V. Bocci

The KLOE electromagnetic calorimeter

Abstract The KLOE calorimeter is a fine lead-scintillating fiber sampling calorimeter. We describe in the following the calibration procedures and the calorimeter performances obtained after 3 years of data taking. We get an energy resolution for electromagnetic showers of 5.4%/ E (GeV) and a time resolution of 56 ps/ E (GeV) . We also present a measurement of efficiency for low-energy photons.

Measurement of the pseudoscalar mixing angle and eta-prime gluonium content with KLOE detector

Abstract We have measured the ratio R ϕ = BR ( ϕ → η ′ γ ) / BR ( ϕ → η γ ) by looking for the radiative decays ϕ → η ′ γ and ϕ → η γ into the final states π + π − 7 γ and 7γ, respectively, in a sample of ∼ 1.4 × 10 9 ϕ mesons produced at the Frascati ϕ factory. We obtain R ϕ = ( 4.77 ± 0.09 stat ± 0.19 syst ) × 10 −3 , from which we derive BR ( ϕ → η ′ γ ) = ( 6.20 ± 0.11 stat ± 0.25 syst ) × 10 −5 . Assuming the η ′ has zero gluonium content, we extract the pseudoscalar mixing angle in the quark-flavor basis, φ P = ( 41.4 ± 0.3 stat ± 0.7 syst ± 0.6 th ) ° . Combining the value of R ϕ with other constraints, we estimate the fractional gluonium content of the η ′ to be Z 2 = 0.14 ± 0.04 and the mixing angle to be φ P = ( 39.7 ± 0.7 ) ° .

Measurement of the DAΦNE luminosity with the KLOE detector using large angle Bhabha scattering

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

Study of the decay φ !f 0 (980)γ ! π + π γ with the KLOE detector

\mathcal{O}(\alpha)

The coincidence matrix ASIC of the level-1 muon barrel trigger of the ATLAS experiment

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.

Study of the branching ratio and charge asymmetry for the decay KS → πeν with the KLOE detector

We measured, with the KLOE detector, the spectrum of pi+pi- invariant mass in a sample of 6.7 x 10^5 e+e- -->pi+pi-g events with the photon at large polar angle (theta_g>45^o) at a centre of mass energy sqrt(s) around the phi mass. We observe a clear contribution from the intermediate process phi -->f0(980)g. A sizeable effect is also observed in the distribution of the forward-backeard asymmetry. We use different theoretical models to fit the spectrum and we determine the f_0 mass and coupling constants to the phi, to pi+pi- and to KK.

Dalitz plot analysis of e+e-→π0π0γ events at \sqrt{s} \simeq{M}_{\phi} with the KLOE detector

The ATLAS barrel level-1 muon trigger processes hit information from the resistive plate chamber detector, identifying candidate muon tracks and assigning them to a programmable p/sub T/ range and to a unique bunch crossing number. The trigger system uses up to seven detector layers and seeks hit patterns compatible with muon tracks in the bending and nonbending projection. The basic principle of the algorithm is to demand a coincidence of hits in the different chamber layers within a path. The width of the road is related to the p/sub T/ threshold to be applied. The system is split into an on-detector and an off-detector part. The on-detector electronics reduces the information from about 350 k channels to about 400 32-bit data words sent via optical fiber to the so-called sector logic (SL). The off-detector SL electronics collects muon candidates and associates them to detector regions-of-interest of /spl Delta//spl eta//spl times//spl Delta//spl Phi/ of 0.1/spl times/0.1. The core of the on-detector electronics is the coincidence matrix ASIC (CMA), which fulfils both the trigger algorithm and the readout of the RPC detector. Each CMA is able to process and readout 192 RPC strips from as many as four detector layers. In order to keep the full level-1 system latency below 2 /spl mu/s, the CMA has to find candidate muon tracks with a latency of a few 25 ns bunch crossing periods. The readout part of the CMA is able to time tag incoming RPC hits with a time interpolator running at the trigger pipeline frequency of 320 MHz and to send the data to the readout system via a serial link. The design of the trigger system and the performances of the ASIC, based on a CMOS 0.18 /spl mu/m technology, are presented.

Measurement of the KL meson lifetime with the KLOE detector

Among some 400 million KsKl pairs produced in e+e- annihilations at DAFNE, about 6500 each of Ks->pi+e-nubar and Ks->pi-e+nu decays have been observed with the KLOE detector. From these, the ratio G(Ks->pienu)/G(Ks->p+p-(g))=(10.19+-0.13)10-4 is obtained, improving the accuracy on BR(Ks->pienu) by a factor of four and providing the most precise test of the DeltaS=DeltaQ rule. From the partial width Gamma(Ks->pienu), a value for f+(K0)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.

Toward Radioguided Surgery with β− Decays: Uptake of a Somatostatin Analogue, DOTATOC, in Meningioma and High-Grade Glioma

We have studied the Dalitz plot of the e(+)e(-) -> pi(0)pi(0)gamma events (N(pi)0(pi)0 gamma similar to 65 000) collected at root s similar or equal to M-phi with the KLOE detector. In the dipion invariant mass (M-pi pi) region below 700MeV, the process under study is dominated by the non- resonant process e(+)e(-) -> omega pi(0) with omega -> pi(0)gamma whereas, for higher M-pi pi values, the radiative phi decay to the f(0)(980) is the dominant mechanism. Different theoretical models are used to fit the Dalitz plot, taking also into account a possible contribution of the sigma(600). For each model, we extract the f(0)(980) mass and its coupling to pi pi, K (K) over bar and to the phi.

A direct search for the C P-violating decay K-S -> 3 pi(0) with the KLOE detector at DA Phi NE

We present a measurement of the KL lifetime using the KLOE detector. From a sample of 4 x 10^8 KS KL pairs following the reaction e+ e- ->phi ->KS KL we select 15 x 10^6 KL ->p0 p0 p0 decays tagged by KS ->pi+ pi- events. From a fit of the proper time distribution we find tau_L = (50.92 +- 0.17{stat} +- 0.25{syst})