K^0 - \bar K^0 mixing and the chiral-bag model

TheB-parameter is determined by the chiralbag model calculation of the amplitude. This is correlated with theK⁺⁰ decay amplitude. The theoretical magnitude ofB-parameter depends on the final state interaction effects inK2 decays. Without the final state interaction correction one findsB(µ _B ² )0.37, with the correction includedB(µ _B ² )0.9. Similar connection between theoretical prediction of theK⁺⁰ decay amplitude and calculated value ofB parameter seems to exist in other approaches too.     

Annihilation amplitudes and factorization in $B^\pm\to\phi K^{*\pm}$

We study the decay , followed by the decay of the outgoing vector mesons into two pseudoscalars. The analysis of the angular distributions of the decay products is shown to provide useful information about the annihilation contributions and possible tests of factorization. Received: 2 April 2003 / Published online: 2 June 2003     

Analysis of $B^{0}_{d} \to \phi K^{{*0}} $ decay mode with supersymmetry

Motivated by the recent measurement of a low longitudinal polarization fraction in the decay mode , which appears not to be in agreement with the standard model expectation, we analyze this mode in the minimal supersymmetric standard model with the mass insertion approximation. Within the standard model, with the factorization approximation, the longitudinal polarization is expected to be . We find that this anomaly can be explained in the minimal supersymmetric standard model with either the LR or the RL mass insertion approximation. PACS. 13.25.Hw, 11.30.Er, 12.60.Jv Received: 9 May 2005, Revised: 26 July 2005, Published online: 30 August 2005     

$$\Lambda _c \to p\bar K^0 \pi \pi $$ and $$\Lambda _c \to p\bar K^0 $$ decay rates

Zeitschrift für Physik C Particles and Fields - Available phase space suppresses the decay $\Lambda _c^ + \to p\overline {K^0 } \pi ^ + \pi ^ - $ in comparison with the decay $\Lambda _c^ +...     

TheK^0 - \bar K^0 B-factor in the QCD-hadronic duality approach

We report on an improved calculation of theB-parameter within the QCD-hadronic duality approach proposed in [1]. Particular emphasis is given to details of the hadronic parametrization which is required to implement this approach. The result we find for the invariantB-parameter (see (1), (2) and (3) for definitions) isBB}=0.39±0.10.     

Near-threshold production of a0(980)-mesons in the reaction \rm {pp \rightarrow d K^ + \bar{K^0}}

Using an effective Lagrangian approach as well as the Quark-Gluon Strings Model, we analyze near-threshold production of a ₀(980)-mesons in the reaction as well as the background of non-resonant -pair production. We argue that the reaction at an energy release MeV is dominated by the intermediate production of the a ₀(980)-resonance. At larger energies the non-resonant -pair production --where the kaons are produced in a relative P-wave-- becomes important. The effects of final-state interactions are evaluated in a unitarized scattering length approach and found to be in the order of a 20% suppression close to threshold. Thus, in present experiments at the Cooler Synchrotron COSY-Jülich for MeV the a ₀ ⁺ signal can reliably be separated from the non-resonant background.Received: 26 February 2004, Published online: 21 September 2004PACS: 25.10. + s Nuclear reactions involving few-nucleon systems - 13.75.-n Hadron-induced low- and intermediate-energy reactions and scattering (energy GeV)     

Effects of final state interactions in B^ + \to D_S^ + \bar K^0 decay

We investigate the effects of final state interactions (FSI) contributions in the nonleptonic two body $B^ + \to D_S^ + \bar K^0$ decay, however the hadronic decay of $B^ + \to D_S^ + \bar K^0$ is analyzed by using “QCD factorization” (QCDF) method and final state interaction (FSI). First, the $B^ + \to D_S^ + \bar K^0$ decay is calculated via QCDF method and only the annihilation graphs exist in that method. Hence, the FSI must be seriously considered to solve the $B^ + \to D_S^ + \bar K^0$ decay and the D ⁰π⁺(D ⁰*ρ⁺), D ⁺π⁰(D ⁺*ρ⁰) and D ⁺η _c (D ⁺*J/ψ) via the exchange of K ^+(*), K ^0(*) and D _s ^+(*) mesones are chosen for the intermediate states. To estimate the intermediate states amplitudes, the QCDF method is again used. These amplitudes are used in the absorptive part of the diagrams. The experimental branching ratio of $B^ + \to D_S^ + \bar K^0$ decay is less than 8 × 10^?4 and the predicted branching ratio is 0.23 × 10^?9 in the absence of FSI effects and it becomes 6.74 × 10^?4 when FSI contributions are taken into account.     

