Search results for "Effective lagrangian"
showing 10 items of 42 documents
Anomalous non-leptonic kaon decays
1992
8 páginas, 1 figura.
Explanation of theΔ5/2−(1930)as aρΔbound state
2009
We use the $\ensuremath{\rho}\ensuremath{\Delta}$ interaction in the hidden gauge formalism to dynamically generate ${N}^{*}$ and ${\ensuremath{\Delta}}^{*}$ resonances. We show, through a comparison of the results from this analysis and from a quark model study with data, that the ${\ensuremath{\Delta}}_{5/{2}^{\ensuremath{-}}}(1930)$, ${\ensuremath{\Delta}}_{3/{2}^{\ensuremath{-}}}(1940)$, and ${\ensuremath{\Delta}}_{1/{2}^{\ensuremath{-}}}(1900)$ resonances can be assigned to $\ensuremath{\rho}\ensuremath{\Delta}$ bound states. More precisely the ${\ensuremath{\Delta}}_{5/{2}^{\ensuremath{-}}}(1930)$ can be interpreted as a $\ensuremath{\rho}\ensuremath{\Delta}$ bound state whereas the $…
Effective-Lagrangian formulation of generalized vector dominance. II
1975
As in a preceding paper we generalize the Lagrangian of Lee and Zumino to include several mutually interacting vector mesons. The treatment is more general in the sense that all possible interactions between the vector mesons, compatible with the field-current proportionality relations, are now discussed. It is moreover demonstrated that also the fields corresponding to the physical vector mesons satisfy a field-current proportionality relation of exactly the same form. Comparison of the different schemes and their implications for the magnetic moments of the vector mesons are discussed.
Strong and Radiative Decays of Heavy Flavored Baryons
1999
We analyze strong one-pion and radiative one-photon decays of heavy flavored baryons within a relativistic three-quark model. Employing the same parameters as were used for the description of the semileptonic decays of heavy baryons, we calculate the couplings of one-pion and one-photon transitions of both ground and excited heavy baryon states. We predict the decay rates for all relevant decay modes and compare them with experimental data when available and with the results of other model calculations.
φ meson mass and decay width in nuclear matter
2002
The $\phi$ meson spectrum, which in vacuum is dominated by its coupling to the $\bar{K} K$ system, is modified in nuclear matter. Following a model based on chiral SU(3) dynamics we calculate the $\phi$ meson selfenergy in nuclear matter considering the $K$ and $\bar{K}$ in-medium properties. For the latter we use the results of previous calculations which account for $S-$ and $P-$wave kaon-nucleon interactions based on the lowest order meson-baryon chiral effective Lagrangian, and this leads to a dressing of the kaon propagators in the medium. In addition, a set of vertex corrections is evaluated to fulfill gauge invariance, which involves contact couplings of the $\phi$ meson to $S-$wave …
Mass and width of the Delta resonance using complex-mass renormalization
2016
The pole mass and width of the Delta resonance are calculated in the relativistic chiral effective field theory approach. We choose a systematic power-counting procedure by applying the complex-mass scheme (CMS).
Effective Field Theory
2015
Effective field theories (EFTs) are a highly important topic in Quantum Field Theory. Here we are going to shortly present some important highlights as well as the renormalization group equations for the Wilson coefficients. Afterwards we shall focus on one illustrative example and present the \(\textit{matching}\) procedure at the one-loop level. The infrared behaviour of EFTs is also covered with this example.
Three pseudoscalar meson production ine+e−annihilation
2013
Conversations with German Rodrigo on the topic of this paper are warmly acknowledged. We would like to thank Henryk Czyz for fruitful discussions on context of MC PHOKHARA 7.0. We also wish to thank Michael R. Pennington for a careful reading of our manuscript and for his suggestions. Lingyun Dai thanks the China Scholarship Council for their support. This research has been supported in part by the funds of the Polish National Science Centre under decisions DEC-2012/04/M/ST2/00240 and DEC-2011/03/B/ST2/00107 (O. S.) and by the Spanish Government and ERDF funds from the EU Commission [Grants No. FPA2007-60323, No. FPA2011-23778, No. CSD2007-00042 (Consolider Project CPAN)]. This paper has be…
Chiral Dynamics of the two Lambda(1405) States
2004
Using a chiral unitary approach for the meson--baryon interactions, we show that two octets of J^{\pi}=1/2^- baryon states, which are degenerate in the limit of exact SU(3) symmetry, and a singlet are generated dynamically. The SU(3) breaking produces the splitting of the two octets, resulting in the case of strangeness S=-1 in two poles of the scattering matrix close to the nominal \Lambda(1405) resonance. These poles are combinations of the singlet state and the octets. We show how actual experiments see just one effective resonance shape, but with properties which change from one reaction to another.
Transition form factors of the N(*()1535) as a dynamically generated resonance
2007
We discuss how electromagnetic properties provide useful tests of the nature of resonances, and we study these properties for the N*(1535) which appears dynamically generated from the strong interaction of mesons and baryons. Within this coupled channel chiral unitary approach, we evaluate the A_1/2 and S_1/2 helicity amplitudes as a function of Q^2 for the electromagnetic N*(1535) to gamma* N transition. Within the same formalism we evaluate the cross section for the reactions gamma N to eta N. We find a fair agreement for the absolute values of the transition amplitudes, as well as for the Q^2 dependence of the amplitudes, within theoretical and experimental uncertainties discussed in the…