The LHC-B experiment is a single arm forward spectrometer optimized to study CP violation in the B system at the LHC. The basic features of the detector and the projected sensitivity of the ...experiment in terms of the measurement of the unitarity angles
α, β and
γ are presented.
We have searched for the C-violating decay η→γγγ in a sample of ∼18 million η mesons produced in φ→ηγ decays, collected with the KLOE detector at the Frascati φ-factory DAΦNE. No signal is observed ...and we obtain the upper limit BR(η→γγγ)⩽1.6×10−5 at 90% CL.
We have measured the ratio
R
S
π
=
Γ(
K
S
→
π
+
π
−(
γ))/
Γ(
K
S
→
π
0
π
0) with the KLOE detector at the DA
ΦNE
e
+
e
− collider. This measurement is fully inclusive with respect to the
π
+
π
−
γ ...final state. The sample of over 10
6 two-pion decays of tagged
K
S
mesons allows a statistical error as low as ∼0.1% to be obtained. The accuracy is limited by systematic uncertainties, which are estimated primarily from data. We find
R
S
π
=2.236±0.003
stat±0.015
syst.
We have measured the cross section σ(e+e−→π+π−γ) at an energy W=mϕ=1.02 GeV with the KLOE detector at the electron–positron collider DAΦNE. From the dependence of the cross section on the invariant ...mass of the two-pion system, we extract σ(e+e−→π+π−) for the mass range 0.35<s<0.95 GeV2. From this result, we calculate the pion form factor and the hadronic contribution to the muon anomaly, aμ.
We have measured the ratio Rϕ=BR(ϕ→η′γ)/BR(ϕ→ηγ) by looking for the radiative decays ϕ→η′γ and ϕ→ηγ into the final states π+π−7γ and 7γ, respectively, in a sample of ∼1.4×109ϕ mesons produced at the ...Frascati ϕ factory. We obtain Rϕ=(4.77±0.09stat±0.19syst)×10−3, from which we derive BR(ϕ→η′γ)=(6.20±0.11stat±0.25syst)×10−5. Assuming the η′ has zero gluonium content, we extract the pseudoscalar mixing angle in the quark-flavor basis, φP=(41.4±0.3stat±0.7syst±0.6th)°. Combining the value of Rϕ with other constraints, we estimate the fractional gluonium content of the η′ to be Z2=0.14±0.04 and the mixing angle to be φP=(39.7±0.7)°.
AbstractWe have measured the cross section σ(e+e–→π+π–γ) with the KLOE detector at DAΦNE, at an energy W=Mφ=1.02 GeV. From the dependence of the cross section on ...\(m(\pi^+\pi^{-})=\sqrt{W^2-2WE_\gamma}\), where Eγ is the energy of the photon radiated from the initial state, we extract σ(e+e–→π+π–) for the mass range 0.35<m2(π+π–)<0.95 GeV2. From our result we extract the pion form factor and the hadronic contribution to the muon anomaly, aμ.
Among some 400 million KSKL pairs produced in e+e− annihilations at DAΦNE, ∼6500 each of KS→π+e−ν¯ and KS→π−e+ν decays have been observed with the KLOE detector. From these, the ratio ...Γ(KS→πeν)/Γ(KS→π+π−)=(10.19±0.13)×10−4 is obtained, improving the accuracy on BR(KS→πeν) by a factor of four and providing the most precise test of the ΔS=ΔQ rule. From the partial width Γ(KS→πeν), a value for f+K0(0)×Vus is obtained that is in agreement with unitarity of the quark-mixing matrix. The lepton charge asymmetry AS=(1.5±9.6stat±2.9syst)×10−3 is compatible with the requirements of CPT invariance. The form-factor slope agrees with recent results from semileptonic KL and K+ decays. These are the first measurements of the charge asymmetry and form-factor slope for semileptonic KS decays.
Readout optimization for the KLOE QCAL tile calorimeters Adinolfi, M; Carboni, G; Conetti, S ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
409, Številka:
1-3
Journal Article
Recenzirano
A tile calorimeter (QCAL) has been designed for the KLOE experiment. Optimization studies have been conducted by testing the coupling between different types of scintillators and WLS fibers. Results ...on light yield, attenuation length of fibers and time resolution are presented.
The LHC-B collaboration is in the process of designing a forward spectrometer, optimized for the detection of Beauty particles, to run at the LHC collider. One very crucial aspect of the design is ...the global multi-level trigger scheme, required to reduce the event rate from around 40 MHz (the LHC beam crossing rate) down to the foreseen recording rate of a few KHz. At Level-1, it is currently envisaged to implement high p sub(t) electron, muon and hadron triggers. The requirements for Level 1 are to accept, with zero deadtime, events at the 40 MHz rate, and to provide an answer within a couple of microseconds. The rejection rate for minimum bias events expected of Level 1 is of the order of one hundred. The 3D-Flow system can implement the above requirements in real time with zero dead-time giving the user the flexibility to change at later time the algorithm, including more signals in the decision process, and to upgrade incrementally the system with changes in granularity and/or segmentation.
We present a measurement of the K–π vector current form-factor parameters for the decay KL→π±e∓ν. We use 328 pb−1 of data collected in 2001 and 2002, corresponding to ∼2 million Ke3 events. ...Measurements of semileptonic form factors provide information about the dynamics of the strong interaction and are necessary for evaluation of the phase-space integral IKe needed to measure the CKM matrix element |Vus| for KL→π±e∓ν decays. Our result is λ+=(28.6±0.5±0.4)×10−3 for a linear fit, and λ+′=(25.5±1.5±1.0)×10−3, λ+″=(1.4±0.7±0.4)×10−3 for a quadratic fit.
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