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.
Using a sample of over 400 million φ→KSKL decays produced during the years 2001 and 2002 at the DAΦNE e+e- collider, the ratio RSπ=Γ(KS→π+π-(γ))/Γ(KS→π0π0) has been measured with the KLOE detector. ...The result is RSπ=2.2555±0.0012stat±0.0021corr-stat±0.0050syst, which is in good agreement with the previously published result based on the KLOE data sample from the year 2000. The average of the KLOE results is RSπ=2.2549±0.0054, reducing the total error by a factor of three, to 0.25%.
We present a measurement of the branching ratio of the CP violating decay KL→π+π− performed by the KLOE experiment at the ϕ factory DAΦNE. We use 328 pb−1 of data collected in 2001 and 2002, ...corresponding to ∼150 million tagged KL mesons. We find BR(KL→π+π−)=(1.963±0.012stat.±0.017syst.)×10−3. This branching ratio measurement is fully inclusive of final-state radiation. Using the above result, we determine the modulus of the amplitude ratio |η+−| to be (2.219±0.013)×10−3 and |ϵ| to be (2.216±0.013)×10−3.
The potential of DA
ΦNE to explore direct radiative decay
φ→
π
+
π
−
γ is studied in detail. Predictions of different theoretical models for this decay are compared. We find that it should be ...possible to discriminate between these models at DA
ΦNE in one year, even assuming a relatively low luminosity
L=10
31
cm
−2
s
−1
. The influence of the decay
φ→
π
+
π
−
γ on the measurement of total cross section
σ(
e
+
e
−→hadrons) by tagging a photon in the reaction
e
+
e
−→
π
+
π
−
γ is also discussed.
We have measured the radiative decays
φ→
ηγ,
φ→
η′
γ selecting
π
+
π
−
γγγ final state in a sample of ∼5×10
7
φ-mesons produced at the Frascati
φ-factory DA
ΦNE. We obtain
Γ(
φ→
η′
γ)/
Γ(
φ→
...ηγ)=(4.70±0.47±0.31)×10
−3. From this result we derive new accurate values for the branching ratio BR(
φ→
η′
γ)=(6.10±0.61±0.43)×10
−5 and the mixing angle of pseudoscalar mesons in the flavour basis
ϕ
P
=(41.8
+1.9
−1.6)°.
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