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R. Kaminski

Publications and source records attributed to R. Kaminski.

At least 55 records · Page 3Linked to original sources
arXiv2006

Forward dispersion relations and Roy equations in pi-pi scattering

We review results of an analysis of pipi interactions in S, P and D waves for two-pion effective mass from threshold to about 1.4 GeV. In particular we show a recent improvement of this analysis above the K anti-K threshold using more data for phase shifts and including the S0 wave inelasticity from pipi -> K anti-K. In addition, we have improved the fit to the f2(1270) resonance and used a more flexible P wave parametrization above the K anti-K threshold and included an estimation of the D2 wave inelasticity. The better accuracy thus achieved also required a refinement of the Regge analysis above 1.42 GeV. We have checked that the pipi scattering amplitudes obtained in this approach satisfy remarkably well forward dispersion relations and Roy's equations.

hep-ph↗
arXiv2006

The pion-pion scattering amplitude. II: Improved analysis above $\bar{K}K$ threshold

We improve, in the energy region between $\bar{K}K$ threshold and $\sim~1.4$ GeV, the energy-dependent phase shift analysis of $ππ$ scattering presented in a previous paper. For the S0 wave we have included more data above $\bar{K}K$ threshold and we have taken into account systematically the elasticity data on the reaction $ππ\to\bar{K}K$. We here made a coupled channel fit. For the D0 wave we have considered information on low energy parameters, and imposed a better fit to the $f_2$ resonance. For both waves the expressions we now find are substantially more precise than the previous ones. We also provide slightly improved D2 and P waves, including the estimated inelasticity for the first, and a more flexible parametrization between 1 and 1.42 GeV for the second. The accuracy of our amplitudes is now such that it requires a refinement of the Regge analysis, for $s^{1/2}\geq1.42$ GeV, which we also carry out. We show that this more realistic input produces $ππ$ scattering amplitudes that satisfy better forward dispersion relations, particularly for $π^0π^0$ scattering.

hep-ph↗
arXiv2006

Final state interactions in B --> pi pi K and B--> K antiK K decays

Analysis of charged and neutral B meson decays into pi+ pi- K, K+ K- K and K0S K0S K0S is performed using a unitary representation of the pi pi and K anti- K final state interactions. Comparison of the theoretical model with the experimental data of the Belle and BaBar Collaborations indicates that charming penguin contributions are necessary to describe the B --> f0(980) K and B --> rho(770) K decays.

hep-ph↗
arXiv2005

B decays into pion-pion-kaon and into kaon-antikaon-kaon: long distance and final-state effects

The interplay of strong and weak decay amplitudes for B -> pion-pion-kaon and B -> kaon-antikaon-kaon, with the pion-pion and kaon-antikaon pairs interacting in isospin-0 S-wave, is analyzed for pion-pion effective mass from threshold to 1.2 GeV. To improve agreement with experiment of a factorization approach with some QCD corrections, addition of long-distance contributions, called charming penguins is necessary.

hep-ph↗
arXiv2005

pi-pi scattering amplitudes constrained by Roy's equations

The scalar-isoscalar, scalar-isotensor and vector-isovector pi-pi amplitudes have been fitted simultaneously to experimental data and to to Roy's equations. Resulting pi-pi phase shifts up to 1600 MeV and near threshold observables have been analyzed. Only the amplitudes fitted to the "down-flat" set of phase shifts in scalar-isoscalar wave fulfill crossing symmetry conditions and can be regarded as physical.

hep-ph↗
arXiv2005

Long-distance effects and final state interactions in B to pion pion K and B to K anti-K K decays

B decays into pion pion K and K anti-K K, where the pion-pion and anti-K K pairs interact in isospin zero S-wave, are studied in the pion-pion effective mass range from threshold to 1.2 GeV. The interplay of strong and weak decay amplitudes is analyzed using an unitary pion-pion and K anti-K coupled channel model. Final state interactions are described in terms of four scalar form factors constrained by unitarity and chiral perturbation theory. Branching ratios for the B decay into f0(980)K, calculated in the factorization approximation with some QCD corrections, are too low as compared to recent data. In order to improve agreement with experiment, we introduce long-distance contributions called charming penguins. Effective mass distributions, branching ratios and asymmetries are compared with the existing data from BaBar and Belle collaborations. A particularly large negative asymmetry in charged B decays is predicted for one set of the charming penguin amplitudes.

hep-ph↗
arXiv2003

Roy's equations and the pion-pion experimental data

Roy's equations are used to check if the scalar-isoscalar pion-pion scattering amplitudes fitted to experimental data fulfill crossing symmetry conditions. It is shown that the amplitudes describing the ``down-flat'' phase shift solution satisfy crossing symmetry below 1 GeV while the amplitudes fitted to the "up-flat'' data do not. In this way the long standing "up-down" ambiguity in the phenomenological determination of the scalar-isoscalar pion-pion amplitudes has been resolved confirming the independent result of the recent joint analysis of the pi+pi- and pi0pi0 data.

hep-ph↗
arXiv2002

Elimination of ambiguities in pion-pion phase shifts using crossing symmetry

Roy's equations, which incorporate crossing symmetry of the pion-pion scattering amplitudes, are used to resolve the present ambiguity between two solutions for the scalar-isoscalar phase shifts below 1 GeV. It is shown that the "down-flat" solution satisfies well Roy's equations and consequently crossing symmetry while the other solution called "up-flat" does not and thus should be eliminated.

