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Sökning: WFRF:(Ciambrone P)

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1.
  • Ahdida, C., et al. (författare)
  • Fast simulation of muons produced at the SHiP experiment using Generative Adversarial Networks
  • 2019
  • Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 14
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents a fast approach to simulating muons produced in interactions of the SPS proton beams with the target of the SHiP experiment. The SHIP experiment will be able to search for new long-lived particles produced in a 400 GeV/c SPS proton beam dump and which travel distances between fifty metres and tens of kilometers. The SHiP detector needs to operate under ultra-low background conditions and requires large simulated samples of muon induced background processes. Through the use of Generative Adversarial Networks it is possible to emulate the simulation of the interaction of 400 GeV/c proton beams with the SHiP target, an otherwise computationally intensive process. For the simulation requirements of the SHiP experiment, generative networks are capable of approximating the full simulation of the dense fixed target, offering a speed increase by a factor of O(10(6)). To evaluate the performance of such an approach, comparisons of the distributions of reconstructed muon momenta in SHiP's spectrometer between samples using the full simulation and samples produced through generative models are presented. The methods discussed in this paper can be generalised and applied to modelling any non-discrete multi-dimensional distribution.
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2.
  • Ahdida, C., et al. (författare)
  • Sensitivity of the SHiP experiment to Heavy Neutral Leptons
  • 2019
  • Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :4
  • Tidskriftsartikel (refereegranskat)abstract
    • Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, generate the observed matter-antimatter asymmetry in the Universe and provide a dark matter candidate. The SHiP experiment will be able to search for HNLs produced in decays of heavy mesons and travelling distances ranging between O(50 m) and tens of kilometers before decaying. We present the sensitivity of the SHiP experiment to a number of HNL's benchmark models and provide a way to calculate the SHiP's sensitivity to HNLs for arbitrary patterns of flavour mixings. The corresponding tools and data files are also made publicly available.
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3.
  • Ahdida, C., et al. (författare)
  • The experimental facility for the Search for Hidden Particles at the CERN SPS
  • 2019
  • Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 14
  • Tidskriftsartikel (refereegranskat)abstract
    • The Search for Hidden Particles (SHiP) Collaboration has shown that the CERN SPS accelerator with its 400 GeV/c proton beam offers a unique opportunity to explore the Hidden Sector [1-3]. The proposed experiment is an intensity frontier experiment which is capable of searching for hidden particles through both visible decays and through scattering signatures from recoil of electrons or nuclei. The high-intensity experimental facility developed by the SHiP Collaboration is based on a number of key features and developments which provide the possibility of probing a large part of the parameter space for a wide range of models with light long-lived super-weakly interacting particles with masses up to O(10) GeV/c(2) in an environment of extremely clean background conditions. This paper describes the proposal for the experimental facility together with the most important feasibility studies. The paper focuses on the challenging new ideas behind the beam extraction and beam delivery, the proton beam dump, and the suppression of beam-induced background.
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4.
  • Ahdida, C., et al. (författare)
  • The magnet of the scattering and neutrino detector for the SHiP experiment at CERN
  • 2020
  • Ingår i: Journal of Instrumentation. - 1748-0221. ; 15:01
  • Tidskriftsartikel (refereegranskat)abstract
    • The Search for Hidden Particles (SHiP) experiment proposal at CERN demands a dedicated dipole magnet for its scattering and neutrino detector. This requires a very large volume to be uniformly magnetized at B > 1.2 T, with constraints regarding the inner instrumented volume as well as the external region, where no massive structures are allowed and only an extremely low stray field is admitted. In this paper we report the main technical challenges and the relevant design options providing a comprehensive design for the magnet of the SHiP Scattering and Neutrino Detector.
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5.
  • Ahdida, C., et al. (författare)
  • Track reconstruction and matching between emulsion and silicon pixel detectors for the SHiP-charm experiment
  • 2022
  • Ingår i: Journal of Instrumentation. - : IOP Publishing. - 1748-0221. ; 17:3
  • Tidskriftsartikel (refereegranskat)abstract
    • In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beam-line. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87% is achieved.
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6.
  • Ahdida, C., et al. (författare)
  • Measurement of the muon flux from 400 GeV/c protons interacting in a thick molybdenum/tungsten target
  • 2020
  • Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About 1011muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to (3.27 +/- 0.07)x1011protons on target was recorded. This amounts to approximatively 1% of a SHiP spill.
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7.
