| 21. |
- Babusci, D., et al.
(författare)
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Precision tests of quantum mechanics and CPT symmetry with entangled neutral kaons at KLOE
- 2022
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479.
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Tidskriftsartikel (refereegranskat)abstract
- The quantum interference between the decays of entangled neutral kaons is studied in the process phi -> KSKL -> 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 the utmost precision the quantum coherence of the entangled kaon pair state, and to search for tiny decoherence and CPT violation effects, which may be justified in a quantum gravity framework. The analysed data sample was collected with the KLOE detector at DA Phi NE, the Frascati phi-factory, and corresponds to an integrated luminosity of about 1.7 fb(-1), i.e. to about 1.7 x 10(9) phi -> KSKL decays produced. From the fit of the observed Delta t distribution, being Delta t the difference of the kaon decay times, the decoherence and CPT violation parameters of various phenomenological models are measured with a largely improved accuracy with respect to previous analyses. The results are consistent with no deviation from quantum mechanics and CPT symmetry, while for some parameters the precision reaches the interesting level at which - in the most optimistic scenarios - quantum gravity effects might show up. They provide the most stringent limits up to date on the considered models.
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| 22. |
- Babusci, D., et al.
(författare)
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Search for light vector boson production in e(+)e(-) -> mu(+)mu(-)gamma interactions with the KLOE experiment
- 2014
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 736, s. 459-464
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Tidskriftsartikel (refereegranskat)abstract
- 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 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(-) -> mu(+)mu(-)gamma, corresponding to the decay U -> mu(+)mu(-). 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 x 10(-5) to 8.6 x 10(-7) for the mass region 520 < m(U) < 980 MeV.
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| 23. |
- Babusci, D., et al.
(författare)
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Study of the Dalitz decay phi -> eta e(+)e(-) with the KLOE detector
- 2015
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 742, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the vector to pseudoscalar conversion decay phi -> eta e(+)e(-), with.. eta -> pi(0)pi(0)pi(0), with the KLOE detector at DA phi NE. The data set of 1.7 fb(-1) of e(+)e(-) collisions at root s similar to M-phi contains a clear conversion decay signal of similar to 31,000 events from which we measured a value of BR(phi -> eta e(+)e-) = (1.075 +/- 0.007 +/- 0.038) x 10(-4). The same sample is used to determine the transition form factor by a fit to the e(+)e(-) invariant mass spectrum, obtaining b(phi eta)=( 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.
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| 24. |
- Babuscih, D., et al.
(författare)
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Measurement of the absolute branching ratio of the K+ -> pi(+) pi(-) pi(+) (gamma) decay with the KLOE detector
- 2014
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 738, s. 128-133
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Tidskriftsartikel (refereegranskat)abstract
- The absolute branching ratio of the K+ -> pi(+) pi(-) pi(+) (gamma) decay, inclusive of final-state radiation, has been measured using similar to 17 million tagged K+ mesons collected with the KLOE detector at DA Phi NE, the Frascati phi-factory. The result is: BR(K+ -> pi(+) pi(-) pi(+) (gamma)) = 0.05565 +/- 0.00031(stat) +/- 0.00025(syst) a factor similar or equal to 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.
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| 25. |
- Balossino, I., et al.
(författare)
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U-Rania : A neutron detector based on μ-rwell technology
- 2020
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 15:9
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Tidskriftsartikel (refereegranskat)abstract
- In the framework of the ATTRACT-uRANIA project, funded by the European Community, we are developing an innovative neutron imaging detector based on micro-Resistive WELL (μ-RWELL) technology. The μ-RWELL, based on the resistive detector concept, ensuring an efficient spark quenching mechanism, is a highly reliable device. It is composed by two main elements: A readout-PCB and a cathode. The amplification stage for this device is embedded in the readout board through a resistive layer realized by means of an industrial process with DLC (Diamond-Like Carbon). A thin layer of \boro on the copper surface of the catode allows the thermal neutrons detection through the release of \litio and α particles in the active volume. This technology has been developed to be an efficient and convenient alternative to the 3He shortage. The goal of the project is to prove the feasibility of such a novel neutron detector by developing and testing small planar prototypes with readout boards suitably segmented with strip or pad readout, equipped with existing electronics or readout in current mode. Preliminary results from the test with different prototypes, showing a good agreement with the simulation, will be presented together with construction details of the prototypes and the future steps of the project.
