Caterina Bloise

• INFN - Istituto Nazionale di Fisica Nucleare

We present a measurement of the radiative decay $\eta\to\pi^0\gamma\gamma$ using 82 million $\eta$ mesons produced in $e^+e^-\to\phi\to\eta\gamma$ process at the Frascati $\phi$-factory DA$\Phi$NE. From the data analysis $1246\pm133$ signal events are observed. By normalising the signal to the well-known $\eta\to3\pi^0$ decay the branching fraction...

A bstract The ratio $$ \mathcal{R} $$ R = Γ( K S → πeν ) / Γ( K S → π ⁺ π − ) has been measured with a sample of 300 million K S mesons produced in ϕ → K L K S decays recorded by the KLOE experiment at the DAΦNE e ⁺ e − collider. K S → πeν events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements....

Tests of the T, CP and CPT symmetries in the neutral kaon system are performed by the direct comparison of the probabilities of a kaon transition process to its symmetry-conjugate. The exchange of in and out states required for a genuine test involving an anti-unitary transformation implied by time-reversal is implemented exploiting the entanglemen...

The Calorimeter of the Mu2e experiment is a complicated detector made of crystal scintillators with dedicated read-out electronics per crystals. The compactness of the Front-End Units matrix, the complexity of the necessary services, and the limited space available after detector installation in the experimental hall make access, manipulation and m...

The Mu2e calorimeter will employ Readout Units, each made of two Silicon Photomultipliers arrays and two Front End Electronics boards. To calibrate them, we have designed, assembled and put in operation an automated Quality Control (QC) station. Gain, collected charge and photon detection efficiency are evaluated for each unit. In this paper, the Q...

The Mu2e experiment at Fermilab will search for the CLFV neutrino-less coherent conversion of a muon into an electron in the field of an aluminum nucleus. The observation of this process would be the evidence of physics beyond the Standard Model. Mu2e comprises a straw-tracker, an electromagnetic calorimeter and an external veto for cosmic rays. Th...

The Mu2e experiment at Fermilab aims to search for the SM forbidden μ−→e− conversion in Al muonic atoms. The signal signature consists of 104.96 MeV electrons, identified by a straw-tube tracker and a crystal calorimeter, made of two annular disks. In order to calibrate the calorimeter disks with minimum ionizing particles (MIP) before the installa...

The Mu2e calorimeter will employ Readout Units, each made of two Silicon Photomultipliers arrays and two Front End Electronics boards. To calibrate them, we have designed, assembled and put in operation an automated Quality Control (QC) station. Gain, collected charge and photon detection efficiency are evaluated for each unit. In this paper, the Q...

A bstract The quantum interference between the decays of entangled neutral kaons is studied in the process ϕ → K S K L → π ⁺ π − π ⁺ π − , which exhibits the characteristic Einstein-Podolsky-Rosen correlations that prevent both kaons to decay into π ⁺ π − at the same time. This constitutes a very powerful tool for testing at the utmost precision th...

The muon has played a central role in establishing the Standard Model of particle physics, and continues to provide valuable information about the nature of new physics. A new complex at Fermilab, the Advanced Muon Facility, would provide the world's most intense positive and negative muon beams by exploiting the full potential of PIP-II and the Bo...

The quantum interference between the decays of entangled neutral kaons is studied in the process $\phi\rightarrow K_S K_L \rightarrow\pi^+\pi^-\pi^+\pi^-$, which exhibits the characteristic Einstein--Podolsky--Rosen correlations that prevent both kaons to decay into $\pi^+\pi^-$ at the same time. This constitutes a very powerful tool for testing at...

A bstract Based on an integrated luminosity of 1.61 fb − 1 e ⁺ e − collision data collected with the KLOE detector at DAΦNE, the Frascati ϕ -factory, a search for the P - and CP -violating decay η → π ⁺ π − has been performed. Radiative ϕ → ηγ decay is exploited to access the η mesons. No signal is observed in the π ⁺ π − invariant mass spectrum, a...

Based on an integrated luminosity of 1.61 fb−1 e+e− collision data collected with the KLOE detector at DAΦNE, the Frascati ϕ-factory, a search for the P- and CP-violating decay η → π+π− has been performed. Radiative ϕ → ηγ decay is exploited to access the η mesons. No signal is observed in the π+π− invariant mass spectrum, and the upper limit on th...

The Mu2e experiment at Fermilab will search for the charged-lepton flavor violating neutrino-less conversion of a negative muon into an electron in the field of an aluminum nucleus. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter and an external veto for cosmic rays. The calorimeter plays an important role in providing ex...

Based on an integrated luminosity of 1.61 fb$^{-1}$ $e^+e^-$ collision data collected with the KLOE detector at DA$\Phi$NE, the Frascati $\phi$-factory, a search for the $P$- and $CP$-violating decay $\eta\to\pi^{+}\pi^{-}$ has been performed. Radiative $\phi\to\eta\gamma$ decay is exploited to access the $\eta$ mesons. No signal is observed in the...