  • Ahdida, C., et al. (författare)
  • Sensitivity of the SHiP experiment to dark photons decaying to a pair of charged particles
  • 2021
  • Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 81:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Dark photons are hypothetical massive vector particles that could mix with ordinary photons. The simplest theoretical model is fully characterised by only two parameters: the mass of the dark photon m(gamma)D and its mixing parameter with the photon, epsilon. The sensitivity of the SHiP detector is reviewed for dark photons in the mass range between 0.002 and 10 GeV. Different productionmechanisms are simulated, with the dark photons decaying to pairs of visible fermions, including both leptons and quarks. Exclusion contours are presented and compared with those of past experiments. The SHiP detector is expected to have a unique sensitivity for m. D ranging between 0.8 and 3.3(-0.5)(+0.2) GeV, and epsilon(2) ranging between 10(-11) and 10(-17).
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8.
  • Ahdida, C., et al. (författare)
  • Sensitivity of the SHiP experiment to light dark matter
  • 2021
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :4
  • Tidskriftsartikel (refereegranskat)abstract
    • Dark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with αD = 0.1 and mA′ = 3mχ, we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to 2 · 1020 protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1 MeV to 300 MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic.
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9.
  • Amelino-Camelia, G., et al. (författare)
  • Physics with the KLOE-2 experiment at the upgraded DA Phi NE
  • 2010
  • Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 68:3-4, s. 619-681
  • Forskningsöversikt (refereegranskat)abstract
    • Investigation at a f-factory can shed light on several debated issues in particle physics. We discuss: (i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, (ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled-kaon states, (iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta' mesons, (iv) the contribution to understand the nature of light scalar mesons, and (v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the e(+)e(-) physics in the continuum with the measurements of (multi) hadronic cross sections and the study of gamma gamma processes.
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10.
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11.
  • Anastasi, A., et al. (författare)
  • 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
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :3
  • 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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12.
  • Anastasi, A., et al. (författare)
  • Measurement of the charge asymmetry for the K-S -> pi e nu decay and test of CPT symmetry with the KLOE detector
  • 2018
  • Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :9
  • 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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13.
  • Babusci, D., et al. (författare)
  • Precision tests of quantum mechanics and CPT symmetry with entangled neutral kaons at KLOE
  • 2022
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479.
  • 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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14.
  • Babusci, D., et al. (författare)
  • Upper limit on the eta -> pi(+)pi(-) branching fraction with the KLOE experiment
  • 2020
  • Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :10
  • Tidskriftsartikel (refereegranskat)abstract
    • 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 -> pi (+)pi (-) has been performed. Radiative phi -> eta gamma decay is exploited to access the eta mesons. No signal is observed in the pi (+)pi (-) invariant mass spectrum, and the upper limit on the branching fraction at 90% confidence level is determined to be B(eta -> pi (+)pi (-)) < 4.9 x 10(-6), which is approximately three times smaller than the previous KLOE result. From the combination of these two measurements we get B( -> pi (+)pi (-)) < 4.4 x 10(-6) at 90% confidence level.
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15.
  • Babusci, D., et al. (författare)
  • Precision measurement of sigma (e(+)e(-) -> pi(+)pi(-)gamma)/sigma(e(+)e(-) ->mu(+)mu(-)gamma) and determination of the pi(+)pi(-) contribution to the muon anomaly with the KLOE detector
  • 2013
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 720:4-5, s. 336-343
  • Tidskriftsartikel (refereegranskat)abstract
    • We have measured the ratio cr (e(+)e(-) -> pi(+)pi(-)gamma)/sigma(e(+)e(-) -> mu(+)mu(-)gamma), with the KLOE detector at DA Phi NE for a total integrated luminosity of similar to 240 pb(-1). From this ratio we obtain the cross section sigma (e(+)e(-) -> pi(+)pi(-)gamma). From the cross section we determine the pion form factor vertical bar F-pi vertical bar(2) and the two-pion contribution to the muon anomaly a(mu) for 0.592< M-pi pi < 0.975 GeV, Delta(pi pi) a(mu) = (385.1 +/- 1.1(stat) +/- 2.7(sys+theo)) x 10(-10). This result confirms the current discrepancy between the Standard Model calculation and the experimental measurement of the muon anomaly. (c) 2013 Elsevier B.V. All rights reserved.
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16.
