scholarly journals Polylogarithms from the Bound State S-matrix

Author(s):  
M. de Leeuw ◽  
B. Eden ◽  
D. le Plat ◽  
T. Meier
Keyword(s):  
2016 ◽  
Vol 31 (28n29) ◽  
pp. 1645014
Author(s):  
Alan R. White

Reggeon unitarity and non-Abelian gauge field copies are focused on as two Gribov discoveries that, it is suggested, may ultimately be seen as the most significant and that could, in the far distant future, form the cornerstones of his legacy. The crucial role played by the Gribov ambiguity in the construction of gauge theory bound-state amplitudes via reggeon unitarity is described. It is suggested that the existence of a physical, unitary, S-Matrix in a gauge theory is a major requirement that could even determine the theory.


1994 ◽  
Vol 09 (27) ◽  
pp. 4801-4810 ◽  
Author(s):  
SUBIR GHOSHAL

We study the boundary S matrix for the reflection of bound states of the two-dimensional sine-Gordon integrable field theory in the presence of a boundary.


1989 ◽  
Vol 67 (1) ◽  
pp. 37-40 ◽  
Author(s):  
L. A. L. Roriz ◽  
A. Delfino

By solving the Lippmann–Schwinger equation in momentum space for a set of two-body separable interactions, we study eir S-matrix pole trajectories. The connection of such a study with the three-body bound-state collapse is also discussed.


2009 ◽  
Vol 819 (3) ◽  
pp. 319-350 ◽  
Author(s):  
G. Arutyunov ◽  
M. de Leeuw ◽  
A. Torrielli
Keyword(s):  

1974 ◽  
Vol 29 (6) ◽  
pp. 859-866 ◽  
Author(s):  
A. Grauel

Introducing correlated continuum wave functions for the two- and re-particle-continuum a microscopic theory of nuclear reactions based on a method of Fano is developed. The S-matrix-elements are given by the matrix-elements between correlated continuum wave functions and bound state wave functions. The antisymmetrization of the continuum wave functions with more than one particle in the continuum is included. The theory can be straightforwardly applied on the n-nucleon-emission process following photo- and particle excitations.


2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Yoshihiko Kobayashi ◽  
Masayuki Matsuo

Abstract We investigate unbound single-particle states in pair-correlated drip-line nuclei by describing a low-energy elastic scattering of a neutron in the $s$-wave within the framework of the coordinate space Hartree–Fock–Bogoliubov (Bogoliubov–de Genne) equation. A numerical study is performed for a neutron drip-line carbon isotope where the neutron $2s_{1/2}$ orbit is located close to zero energy. Analyzing the S-matrix poles of the elastic scattering, we discuss properties of the $s$-wave quasiparticle resonance and, in particular, behaviors characteristic to drip-line nuclei. It is found that the S-matrix has two pairs of poles; one pair appears as either a weakly bound state, a virtual state or a resonance while the other pair makes a contribution analogous to a bound single-particle state. The $s$-wave quasiparticle resonance emerges with a large variation depending on the pairing gap and the single-particle energy of the $s$-orbit.


2004 ◽  
Vol 19 (26) ◽  
pp. 1949-1967 ◽  
Author(s):  
EEF VAN BEVEREN ◽  
GEORGE RUPP

The classification of scalar and vector mesons is reviewed within the framework of the Resonance-Spectrum Expansion (RSE). This method allows a simple and straightforward description of non-exotic meson–meson scattering, incorporating the effects of quark confinement and OZI-allowed decay in a fully nonperturbative way. Results for resonances and bound states are compared to experiment, on the basis of computed pole positions and cross-sections. New predictions for open-charm and -bottom scalar mesons are presented.Concretely, observed vector states for [Formula: see text] and [Formula: see text] are reproduced, and others are predicted. In the light scalar sector, the now established two nonets, one below 1 GeV and one in the region 1.3–1.5 GeV, are easily described, through the appearance of extra poles in the S-matrix. The recently found [Formula: see text](2317) meson is accurately reproduced by the same mechanism, as a quasi-bound state in the coupled [Formula: see text] system.In S-wave Dπ and Bπ scattering, new resonances are foreseen close to threshold, i.e. a [Formula: see text] at 2.16±0.05 GeV some 250 MeV wide, and a [Formula: see text] at 5.47±0.05 GeV with a width of about 50 MeV. Additional predictions concern the existence of [Formula: see text] and [Formula: see text] scalar mesons, stable with respect to OZI-allowed decay to BK and BD, respectively, namely at 5.61±0.05 GeV resp. 6.64±0.05 GeV.


2010 ◽  
Vol 25 (07) ◽  
pp. 535-547 ◽  
Author(s):  
BASUDEB SAHU ◽  
Y. K. GAMBHIR ◽  
C. S. SHASTRY

Most of the decaying systems namely α-decay and proton radio activity have extremely narrow widths and hence are termed as quasi-bound states. There are three methods available for the computation of very narrow widths. First, the analytic S-matrix method which treats resonance as a pole in complex energy plane with its real part representing resonance energy and the imaginary part the half width. Another two methods namely (i) direct (D) method and (ii) distorted wave (DW) method are based on the property of the quasi-bound state wave function which is quite similar to a bound state wave function in the interior region and is matched with an outgoing spherical wave representing decaying behavior. We make a comparative study of these methods by applying them to the α-decay systems whose experimental results of Q-value and decay half-lives are known recently. It is observed that all the three methods give practically the same results for widths calculated at the same Q-value and explain the experimental results of Q-values and half-lives in several α-decaying nuclei quite well with a proper Coulomb nuclear interaction potential for the α+daughter nucleus system.


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