Cargando…
BHLS[Formula: see text] upgrade: [Formula: see text] spectra, muon HVP and the [[Formula: see text] ] system
The generic hidden local symmetry (HLS) model has recently given rise to its [Formula: see text] variant, defined by introducing symmetry breaking mostly in the vector meson sector; the central mechanism is a modification of the covariant derivative at the root of the HLS approach. However, the desc...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer Berlin Heidelberg
2022
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8884113/ https://www.ncbi.nlm.nih.gov/pubmed/35250375 http://dx.doi.org/10.1140/epjc/s10052-022-10096-4 |
Sumario: | The generic hidden local symmetry (HLS) model has recently given rise to its [Formula: see text] variant, defined by introducing symmetry breaking mostly in the vector meson sector; the central mechanism is a modification of the covariant derivative at the root of the HLS approach. However, the description of the [Formula: see text] dipion spectra, especially the Belle one, is not fully satisfactory, whereas the simultaneous dealing with its annihilation sector ([Formula: see text] ) is optimum. We show that this issue is solved by means of an additional breaking term which also allows us to consistently include the mixing properties of the [Formula: see text] system within this extended [Formula: see text] ([Formula: see text] ) scope. This mechanism, an extension of the usual ’t Hooft determinant term, only affects the kinetic energy part of the [Formula: see text] Lagrangian. One thus obtains a fair account for the [Formula: see text] dipion spectra which complements the fair account of the annihilation channels already reached. The Belle dipion spectrum is found to provide evidence in favor of a violation of the conserved vector current (CVC) in the [Formula: see text] lepton decay; this evidence is enforced by imposing the conditions [Formula: see text] on [Formula: see text] axial current matrix elements. [Formula: see text] is found to recover the usual (completed) formulae for the [[Formula: see text] ] mixing parameters, and the global fits return mixing parameter values in agreement with expectations and better uncertainties. Updating the muon hadronic vacuum polarization (HVP), one also argues that the strong tension between the KLOE and BaBar pion form factors imposes to provide two solutions, namely [Formula: see text] and [Formula: see text] , in units of [Formula: see text] , rather than some combination of these. Taking into account common systematics, their differences from the experimental BNL-FNAL average value exhibit significance [Formula: see text] (KLOE) and [Formula: see text] (BaBar), with fit probabilities favoring the former. |
---|