Scalar mesons at KLOE

Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Bacci, C.; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, S. S.; Bossi, F.; Branchini, P.; Campana, P.; Capon, G.; Capussela, T.; Ceradini, F.; Chi, S.; Chiefari, G.; Ciambrone, P.; Crucianelli, F.; Lucia, E. De; Santis, A. De; Simone, P. De; Zorzi, G. De; Denig, A.; Domenico, A. Di; Donato, C. Di; Micco, B. Di; Doria, A.; Dreucci, M.; Felici, G.; Ferrari, A.; Ferrer, M. L.; Fiore, S.; Forti, C.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Graziani, E.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee‐Franzini, J.; Leone, D.; Martini, M.; Massarotti, P.; Mei, W.; Meola, S.; Miscetti, S.; Moulson, M.; Müller, S.; Murtas, F.; Napolitano, M.; Nguyen, F.; Palutan, M.; Passeri, A.; Patera, V.; Perfetto, F.; Primavera, M.; Santangelo, P.; Saracino, G.; Sciascia, B.; Sciubba, A.; Sibidanov, A.; Spadaro, T.; Testa, M.; Tortora, L.; Valente, P.; Venanzoni, G.; Versaci, R.; Xu, G. F.

doi:10.1016/j.nuclphysbps.2008.12.065

Cited by 57 publications

(67 citation statements)

References 15 publications

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“…Such an approach to the 2π channel below 1 GeV has recently been completed in [36], relying on a close relation between ππ scattering, the pion vector form factor, and the HVP integral [37][38][39][40][41]. As a result, it was found that despite the known tension between BaBar [42,43] and KLOE [44][45][46][47], each data set by itself is consistent with QCD constraints, and a global fit then defines an average that only uses as additional input information on the covariance matrices as provided by experiment.…”

Section: Introductionmentioning

confidence: 99%

Three-pion contribution to hadronic vacuum polarization

Hoferichter

Hoid

Kubis

2019

J. High Energ. Phys.

359

220

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We address the contribution of the 3π channel to hadronic vacuum polarization (HVP) using a dispersive representation of the e + e − → 3π amplitude. This channel gives the second-largest individual contribution to the total HVP integral in the anomalous magnetic moment of the muon (g − 2) µ , both to its absolute value and uncertainty. It is largely dominated by the narrow resonances ω and φ, but not to the extent that the off-peak regions were negligible, so that at the level of accuracy relevant for (g − 2) µ an analysis of the available data as model independent as possible becomes critical. Here, we provide such an analysis based on a global fit function using analyticity and unitarity of the underlying γ * → 3π amplitude and its normalization from a chiral low-energy theorem, which, in particular, allows us to check the internal consistency of the various e + e − → 3π data sets. Overall, we obtain a 3π µ | ≤1.8 GeV = 46.2(6)(6) × 10 −10 as our best estimate for the total 3π contribution consistent with all (low-energy) constraints from QCD. In combination with a recent dispersive analysis imposing the same constraints on the 2π channel below 1 GeV, this covers nearly 80% of the total HVP contribution, leading to a HVP µ = 692.3(3.3) × 10 −10 when the remainder is taken from the literature, and thus reaffirming the (g−2) µ anomaly at the level of at least 3.4σ. As side products, we find for the vacuum-polarization-subtracted masses M ω = 782.63(3)(1) MeV and M φ = 1019.20(2)(1) MeV, confirming the tension to the ω mass as extracted from the 2π channel.