  • Archilli, F., et al. (författare)
  • Search for a vector gauge boson in phi meson decays with the KLOE detector KLOE-2 Collaboration
  • 2012
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 706:4-5, s. 251-255
  • Tidskriftsartikel (refereegranskat)abstract
    • The existence of a light dark force mediator has been tested with the KLOE detector at DA Phi NE. This particle, called U. is searched for using the decay chain phi -> eta U, eta -> pi(+)pi(-)pi(0), U -> e(+)e(-). No evidence is found in 1.5 fb(-1) of data. The resulting exclusion plot covers the mass range 5 < M-U < 470 MeV, setting an upper limit on the ratio between the U boson coupling constant and the One structure constant, alpha'/alpha, of <= 2 x 10(-5) at 90% C.L. for 50 < M-U < 420 MeV.
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17.
  • Babusci, D., et al. (författare)
  • Measurement of Γ(η→π+π-γ)/Γ(η→π+π-π0) with the KLOE detector
  • 2013
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 718:3, s. 910-914
  • Tidskriftsartikel (refereegranskat)abstract
    • The ratio Rη=Γ(η→π+π-γ)/Γ(η→π+π-π0) has been measured by analysing 22 million φ→ηγ decays collected by the KLOE experiment at DAΦNE, corresponding to an integrated luminosity of 558 pb-1. The η→π+π-γ proceeds both via the ρ resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, Rη=0.1856±0.0005stat±0.0028syst, points out a sizable contribution of the direct term to the total width. The di-pion invariant mass for the η→π+π-γ decay could be described in a model-independent approach in terms of a single free parameter, α. The determined value of the parameter α is α=(1.32±0.08stat-0.09syst+0.10±0.02theo) GeV-2.
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18.
  • Babusci, D., et al. (författare)
  • Search for light vector boson production in e(+)e(-) -> mu(+)mu(-)gamma interactions with the KLOE experiment
  • 2014
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 736, s. 459-464
  • 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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19.
  • Babusci, D., et al. (författare)
  • Study of the Dalitz decay phi -> eta e(+)e(-) with the KLOE detector
  • 2015
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 742, s. 1-6
  • 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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20.
  • Babuscih, D., et al. (författare)
  • Measurement of the absolute branching ratio of the K+ -> pi(+) pi(-) pi(+) (gamma) decay with the KLOE detector
  • 2014
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 738, s. 128-133
  • 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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21.
  • Milstead, David A., et al. (författare)
  • The active muon shield in the SHiP experiment
  • 2017
  • Ingår i: Journal of Instrumentation. - 1748-0221. ; 12
  • Tidskriftsartikel (refereegranskat)abstract
    • The SHiP experiment is designed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. An essential task for the experiment is to keep the Standard Model background level to less than 0.1 event after 2 x 10(20) protons on target. In the beam dump, around 10(11) muons will be produced per second. The muon rate in the spectrometer has to be reduced by at least four orders of magnitude to avoid muon-induced combinatorial background. A novel active muon shield is used to magnetically deflect the muons out of the acceptance of the spectrometer. This paper describes the basic principle of such a shield, its optimization and its performance.
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22.
  • Anastasi, A., et al. (författare)
  • Limit on the production of a new vector boson in e+e− → Uγ, U → π+π− with the KLOE experiment
  • 2016
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 757, s. 356-361
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract 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 − → U γ , 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 compensates for a loss of sensitivity of previous KLOE U → e + e − , μ + μ − searches due to the small branching ratios in the ρ – ω resonance region. We found no evidence for a signal and set a limit at 90% CL on the mixing strength between the photon and the dark photon, ε 2 , in the U mass range between 527 and 987 MeV . Above 700 MeV this new limit is more stringent than previous ones.
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23.
  • Anastasi, A., et al. (författare)
  • Precision measurement of the η → π + π − π 0 Dalitz plot distribution with the KLOE detector
  • 2016
  • Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :5
  • Tidskriftsartikel (refereegranskat)abstract
    • Using 1.6 fb−1 of e + e − → ϕ → ηγ data collected with the KLOE detector at DAΦNE, the Dalitz plot distribution for the η → π + π − π 0 decay is studied with the world’s largest sample of ∼ 4.7 · 106 events. 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 sensitive to all charge conjugation conserving terms of the expansion, including a gX 2 Y term. The statistical uncertainty of all parameters is improved by a factor two with respect to earlier measurements.
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24.
