The ratio Rη=Γ(η→π+π−γ)/Γ(η→π+π−π0) has been measured by analysing 22 million ϕ→ηγ decays collected by the KLOE experiment at DAΦNE, corresponding to an integrated luminosity of 558 pb−1. The η→π+π−γ ...proceeds both via the ρ resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, Rη=0.1856±0.0005stat±0.0028syst, points out a sizable contribution of the direct term to the total width. The di-pion invariant mass for the η→π+π−γ decay could be described in a model-independent approach in terms of a single free parameter, α. The determined value of the parameter α is α=(1.32±0.08stat−0.09syst+0.10±0.02theo) GeV−2.
We have studied the vector to pseudoscalar conversion decay ϕ→ηe+e−, with η→π0π0π0, with the KLOE detector at DAΦNE. The data set of 1.7 fb−1 of e+e− collisions at s∼Mϕ contains a clear conversion ...decay signal of ∼31,000 events from which we measured a value of BR(ϕ→ηe+e−)=(1.075±0.007±0.038)×10−4. The same sample is used to determine the transition form factor by a fit to the e+e− invariant mass spectrum, obtaining bϕη=(1.28±0.10−0.08+0.09) GeV−2, that improves by a factor of five the precision of the previous measurement and is in good agreement with VMD expectations.
We present a precise measurement of the ratio RK=Γ(K→eν(γ))/Γ(K→μν(γ)) and a study of the radiative process K→eνγ, performed with the KLOE detector. The results are based on data collected at the ...Frascati e+e− collider DAΦNE for an integrated luminosity of 2.2 fb−1. We find RK=(2.493±0.025stat±0.019syst)×10−5, in agreement with the Standard Model expectation. This result is used to improve constraints on parameters of the Minimal Supersymmetric Standard Model with lepton flavor violation. We also measured the differential decay rate dΓ(K→eνγ)/dEγ for photon energies 10<Eγ< 250 MeV. Results are compared with predictions from theory.
The absolute branching ratio of the K+→π+π−π+(γ) decay, inclusive of final-state radiation, has been measured using ∼17 million tagged K+ mesons collected with the KLOE detector at DAΦNE, the ...Frascati ϕ-factory. The result is:BR(K+→π+π−π+(γ))=0.05565±0.00031stat±0.00025syst a factor ≃ 5 more precise with respect to the previous result. This work completes the program of precision measurements of the dominant kaon branching ratios at KLOE.
Data handling, reconstruction, and simulation for the KLOE experiment Ambrosino, F.; Antonelli, A.; Antonelli, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Volume:
534, Issue:
3
Journal Article
Peer reviewed
Open access
The broad physics program of the KLOE experiment is based on the high event rate at the Frascati φ
factory, and calls for an up-to-date system for data acquisition and processing. In this review of ...the KLOE offline environment, the architecture of the data-processing system and the programs developed for data reconstruction and Monte Carlo simulation are described, as well as the various procedures used for data handling and transfer between the different components of the system.
Using a large sample of pure, slow, short lived K0 mesons collected with KLOE detector at DAΦNE, we have measured the KS lifetime. From a fit to the proper time distribution we find ...τ(KS)=(89.562±0.029stat±0.043syst) ps. This is the most precise measurement to date of the short lived K0 meson lifetime, in good agreement with the world average derived from previous measurements. We observe no dependence of the lifetime on the direction of the KS in galactic coordinates.
We describe the method of measuring the integrated luminosity of the e+e- collider DAΦNE, the Frascati φ-factory. The measurement is done with the KLOE detector selecting large angle Bhabha ...scattering events and normalizing them to the effective cross section. The e+e-→e+e-(γ) cross section is calculated using different event generators which account for the \(\mathcal{O}(\alpha)\) radiative initial and final state corrections, and the φ resonance contribution. The accuracy of the measurement is 0.6%, where 0.3% comes from systematic errors related to the event counting and 0.5% from theoretical evaluations of the cross section.
The trigger system of the KLOE experiment Adinolfi, M; Ambrosino, F; Antonelli, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2002, Volume:
492, Issue:
1
Journal Article
Peer reviewed
Open access
We present the design of the trigger system for the KLOE experiment at the Frascati
φ-factory DAΦNE. The detector consists of a large-volume drift chamber and a calorimeter both immersed in a
0.52
T
...solenoidal field. The trigger, structured with a first- and a second-decision level, is based on the multiplicity of energy deposits in the calorimeter and of hits in the drift chamber. The selection criteria are described and the efficiency for detecting
φ decays is evaluated using data.
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