Rare φ decays Di Donato, Camilla
The European physical journal. C, Particles and fields,
7/2004, Volume:
33, Issue:
S1
Journal Article
Peer reviewed
Open access
AbstractThe Kloe experiment has collected an integrated luminosity ~ 500 pb–1 up to now, which means ~ 1.65×109 φ decays. The huge amount of events allowed us to measure rare φ decays. We measured ...the radiative decays of the φ meson into π0, η and η′(958). These measurements are relevant to assess the mixing in the pseudoscalar nonet as well as to evaluate the gluon content in the η′(958). Moreover also the radiative decays into π0π0γ and ηπ0γ have been measured. These decays are dominated by the final states f0(980) and a0(980). The measurement of the branching ratios and of the π0π0 or ηπ0 invariant mass spectrum helps to understand the controversial nature of the above scalar mesons.PACS: PACS-key e+e– collisions – PACS-key φ radiative decays
We have measured the ratio R=Γ(KL→γγ)/Γ(KL→π0π0π0) using the KLOE detector. From a sample of ∼109φ-mesons produced at DAΦNE, the Frascati φ-factory, we select ∼1.6×108KL-mesons tagged by observing ...KS→π+π− following the reaction e+e−→φ→KLKS. From this sample we select 27,375 KL→γγ events and obtain R=(2.79±0.02stat±0.02syst)×10−3. Using the world average value for BR(KL→π0π0π0), we obtain BR(KL→γγ)=(5.89±0.07±0.08)×10−4 where the second error is due to the uncertainty on the π0π0π0 branching fraction.
The KLOE computing environment Moulson, M.
IEEE transactions on nuclear science,
06/2004, Volume:
51, Issue:
3
Journal Article
Peer reviewed
The KLOE experiment at DA/spl Phi/NE is largely devoted to the study of discrete symmetries in the K/sub S/K/sub L/ system. During 2001-2002, KLOE collected 1.4/spl times/10/sup 9//spl phi/ decays, ...for a total data volume of nearly 200 TB. We describe the KLOE computing environment, outlining our solutions to issues of calibration, reconstruction, data reduction, and data access for analysis. We discuss the performance of the system, with particular emphasis on the data-processing and transfer rates, and also describe the generation of large Monte Carlo samples. The KLOE computing environment has been demonstrated to be flexible and scalable in the presence of rapidly evolving data taking conditions.
We present a study of the reaction e+e−→π+π−π0 at the φ peak, W=M(φ)=1019.4 MeV, observed with the KLOE detector at DAΦNE. The reaction is dominated by φ production and decay, e+e−→φ→π+π−π0. From a ...fit to the Dalitz plot density distribution we obtain the ρ-meson parameters for its three charge states. We also find the relative amplitudes for φ→ρπ and φ→π+π−π0 and the cross section for e+e−→ωπ0 with ω→π+π−.
We report the results on the radiatve decays θ → η′γ,
θ →
π
0
π
0
γ and
θ →
ηπ
0
γ obtained with the KLOE detector at the DAΦNE θ-factory, using a sample of ∼ 16 pb
−1. The value of the branching ...ratio for the θ → η′γ decay is related to the
s
s
and gluon content of the η′. A fit to the two-pseudoscalar invariant mass for the
π
0
π
0
γ and
ηπ
0
γ final states gives the contribution of the direct terms
θ →
f
0
γ,
σ →
σγ and
θ →
a
0
γ, allowing us to investigate the nature of these light scalar mesons.
We have measured the branching ratio BR(
φ→
π
0
π
0
γ) with the KLOE detector using a sample of ∼5×10
7
φ decays.
φ mesons are produced at DA
ΦNE, the Frascati
φ-factory. We find BR(
φ→
π
0
π
0
...γ)=(1.09±0.03
stat±0.05
syst)×10
−4. We fit the two-pion mass spectrum to models to disentangle contributions from various sources.
In a sample of 5.3×10
7,
φ-decays observed with the KLOE detector at the Frascati
φ-factory DA
ΦNE we find 605
ηπ
0
γ events with
η→
γγ and 197
ηπ
0
γ events with
η→
π
+
π
−
π
0. The decay
ηπ
0
γ is ...dominated by the process
φ→
a
0
γ. From a fit to the
ηπ
0 mass spectrum we find BR(
φ→
a
0(980)
γ)=(7.4±0.7)×10
−5.
We present a measurement of the branching ratio
BR(K
S→π
±e
∓
ν
̄
(ν))
performed using the KLOE detector.
K
S
-mesons are produced in the reaction
e
+
e
−→
φ→
K
S
K
L
at the DA
ΦNE collider. In a ...sample of ∼5×10
6
K
S
-tagged events we find 624±30 semileptonic
K
S
decays. Normalizing to the
K
S
→
π
+
π
− count in the same data sample, we obtain BR(
K
S
→
πeν)=(6.91±0.37)×10
−4, in agreement with the Standard Model expectation.
PDF
