Search results for "FADD"
showing 10 items of 74 documents
LOCAL STRONG AND COULOMB POTENTIALS IN THE THREE-NUCLEON SYSTEM
1976
Publisher Summary This chapter focuses on local strong and Coulomb potentials in the three-nucleon system. Attempts to use local potentials in three-nucleon calculations with the Faddeev equations are impeded by the fact that for increasing energies contributions from higher and higher subsystem, angular momentum states become important, which quickly make the system of coupled equations unwieldy. However, if long-range interactions such as the Coulomb potential were added, such a procedure would not be useful at all. Several approaches exist that deal with the problems arising from the infinite range of the latter. In the work of Noble and Bencze, the Faddeev equations are modified so that…
N*(1920)(1/2+) STATE IN THE $NK\bar{K}$ SYSTEM
2013
We study the three body $N \bar{K} K$ system by using the fixed center approximation to the Faddeev equations, taking the interaction between $N$ and $\bar{K}$, $N$ and $K$, and $\bar{K}$ and $K$ from the chiral unitary approach. Our results suggest that a $N\bar{K}K$ hadron state, with spin-parity $J^P=1/2^+$, and mass around 1920 MeV, can be formed.
Binding of the BDD¯ and BDD systems
2017
We study theoretically the $BD\overline{D}$ and $BDD$ systems to see if they allow for possible bound or resonant states. The three-body interaction is evaluated implementing the fixed center approximation to the Faddeev equations which considers the interaction of a $D$ or $\overline{D}$ particle with the components of a $BD$ cluster, previously proved to form a bound state. We find an $I({J}^{P})=1/2({0}^{\ensuremath{-}})$ bound state for the $BD\overline{D}$ system at an energy around 8925--8985 MeV within uncertainties, which would correspond to a bottom hidden-charm meson. In contrast, for the $BDD$ system, which would be bottom double-charm and hence manifestly exotic, we have found h…
Three body systems with strangeness and exotic systems
2010
We report on four $\Sigma$'s and three $\Lambda$'s, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave $(1/2)^+$ resonances found by solving the Faddeev equations in the coupled channel approach, which can be associated to the existing $S$ = -1, $J^P= 1/2^+$ low lying baryon resonances. On the other hand we also report on a new, hidden strangeness $N^*$ state, mostly made of $K \bar{K} N$, with mass around 1920 MeV, which we think could be responsible for the peak seen in the $\gamma p \to K^+ \Lambda$ around this energy. Finally we address a very novel topic in which we show how few body systems of several $\rho$ mesons can be produced, with their spins aligned up to J=6, and …
Coulomb effects in three-body reactions with two charged particles
1978
We present the details of a novel approach to the treatment of Coulomb effects in atomic and nuclear reactions of the three-body type in which two of the particles are charged. Based on three-body integral equations the formalism allows the practical calculation of elastic, inelastic, rearrangement, and breakup processes with full inclusion of the Coulomb repulsion or attraction in a mathematically correct way. No restrictions need to be made concerning the form of the short-range interactions between the three pairs. A particular virtue of our method lies in the fact that it corroborates, and gives precise meaning to, the intuitively anticipated conception of how to describe such reactions.
Faddeev fixed-center approximation to theNK̄Ksystem and the signature of aN*(1920)(1/2+) state
2011
We perform a calculation for the three body $N \bar{K} K$ scattering amplitude by using the fixed center approximation to the Faddeev equations, taking the interaction between $N$ and $\bar{K}$, $N$ and $K$, and $\bar{K}$ and $K$ from the chiral unitary approach. The resonant structures show up in the modulus squared of the three body scattering amplitude and suggest that a $N\bar{K}K$ hadron state can be formed. Our results are in agreement with others obtained in previous theoretical works, which claim a new $N^*$ resonance around 1920 MeV with spin-parity $J^P=1/2^+$. The existence of these previous works allows us to test the accuracy of the fixed center approximation in the present pro…
QUASIPARTICLE CALCULATIONS FOR THE THREE-NUCLEON SYSTEM
1972
Publisher Summary This chapter discusses the quasiparticle calculations for the three-nucleon system. There are three methods for solving the integral equations for the three-body problem with local two-body potentials; one method consists of the direct solution of the Faddeev equations, and the other two methods make different use of the quasiparticle idea that is based on the splitting of the occurring two-body potentials into a sum of separable terms and a rest potential. The chapter describes the term “form factors” and “coupling strengths.” A similar splitting is obtained for the T-matrices Tγ. With its help, it is possible to transform the Faddeev-type equations for the three-body tra…
New approach for numerical solution of configuration-space Faddeev equations
1996
A new computational scheme for solving the bound state configuration-space Faddeev equations is applied. The scheme is based on the spline-approximation and the adiabatic limit of Faddeev equations. An ordering of variables being in agreement with the limit was chosen. As a result the matrix of the eigenvalue problem has a sparse block structure. Calculations of the bound states of µpp, µdd, µtt mesic molecules and ¯pdd, ¯ptt antiprotonic ones, were performed. To check the method, calculations of the binding energies for such systems as the positronium ion Ps−,3H and3He were carried out. The results are compared with the best results of other authors.
Chiral unitary approach to the K^- deuteron scattering length
2000
Starting from a recent model where the Kbar N amplitudes are evaluated from the chiral Lagrangians using a coupled channel unitary method, we evaluate here the scattering length for K^- deuteron scattering. We find that the double scattering contribution is very large compared to the impulse approximation and that the charge exchange contribution of this rescattering is as large as the sequential K^- scattering on the two nucleons. Higher order rescattering corrections are evaluated using coupled channels with K^- and Kbar^0 within the integral form of the fixed centre approximation to the Faddeev equations. The higher order corrections involving intermediate pions and hyperons are found ne…
Solution to Faddeev equations with two-body experimental amplitudes as input and application toJP=1/2+,S=0baryon resonances
2009
We solve the Faddeev equations for the two meson-one baryon system $\ensuremath{\pi}\ensuremath{\pi}N$ and coupled channels using the experimental two-body $t$ matrices for the $\ensuremath{\pi}N$ interaction as input and unitary chiral dynamics to describe the interaction between the rest of coupled channels. In addition to the ${N}^{*}(1710)$ obtained before with the $\ensuremath{\pi}\ensuremath{\pi}N$ channel, we obtain, for ${J}^{\ensuremath{\pi}}=1/{2}^{+}$ and total isospin of the three-body system $I=1/2$, a resonance peak whose mass is around 2080 MeV and width 54 MeV, while for $I=3/2$ we find a peak around 2126 with 42 MeV of width. These two resonances can be identified with the …