THE NEXT STEP IN LEPTONIC DECAYS OF ETA AND KL BOUND STATES

1992 ◽  
Vol 07 (09) ◽  
pp. 1935-1951 ◽  
Author(s):  
G.A. KOZLOV
Keyword(s):  
Field Theory ◽  
Transition Form Factor ◽  
Bound States ◽  
Three Dimensional ◽  
Bound State ◽  
Quantum Field ◽  
Relative Momentum ◽  
Transition Form ◽  
Structure Transition ◽  
Leptonic Decays

A systematic discussion of the probability of eta and KL bound-state decays—[Formula: see text] and [Formula: see text](l=e, μ)—within a three-dimensional reduction to the two-body quantum field theory is presented. The bound-state vertex function depends on the relative momentum of constituent-like particles. A structure-transition form factor is defined by a confinement-type quark-antiquark wave function. The phenomenology of this kind of decays is analyzed.

scholarly journals EXACT-PROPAGATOR INSTANTANEOUS BETHE–SALPETER EQUATION FOR QUARK–ANTIQUARK BOUND STATES

2006 ◽  
Vol 21 (21) ◽  
pp. 1657-1673 ◽  
Author(s):  
ZHI-FENG LI ◽  
WOLFGANG LUCHA ◽  
FRANZ F. SCHÖBERL
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Bound States ◽  
Lattice Gauge Theory ◽  
Bound State ◽  
State Equation ◽  
Wave Functions ◽  
Quantum Field ◽  
Lattice Gauge ◽  
Instantaneous Approximation

Recently an instantaneous approximation to the Bethe–Salpeter formalism for the analysis of bound states in quantum field theory has been proposed which retains, in contrast to the Salpeter equation, as far as possible the exact propagators of the bound-state constituents, extracted nonperturbatively from Dyson–Schwinger equations or lattice gauge theory. The implications of this improvement for the solutions of this bound-state equation, i.e. the spectrum of the mass eigenvalues of its bound states and the corresponding wave functions, when considering the quark propagators arising in quantum chromodynamics are explored.

scholarly journals A conjecture on the minimal size of bound states

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Ben Freivogel ◽  
Thomas Gasenzer ◽  
Arthur Hebecker ◽  
Sascha Leonhardt
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Holes ◽  
Quantum Gravity ◽  
Bound States ◽  
Bound State ◽  
Quantum Field ◽  
Minimal Size ◽  
Sharp Form ◽  
Weak Gravity

We conjecture that, in a renormalizable effective quantum field theory where the heaviest stable particle has mass mm, there are no bound states with radius below 1/m1/m (Bound State Conjecture). We are motivated by the (scalar) Weak Gravity Conjecture, which can be read as a statement forbidding certain bound states. As we discuss, versions for uncharged particles and their generalizations have shortcomings. This leads us to the suggestion that one should only constrain rather than exclude bound objects. In the gravitational case, the resulting conjecture takes the sharp form of forbidding the adiabatic construction of black holes smaller than 1/m1/m. But this minimal bound-state radius remains non-trivial as M_\mathrm{P}\to \inftyMP→∞, leading us to suspect a feature of QFT rather than a quantum gravity constraint. We find support in a number of examples which we analyze at a parametric level.

Form Factor of the Two Fermions Bound State: The Case of Equal Masses and Vector Currentl

2021 ◽  
Vol 24 (2) ◽  
pp. 133-144
Author(s):  
Yu. D. Chernichenko
Keyword(s):  
Field Theory ◽  
Form Factor ◽  
Hamiltonian Formulation ◽  
Three Dimensional ◽  
Vector Current ◽  
Bound State ◽  
Quantum Field ◽  
Quasipotential Approach ◽  
New Form ◽  
Relativistic Particles

New form factor components of two relativistic with equal masses fermions bound state in the case of a vector current are obtained. Consideration is performed within the framework of the relativistic quasipotential approach on the basis of covariant Hamiltonian formulation of quantum field theory by transition to three-dimensional relativistic configurational representation in the case of two relativistic particles with equal masses and spin 1/2.

