Search results for "baryon"
showing 10 items of 759 documents
Parity-violating effects in electroproduction of theΔ(1232)by polarized electrons
1982
Parity-violating effects in the (quasi)elastic scattering of longitudinally polarized electrons from spin-\textonehalf{} targets are discussed in the framework of the unified guage theories of weak and electromagnetic interactions. In particular, the $R\ensuremath{-}L$ asymmetry in electroproduction of the $\ensuremath{\Delta}(1232)$ is studied in considerable detail, taking into account the full spin-$\frac{3}{2}$ structure of this resonance. Our results are valid for all values of $E$ and the entire range of ${Q}^{2}$. Numerical predictions are given for the standard Weinberg-Salam model at several energies of the electron beam.
Are there three Xi (1950) states?
2012
Different experiments on hadron spectroscopy have long suspected the existence of several cascade states in the $1900-2000 {\rm MeV}$ region. They are usually labeled under the common name of $\Xi (1950)$. As we argue here, there are also theoretical reasons supporting the idea of several $\Xi (1950)$ resonances. In particular, we propose the existence of three $\Xi(1950)$ states: one of these states would be part of a spin-parity $(1/2)^{-}$ decuplet and the other two probably would belong to the $(5/2)^{+}$ and $(5/2)^{-}$ octets. We also identify which decay channels are the more appropriate for the detection of each of the previous states.
Predictions forNDK,K̄DNandNDD̄molecules
2012
In this work baryon systems made of three hadrons which contain one nucleon and one D meson, and in addition another meson, , K or , are investigated using the Fixed Center Approximation to the Faddeev equations. In this work we use Λc(2595), X(3700) and D*s0(2317) bound states as a cluster and a third particle scattering form that clusters. In all cases we find bound states and quasibound states.
Chiral coupled channel dynamics of theΛ(1520)and theK−p→π0π0Λreaction
2005
We study the $\ensuremath{\Lambda}(1520){D}_{03}$ in a chiral coupled channel approach. This resonance appears to be dynamically generated from the interaction of the decuplet of baryons and the octet of mesons in s wave, and its treatment is improved here with the phenomenological inclusion of the $\overline{K}N$ and $\ensuremath{\pi}\ensuremath{\Sigma}$ channels in d wave. Since the most important building block in $\ensuremath{\Lambda}(1520)$ is the $\ensuremath{\pi}{\ensuremath{\Sigma}}^{*}(1385){P}_{13}$ channel, we study the ${K}^{\ensuremath{-}}p\ensuremath{\rightarrow}\ensuremath{\pi}{\ensuremath{\Sigma}}^{*}(1385)({\ensuremath{\pi}}^{0}\ensuremath{\Lambda})$ reaction in the region …
Limits to the fixed center approximation to Faddeev equations: The case of theϕ(2170)
2011
The fixed center approximation to the Faddeev equations has been used lately with success in the study of bound systems of three hadrons. It is also important to set the limits of the approach in those problems to prevent proliferation of inaccurate predictions. In this paper, we study the case of the $\ensuremath{\phi}(2170)$, which has been described by means of Faddeev equations as a resonant state of $\ensuremath{\phi}$ and $K\overline{K}$, and show the problems derived from the use of the fixed center approximation in its study. At the same time, we also expose the limitations of an alternative approach recently proposed.
Dynamically generated N* resonances from the interaction of two mesons and a baryon
2009
We have studied the ππN system and coupled channels by using of the Faddeev equations and two N* and one Δ states, all of them with JP = 1/2+, have been found in the formalism as dynamically generated states. In addition, signatures for a new N* resonance with JP = 1/2+ are found around an energy of 1920 MeV in the three-body center of mass system.
The helicity matching approach to heavy hadron form factors
1991
Abstract I discuss the helicity matching approach to current-induced transitions among heavy hadrons. This approach provides a simple and intuitively appealing access to the calculation of heavy hadron form factors which is entirely equivalent to the approach of Isgur and Wise and other authors, who use different techniques to obtain the same results. We work out explicit examples in the meson and baryon sectors and discuss possible approximations to the most general approach and some of their implications for future experiments.
Unitary theory of the deuteron photodisintegration.
1989
The deuteron photodisintegration in the \ensuremath{\Delta}-resonance region is calculated within a unitary theory of the NN-N\ensuremath{\Delta}-\ensuremath{\pi}NN system coupled to the photon. The photoexcitation amplitude of the \ensuremath{\Delta} is deduced from the ${M}_{1+}$((3/2) pion photoproduction amplitude consistently with its background term and the \ensuremath{\pi}N interaction. The NN-N\ensuremath{\Delta} transition amplitude is obtained from the coupled equations for the NN-N\ensuremath{\Delta}-\ensuremath{\pi}NN system. The one-pion-exchange currents as well as the normal single-nucleon current are included. The polarization parameters are reproduced quantitatively, but th…
Unitary coupled channel analysis of theΛ(1520)resonance
2006
We study the � (1520) resonance in a coupled-channel approach involving the π� (1385) ,K� (1530), ¯ KN, and π� channels. Implementing unitarity in coupled channels, we make an analysis of the relative importance of the different mechanisms that contribute to the dynamical structure of this resonance. From experimental information on some partial wave amplitudes and constraints imposed by unitarity, we get a comprehensive description of the amplitudes and hence the couplings to the different channels. We test these amplitudes in different reactions like K − p → �π π, γp → K + K − p, γp → K + π 0 π 0 � ,a ndπ − p → K 0 K − p and find a fair
Rare baryon decaysΛb→Λℓ+ℓ−(ℓ=e,μ,τ) andΛb→Λγ: Differential and total rates, lepton- and hadron-side forward-backward asymmetries
2013
Using the covariant constituent quark model previously developed by us, we calculate the differential rate and the forward-backward asymmetries on the lepton and hadron side for the rare baryon decays ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ ($\ensuremath{\ell}=e$, $\ensuremath{\mu}$, $\ensuremath{\tau}$) and ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\gamma}$. We use helicity methods to write down a threefold joint angular decay distribution for the cascade decay ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}(\ensuremath{\rightarrow}p{\…