Scattering amplitudes and bound state energies for one-dimensional, weak potentials

1999 ◽  
Vol 67 (7) ◽  
pp. 616-619 ◽  
Author(s):  
S. H. Patil
2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gavin K. C. Cheung ◽  
◽  
Christopher E. Thomas ◽  
David J. Wilson ◽  
Graham Moir ◽  
...  

Abstract Elastic scattering amplitudes for I = 0 DK and I = 0, 1 $$ D\overline{K} $$ D K ¯ are computed in S, P and D partial waves using lattice QCD with light-quark masses corresponding to mπ = 239 MeV and mπ = 391 MeV. The S-waves contain interesting features including a near-threshold JP = 0+ bound state in I = 0 DK, corresponding to the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ (2317), with an effect that is clearly visible above threshold, and suggestions of a 0+ virtual bound state in I = 0 $$ D\overline{K} $$ D K ¯ . The S-wave I = 1 $$ D\overline{K} $$ D K ¯ amplitude is found to be weakly repulsive. The computed finite-volume spectra also contain a deeply-bound D* vector resonance, but negligibly small P -wave DK interactions are observed in the energy region considered; the P and D-wave $$ D\overline{K} $$ D K ¯ amplitudes are also small. There is some evidence of 1+ and 2+ resonances in I = 0 DK at higher energies.


2020 ◽  
Vol 35 (23) ◽  
pp. 2050140
Author(s):  
Eduardo López ◽  
Clara Rojas

We solve the one-dimensional time-independent Klein–Gordon equation in the presence of a smooth potential well. The bound state solutions are given in terms of the Whittaker [Formula: see text] function, and the antiparticle bound state is discussed in terms of potential parameters.


1994 ◽  
Vol 182 (1) ◽  
pp. 89-96 ◽  
Author(s):  
L. S. Brizhik ◽  
A. A. Eremko

Author(s):  
Arkady A. Tseytlin

We discuss possible definition of open string path integral in the presence of additional boundary couplings corresponding to the presence of masses at the ends of the string. These couplings are not conformally invariant implying that as in a non-critical string case one is to integrate over the one-dimensional metric or reparametrizations of the boundary. We compute the partition function on the disc in the presence of an additional constant gauge field background and comment on the structure of the corresponding scattering amplitudes.


1998 ◽  
Vol 13 (06) ◽  
pp. 903-914 ◽  
Author(s):  
AKIKAZU HASHIMOTO

Fractional strings in the spectrum of states of open strings attached to a multiply wound D-brane is explained. We first describe the fractional string states in the low energy effective theory where the topology of multiple winding is encoded in the gauge holonomy. The holonomy induces twisted boundary conditions responsible for the fractional moding of these states. We also describe fractional strings in world sheet formulation and compute simple scattering amplitudes for Hawking emission/absorption. Generalization to fractional DN-strings in a one-brane five-brane bound state is described. When a one-brane and a five-brane wraps Q1 and Q5 times respectively around a circle, the momentum of DN-strings is quantized in units of 2π/LQ1Q5. These fractional states appear naturally in the perturbative spectrum of the theory.


1992 ◽  
Vol 70 (8) ◽  
pp. 670-682 ◽  
Author(s):  
Tao Zhang ◽  
Lixin Xiao ◽  
Roman Koniuk

We present a new relativistic bound-state formalism for two interacting Fermi–Dirac particles. The kernel of the integral equation for the bound-state system is generated by summing Feynman scattering amplitudes and multiplying by a bound-state amplitude. The method is illustrated through calculations of the hyperfine and fine splittings of positronium up to order α5. Our calculations of the one-loop contributions are carried out in the explicitly covariant Feynman gauge. We also present new results for the hyperfine and fine splittings in positronium to order α5 for arbitrary principal quantum number n, which are easily obtained owing to the virtue of conceptual and calculational simplicity of our formalism. In addition, we present the one-loop renormalization scheme in our formalism.


2006 ◽  
Vol 21 (02) ◽  
pp. 313-325 ◽  
Author(s):  
VÍCTOR M. VILLALBA ◽  
CLARA ROJAS

We solve the Klein–Gordon equation in the presence of a spatially one-dimensional cusp potential. The bound state solutions are derived and the antiparticle bound state is discussed.


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