We have measured the ratio cr (e(+)e(-) -> pi(+)pi(-)gamma)/sigma(e(+)e(-) -> mu(+)mu(-)gamma), with the KLOE detector at DA Phi NE for a total integrated luminosity of similar to 240 pb(-1). ...From this ratio we obtain the cross section sigma (e(+)e(-) -> pi(+)pi(-)gamma). From the cross section we determine the pion form factor vertical bar F-pi vertical bar(2) and the two-pion contribution to the muon anomaly a(mu) for 0.592< M-pi pi < 0.975 GeV, Delta(pi pi) a(mu) = (385.1 +/- 1.1(stat) +/- 2.7(sys+theo)) x 10(-10). This result confirms the current discrepancy between the Standard Model calculation and the experimental measurement of the muon anomaly. (c) 2013 Elsevier B.V. All rights reserved.
We have measured the ratio σ(e+e−→π+π−γ)/σ(e+e−→μ+μ−γ), with the KLOE detector at DAΦNE for a total integrated luminosity of ∼240 pb−1. From this ratio we obtain the cross section σ(e+e−→π+π−). From ...the cross section we determine the pion form factor |Fπ|2 and the two-pion contribution to the muon anomaly aμ for 0.592<Mππ<0.975 GeV, Δππaμ=(385.1±1.1stat±2.7sys+theo)×10−10. This result confirms the current discrepancy between the Standard Model calculation and the experimental measurement of the muon anomaly.
Taking advantage of both the low-emittance proton beam of the cooler synchrotron COSY and the high momentum precision of the COSY-11 detector system, the mass distribution of the {eta}{sup '} meson ...was measured with a resolution of 0.33 MeV/c{sup 2} (FWHM), improving the experimental mass resolution by almost an order of magnitude with respect to previous results. Based on the sample of more than 2300 reconstructed pp{yields}pp{eta}{sup '} events, the total width of the {eta}{sup '} meson was determined to be {Gamma}{sub {eta}}{sup '}=0.226{+-}0.017(stat){+-}0.014(syst) MeV/c{sup 2}.
We report the first observation of the rare eta--e super(+)e super(-)e super(+)e super(-)( gamma ) decay based on 1.7 fb super(-1) collected by the KLOE experiment at the DAPhiNE phi-factory. The ...selection of the e super(+)e super(-)e super(+)e super(-) final state is fully inclusive of radiation. We have identified 362+/-29 events resulting in a branching ratio of (2.4+/-0.2stat+bckg+/-0.1syst)x10 super(-5).
Dark Forces at DAΦNE Curciarello, F.
EPJ Web of Conferences,
2015, Volume:
96
Journal Article, Conference Proceeding
Peer reviewed
Open access
The DAΦNE Φ-factory is an ideal place to search for forces beyond the Standard Model. By using the KLOE detector, limits on U-boson coupling ε2 of the order of 10−5 ÷ 10−7 and on the αD × ε2 product ...have been set through the study of the Φ Dalitz decay, Uγ events and the Higgsstrahlung process. An improvement of these limits is expected thanks to the KLOE detector and DAΦNE upgrades of KLOE-2.
Proton-proton and proton-
invariant-mass distributions and the total cross-section for the
pp
pp
reaction have been determined near the threshold at an excess energy of
Q
= 10 MeV. The experiment has ...been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant-mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of
Q
= 15.5 MeV and
Q
= 40 MeV.
Proton-proton and proton-eta invariant-mass distributions and the total cross-section for the pp -> pp eta reaction have been determined near the threshold at an excess energy of Q = 10 MeV. The ...experiment has been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant-mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of Q = 15.5 MeV and Q = 40 MeV.
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