Based on a sample of 300 million KS mesons produced in ϕ→KLKS decays recorded by the KLOE experiment at the DAΦNE e+e− collider we have measured the branching fraction for the decay KS→πμν. The KS mesons are identified by the interaction of KL mesons in the detector. The KS→πμν decays are selected by a boosted decision tree built with kinematic var...

Based on a sample of 300 million $K_S$ mesons produced in $\phi \to K_L K_S$ decays recorded by the KLOE experiment at the DA$\Phi$NE $e^+e^-$ collider we have measured the branching fraction for the decay $K_S \to \pi \mu \nu$. The $K_S$ mesons are identified by the interaction of $K_L$ mesons in the detector. The $K_S \to \pi \mu \nu$ decays are...

The Mu2e experiment at Fermilab searches for the coherent neutrino-less muon to electron conversion in the Coulomb field of an aluminium nucleus. This charged-lepton flavour violating process is characterised by a distinctive signature of a mono-energetic electron (~105 MeV/c) and its observation will be a clear signature of new physics beyond the...

Using 1.63 fb⁻¹ of integrated luminosity collected by the KLOE experiment about 7 × 10⁴KS → π±e∓ν decays have been reconstructed. The measured value of the charge asymmetry for this decay is AS = (−4.9 ± 5.7stat ± 2.6syst) × 10⁻³, which is almost twice more precise than the previous KLOE result. The combination of these two measurements gives AS =...

We searched for the μ⁺μ⁻ decay of a light vector gauge boson, also known as dark photon, in the e⁺e⁻→μ⁺μ⁻γISR process by means of the Initial State Radiation (ISR) method. We used 1.93 fb⁻¹ of data collected by the KLOE experiment at the DAΦNE ϕ-factory. No structures have been observed over the irreducible μ⁺μ⁻ background. A 90% CL limit on the ra...

We searched for the µ + µ − decay of a light vector gauge boson, also known as dark photon, in the e + e − → µ + µ − γ ISR process by means of the Initial State Radiation (ISR) method. We used 1.93 fb −1 of data collected by the KLOE experiment at the DAΦNE φ-factory. No structures have been observed over the irreducible µ + µ − background. A 90% C...

Using 1.63 fb$^{-1}$ of integrated luminosity collected by the KLOE experiment about $7\times 10^4$ $K_S \rightarrow \pi^{\pm}e^{\mp}\nu$ decays have been reconstructed. The measured value of the charge asymmetry for this decay is $A_S = (-4.9 \pm 5.7_{stat} \pm 2.6_{syst}) \times 10^{-3}$, which is almost twice more precise than the previous KLOE...

A bstract The three precision measurements of the cross section σ ( e ⁺ e ⁻ → π ⁺ π ⁻ γ(γ)) using initial state radiation by the KLOE collaboration provide an important input for the prediction of the hadronic contribution to the anomalous magnetic moment of the muon. These measurements are correlated for both statistical and systematic uncertainti...

We propose an evolution of the Mu2e experiment, called Mu2e-II, that would leverage advances in detector technology and utilize the increased proton intensity provided by the Fermilab PIP-II upgrade to improve the sensitivity for neutrinoless muon-to-electron conversion by one order of magnitude beyond the Mu2e experiment, providing the deepest pro...

We have measured the running of the effective QED coupling constant α(s) in the time-like region 0.6<s<0.975 GeV with the KLOE detector at DAΦNE using the Initial-State Radiation process e+e−→μ+μ−γ. It represents the first measurement of the running of α(s) in this energy region. Our results show a more than 5σ significance of the hadronic contribu...

Using 1.6 fb−1of e+e−→ ϕ → ηγ data collected with the KLOE detector at DAΦNE, the Dalitz plot distribution for the η → π+π−π0decay is studied with the world’s largest sample of ∼ 4.7 · 106events. The Dalitz plot density is parametrized as a polynomial expansion up to cubic terms in the normalized dimensionless variables X and Y. The experiment is s...

A measurement of the vector to pseudoscalar conversion decay ϕ→π0e+e− with the KLOE experiment is presented. A sample of ∼9500 signal events was selected from a data set of 1.7 fb−1 of e+e− collisions at s∼mϕ collected at the DAΦNE e+e− collider. These events were used to perform the first measurement of the transition form factor |Fϕπ0(q2)| and a...

The recent interest in a light gauge boson in the framework of an extra U(1) symmetry motivates searches in the mass range below 1 GeV. We present a search for such a particle, the dark photon, in e+e−→Uγ,U→π+π− based on 28 million e+e−→π+π−γ events collected at DAΦNE by the KLOE experiment. The π+ π− production by initial-state radiation compensat...

The existence of a new force beyond the Standard Model is compelling because it could explain several striking astrophysical observations which fail standard interpretations. We searched for the light vector mediator of this dark force, the U boson, with the KLOE detector at the DAΦNE e + e − collider. Using an integrated luminosity of 1.54 fb −1 ,...

