scholarly journals ISOBAR RESCATTERING MODEL AND LIGHT SCALAR MESONS

2005 ◽  
Vol 20 (27) ◽  
pp. 6149-6158 ◽  
Author(s):  
J. SCHECHTER

We use a toy model to discuss the problem of parameterizing the possible contribution of a light scalar meson, sigma, to the final state interactions in the non leptonic decays of heavy mesons.

2020 ◽  
Vol 61 (4) ◽  
Author(s):  
Gernot Eichmann ◽  
Christian S. Fischer ◽  
Walter Heupel ◽  
Nico Santowsky ◽  
Paul C. Wallbott

AbstractIn this feature article we summarise and highlight aspects of the treatment of four-quark states with functional methods. Model approaches to those exotic mesons almost inevitably have to assume certain internal structures, e.g. by grouping quarks and antiquarks into (anti-)diquark clusters or heavy-light $$q{\bar{q}}$$ q q ¯ pairs. Functional methods using Dyson–Schwinger and Bethe–Salpeter equations can be formulated without such prejudice and therefore have the potential to put these assumptions to test and discriminate between such models. So far, functional methods have been used to study the light scalar-meson sector and the heavy-light sector with a pair of charmed and a pair of light quarks in different quantum number channels. For all these states, the dominant components in terms of internal two-body clustering have been identified. It turns out that chiral symmetry breaking plays an important role for the dominant clusters in the light meson sector (in particular for the scalar mesons) and that this property is carried over to the heavy-light sector. Diquark-antidiquark components, on the other hand, turn out to be almost negligible for most states with the exception of open-charm heavy-light exotics.


2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Yoshiki Kuroda ◽  
Masayasu Harada ◽  
Shinya Matsuzaki ◽  
Daisuke Jido

Abstract We propose a novel mechanism to reproduce the observed mass hierarchy for scalar mesons lighter than 1 GeV (called the inverse hierarchy), regarding them as mesons made of a quark and an anti-quark ($q\bar{q}$ mesons). The source is provided by the SU(3) flavor-symmetry breaking induced by the U(1) axial anomaly. In particular, the anomaly term including the explicit chiral symmetry breaking plays a significant role in the light scalar meson spectrum. To be concrete, we construct a linear sigma model for scalar mesons of $q\bar{q}$ type together with their pseudoscalar chiral partners, including an anomaly-induced explicit chiral symmetry-breaking term. We find that, due to the proposed mechanism, the inverse hierarchy, i.e., $m\left[ a_0 (980) \right] \simeq m\left[ f_0 (980) \right] > m \left[ K_0^\ast (700) \right] > m \left[ f_0(500) \right]$, is indeed realized. Consequently, the quark content of $f_0 (500)$ is dominated by the isoscalar $\bar uu+ \bar dd$ component, and $f_0 (980)$ by the strange quark bilinear one, $s\bar{s}$.


2007 ◽  
Vol 22 (02n03) ◽  
pp. 406-415 ◽  
Author(s):  
BERND KRUSCHE

A diverse experimental program for the study of the photoproduction of mesons off nuclei has been carried out - and is still running - at the Mainz MAMI and Bonn ELSA electron accelerators with the TAPS, Crystal Barrel, and Crystal Ball calorimeters. It is motivated as a detailed study of the in-medium properties of hadrons and the meson - nucleus interactions. Typical examples for the in-medium behavior of vector mesons (ω), scalar mesons (σ), and nucleon resonances ( P 33(1232), S 11(1535), D 15(1520)) are discussed. Special attention is paid to meson - nucleus final state interactions.


2012 ◽  
Vol 27 (23) ◽  
pp. 1250135 ◽  
Author(s):  
QIAN WANG ◽  
GANG LI ◽  
QIANG ZHAO

We evaluate the decay branching ratios of χc1 → PS, in a quark model parametrization scheme, where P and S stand for pseudoscalar and scalar meson, respectively. An interesting feature of this decay process is that the [Formula: see text] annihilate via the pQCD hair-pin diagram is supposed to be dominant. Hence, this decay process should be sensitive to the quark components of the final-state light mesons, and would provide a great opportunity for testing the mixing relations among the scalar mesons, i.e. f0(1370), f0(1500) and f0(1710), by tagging the final state pseudoscalar mesons.


2019 ◽  
Vol 79 (12) ◽  
Author(s):  
Z. J. Ajaltouni ◽  
E. Di Salvo

AbstractWe consider two-body and quasi-two-body decays of the type $$f_1 \rightarrow f_2 B$$f1→f2B, where $$f_1$$f1 and $$f_2$$f2 are spin-1/2 fermions and B a spin-0 or spin-1 boson. After recalling the non-covariant formalism for decay amplitudes, we derive the expression of the differential decay width and of the polarizations of the final spinning particles, both on- and off-shell. We find an intriguing geometrical interpretation of the results about the polarization. We also illustrate some methods for measuring the polarizations of the resonances and for optimizing data analysis. Then we propose applications to semi-leptonic weak decays, with a major attention to the T-odd component of the polarization; this may help to find, simultaneously, possible time-reversal violations and hints to physics beyond the standard model. We suggest also a CPT test. Last, we discuss some T-odd observables for the production process of $$f_1$$f1 and for the study of the strong final state interactions of non-leptonic decays.


2007 ◽  
Vol 651 (2-3) ◽  
pp. 129-134 ◽  
Author(s):  
L. Maiani ◽  
A.D. Polosa ◽  
V. Riquer

Sign in / Sign up

Export Citation Format

Share Document