(nS)π+π- final states. (orig.)

  18. A lattice QCD determination of potentials between pairs of static-light mesons

    Energy Technology Data Exchange (ETDEWEB)

    Hetzenegger, Martin


    Potentials between pairs of static-light mesons are interesting in a sense that they give insights in the nature of strong interactions from first principles for multiquark systems. For large heavy quark masses, e.g., the spectra of heavy-light mesons are determined by excitations of the light quark and gluonic degrees of freedom. In particular, the vector-pseudoscalar splitting vanishes and a static-light meson can be interpreted as either a B, a B{sup *}, a D or a D{sup *} heavy-light meson. Calculating potentials between two static-light mesons also enables investigations of possible bound tetraquark states or for particles that are close to the meson-antimeson threshold, such as the X(3872) or the Z{sup +}(4430).

  19. Higgs-mediated FCNCs: Natural Flavour Conservation vs. Minimal Flavour Violation

    CERN Document Server

    Buras, Andrzej J; Gori, Stefania; Isidori, Gino


    We compare the effectiveness of two hypotheses, Natural Flavour Conservation (NFC) and Minimal Flavour Violation (MFV), in suppressing the strength of flavour-changing neutral-currents (FCNCs) in models with more than one Higgs doublet. We show that the MFV hypothesis, in its general formulation, is more stable in suppressing FCNCs than the hypothesis of NFC alone when quantum corrections are taken into account. The phenomenological implications of the two scenarios are discussed analysing meson-antimeson mixing observables and the rare decays B -> mu+ mu-. We demonstrate that, introducing flavour-blind CP phases, two-Higgs doublet models respecting the MFV hypothesis can accommodate a large CP-violating phase in Bs mixing, as hinted by CDF and D0 data and, without extra free parameters, soften significantly in a correlated manner the observed anomaly in the relation between epsilon_K and S_psi_K.

  20. Demonstration of string breaking in quantum chromodynamics by large-scale eigenvalue computations (United States)

    Attig, N.; Bali, G. S.; Düssel, Th.; Lippert, Th.; Neff, H.; Prkaçin, Z.; Schilling, K.


    We present results of our ongoing determination of "string breaking" in quantum chromodynamics (QCD) including two dynamical light quarks. Our investigation of the fission of the string between a heavy (static) quark and a corresponding antiquark into a meson-antimeson system is based on dynamical configurations of size 24×40. The all-to-all light quark propagators occurring in the transition element are computed from a set of 200 low-lying eigenmodes of the Hermitian Wilson-Dirac matrix which encodes the effect of the dynamical quarks. These eigenmodes are calculated on the 1312-node IBM p690 system at the John von Neumann Institute in Jülich. Combining the eigenvalue computations with a variety of ground state enhancing optimization methods we determine the matrix elements of the two-by-two system with so far unprecedented accuracy. We observe—for the first time ever in a simulation of 4-dimensional lattice-QCD— level-splitting as the perfect signature for dynamical string breaking between ground state and excited potential.

  1. Spectroscopy of mesonic molecules with heavy-light flavour mesons

    CERN Document Server

    Rathaud, D P


    In this work, we have calculated the mass spectra and decay properties of dimesonic (meson-antimeson) bound state in the variational scheme. The intermesonic interaction considered as the Hellmann potential and One Pion Exchange potential. The mass spectra of the $D\\bar{D^{*}}$, $D\\bar{D_{s}^{*}}$, $D_{s}\\bar{D^{*}}$, $D_{s}\\bar{D_{s}^{*}}$, $D^{*}\\bar{D^{*}}$, $D_{s}^{*}\\bar{D_{s}^{*}}$, $D\\bar{B^{*}}$, $D\\bar{B_{s}^{*}}$, $D_{s}\\bar{B^{*}}$, $D_{s}\\bar{B_{s}^{*}}$, $B^{*}\\bar{D}$,$B^{*}\\bar{D_{s}}$, $B\\bar{B^{*}}$, $B_{s}\\bar{B^{*}}$, $B_{c}\\bar{B^{*}}$, $B^{*}\\bar{B^{*}}$, $B^{*}\\bar{B_{s}^{*}}$, $B_{s}^{*}\\bar{B_{s}^{*}}$ etc.. are calculated. The states X(3872), $X_{2c}(4013)$ ,$Z_{b}(10610)/X_{b}$ and $Z_{b}(10650)/X_{b2}$ are compared with $D\\bar{D^{*}}$, $D^{*}\\bar{D^{*}}$, $B\\bar{B^{*}}$ and $B^{*}\\bar{B^{*}}$ dimesonic bound states. To probe the molecular structure of the compared states, we have calculated the decay properties sensitive to their long and short distance structure of hadorinc molecul...