The existence of a new force beyond the Standard Model is compelling because it could explain several striking astrophysical observations which fail standard interpretations. We searched for the light vector mediator of this dark force, the $\mathrm{U}$ boson, with the KLOE detector at the DA$\Phi$NE $\mathrm{e}^{+}\mathrm{e}^{-}$ collider. Using a...

The KLOE-2 experiment at the Frascati Laboratory has recently obtained several results on dark photon searches. We present published analyses and the preliminary results of the study of the final states with e+e-γ, and μ+μ- plus missing energy.

We searched for evidence of a Higgsstrahlung process in a secluded sector, leading to a final state with a dark photon U and a dark Higgs boson h', with the KLOE detector at DAFNE. We investigated the case of h' lighter than U, with U decaying into a muon pair and h' producing a missing energy signature. We found no evidence of the process and set...

In this paper we discuss the recent finalized analyses by the KLOE experiment at DA$\Phi$NE: the CPT and Lorentz invariance test with entangled $K^0 \bar{K}^0$ pairs, and the precision measurement of the branching fraction of the decay ${ K^+} \rightarrow \pi^+\pi^-\pi^+(\gamma)$. We also present the status of an ongoing analysis aiming to precisel...

The KLOE experiment at the Frascati φ-factory recently obtained results on i) CPT and Lorentz invariance tests from the study of quantum interference of the neutral kaon pairs; ii) precision measurement of the branching fraction, BR(K+ → π+π-π+(γ)) = 0.05565 ± 0.00031stat ± 0.00025syst, and iii) on dark photon searches with the analysis of the e+e-...

The muon anomalous magnetic moment is one of the most precisely measured quantities in particle physics and a persistent discrepancy of about 3 σ between standard model (SM) prediction and the experimental measurement has been observed. The leading order contribution is actually the main source of uncertainty in the theoretical evaluation of the mu...

We have studied the vector to pseudoscalar conversion decay phi -> eta e+e-, with eta -> pi0pi0pi0, with the KLOE detector at DAPHNE. The data set of 1.7 fb-1 of e+e- collisions at sqrt(s)~Mphi contains a clear conversion decay signal of ~31,000 events from which we measured a value of BR(phi -> eta e+e-)=(1.075+-0.007+-0.038)x10-4. The same sample...

Measurement of the absolute branching ratio of the K + → π + π − π + (γ) decay with the KLOE detector KLOE/KLOE-2 Collaboration 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 DANE, the Frascati φ-factory....

We have searched for a light vector boson U, the possible carrier of a “dark force”, with the KLOE detector at the DAFNE 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 239.3pb−1, we look for a dimuon mass peak in the reaction e+e−→μ+μ...

We have searched for a light vector boson $U$, the possible carrier of a "dark force", with the KLOE detector at the DA$\Phi$NE $e^+e^-$ collider, motivated by the astrophysical evidence for the presence of "dark matter" in the universe. Using $e^+e^-$ collisions collected for an integrated luminosity of $239.3$~pb$^{-1}$, we look for a dimuon mass...

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 the astrophysi- cal evidence for the presence of “dark matter” in the universe. Using e+e− collisions collected for an integrated luminosity of 239. 3 pb−1, we look for a dimuon mass peak in the reacti...

Neutral kaon pairs produced in phi decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process phi->K_S K_L->pi+pi-pi+pi- based on 1.7 fb-1 of data collected by the KLOE experiment at the Frascati phi-factory DAFNE. The data are used to...

One of the basic motivations of the KLOE and KLOE-2 collaborations is the test of fundamental symmetries and the search for phenomena beyond the Standard Model via the hadronic and leptonic decays of ground-state mesons and via their production in the fusion of virtual gamma quanta exchanged between colliding electrons and positrons. This contribut...

We have carried out a new direct search for the CP violating decay KS -> 3pi0 with 1.7 fb^-1 of e+e- collisions collected by the KLOE detector at the phi-factory DAFNE. We have searched for this decay in a sample of about 5.9 x 10^8 KS KL events tagging the KS by means of the KL interaction in the calorimeter and requiring six prompt photons. With...

We have measured the ratio σ ( e + e − → π + π − γ ) / σ ( e + e − → μ + μ − γ ) , with the KLOE detector at DAΦNE for a total integrated luminosity of ∼ 240 pb − 1 . From this ratio we obtain the cross section σ ( e + e − → π + π − ) . From the cross section we determine the pion form factor | F π | 2 and the two-pion contribution to the muon anom...

We present a new limit on the production of a light dark-force mediator with the KLOE detector at DAΦNE. This boson, called U, has been searched for in the decay ϕ → η U , U → e + e − , analyzing the decay η → π 0 π 0 π 0 in a data sample of 1.7 fb − 1 . No structures are observed in the e + e − invariant mass distribution over the background. This...