scholarly journals ηtransitions between charmonia with meson loop contributions

2013 ◽  
Vol 87 (5) ◽  
Author(s):  
Dian-Yong Chen ◽  
Xiang Liu ◽  
Takayuki Matsuki
Keyword(s):  
Meson Loop

How to distinguish a molecule from an 'elementary' particle?

2014 ◽  
Vol 23 (07) ◽  
pp. 1461002
Author(s):  
L. Y. Dai ◽  
M. Shi ◽  
G. Y. Tang ◽  
H. Q. Zheng
Keyword(s):  
Elementary Particle ◽  
Model Analysis ◽  
Molecular State ◽  
Counting Rule ◽  
Interaction Field ◽  
Effective Lagrangian ◽  
Meson Loop

We discuss how to use Morgan's pole counting rule to distinguish a molecular state from an 'elementary' particle. As two examples we focus on X(3872) and f0(980) particles. A molecule may be generated from a meson loop bubble chain, and an 'elementary' particle is related to an explicit interaction field in the effective lagrangian and propagates with a Breit–Wigner propagator. For X(3872) it is found that the data favor the 'elementary' particle explanation. For f0(980) the study becomes much more difficult, since highly nonperturbative dynamics is involved. A unitarization model analysis suggests that f0(980)'s property is quite exotic. Unlike other light scalars, it does not behave like a [Formula: see text] state, and could be interpreted as a molecule.

scholarly journals ENERGY SPECTRA OF ANTI-NUCLEONS IN FINITE NUCLEI

2005 ◽  
Vol 20 (08n09) ◽  
pp. 2014-2017
Author(s):  
G. MAO ◽  
J. GONG ◽  
H. STÖCKER ◽  
W. GREINER
Keyword(s):  
Bound States ◽  
Energy Spectra ◽  
Quantum Vacuum ◽  
Body System ◽  
Many Body ◽  
Field Equations ◽  
Meson Loop ◽  
Dirac Sea ◽  
The One ◽  
Finite Nuclei

The quantum vacuum in a many-body system of finite nuclei has been investigated within the relativistic Hartree approach which describes the bound states of nucleons and anti-nucleons consistently. The contributions of the Dirac sea to the source terms of the meson-field equations are taken into account up to the one-nucleon loop and one-meson loop. The tensor couplings for the ω- and ρ-meson are included in the model. The overall nucleon spectra of shell-model states are in agreement with the data. The calculated anti-nucleon spectra in the vacuum differ about 20 – 30 MeV with and without the tensor-coupling effects.

Manifestation of intermediate meson loop effects in charmonium decays

2010 ◽  
Vol 34 (9) ◽  
pp. 1181-1184 ◽  
Author(s):  
Zhang Yuan-Jiang ◽  
Li Gang ◽  
Zhao Qiang
Keyword(s):  
Meson Loop

scholarly journals Effects of heavy meson loops on higher charmonia radiative transitions

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Wen-Hua Qin ◽  
Chun-Sheng An ◽  
Gang Li ◽  
Chao Wang ◽  
Yan Wang
Keyword(s):  
Bound States ◽  
Heavy Meson ◽  
Effective Field ◽  
Final States ◽  
Charmed Meson ◽  
Radiative Transitions ◽  
Meson Loop ◽  
Channel Effects ◽  
Coupled Channel ◽  
Insight Into

Abstract Radiative transitions between charmonium states offer an insight into the internal structure of heavy quark bound states within QCD. In this work, we performed a systematically investigation of the radiative transitions of $$\psi (nS) \rightarrow \gamma \chi _{cJ}(mP)$$ψ(nS)→γχcJ(mP) and $$\psi (nD) \rightarrow \gamma \chi _{cJ}(mP)$$ψ(nD)→γχcJ(mP) via intermediate charmed meson loop with a non-relativistic effective field theory. We only focus on the line-shape behavior of the distributions via different intermediate meson loops. Our results show that the coupled-channel effects of these decays are relatively weak, while the coupled channel effects has obvious enhancement when the inial (final) states are closed to the thresholds of charmed-mesons pair.

scholarly journals Meson loop effects on the pion electromagnetic form factor

2004 ◽  
Vol 69 (6) ◽  
Author(s):  
F. Carvalho ◽  
F. O. Durães ◽  
F. S. Navarra ◽  
M. Nielsen
Keyword(s):  
Form Factor ◽  
Electromagnetic Form Factor ◽  
Pion Electromagnetic Form Factor ◽  
Meson Loop ◽  
Pion Electromagnetic Form

CHIRAL SYMMETRY AND MESON LOOP MODEL FOR NON-LEPTONIC K AND D WEAK DECAYS

1991 ◽  
Vol 06 (07) ◽  
pp. 543-551 ◽  
Author(s):  
R.E. KARLSEN ◽  
M.D. SCADRON
Keyword(s):  
Chiral Symmetry ◽  
Vector Boson ◽  
Loop Model ◽  
First Order ◽  
Weak Decays ◽  
Meson Loop ◽  
W Vector Boson

We show that K→ππ and charmed [Formula: see text] decays can be understood using chiral symmetry and a meson loop model to simulate first order weak decays driven by the heavy-W vector boson.

NUCLEON ELECTROMAGNETIC FORM FACTORS AND CHIRAL SINGULARITIES

1999 ◽  
Vol 08 (04) ◽  
pp. 355-379
Author(s):  
C. D. JOHNSON ◽  
R. TEGEN
Keyword(s):  
Closed Form ◽  
Scattering Amplitude ◽  
Form Factors ◽  
Electromagnetic Form Factors ◽  
Threshold Behaviour ◽  
Gauge Invariant ◽  
Meson Loop ◽  
Loop Approximation ◽  
Quark Substructure

Chiral singularities in both nucleon isovector radii are calculated in closed form. Within a one-meson-loop approximation we implement in an explicitly gauge invariant manner quark substructure in the γ π π and πNN vertex functions. The coefficients of log mπ and [Formula: see text] terms are directly related to gA and to the threshold behaviour of the πN amplitude A(-)(ν,0) which are 1 and 0, respectively, if only the N pole is considered in the πN scattering amplitude. This result is remarkably independent of the cut-off procedure. If mesonic substructure at the γ π π vertex is included, however, gA becomes slightly smaller than 1 and [Formula: see text] becomes moderately negative. This hints at important contributions to both gA and [Formula: see text] from the Δ(1232) and possibly other N*, Δ* resonances in this approach.

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