  • Anastasi, A., et al. (författare)
  • Search for dark Higgsstrahlung in e(+0)e(-) -> mu(+)mu(-) and missing energy events with the KLOE experiment
  • 2015
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 747, s. 365-372
  • Tidskriftsartikel (refereegranskat)abstract
    • 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 DA Phi NE. 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 upper limits to its parameters in the range 2m(mu) < m(U) < 1000 MeV, m(h') < m(U). (C) 2015 The Authors. Published by Elsevier B.V.
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25.
  • Babusci, D., et al. (författare)
  • Direct tests of T, CP, CPT symmetries in transitions of neutral K mesons with the KLOE experiment
  • 2023
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 845
  • Tidskriftsartikel (refereegranskat)abstract
    • 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 antiunitary transformation implied by time-reversal is implemented exploiting the entanglement of K0K0 pairs produced at a 0 -factory.A data sample collected by the KLOE experiment at DAONE corresponding to an integrated luminosity of about 1.7 fb-1 is analysed to study the At distributions of the 0 -> KSKL -> pi+pi- pi +/- e -/+ v and 0 -> KSKL -> pi +/- e -/+ v3 pi 0 processes, with At the difference of the kaon decay times. A comparison of the measured At distributions in the asymptotic region At â … iS allows to test for the first time T and CPT symmetries in kaon transitions with a precision of few percent, and to observe CP violation with this novel method.
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26.
  • Babusci, D., et al. (författare)
  • Limit on the production of a light vector gauge boson in phi meson decays with the KLOE detector
  • 2013
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 720:1-3, s. 111-115
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a new limit on the production of a light dark-force mediator with the KLOE detector at DA Phi NE. This boson, called U, has been searched for in the decay phi -> eta U, U -> e(+)e(-), analyzing the. decay eta -> pi(0)pi(0)pi(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 search is combined with a previous result obtained from the decay eta -> pi(+)pi(-)pi(0), increasing the sensitivity. We set an upper limit at 90% C.L. on the ratio between the U boson coupling constant and the fine structure constant of alpha'/alpha < 1.7 x 10(-5) for 30 < M-U < 400 MeV and alpha'/alpha <= 8 x 10(-6) for the sub-region 50 < M-U <210 MeV. This result assumes the Vector Meson Dominance expectations for the phi eta gamma* transition form factor. The dependence of this limit on the transition form factor has also been studied.
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27.
  • Babusci, D., et al. (författare)
  • Measurement of eta meson production in gamma gamma interactions and Gamma(eta -> gamma gamma) with the KLOE detector
  • 2013
  • Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :1, s. 119-
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a measurement of eta meson production in photon-photon interactions produced by electron-positron beams colliding with root s = 1 GeV. The measurement is done with the KLOE detector at the phi-factory DA Phi NE with an integrated luminosity of 0.24 fb(-1). The e(+)e(-) -> e(+)e(-)eta cross section is measured without detecting the outgoing electron and positron, selecting the decays eta -> pi(+)pi(-)pi(0) and eta -> pi(0)pi(0)pi(0). The most relevant background is due to e(+)e(-) -> eta gamma when the monochromatic photon escapes detection. The cross section for this process is measured as sigma(e(+)e(-) -> eta gamma) = (856 +/- 8(stat) +/- 16(syst)) pb. The combined result for the e(+)e(-) -> e(+)e(-)eta cross section is sigma(e(+)e(-) -> e(+)e(-)eta) = (32.72 +/- 1.27(stat) +/- 0.70(syst)) pb. From this we derive the partial width Gamma(eta -> gamma gamma) = (520 +/- 20(stat) +/- 13(syst)) eV. This is in agreement with the world average and is the most precise measurement to date.
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28.
  • Babusci, D., et al. (författare)
  • Measurement of the K-S ? : pe? branching fraction with the KLOE experiment
  • 2023
  • Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :2
  • Tidskriftsartikel (refereegranskat)abstract
    • The ratio R = gamma(K-S -> pi e nu)/gamma(KS -> pi(+)pi(-)) has been measured with a sample of 300 million KS mesons produced in phi -KLKS decays recorded by the KLOE experiment at the DA Phi NE e(+)e(-) collider. K-S -> pi e nu events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of K-L -> pi e nu decays are used to evaluate signal selection efficiencies. With 49647 +/- 316 signal events we measure R = (1.0421 +/- 0.0066(stat) +/- 0.0075(syst)) x 10(-3). The combination with our previous measurement gives R = (1.0338 +/- 0.0054(stat) +/- 0.0064(syst)) x 10(-3). From this value we derive the branching fraction B(K-S -> pi e nu) = (7.153 +/- 0.037(stat)+/- 0.044(syst)) x 10(-4) and f(+)(0)|V-us| = 0.2170 +/- 0.009.
