scholarly journals WHAT COULD BE LEARNT FROM POSITRONIUM FOR QUARKONIUM?

2004 ◽  
Vol 19 (23) ◽  
pp. 3905-3917 ◽  
Author(s):  
CHRISTOPHER SMITH
Keyword(s):  
Binding Energy ◽  
Bound State ◽  
State Decay ◽  
Positronium Decay

In order to fulfill Low's theorem requirements, a new lowest order basis for bound state decay computations is proposed, in which the binding energy is treated non-perturbatively. The properties of the method are sketched by reviewing standard positronium decay processes. Then, it is shown how applying the method to quarkonia sheds new light on some longstanding puzzles.

scholarly journals A NEW BASIS FOR QED BOUND STATE COMPUTATIONS

2002 ◽  
Vol 17 (28) ◽  
pp. 4113-4132 ◽  
Author(s):  
J. PESTIEAU ◽  
C. SMITH
Keyword(s):  
Light Scattering ◽  
Binding Energy ◽  
Scattering Amplitude ◽  
Bound State ◽  
External Momentum ◽  
Simple Method ◽  
Positronium Decay

A simple method to compute QED bound state properties is presented, in which binding energy effects are treated nonperturbatively. It is shown that to take the effects of all ladder Coulomb photon exchanges into account, one can simply perform the derivative of standard QED amplitudes with respect to the external momentum. For example, the derivative of the light-by-light scattering amplitude gives an amplitude for orthopositronium decay to three photons where any number of Coulomb photon exchanges between the e+e-is included.Various applications are presented. From them, it is shown that binding energy must be treated nonperturbatively in order to preserve the analyticity of positronium decay amplitudes.Interesting perspectives for quarkonium physics are briefly sketched.

scholarly journals An event excess observed in the deeply bound region of the 12C (K−, p) missing-mass spectrum

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Yudai Ichikawa ◽  
Junko Yamagata-Sekihara ◽  
Jung Keun Ahn ◽  
Yuya Akazawa ◽  
Kanae Aoki ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Binding Energy ◽  
Decay Channel ◽  
Peak Shift ◽  
Bound State ◽  
Elastic Peak ◽  
Missing Mass ◽  
Decay Modes ◽  
Kaon Momentum ◽  
First Time

Abstract We have measured, for the first time, the inclusive missing-mass spectrum of the $^{12}$C$(K^-, p)$ reaction at an incident kaon momentum of 1.8 GeV/$c$ at the J-PARC K1.8 beamline. We observed a prominent quasi-elastic peak ($K^-p \rightarrow K^-p$) in this spectrum. In the quasi-elastic peak region, the effect of secondary interaction is apparently observed as a peak shift, and the peak exhibits a tail in the bound region. We compared the spectrum with a theoretical calculation based on the Green’s function method by assuming different values of the parameters for the $\bar{K}$–nucleus optical potential. We found that the spectrum shape in the binding-energy region $-300 \, \text{MeV} < B_{K} < 40$ MeV is best reproduced with the potential depths $V_0 = -80$ MeV (real part) and $W_0 = -40$ MeV (imaginary part). On the other hand, we observed a significant event excess in the deeply bound region around $B_{K} \sim 100$ MeV, where the major decay channel of $K^- NN \to \pi\Sigma N$ is energetically closed, and the non-mesonic decay modes ($K^- NN \to \Lambda N$ and $\Sigma N$) should mainly contribute. The enhancement is fitted well by a Breit–Wigner function with a kaon-binding energy of 90 MeV and width 100 MeV. A possible interpretation is a deeply bound state of a $Y^{*}$-nucleus system.

scholarly journals POSITRONIUM DECAY: GAUGE INVARIANCE AND ANALYTICITY

2002 ◽  
Vol 17 (10) ◽  
pp. 1355-1398 ◽  
Author(s):  
J. PESTIEAU ◽  
C. SMITH ◽  
S. TRINE
Keyword(s):  
Wave Function ◽  
Form Factor ◽  
Binding Energy ◽  
Gauge Invariance ◽  
Dispersion Relations ◽  
Decay Rates ◽  
Effective Form ◽  
Theoretical Predictions ◽  
Positronium Decay ◽  
Analysis Of Binding Energy

The construction of positronium decay amplitudes is handled through the use of dispersion relations. In this way, emphasis is put on basic QED principles: gauge invariance and soft-photon limits (analyticity).A firm grounding is given to the factorization approaches, and some ambiguities in the spin and energy structures of the positronium wave function are removed. Nonfactorizable amplitudes are naturally introduced. Their dynamics are described, especially regarding the enforcement of gauge invariance and analyticity through delicate interferences. The important question of the completeness of the present theoretical predictions for the decay rates is then addressed. Indeed, some of those nonfactorizable contributions are unaccounted for by NRQED analyses. However, it is shown that such new contributions are highly suppressed, being of [Formula: see text].Finally, a particular effective form factor formalism is constructed for parapositronium, allowing a thorough analysis of binding energy effects and analyticity implementation.