  2. D{sup 0} mixing and CP violation

    Energy Technology Data Exchange (ETDEWEB)

    Bobrowski, Markus [Karlsruher Institut fuer Technologie (KIT), Institut fuer Theoretische Teilchenphysik (Germany); Lenz, Alexander [Universitaet Regensburg, Institut fuer Theoretische Physik (Germany)


    We report the results of a recent study on D{sup 0}- anti D{sup 0} mixing and argue that currently a CP violating weak phase of the order of some per mille can not be excluded in the Standard Model. Our work relies on a short-distance analysis of the {Delta}C=2 Hamiltonian, using the framework of Heavy Quark Expansion (HQE), an expansion in powers of the inverse charm quark mass. We demonstrate that, as expected, the dominant contribution is related to effects of SU(3) flavour symmetry breaking present in higher orders of the HQE: they appear for the first time in meson-antimeson transitions with an intermediate state coupling to the sea quark background of the meson, associated with operators of dimension 10 and 12. A factorisation approach is used to simplify the operator basis. Due to a lifting of GIM suppression by one power of m{sub s}/m{sub c}, the contribution to y={Delta}{Gamma}/2{Gamma} is found to exceed that of the formally leading dimension six by a factor close to ten.

  3. Charm mixing in the framework of HQE

    Energy Technology Data Exchange (ETDEWEB)

    Bobrowski, Markus; Lenz, Alexander [Universitaet Regensburg (Germany)


    In this talk we issue the quark-level analysis of meson-antimeson mixing in the charm system. Although a naive application of the heavy-quark-expansion (HQE) approach to D{sup 0} mesons fails to reproduce the experimental width differences by orders of magnitude, we argue that currently there seem to be no indications for a complete breakdown of HQE-based techniques in the leading dimensions 6 and 7. The smallness of current quark-level based theory predictions can be understood as a result of efficient GIM interference between numerically rather large diagrams; any mechanism, which helps to lift this suppression, could possibly serve as a solution to this problem: This may be new physics modifications of CKM couplings or enhancement of SU(3){sub F} symmetry breaking. Within the Standard Model, GIM lifting is sometimes supposed to come along with the cutting of internal quark loops in dimension 9 and 12 of the HQE. Reliable results for the quark-level expectation could finally provide a test of quark-hadron duality in the charm sector.

  4. 54. Annual symposium of the Austrian Physical Society

    International Nuclear Information System (INIS)

    The papers presented were organized under the following sessions: main session (from attoseconds to RGB to telecom, density functional calculations, magnetic anisotropy of nanostructures, quantum cascade laser, bose-einstein condensates, DNA molecular force sensor); Fritz-Kohlrausch-price 2004 (nanoscale building blocks), Max-Auwaerter-price 2004 (electron emission and nano defects, magnetic rings), AT + S price 2004 (conducting atomic-force microscopy for nanoscale studies), Viktor-Hess-price 2004 (entanglement for meson-antimeson systems), Roman-Ulrich-Sexl-price 2004 (teaching physics ); acoustics; atomic-, molecular- and plasma physics (kinetic electron emission, accelerated-mass spectrometry of molecules, dissociative electron attachment, voc measurements); solid physics (spin relaxation, nano clean room reactor, proton transport through nanotubes); nuclear and particle physics (color reconnection, supersymmetry at Large Hadron Collider, pionic hydrogen, kaonic hydrogen, quantum chaos, quantum dwell time, trigger system simulation, ATLAS initial detector layout, QCD); medical-, bio-and environmental physics (PTR-MS, validation Monte Carlo FLUKA codes, Gamma camera- positron emission tomography); neutrons and synchrotron radiation physics (3D synchrotron micro on human bones); surface and thin film analysis; quantum electronics, electrodynamics and optics (teleportation, optic induced changes in interaction in BEC, electronic feed back cooling single ions) and poster sessions with topics dealing with the subjects above mentioned. This book of abstracts contains their summaries and those contributions which are in the INIS subject scope are indexed individually. (nevyjel)

  5. Partners of the X(3872) and heavy quark spin symmetry breaking (United States)

    Entem, D. R.; Ortega, P. G.; Fernández, F.


