A simulation code to assist designing space missions of the Airwatch type

The design of an Airwatch type space mission can greatly benefit from a flexible simulation code for establishing the values of the main parameters of the experiment. We present here a code written for this purpose. The cosmic ray primary spectrum at very high energies, the atmosphere modelling, the fluorescence yield, the photon propagation and the detector response are taken into account in order to optimize the fundamental design parameters of the experiment, namely orbit height, field of view, mirror radius, number of pixels of the focal plane, threshold of photo-detection. The optimization criterion will be to maximize counting rates versus mission cost, which imposes limits both on weight and power consumption. Preliminary results on signals with changing energy and zenith angle of incident particles are shown

Measurement of the absolute branching ratio of the K+→π+π−π+(γ) decay with the KLOE detector

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

Search for light vector boson production in e+e−→μ+μ−γ interactions with the KLOE experiment

We have searched for a light vector boson U , the possible carrier of a “dark force”, with the KLOE detector at the DAΦNE e+e− collider, motivated by astrophysical evidence for the presence of dark matter in the Universe. Using e+e− collisions collected with an integrated luminosity of 239.3 pb −1 , we look for a dimuon mass peak in the reaction e+e−→μ+μ−γ , corresponding to the decay U→μ+μ− . We find no evidence for a U vector boson signal. We set a 90% CL upper limit for the mixing parameter squared between the photon and the U boson of 1.6×10−5 to 8.6×10−7 for the mass region 520<mU<980 MeV

Study of the Dalitz decay ϕ→ηe+e− with the KLOE detector

We have studied the vector to pseudoscalar conversion decay ϕ→ηe+e− , with η→π0π0π0 , with the KLOE detector at DA Φ NE. 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

Searching for Neutrinoless Double-Beta Decay of 130Te with CUORE

Neutrinoless double-beta (0 <math id="M1" xmlns="http://www.w3.org/1998/Math/MathML"><mi>ν</mi><mi>β</mi><mi>β</mi></math> ) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0 <math id="M2" xmlns="http://www.w3.org/1998/Math/MathML"><mi>ν</mi><mi>β</mi><mi>β</mi></math> decay of 130Te using an array of 988 TeO2 crystal bolometers operated at 10 mK. The detector will contain 206 kg of 130Te and have an average energy resolution of 5 keV; the projected 0 <math id="M3" xmlns="http://www.w3.org/1998/Math/MathML"><mi>ν</mi><mi>β</mi><mi>β</mi></math> decay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1 <math id="M4" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>σ</mi></mrow></math> (9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach

Limits on muon-neutrino to tau-neutrino oscillations induced by a sterile neutrino state obtained by OPERA at the CNGS beam

The OPERA experiment, exposed to the CERN to Gran Sasso ν μ beam, collected data from 2008 to 2012. Four oscillated ν τ Charged Current interaction candidates have been detected in appearance mode, which are consistent with ν μ → ν τ oscillations at the atmospheric Δ m 2 within the “standard” three-neutrino framework. In this paper, the OPERA ν τ appearance results are used to derive limits on the mixing parameters of a massive sterile neutrino

Measurement of the TeV atmospheric muon charge ratio with the complete OPERA data set

The OPERA detector, designed to search for νμ→ντ oscillations in the CNGS beam, is located in the underground Gran Sasso laboratory, a privileged location to study TeV-scale cosmic rays. For the analysis here presented, the detector was used to measure the atmospheric muon charge ratio in the TeV region. OPERA collected charge-separated cosmic ray data between 2008 and 2012. More than 3 million atmospheric muon events were detected and reconstructed, among which about 110000 multiple muon bundles. The charge ratio Rμ≡Nμ+/Nμ- was measured separately for single and for multiple muon events. The analysis exploited the inversion of the magnet polarity which was performed on purpose during the 2012 Run. The combination of the two data sets with opposite magnet polarities allowed minimizing systematic uncertainties and reaching an accurate determination of the muon charge ratio. Data were fitted to obtain relevant parameters on the composition of primary cosmic rays and the associated kaon production in the forward fragmentation region. In the surface energy range 1–20 TeV investigated by OPERA, Rμ is well described by a parametric model including only pion and kaon contributions to the muon flux, showing no significant contribution of the prompt component. The energy independence supports the validity of Feynman scaling in the fragmentation region up to 200  TeV/nucleon primary energy

Observation of tau neutrino appearance in the CNGS beam with the OPERA experiment

The OPERA experiment is searching for oscillations in appearance mode, i.e., via the direct detection of leptons in charged-current interactions. The evidence of appearance has been previously reported with three candidate events using a sub-sample of data from the 2008–2012 runs. We report here a fourth candidate event, with the decaying into a hadron, found after adding the 2012 run events without any muon in the final state to the data sample. Given the number of analyzed events and the low background, oscillations are established with a significance of 4.2

Initial performance of the CUORE-0 experiment

CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of 130Te . We present the first data analysis with 7.1kg·y of total TeO2 exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to 2.57MeV ) and in the α background-dominated region (2.70 to 3.90MeV ) have been measured to be 0.071±0.011 and 0.019±0.002counts/(keV·kg·y) , respectively. The latter result represents a factor of 6 improvement from a predecessor experiment, Cuoricino. The results verify our understanding of the background sources in CUORE-0, which is the basis of extrapolations to the full CUORE detector. The obtained energy resolution (full width at half maximum) in the region of interest is 5.7keV . Based on the measured background rate and energy resolution in the region of interest, CUORE-0 half-life sensitivity is expected to surpass the observed lower bound of Cuoricino with one year of live time