Experimental study of the e+e− → π+π−π0 reaction by SND detector in the energy range s = 0.42 – 1.38 GeV

Ачасов, М. Н.; Beloborodov, K.; Berdyugin, A. V.; Богданчиков, А. Г.; Bozhenok, A. V.; Bukin, A. D.; Bukin, D.A.; Dimova, T.; Golubev, V. B.; Korol, A. A.; Koshuba, S. V.; Пахтусова, Е. В.; Perevedentsev, E. A.; Pyata, E.E.; Serednyakov, S. I.; Shatunov, Yu. M.; Sidorov, V.; Силагадзе, З. К.; Valishev, Alexander; Vasiljev, A. V.

doi:10.1063/1.1799678

Cited by 11 publications

(23 citation statements)

References 8 publications

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“…The BESIII Collaboration has recently published the Born cross section spectrum [23] for the e + e − → π + π − π 0 annihilation over the 0.7 ÷ 3.0 GeV energy range collected in the ISR mode. This new data sample comes complementing the spectra collected at the VEPP-2M Collider by CMD2 [61,42,62,63] and SND [64,65] covering the ω and φ peak regions. Besides, the only data on the 3π cross section stretching over the intermediate region was collected much earlier [66] by the former Neutral Dectector (ND).…”

Section: Update Of the 3π Annihilation Channelmentioning

confidence: 95%

“…as single representative of the 3π annihilation channel) and conclude about its consistency with the already analyzed data samples covering the other annihilation channels, namely ππ, (π 0 /η)γ and both KK modes. A second step is devoted to consistency studies between the BESIII spectrum and those previously collected in the same 3π channel by the ND [66], CMD2 [61,42,62] and SND [64,65] detectors.…”

Section: Update Of the 3π Annihilation Channelmentioning

confidence: 99%

“…In the ω region, at least, the normalized residual distribution is clearly energy dependent. The normalized (pseudo-)residuals of the unfitted data samples displayed 26 , namely those from [41,64] in the ω region and from [61,65] in the φ region, likewise corrected for the normalization uncertainty, are, instead, satisfactory 27 , despite being unfitted. The fit process allows to compute the (global) χ 2 distance of the NSK samples to the (BESIII) fit function and returns χ 2 /N = 180/158, a reasonable value for unfitted data.…”

Section: The Besiii 3π Data Sample In Isolation Within Ebhlsmentioning

confidence: 99%

“…A specific analysis for the process e + e − → π + π − may also be found in [124,125]. The leading effect is due to initial state radiation, where the observed cross-section is given by a convolution 65 :…”

Section: Energy Shift Of Resonances and Secondary Isr Photonsmentioning

confidence: 99%

“…(151) 64 For a discussion of the radiative correction tools see [118,119]. 65 Here one only considers the ISR part at order O(α) which yields the main shift between the observed and the physical peak cross-sections. For a more complete discussion of photon radiation effects see e.g.…”

Section: Energy Shift Of Resonances and Secondary Isr Photonsmentioning

confidence: 99%

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BHLS$_2$ Upgrade : $τ$ spectra, muon HVP and the [$π^0,~η,~η^\prime$] System

Benayoun,

DelBuono,

Jegerlehner

2021

Preprint

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The generic Hidden Local Symmetry (HLS) model has recently given rise to its BHLS 2 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 τ dipion spectra, especially the Belle one, is not fully satisfactory whereas the simultaneous dealing with its annihilation sector (e + e − → π + π − /π + π − π 0 /π 0 γ/ηγ/K + K − /K L K S ) is optimum. We show that this issue is solved by means of an additional breaking term which also allows to consistently include the mixing properties of the [π 0 , η, η ′ ] system within this extended BHLS 2 (EBHLS 2 ) scope. This mechanism, an extension of the usual 't Hooft determinant term, only affects the kinetic energy part of the BHLS 2 Lagrangian. One thus obtains a fair account for the τ 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 CVC in the τ lepton decay; this evidence is enforced by imposing the conditions < 0|J q µ |[q ′ q ′ ](p) >= ip µ f q δ qq ′ , {[qq], q = u, d, s} on EBHLS 2 axial current matrix elements. EBHLS 2 is found to recover the usual (completed) formulae for the [π 0 , η, η ′ ] mixing parameters and the global fits return mixing parameter values in agreement with expectations and better uncertainties. Updating the muon HVP, one also argues that the strong tension between the KLOE and BaBar pion form factors imposes to provide two solutions : a HV P −LO µ (KLOE) = 687.31 ± 2.93 and a HV P −LO µ (BaBar) = 692.36 ± 2.95, in units of 10 −10 , rather than some combination of these. Taking into account common systematics, their differences with the experimental BNL-FNAL average value exhibit significances > 5.4σ (KLOE) and > 4.1σ (BaBar) with fit probabilities favoring the former.

