Search results for "Nuclear and high energy physics"
showing 10 items of 8241 documents
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{\…
Measurements of baryon pair decays of chi(cJ) mesons
2013
Using 106 $\times 10^{6}$ $\psi^{\prime}$ decays collected with the BESIII detector at the BEPCII, three decays of $\chi_{cJ}$ ($J=0,1,2$) with baryon pairs ($\llb$, $\ssb$, $\SSB$) in the final state have been studied. The branching fractions are measured to be $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Lambda\bar\Lambda) =(33.3 \pm 2.0 \pm 2.6)\times 10^{-5}$, $(12.2 \pm 1.1 \pm 1.1)\times 10^{-5}$, $(20.8 \pm 1.6 \pm 2.3)\times 10^{-5}$; $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Sigma^{0}\bar\Sigma^{0})$ = $(47.8 \pm 3.4 \pm 3.9)\times 10^{-5}$, $(3.8 \pm 1.0 \pm 0.5)\times 10^{-5}$, $(4.0 \pm 1.1 \pm 0.5) \times 10^{-5}$; and $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Sigma^{+}\bar\Sigma^{-})$ = $(45.4 \pm…
Λ(1520)andΣ(1385)in the nuclear medium
2006
Recent studies of the {lambda}(1520) resonance within chiral unitary theory with coupled channels find the resonance as a dynamically generated state from the interaction of the decuplet of baryons and the octet of mesons, essentially a quasibound state of {pi}{sigma}{sup *}(1385) in this case, although the coupling of the {lambda}(1520) to the KN and {pi}{sigma} makes this picture only approximate. The {pi}{sigma}{sup *}(1385) decay channel of the {lambda}(1520) is forbidden in free space for the nominal mass of the {sigma}{sup *}(1385), but the coupling of the {pi} to ph components in the nuclear medium opens new decay channels of the {lambda}(1520) in the nucleus and produces a much larg…
Weak decay ofΛc+for the study ofΛ(1405)andΛ(1670)
2015
We study the ${\mathrm{\ensuremath{\Lambda}}}_{c}$ decay process to ${\ensuremath{\pi}}^{+}$ and the meson-baryon final state for the analysis of $\mathrm{\ensuremath{\Lambda}}$ resonances. Considering the Cabibbo-Kobayashi-Maskawa matrix, color suppression, diquark correlation, and the kinematical condition, we show that the final meson-baryon state should be in a pure $I=0$ combination, when the meson-baryon invariant mass is small. Because the $I=1$ contamination usually makes it difficult to analyze $\mathrm{\ensuremath{\Lambda}}$ resonances directly from experiments, the ${\mathrm{\ensuremath{\Lambda}}}_{c}$ decay is an ideal process to study $\mathrm{\ensuremath{\Lambda}}$ resonances.…