The nature of the light scalar mesons

Vijande, J.; Valcarce, A.; Fernández, F.

doi:10.1063/1.2130147

Cited by 3 publications

(5 citation statements)

References 41 publications

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“…[210,211] while -just as in our study -the same resonance was found to be compatible with an excited qq state in Ref. [102]. according to Eq.…”

Section: B Masses Of the Excited Statessupporting

confidence: 87%

“…Excited mesons were a subject of interest already several decades ago [97,98]; to date, they have been considered in a wide range of approaches including QCD models / chiral Lagrangians [99][100][101][102][103][104], Lattice QCD [105][106][107][108][109][110], Bethe-Salpeter equation [111][112][113][114], NJL Model and its extensions [115][116][117][118][119][120][121][122][123][124][125], light-cone models [126], QCD string approaches [127] and QCD domain walls [128]. Chiral symmetry has also been suggested to become effectively restored in excited mesons [129,130] rendering their understanding even more important.…”

Section: Introductionmentioning

confidence: 99%

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Excited scalar and pseudoscalar mesons in the extended linear sigma model

Parganlija

Giacosa

2017

Eur. Phys. J. C

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We present an in-depth study of masses and decays of excited scalar and pseudoscalar states in the Extended Linear Sigma Model (eLSM). The model also contains ground-state scalar, pseudoscalar, vector and axial-vector mesons. The main objective is to study the consequences of the hypothesis that the resonance, observed a decade ago by the BES Collaboration and recently by LHCb, represents an excited scalar quarkonium. In addition we also analyse the possibility that the new resonance, observed recently by BABAR, may also be an excited scalar state. Both hypotheses receive justification in our approach although there appears to be some tension between the simultaneous interpretation of / and pseudoscalar mesons , , and K(1460) as excited states.

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“…[210,211] while -just as in our study -the same resonance was found to be compatible with an excited qq state in Ref. [102]. according to Eq.…”

Section: B Masses Of the Excited Statessupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Excited scalar and pseudoscalar mesons in the extended linear sigma model

Parganlija

Giacosa

2017

Eur. Phys. J. C

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“…Thus, f 0 (1760) was identified as the state with the largest glueball component [1186]. The scheme can be extended to contain not only qq mesons and glueballs but also tetraquarks [1169,1187] and/or hybrids [1176]. The possible discovery of a further scalar meson at 1810 MeV/c 2 was suggested to require the extension into one of these directions [1188].…”

Section: Glueball-qq Mixing Scenariosmentioning

confidence: 97%

Glueballs, hybrids, multiquarks

2007

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Glueballs, hybrids and multiquark states are predicted as bound states in models guided by quantum chromo dynamics (QCD), by QCD sum rules or QCD on a lattice. Estimates for the (scalar) glueball ground state are in the mass range from 1000 to 1800 MeV, followed by a tensor and a pseudoscalar glueball at higher mass. Experiments have reported evidence for an abundance of meson resonances with 0 −+ , 0 ++ and 2 ++ quantum numbers. In particular, the sector of scalar mesons is full of surprises starting from the elusive and mesons. The a 0 (980) and f 0 (980), discussed extensively in the literature, are reviewed with emphasis on their Janus-like appearance as KK molecules, tetraquark states or qq mesons. Most exciting is the possibility that the three mesons f 0 (1370), f 0 (1500), and f 0 (1710) might reflect the appearance of a scalar glueball in the world of quarkonia. However, the existence of f 0 (1370) is not beyond doubt and there is evidence that both f 0 (1500) and f 0 (1710) are flavour octet states, possibly in a tetraquark composition. We suggest a scheme in which the scalar glueball is dissolved into the wide background into which all scalar flavour-singlet mesons collapse.There is an abundance of meson resonances with the quantum numbers of the . Three states are reported below 1.5 GeV/c 2 whereas quark models expect only one, perhaps two. One of these states, (1440), was the prime glueball candidate for a long time. We show that (1440) is the first radial excitation of the meson.Hybrids may have exotic quantum numbers which are not accessible by qq mesons. There are several claims for J P C = 1 −+ exotics, some of them with properties as predicted from the flux tube model interpreting the quark-antiquark binding by a gluon string. The evidence for these states depends partly on the assumption that meson-meson interactions are dominated by s-channel resonances. Hybrids with non-exotic quantum numbers should appear as additional states. Light-quark mesons exhibit a spectrum of (squared) masses which are proportional to the sum of orbital angular momentum and radial quantum numbers. Two states do not fall under this classification. They are discussed as hybrid candidates.The concept of multiquark states has received revived interest due to new resonances in the spectrum of states with open and hidden charm. The new states are surprisingly narrow and their masses and their decay modes often do not agree with simple quark-model expectations.Lattice gauge theories have made strong claims that glueballs and hybrids should appear in the meson spectrum. However, the existence of a scalar glueball, at least with a reasonable width, is highly questionable. It is possible that hybrids will turn up in complex multibody final states even though so far, no convincing case has been made for them by experimental data. Lattice gauge theories fail to identify the nonet of scalar mesons. Thus, at the present status of approximations, lattice gauge theories seem not to provide a trustworthy guide into unknown territory ...

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“…First of all we center our attention on the light scalar-isoscalar mesons. In [18] scalar mesons below 2 GeV were studied in terms of the mixing of a chiral nonet of tetraquarks with conventional q q states using the scheme described in Section 2.8.. We show in Table 8 results for the energies and dominant flavor component of the scalar-isoscalar mesons when considering also the mixing with a scalar glueball based on intuition from lattice QCD [30,31,32,33]. The results show a nice correspondence between theoretical predictions and experiment.…”

Section: Probabilities In Four-quark Systemsmentioning

confidence: 84%

“…A sketch of these mixing interactions is drawn in Figure 3. Such approach has been used in a series of papers to describe the light-scalar mesons and the open-charm and open-bottom meson sectors [17,18,19,20].…”

Section: Figurementioning

confidence: 99%