Bound-state decay of rhenium-187

1984 ◽  
Vol 281 ◽  
pp. 363 ◽  
Author(s):  
R. D. Williams ◽  
W. A. Fowler ◽  
S. E. Koonin
Keyword(s):  
Bound State ◽  
State Decay

scholarly journals LORENTZ BOOSTED NN POTENTIAL FOR FEW-BODY SYSTEMS: APPLICATION TO THE THREE-NUCLEON BOUND STATE

2003 ◽  
Vol 18 (02n06) ◽  
pp. 124-127 ◽  
Author(s):  
H. KAMADA ◽  
W. GLÖCKLE ◽  
J. GOLAK ◽  
CH. ELSTER
Keyword(s):  
Quantum Mechanics ◽  
Binding Energy ◽  
Schrodinger Equation ◽  
Relativistic Quantum ◽  
Bound State ◽  
Nucleon Nucleon ◽  
Relativistic Quantum Mechanics ◽  
Equal Time ◽  
Momentum Change ◽  
Approximate Scheme

In the context of equal time relativistic quantum mechanics we introduce a Lorentz boosted potential. The dynamical input are nonrelativistic realistic nucleon-nucleon (NN) potentials, which by a suitable momentum change are analytically transformed into NN potentials fulfilling the relativistic two-nucleon Schrödinger equation in the c.m. system. The binding energy of the three nucleon (3N) bound state is calculated and we find that the boost effects for the two-body subsystems are repulsive and lower the binding energy. In addition we compare to a recently proposed approximate scheme.

scholarly journals THE POSSIBLE DI-OMEGA DIBARYON IN QUARK CLUSTER MODEL

2014 ◽  
Vol 26 ◽  
pp. 1460120 ◽  
Author(s):  
L. R. DAI ◽  
J. LIU ◽  
L. YUAN
Keyword(s):  
Binding Energy ◽  
Quark Model ◽  
Cluster Model ◽  
Bound State ◽  
Nucleon Nucleon ◽  
Scattering Data ◽  
Nucleon Scattering ◽  
Scalar Mesons ◽  
Ideal Mixing ◽  
The Ideal

The mixing of scalar mesons is introduced into the baryon-baryon system in the chiral SU(3) quark model to further dynamically investigate the Di-omega state by using the same parameters as those in reasonably describing the experimental hyperon-nucleon and nucleon-nucleon scattering data. Two different mixings of scalar mesons, the ideal mixing and 19° mixing, are discussed, and compared with no mixing. The results show that it is still deeply bound state if 19° mixing is adopted, the same as those of no mixing. However, for ideal mixing, the binding energy is reduced quite a lot, yet it is still a bound state.

BINDING ENERGIES IN WEAKLY COUPLED (2+1)-DIMENSIONAL QUANTUM FIELD THEORIES

1991 ◽  
Vol 06 (29) ◽  
pp. 2705-2711
Author(s):  
G. GAT ◽  
B. ROSENSTEIN
Keyword(s):  
Perturbation Theory ◽  
Binding Energy ◽  
Bound State ◽  
Binding Energies ◽  
Field Theories ◽  
General Question ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Weakly Coupled ◽  
Gross Neveu Model

We calculate the binding energy of the two-particle threshold bound state in the (2+1)-dimensional Gross-Neveu model. This model was recently shown to be renormalizable within the 1/N expansion. The binding energy is found to be ΔE=4mc-8Nf where m is the mass of the elementary fermion and Nf is the number of flavors. The general question of consistency of the perturbation theory within the framework of the Bethe-Salpeter equation is discussed.

scholarly journals Structure of Xb from line shape analysis

2016 ◽  
Vol 31 (05) ◽  
pp. 1650035
Author(s):  
Yue Ma ◽  
Guo-Ying Chen
Keyword(s):  
Binding Energy ◽  
Shape Analysis ◽  
Line Shape ◽  
Production Line ◽  
Bound State ◽  
Shape Measurement ◽  
Line Shape Analysis ◽  
Elementary State ◽  
Two Parameters ◽  
Shed Light

We study the production line shape of [Formula: see text] near threshold, where the [Formula: see text] pair comes from the resonance [Formula: see text]. Our study shows that the line shape depends sensitively on the binding energy and the probability of finding an elementary state in the physical bound state. Both of the two parameters are crucial to identify the structure of [Formula: see text]. Therefore, the line shape measurement can shed light on the structure of [Formula: see text].

Sign in / Sign up

Export Citation Format

Share Document