The $$D_s^+ \rightarrow a_0(980) e^+ \nu _e$$ reaction and the $$a_0(980)-f_0(980)$$ mixing

AbstractWe perform a study of the $$D_s^+ \rightarrow a_0(980)(f_0(980)) e^+ \nu _e$$ D s + → a 0 ( 980 ) ( f 0 ( 980 ) ) e + ν e reactions investigating the different sources of isospin violation which make the production of the $$a_0(980)$$ a 0 ( 980 ) possible. We find that loops involving kaons in the production mechanism provide a source of isospin violation since they do not cancel due to the different mass of charged and neutral kaons, but we also find that the main source comes from the breaking of isospin in the meson-meson transition T matrices, which contain information on the nature of the low lying scalar mesons. The reaction is thus very sensitive to the nature of the $$a_0(980)$$ a 0 ( 980 ) and $$f_0(980)$$ f 0 ( 980 ) resonances. Our results are consistent with the present upper bound for $$a_0(980)$$ a 0 ( 980 ) production and only a factor three smaller, indicating that future runs with more statistics should find actual numbers for this reaction from where we can learn more about the origin of the scalar resonances and their nature.

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The Fragmented Glueball: A Personal View

EPJ Web of Conferences ◽

10.1051/epjconf/202225808005 ◽

2022 ◽

Vol 258 ◽

pp. 08005

Author(s):

Eberhard Klempt

Keyword(s):

Mass Range ◽

Personal View ◽

Scalar Mesons ◽

Clear Peak ◽

Low Mass ◽

Singlet Component ◽

Limited Mass ◽

Channel Analysis ◽

Coupled Channel ◽

Scalar Resonances

A coupled-channel analysis has been performed to identify the spectrum of scalar mesons. The data include BESIII data on radiative J/ψ decays into π0π0, KS KS, ηη, and ωϕ, 15 Dalitz plots from ¯N annihilation at rest at LEAR, the CERN-Munich multipoles for ππ elastic scattering, the S-wave from BNL data on ππ scattering into KS KS, from GAMS data on ππ π0π0; ηη, and ηη', and NA48/2 data on low-mass ππ interactions from K± → ππe±v decays. The analysis reveals the existence of ten scalar isoscalar resonances. The resonances can be grouped into two classes: resonances with a large SU(3) singlet component and those with a large octet component. The production of isoscalar resonances with a large octet component should be suppressed in radiative J/ψ decays. However, in a limited mass range centered at 1900MeV, these mesons are produced abundantly. Mainly-singlet scalar resonances are produced over the full mass range but with larger intensity at 1900MeV. The total scalar isoscalar yield in radiative decays into scalar mesons shows a clear peak which is interpreted as the scalar glueball of lowest mass.

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Mixing Angle of Scalar Mesons and Kaon Polarizability in a Chiral Quark σ-Model

International Journal of Modern Physics A ◽

10.1142/s0217751x97002395 ◽

1997 ◽

Vol 12 (24) ◽

pp. 4399-4409 ◽

Cited By ~ 5

Author(s):

D. Ebert ◽

M. K. Volkov ◽

T. Feldmann

Keyword(s):

Chiral Symmetry ◽

Symmetry Limit ◽

Mixing Angle ◽

Scalar Mesons ◽

Neutral Kaons

Using present data for the decays f0 → γγ, f0 → ππ, we determine the mixing angle of scalar mesons in a chiral quark σ-model. This value is employed for an analysis of the kaon polarizability. It is shown that pole diagrams from intermediate scalar mesons and their mixing angle significantly affect the electromagnetic polarizability of charged and neutral kaons. Our results are compared to other models and the results of the chiral symmetry limit.

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a0(980)–f0(980) mixing in χc1 decay

EPJ Web of Conferences ◽

10.1051/epjconf/201919904009 ◽

2019 ◽

Vol 199 ◽

pp. 04009

Author(s):

M Bayar ◽

V. R. Debastiani

Keyword(s):

Experimental Measurement ◽

Isospin Breaking ◽

Total Amplitude ◽

Isospin Violation ◽

Neutral Kaons ◽

Good Agreement

We investigate the isospin breaking in the ${\chi _{c1}} \to {\pi ^0}{\pi ^ + }{\pi ^ - }$ and ${\chi _{c1}} \to {\pi ^0}{\pi ^0}\eta $ decays and its relation to the a0(980) – f0(980) mixing, which was measured by the BESIII Collaboration. The isospin violation is introduced through the use of different masses for the charged and neutral kaons, either in the propagators of pairs of mesons created in the χc1 decay, or in the propagators inside the T matrix. We find that the most important effect in the total amplitude is the isospin breaking inside the T matrix which is essential to get a good agreement with the experimental measurement of the mixing.

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