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| 26. |
- Scherzinger, Julius, et al.
(författare)
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A comparison of untagged gamma-ray and tagged-neutron yields from 241AmBe and 238PuBe sources
- 2017
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 127, s. 98-102
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Tidskriftsartikel (refereegranskat)abstract
- Untagged gamma-ray and tagged-neutron yields from 241AmBe and 238PuBe mixed-field sources have been measured. Gamma-ray spectroscopy measurements from 1 to 5 MeV were performed in an open environment using a CeBr3 detector and the same experimental conditions for both sources. The shapes of the distributions are very similar and agree well with previous data. Tagged-neutron measurements from 2 to 6 MeV were performed in a shielded environment using a NE-213 liquid-scintillator detector for the neutrons and a YAP(Ce) detector to tag the 4.44 MeV gamma-rays associated with the de-excitation of the first-excited state of 12C. Again, the same experimental conditions were used for both sources. The shapes of these distributions are also very similar and agree well with previous data, each other, and the ISO recommendation. Our 238PuBe source provides approximately 2.6 times more 4.44 MeV gamma-rays and 2.4 times more neutrons over the tagged-neutron energy range, the latter in reasonable agreement with the original full-spectrum source-calibration measurements performed at the time of their acquisition.
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| 27. |
- Scherzinger, Julius, et al.
(författare)
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Tagging fast neutrons from a Cf-252 fission-fragment source
- 2017
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 128, s. 270-274
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Tidskriftsartikel (refereegranskat)abstract
- Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a Cf-252 source sealed on one side with a very thin layer of Au. The source is positioned within a gaseous He-4 scintillator detector. Together with a particles, both light and heavy fission fragments pass through the thin layer of Au and are detected. The fragments enable the corresponding fission neutrons, which are detected in a NE-213 liquid-scintillator detector, to be tagged. The resulting continuous polychromatic beam of tagged neutrons has an energy dependence that agrees qualitatively with expectations. We anticipate that this technique will provide a cost-effective means for the characterization of neutron-detector efficiency in the energy range 1-6 MeV.
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| 28. |
- Anastasi, A., et al.
(författare)
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Combination of KLOE sigma (e(+) e(-) -> pi(+)pi(-) gamma(gamma)) measurements and determination of a(mu)(pi+pi-) in the energy range 0.10 < s < 0.95 GeV2
- 2018
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :3
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Tidskriftsartikel (refereegranskat)abstract
- The three precision measurements of the cross section sigma (e(+)e(-) -> pi(+)pi(-)gamma(gamma)) 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 uncertainties and, therefore, the simultaneous use of these measurements requires covariance matrices that fully describe the correlations. We present the construction of these covariance matrices and use them to determine a combined KLOE measurement for sigma (e(+)e(-) -> pi(+)pi(-)gamma(gamma)). We find, from this combination, a two-pion contribution to the muon magnetic anomaly in the energy range 0.10 < s < 0.95 GeV2 of a(mu)(pi+pi-) (489.8 +/- 1.7(stat) +/- 4.8(sys)) x 10(-10).
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| 29. |
- Anastasi, A., et al.
(författare)
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Measurement of the charge asymmetry for the K-S -> pi e nu decay and test of CPT symmetry with the KLOE detector
- 2018
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :9
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Tidskriftsartikel (refereegranskat)abstract
- Using 1.63 fb(-1) of integrated luminosity collected by the KLOE experiment about 7 x 10(4) K-S -> pi(+/-)e(-/+)nu decays have been reconstructed. The measured value of the charge asymmetry for this decay is A(S) = (-4.9 +/- 5.7(stat) +/- 2.6(syst)) x 10(-3) which is almost twice more precise than the previous KLOE result. The combination of these two measurements gives A(S) = (3.8 +/- 5.0(stat) +/- 2.6(syst)) x 10(-3) and, together with the asymmetry of the K-L semileptonic decay, provides significant tests of the CPT symmetry. The obtained results are in agreement with CPT invariance.
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| 30. |
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