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Section: Introductionmentioning

confidence: 99%

Three-pion contribution to hadronic vacuum polarization

Hoferichter

Hoid

Kubis

2019

J. High Energ. Phys.

359

220

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“…The kaon-loop model was suggested in Ref. [12] and confirmed by experiment ten years later [19,20,21,22], Figs. 3, 4. In Ref.…”

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confidence: 58%

Light scalar mesons as manifestation of spontaneously broken chiral symmetry

Achasov

2010

Phys. Part. Nuclei

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It is shown that all predictions for the light scalars, based on their four-quark nature, are supported by experiment. The future research program is outlined also. PACS numbers: PACS numbers: 12.39.-x, 13.40.-f, 13.60. Le, 13.75. Lb 1 Introduction OVERTURE Peter Higgs, C. R. Physique 8 (2007) 970-972:" Another example, which comes closer to the kind of symmetry breaking which is of interest in particle physics, is superfluidity. In 1947 Bogoliubov studied Bose condensation of an infinite system of neutral spinless bosons with short-range repulsive two-body interactions. Such a condensate is characterised by a 'macroscopic wave function' (the order parameter) which is complex; its modulus squared is a measure of the observable condensate density, but its argument (which is unobservable) is arbitrary, thus breaking the symmetry of the dynamics under rotations of the boson wave functions in the Argand diagram. The short-range interactions are represented in the second-quantised Hamiltonian by a term proportional to the square of the particle density, that is, to a quartic in the components of the scalar quantum field." See also, N.N. OutlineThe a 0 (980) and f 0 (980) mesons are well-established parts of the proposed light scalar meson nonet [1]. From the beginning, the a 0 (980) and f 0 (980) mesons became one of the central problems of nonperturbative QCD, as they are important for understanding the way chiral symmetry is realized in the low-energy region and, consequently, for understanding confinement. Many experimental and theoretical papers have been devoted to this subject. There is much evidence that supports the four-quark model of light scalar mesons [2,3].

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“…The decays φ(1020) → γa 0 (980) → γπ 0 η and φ(1020) → γf 0 (980) → γππ have been studied to date not only theoretically but also experimentally with e + e − colliders using the Spherical Neutral Detector (SND) [45][46][47][48] and the CMD-2 (Cryogenic Magnetic Detector) [49,50] at the Novosibirsk-based Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences, and the KLOE detector (K LOng Experiment) at the Frascati φ-factory (Italy) [51][52][53][54][55][56][57].…”

Section: Introduction Nature Of Scalar Mesonsmentioning

confidence: 99%

Strong isospin symmetry breaking in light scalar meson production

Achasov

Shestakov

2019

Phys.-Usp.

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Siberian Branch of the Russian Academy of Sciences, prosp. Akademika Koptyuga 4, 630090 Novosibirsk, Russian FederationIsospin symmetry breaking is discussed as a tool for studying the nature and production mechanisms of light scalar mesons. We are concerned with isospin breaking effects with an amplitude ∼ √ m d − mu (instead of the usual ∼ m d − mu), where mu and m d are the u and d quark masses, whose magnitude and phase vary with energy in a resonance-like way characteristic of the KK threshold region. We consider a variety of reactions that can experimentally reveal (or have revealed) the mixing of a 0 0 (980) and f0 (980) resonances that breaks the isotopic invariance due to the mass difference between K + and K 0 mesons. Experimental results on the search for a 0 0 (980) − f0(980) mixing in f1(1285) → f0(980)π 0 → π + π − π 0 and η(1405) → f0(980)π 0 → π + π − π 0 decays suggest a broader perspective on the isotopic symmetry breaking effects due to the K + and K 0 mass difference. It has become clear that not only the a 0 0 (980) − f0(980) mixing but also any mechanism producing KK pairs with a definite isospin in an S wave gives rise to such effects, thus suggesting a new tool for studying the nature and production mechanisms of light scalars. Of particular interest is the case of a large isotopic symmetry breaking in the η(1405) → f0(980)π 0 → π + π − π 0 decay due to the occurrence of anomalous Landau thresholds (logarithmic triangle singularities), i.e., due to the η(1405) → (K * K +K * K) → (K + K − + K 0K 0 )π 0 → f0(980)π 0 → π + π − π 0 transition (where it is of fundamental importance that the K * meson has a finite width).

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Scalar mesons at KLOE

Cited by 57 publications

References 15 publications

Three-pion contribution to hadronic vacuum polarization

Three-pion contribution to hadronic vacuum polarization

Light scalar mesons as manifestation of spontaneously broken chiral symmetry

Strong isospin symmetry breaking in light scalar meson production

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