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29.
  • Anastasi, A., et al. (författare)
  • Limit on the production of a low-mass vector boson in e(+)e(-) -> U gamma, U -> e(+)e(-) with the KLOE experiment
  • 2015
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 750, s. 633-637
  • Tidskriftsartikel (refereegranskat)abstract
    • 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 DA Phi NE e(+)e(-) collider. Using an integrated luminosity of 1.54 fb(-1), we studied the process e(+)e(-) -> U gamma, with U -> e(+)e(-), using radiative return to search for a resonant peak in the dielectron invariant-mass distribution. We did not find evidence for a signal, and set a 90% CL upper limit on the mixing strength between the Standard Model photon and the dark photon, epsilon(2), at 10(-6)-10(-4) in the 5-520 MeV/c(2) mass range.
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30.
  • Babusci, D., et al. (författare)
  • A new limit on the CP violating decay K-S -> 3 pi(0) with the KLOE experiment
  • 2013
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 723:1-3, s. 54-60
  • Tidskriftsartikel (refereegranskat)abstract
    • We have carried out a new direct search for the CP violating decay K-S -> 3 pi(0) with 1.7 fb(-1) of e(+)e(-) collisions collected by the KLOE detector at the Phi-factory DA Phi NE. We have searched for this decay in a sample of about 5.9 x 10(8) KSKL events tagging the K-S by means of the K-L interaction in the calorimeter and requiring six prompt photons. With respect to our previous search, the analysis has been improved by increasing of a factor four the tagged sample and by a more effective background rejection of fake K-S tags and spurious clusters. We find no candidates in data and simulated background samples, while we expect 0.12 standard model events. Normalizing to the number of K-S -> 2 pi(0) events in the same sample, we set the upper limit on BR(K-S -> 3 pi(0)) <= 2.6 x 10(-8) at 90% C.L., five times lower than the previous limit. We also set the upper limit on the eta(000) parameter, vertical bar eta(000)vertical bar <= 0.0088 at 90% C.L., improving by a factor two the latest direct measurement. (c) 2013 Elsevier B.V. All rights reserved.
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31.
  • Babusci, D., et al. (författare)
  • Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment
  • 2014
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 730, s. 89-94
  • Tidskriftsartikel (refereegranskat)abstract
    • 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 -> KSKL -> pi(+)pi(-)pi(+)pi(-) based on 1.7 fb(-1) of data collected by the KLOE experiment at the Frascati phi-factory DA Phi NE. The data are used to perform a Measurement of the CPT-violating parameters Delta a(mu) for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are: Delta a(0) = (-6.0 +/- 7.7(stat)+/- 3.1(syst)) X 10(-18) GeV, Delta a(x) = (0.9 +/- 1.5(stat)+/- 0.6(syst)) X 10(-18) GeV, Delta a(y) = (-2.0 +/- 1.5(stat)+/- 0.5(syst)) X 10(-18) GeV, Delta a(z) = (3.1 +/- 1.7(stat)+/- 0.5(syst)) X 10(-18) GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension. (C) 2014 The Authors. Published by Elsevier B.V.
  •  
32.
  • Aloisio, A, et al. (författare)
  • An FPGA Based General Purpose DAQ Module for the KLOE-2 Experiment
  • 2011
  • Ingår i: Journal of Physics: Conference Series. ; 331
  • Tidskriftsartikel (refereegranskat)abstract
    • A general purpose FPGA based DAQ module has been developed based on a Virtex-4 FPGA. It is able to acquire up to 1024 different channels distributed over 10 slave cards. The module has an optical interface a RS-232 a USB and a Gigabit Interface. The KLOE-2 experiment is going to use it to collect data from the Inner tracker and the QCALT. An embedded processor (power pc 604) is present on the FPGA and a telnet server has been developed and installed. A new general purpose data taking system has been based on this module to acquire the Inner Tracker. The system is at the moment working at LNF (Laboratori Nazionali di Frascati).
  •  
33.