    Since the discovery of the X(3872) the study of heavy meson molecules has been the subject of many investigations. Different experiments have looked for its spin partners and the bottom analogs. On the theoretical side different approaches have been used to understand this state. Some of them as Effective Field Theories (EFT) that impose Heavy Quark Spin Symmetry (HQSS) and so they make predictions for the partners of the X(3872), suggesting the existence of a JPC = 2++ partner in the charm sector or JPC = 1++ or 2++ analogs in the bottom sector. In this work, in order to understand the X(3872), we use a Chiral Quark Model in which, due to the proximity to the DD* threshold, we include cc ¯ states coupled to meson-antimeson DD* molecular components. In this coupled channel model the relative position of the bare cc ¯ states with two meson thresholds are very important. We have looked for the X(3872) partners and we do not find a bound state in the D* D* JPC = 2++. In the bottom sector we find the opposite situation where the B* B* with JPC = 2++ is bounded while the JPC = 1++ is not. These results show how the coupling with cc ¯ states can induce different results than those expected by HQSS. The reason is that this symmetry is worse in the open heavy meson sector than in the hidden heavy meson sector.

  6. The custodially protected Randall-Sundrum model. Theoretical aspects and flavour phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Blanke, Monika


    Models with a warped extra dimension, so-called Randall-Sundrum models, provide an appealing solution to the gauge and flavour hierarchy problems of the Standard Model. After introducing the theoretical basics of such models, we concentrate on a specific model whose symmetry structure is extended to protect the T parameter and the Zb{sub L} anti b{sub L} coupling from large corrections. We introduce the basic action and discuss in detail effects of electroweak symmetry breaking and the flavour structure of the model. Then we analyse meson-antimeson mixing and rare decays that are affected by new tree level contributions from the Kaluza-Klein modes of the gauge bosons and from the Z boson in an important manner. After deriving analytic expressions for the most important K and B physics observables, we perform a global numerical analysis of the new effects in the model in question. We confirm the recent findings that a stringent constraint on the model is placed by CP-violation in K{sup 0} - anti K{sup 0} mixing. However, even for Kaluza-Klein particles in the reach of the LHC an agreement with all available data can be obtained without significant fine-tuning. We find possible large effects in either CP-violating effects in the B{sub s} - anti B{sub s} system or in the rare K decays, but not simultaneously. In any case the deviations from the Standard Model predictions in the rare B decays are small and difficult to measure. The specific pattern of new flavour effects allows to distinguish this model from other New Physics frameworks, which we demonstrate explicitly for the case of models with Minimal Flavour Violation and for the Littlest Higgs model with T-parity. (orig.)

  7. It wasn't only about CP, or even B mesons (United States)

    Olsen, Stephen Lars


    Although the primary motivation and design theme for the B-factories and their experiments was the study of CP violations in the b-quark sector and testing the Kobayashi-Maskawa suggestion that CP violation could be incorporated into the Standard Model as an irreducible complex phase in the weak-interaction quark-flavor mixing matrix, both the BaBar and Belle research programs made a number of important measurements that had nothing to do with either CP violation or the b-quark sector. These include the unexpected discovery of D0 -D0 bar mixing and a number of charmoniumlike mesons with properties that do not match expectations for conventional charmed-quark anticharmed-quark (ccbar) mesons. In principle, these state, which are now commonly known as theXYZ mesons, are described in the Standard Model by the long-distance regime of QCD, but, since first-principle long-distance QCD calculations are hopelessly difficult, a number of ``QCD-inspired'' models for nonstandard mesons have been proposed. Some of these attribute the XYZ states to loosely bound meson-antimeson molecule-like structures, and others to tightly bound diquark-diantiquark tetraquarks, or quark-antiquark-gluon hybrids. None of the proposed models can give a comprehensive description of the spectrum of the observed states and their measured properties. In this talk I describe a few of the XYZ mesons found by BaBar and Belle and why they are considered to be nonstandard. In addition I suggest some future measurements that could be done at BESIII, BelleII and Panda that might establish patterns that may help decipher some of the mysteries of long-distance QCD. Supported by project code IBS-R016-D.

  8. Two approaches towards the flavour puzzle. Dynamical minimal flavour violation and warped extra dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Michaela E.


    out the flavour and electroweak (EW) sector, including a derivation of Feynman rules. Moreover, we determine the contributions to the effective Hamiltonian for meson-antimeson mixing due to KK gluon and KK photon exchange. (orig.)