scholarly journals ON THE BOUND STATES IN A NONLINEAR QUANTUM FIELD THEORY OF A SPINOR FIELD WITH HIGHER DERIVATIVES

1999 ◽  
Vol 14 (11) ◽  
pp. 1651-1662
Author(s):  
A. D. MITOV ◽  
M. N. STOILOV ◽  
D. Ts. STOYANOV
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Spinor Field ◽  
Bound States ◽  
Bound State ◽  
Quantum Field ◽  
Coupling Constant ◽  
Nonlinear Quantum ◽  
Higher Derivatives ◽  
Fermi Type

We consider a model with higher derivatives for a spinor field with Fermi-type self-interaction. The problem of two-particle bound states is investigated with the help of the Bethe–Salpeter equation. It is shown that a scalar bound state exists when the coupling constant has a very finely tuned magnitude.

scholarly journals Colourful Poincaré symmetry, gravity and particle actions

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Joaquim Gomis ◽  
Euihun Joung ◽  
Axel Kleinschmidt ◽  
Karapet Mkrtchyan
Keyword(s):  
Field Theory ◽  
Free Particle ◽  
Three Dimensional ◽  
Background Field ◽  
Quantum Field ◽  
Symmetry Factor ◽  
Starting Point ◽  
Poincaré Algebra ◽  
Poincaré Symmetry ◽  
Three Space

Abstract We construct a generalisation of the three-dimensional Poincaré algebra that also includes a colour symmetry factor. This algebra can be used to define coloured Poincaré gravity in three space-time dimensions as well as to study generalisations of massive and massless free particle models. We present various such generalised particle models that differ in which orbits of the coloured Poincaré symmetry are described. Our approach can be seen as a stepping stone towards the description of particles interacting with a non-abelian background field or as a starting point for a worldline formulation of an associated quantum field theory.

RETARDATION EFFECTS IN COVARIANT THREE-DIMENSIONAL BOUND STATE WAVE FUNCTIONS

2005 ◽  
Vol 14 (06) ◽  
pp. 931-947 ◽  
Author(s):  
F. PILOTTO ◽  
M. DILLIG
Keyword(s):  
Bound States ◽  
Three Dimensional ◽  
Bound State ◽  
Relative Energy ◽  
Wave Functions ◽  
Three Dimensions ◽  
State Wave ◽  
Scalar Diquark ◽  
Bound State Wave Function ◽  
Retardation Effects

We investigate the influence of retardation effects on covariant 3-dimensional wave functions for bound hadrons. Within a quark-(scalar) diquark representation of a baryon, the four-dimensional Bethe–Salpeter equation is solved for a 1-rank separable kernel which simulates Coulombic attraction and confinement. We project the manifestly covariant bound state wave function into three dimensions upon integrating out the non-static energy dependence and compare it with solutions of three-dimensional quasi-potential equations obtained from different kinematical projections on the relative energy variable. We find that for long-range interactions, as characteristic in QCD, retardation effects in bound states are of crucial importance.

scholarly journals AdS3 GRAVITATIONAL INSTANTONS FROM CONFORMAL FIELD THEORY

1999 ◽  
Vol 14 (28) ◽  
pp. 1961-1981 ◽  
Author(s):  
SHUHEI MANO
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Bound States ◽  
Three Dimensional ◽  
Partition Functions ◽  
De Sitter ◽  
Btz Black Hole ◽  
Gravitational Instantons ◽  
Conformal Field ◽  
Horizon Geometry

A conformal field theory on the boundary of three-dimensional asymptotic anti-de Sitter spaces which appear as near horizon geometry of D-brane bound states is discussed. It is shown that partition functions of gravitational instantons appear as high and low temperature limits of the partition function of the conformal field theory. The result reproduces phase transition between the anti-de Sitter space and the BTZ black hole in the bulk gravity.

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