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Section: Update Of the 3π Annihilation Channelmentioning

confidence: 95%

Section: Update Of the 3π Annihilation Channelmentioning

confidence: 99%

Section: The Besiii 3π Data Sample In Isolation Within Ebhlsmentioning

confidence: 99%

Section: Energy Shift Of Resonances and Secondary Isr Photonsmentioning

confidence: 99%

Section: Energy Shift Of Resonances and Secondary Isr Photonsmentioning

confidence: 99%

See 3 more Smart Citations

BHLS$_2$ Upgrade : $τ$ spectra, muon HVP and the [$π^0,~η,~η^\prime$] System

Benayoun,

DelBuono,

Jegerlehner

2021

Preprint

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LHC lifetime frontier and visible decay searches in composite asymmetric dark matter models

Kamada

Kuwahara

2022

J. High Energ. Phys.

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The LHC lifetime frontier will probe dark sector in near future, and the visible decay searches at fixed-target experiments have been exploring dark sector. Composite asymmetric dark matter with dark photon portal is a promising framework explaining the coincidence problem between dark matter and visible matter. Dark strong dynamics provides rich structure in the dark sector: the lightest dark nucleon is the dark matter, while strong annihilation into dark pions depletes the symmetric components of the dark matter. Dark photons alleviate cosmological problems. Meanwhile, dark photons make dark hadrons long-lived in terrestrial experiments. Moreover, the dark hadrons are produced through the very same dark photon. In this study, we discuss the visible decay searches for composite asymmetric dark matter models. For a few GeV dark nucleons, the LHC lifetime frontier, MATHUSLA and FASER, has a potential to discover their decay when kinetic mixing angle of dark photon is ϵ ≳ 10−4. On the other hand, fixed-target experiments, in particular SeaQuest, will have a great sensitivity to dark pions with a mass below GeV and with kinetic mixing ϵ ≳ 10−4 in addition to the LHC lifetime frontier. These projected sensitivities to dark hadrons in dark photon parameter space are comparable with the future sensitivities of dark photon searches, such as Belle-II and LHCb.

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Two body final states production in electron-positron annihilation and their contributions to (g − 2)μ

Wang

Fang

Dai

2023

J. High Energ. Phys.

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In this paper, we study the processes of e+e− annihilation into two body final states, either two pseudoscalar mesons or one meson with a photon. The hadronic vacuum polarization form factors are calculated within the framework of resonance chiral theory in the energy region of E ≲ 2 GeV, with final state interactions taken into account. A joint analysis on the processes of e+e−→ π+π−, K+K−, $$ {K}_L^0{K}_S^0 $$ K L 0 K S 0 , π0γ, and ηγ has been performed, and the latest experimental data are included. Based on the vacuum polarization form factors of these processes, we estimate their contributions to the lowest order of anomalous magnetic moment of the muon, (g – 2)μ. Combined with other contributions from hadronic vacuum polarization and other interactions from the standard model, the discrepancy between theoretical prediction and experimental measurement is ∆aμ = (24.1 ± 5.4) × 10−10, i.e., 4.5σ.

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Experimental study of the e+e− → π+π−π0 reaction by SND detector in the energy range s = 0.42 – 1.38 GeV

Cited by 11 publications

References 8 publications

BHLS$_2$ Upgrade : $τ$ spectra, muon HVP and the [$π^0,~η,~η^\prime$] System

BHLS$_2$ Upgrade : $τ$ spectra, muon HVP and the [$π^0,~η,~η^\prime$] System

LHC lifetime frontier and visible decay searches in composite asymmetric dark matter models

Two body final states production in electron-positron annihilation and their contributions to (g − 2)μ

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