Similarities and differences between the inclusive reactionsK^ - p \to \bar K^0 X_1 and\bar vp \to \mu ^ + X_2

We study in detail some aspects of “jet universality” in soft and hard processes interpreted by quark-parton diagrams. Using the framework of the Dual Topological Unitarization model for the soft process \(K^ - p \to \bar K^0 X_1 \) we compare hadron longitudinal momentum distributions and multiplicities in the “one-chain” part of this reaction to those in \(\bar vp \to \mu ^ + X_2 \) . We observe not only close similarities (e.g. the same π⁺/π^? ratio over the whole Feynman-x region) but also some significant differences in the jet systemsX ₁,X ₂, such as a lower cross-section in the central region and a smaller average multiplicity of the jets inX ₁.     

Bounds on the hadronic matrix element in theK^0 - \bar K^0 transition amplitude

The hadronic matrix element in the \(K^0 - \bar K^0 \) transition amplitude has been calculated in a variety of models and doubt has arisen as to its size and sign. In this paper the present experimental constraints on the Kobayashi-Maskawa matrix elements are used to establish the positive sign of the hadronic matrix element in the six quark model and to place bounds on its magnitude. The bounds are 0.04<B<1.2 whereB=+1 gives the vacuum saturation estimate of the hadronic matrix element. The experimental information also restricts the number of possible solutions to theK _s -K _l mass difference and the CP parameter in the Kobayashi-Maskawa model.     

QCD Calculation ofK^0 - \bar K^0 mixing from three-point function sum rules

We calculate theB parameter for \(K^0 - \bar K^0 \) mixing in the framework of QCD sum rules for a three-point function involving pseudoscalar currents, and contrast our results with other calculations. We findB=0.5±0.1±0.2, where the first error reflects uncertainties in the various QCD parameters and the second one is an estimate of uncalculated three-loop radiative and higher order quark mass corrections.     

Partial wave analysis of $\bar pp \to \bar \Lambda \Lambda$

A partial wave analysis of PS185 data for is presented. A ³ S ₁ cusp is identified in the inverse process at threshold, using detailed balance to deduce cross sections from . Partial wave amplitudes for ³ P ₀, ³ F ₃, ³ D ₃ and ³ G ₃ exhibit a behaviour very similar to resonances observed in Crystal Barrel data. With this identification, the data then provide evidence for a new I = 0, J ^PC = 1^- resonance with mass MeV, MeV, coupling to both ³ S ₁ and ³ D ₁.Received: 4 June 2004, Published online: 9 July 2004     

Overview of the CKM physics opportunities beyond K^ + \to \pi ^ + \nu \bar \nu

A new experiment CKM is accepted by Fermilab for a very sensitive study of rare kaon decay $K^ + \to \pi ^ + \nu \bar \nu $ on an intense separated kaon beam. The high quality of the beam and CKM setup make it possible to perform an important set of other kaon-decay measurements in parallel with the main research program: (1) the search for new physics effects beyond the Standard Model (search for new P, S, T interactions and lepton flavor violation in kaon decays); (2) further search for direct CP violation in charged kaon decays; (3) study of low-energy hadron physics in pure conditions of decay processes (K ⁺ → π ⁺ l ⁺ l ^?; ππlν _l; π ⁰ γγ, etc.). The expected results of these studies are compared with other experimental programs.     

A kinematically complete measurement of K^+ \to \pi^+ \pi^0 \pi^0 decays

In a kinematically complete setting, the decays of stopped were measured. In the frame work of the Weinberg polynomial expansion, the coefficients up to quadratic terms were deduced. The results are in good agreement with previous measurements and consistent with CP conservation expectations. The empirical rule is violated. Received: 16 October 1999 / Published online: 27 January 2000     

Measurement of charged kaon semileptonic decay branching fraction K^ - \to e^ - \bar \nu _e \pi ^0 using ISTRA+ detector

The ratio of branching fractions for \(K^ - \to e^ - \bar \nu _e \pi ^0\) andK ^? → π^?π⁰ decays has been measured using the ISTRA+ spectrometer. The result of our measurement is the following: $$\mathcal{R}_{Ke_3 /K_{2\pi } } = 0.2423 \pm 0.0015(stat.) \pm 0.0037(syst.).$$ Using the current PDG value for the K _2π branching fraction, this result leads to the measured K _e3 branching fraction of Br(K _e3) = 0.0501 ± 0.0009 and to the value of |V _us |f ₊(0) = 0.2115 ± 0.0021.