  • Anastasi, A., et al. (författare)
  • Combined limit on the production of a light gauge boson decaying into mu(+) mu(-) and pi(+) pi(-)
  • 2018
  • Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 784, s. 336-341
  • Tidskriftsartikel (refereegranskat)abstract
    • We searched for the mu(+) mu(-) decay of a light vector gauge boson, also known as dark photon, in the e(+) e(-) -> mu(+) mu(-) gamma(ISR) process by means of the Initial State Radiation (ISR) method. We used 1.93fb(-1) of data collected by the KLOE experiment at the DA Phi NE phi-factory. No structures have been observed over the irreducible mu(+) mu(-) background. A 90% CL limit on the ratio epsilon(2)= alpha'/alpha between the dark coupling constant and the fine structure constant of 3 x 10(-6)-2 x 10(-7) has been set in the dark photon mass region between 519 MeV and 973 MeV. This new limit has been combined with the published result obtained investigating the hypothesis of the dark photon decaying into hadrons in e(+) e(-) -> pi(+) pi(-) gamma(ISR) events. The combined 90% CL limit increases the sensitivity especially in the rho-omega interference region and excludes epsilon(2) greater than (13 - 2) x 10(-7). For dark photon masses greater than 600 MeV the combined limit is lower than 8 x 10(-7) resulting more stringent than present constraints from other experiments.
  •  
34.
  • Babusci, D., et al. (författare)
  • Measurement of the branching fraction for the decay K-S -> pi mu nu with the KLOE detector
  • 2020
  • Ingår i: Physics Letters B. - : ELSEVIER. - 0370-2693 .- 1873-2445. ; 804
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on a sample of 300 million K-S mesons produced in phi -> KLKS 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 -> pi mu nu. The K-S mesons are identified by the interaction of K-L mesons in the detector. The K-S -> pi mu nu decays are selected by a boosted decision tree built with kinematic variables and by a time-of-flight measurement. Signal efficiencies are evaluated with data control samples of K-L -> pi mu nu decays. A fit to the reconstructed muon mass distribution finds 7223 +/- 180 signal events. Normalising to the K-S -> pi(+)pi(-) decay events the result for the branching fraction is B(K-S -> pi mu nu) = (4.56 +/- 0.11(stat) +/- 0.17(syst)) x 10(-4). It is the first measurement of this decay mode and the result allows an independent determination of vertical bar V-us vertical bar and a test of the lepton-flavour universality. (c) 2020 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
  •  
35.
  • Branchini, P., et al. (författare)
  • Front-end DAQ strategy and implementation for the KLOE-2 experiment
  • 2013
  • Ingår i: Journal of Instrumentation. - 1748-0221. ; 8, s. T04004-
  • Tidskriftsartikel (refereegranskat)abstract
    • A new front-end data acquisition (DAQ) system has been conceived for the data collection of the new detectors which will be installed by the KLOE2 collaboration. This system consists of a general purpose FPGA based DAQ module and a VME board hosting up to 16 optical links. The DAQ module has been built around a Virtex-4 FPGA and it is able to acquire up to 1024 different channels distributed over 16 front-end slave cards. Each module is a general interface board (GIB) which performs also first level data concentration tasks. The GIB has an optical interface, a RS-232, an USB and a Gigabit Ethernet Interface. The optical interface will be used for DAQ purposes while the Gigabit Ethernet interface for monitoring tasks and debug. Two new detectors exploit this strategy to collect data. Optical links are used to deliver data to the VME board which performs data concentration tasks. The return optical link from the board to the GIB is used to initialize the front-end cards. The VME interface of the module implements the VME 2eSST protocol in order to sustain a peak data rate of up to 320 MB/s. At the moment the system is working at the Frascati National Laboratory (LNF).
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36.
  • Anastasi, A., et al. (författare)
  • Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector
  • 2017
  • Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 767, s. 485-492
  • Tidskriftsartikel (refereegranskat)abstract
    • We have measured the running of the effective QED coupling constant alpha(s) in the time-like region 0.6 < root s < 0.975 GeV with the KLOE detector at DA Phi NE using the Initial-State Radiation process e(+) e(-) -> mu(+) mu(-)gamma. It represents the first measurement of the running of alpha(s) in this energy region. Our results show a more than 5 sigma significance of the hadronic contribution to the running of alpha(s), which is the strongest direct evidence both in time- and space-like regions achieved in a single measurement. By using the e(+) e(-) -> pi(+) pi(-) cross section measured by KLOE, the real and imaginary parts of the shift Delta alpha(s) have been extracted. From a fit of the real part of Delta alpha(s) and assuming the lepton universality the branching ratio BR(omega -> mu(+) mu(-)) = (6.6 +/- 1.4(stat) +/- 1.7(syst)) (.) 10 (5)has been determined.
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