hep-ph↗
arXiv2002

A New Analysis of the pi+pi- and pi0pi0 Data

A joint analysis of the pi+pi- and pi0pi0 S-wave amplitudes including results of three experiments has been performed. Using our theoretical model of the pion-pion production in which not only the pion exchange but also the a1(1260) meson exchange were taken into account we have obtained a unique solution (called "down-flat") for the scalar-isoscalar phase shifts. Thus a long-standing problem of ambiguities in the S-wave isoscalar amplitude has been finally resolved and the second ("up-flat") solution was eliminated.

hep-ph↗
arXiv2002

Elimination of Ambiguities in pi-pi Amplitudes Using Roy's Equations

Roy's equations are used to check if scalar-isoscalar pi-pi amplitudes fitted to the ``up-flat'' and ``down-flat'' phase shift solutions fulfill crossing symmetry below 1 GeV. It is shown that the amplitude fitted to the ``down-flat'' solution satisfies crossing symmetry while the ``up-flat'' one does not. In such a way the ``up-down'' ambiguity in the scalar-isoscalar phase shifts is resolved in favour of the ``down-flat'' solution.

hep-ph↗
arXiv2001

Comment on `Analysis of O(p^2) Corrections to <2pi|Q_{7,8}|K>'

We extend in several respects our earlier work on O(p^2) corrections to matrix elements of the electroweak penguin operator O_{ewp}. First, to facilitate comparison with certain lattice studies we calculate O(p^2) corrections to in the SU(3) limit of equal light quark masses. Next, we demonstrate how an apparent disagreement in the literature regarding whether higher order chiral contributions increase or decrease <2pi_{I=2}|O_{ewp}|K> is simply a consequence of how the leading order chiral amplitude is defined. Finally, we address an aspect of the epsilon'/epsilon problem by estimating O(p^2) corrections to recent determinations of <2pi_{I=2}|Q_{7,8}|K> which were carried out in the chiral limit.

hep-ph↗
arXiv2000

Theoretical constraints on interaction amplitudes of light mesons

We impose unitarity constraints on the S-wave isoscalar pion-pion amplitudes extracted from the analysis of the pi- p ---> pi+ pi- n data which have been measured by the CERN-Cracow-Munich collaboration on a transversely polarized target at 17.2 GeV/c pi- momentum. Two "steep" solutions contain a narrow S-wave f0(750) resonance under the rho(770) and exhibit a considerable inelasticity eta which is in disagreement with the four pion production data below the KKbar threshold. We impose eta= 1 for all data points and examine four sets of solutions for the S-wave isoscalar phase-shifts. The "down-flat" and "up-flat" solutions easily pass the eta=1 constraint but the remaining "down-steep" and "up-steep" are eliminated. We conclude that the 17.2 GeV data cannot be described by a relatively narrow f0(750).

hep-ph↗
arXiv1999

Further study of the pi-pi S-wave isoscalar amplitude below the K - Kbar threshold

We continue the analysis of S-wave production amplitudes for the reaction pi- p -> pi+ pi- n involving the data obtained by the CERN--Cracow-Munich collaboration on a transversely polarized target at 17.2 GeV/c pi- momentum. This study deals with the region below the K - Kbar threshold. In particular, we study the "up-steep" solution containing a narrow S-wave resonance under the rho(770). This solution exhibits a considerable inelasticity (eta) which does not have any physical interpretation. Assuming that this inelasticity behaviour represents an unlikely fluctuation we impose eta = 1 for all data points. This leads to non-physical results in one third of the pi+pi- effective mass bins and in the remaining mass bins some parameters behave in a queer way. The situation is even worse for the "down-steep" solution. We conclude that the 17.2 GeV data cannot be described by a relatively narrow f0(750). The "down-flat" and "up-steep" solutions which easily pass the eta = 1 constraint exhibit a slow increase of phase shifts in the rho(770) mass range.

hep-ph↗
arXiv1999

Properties of scalar--isoscalar mesons from multichannel interaction analysis below 1800 MeV

Scalar-isoscalar mesons are studied using an unitary model in three channels: pi-pi, K-anti K and an effective 2pi-2pi. All the solutions, fitted to the pi-pi and K-anti K data, exhibit a wide f0(500), a narrow f0(980) and two relatively narrow resonances, lying on different sheets between 1300 MeV and 1500 MeV. These latter states are similar to the f0(1370) and f0(1500) seen in experiments at CERN. Branching ratios are compared with available data. We have started investigations of some crossing symmetry and chiral constraints imposed near the pi-pi threshold on the scalar-isoscalar, scalar-isotensor and P-wave pi-pi amplitudes.

hep-ph↗
arXiv1999

Scalar Mesons and Multichannel Amplitudes

Properties of scalar-isoscalar mesons are analysed using separable interactions in three decay channels: pion-pion, kaon-antikaon and an effective 2pion-2pion. We obtain different solutions by fitting various data on the pion-pion and kaon-antikaon phase shifts and inelasticities including the CERN-Cracow-Munich measurements of the pion- p --> pion+ pion- n reaction on a polarized target. Analytical structure of the meson-meson multichannel amplitudes is studied with a special emphasis on the role played by the S-matrix zeroes. S-matrix poles are found in the complex energy plane and interpreted as scalar resonances. We see a wide f0(500), a narrow f0(980) and a relatively narrow f0(1400). In one solution a resonance at about 1700 MeV is also found. Total, elastic and inelastic channel cross sections, branching ratios and coupling constants are evaluated and compared with data. We construct approximation to our model and show that the Breit-Wigner approach has a limited phenomenological applicability.

hep-ph↗