D. Babusci, D. Badoni, I. Balwierz-Pytko, G. Bencivenni, C. Bini, C. Bloise, F. Bossi, P. Branchini, A. Budano, L. Caldeira Balkest, G. Capon, F. Ceradini, P. C… 展开作者
D. Babusci, D. Badoni, I. Balwierz-Pytko, G. Bencivenni, C. Bini, C. Bloise, F. Bossi, P. Branchini, A. Budano, L. Caldeira Balkest, G. Capon, F. Ceradini, P. Ciambrone, F. Curciarello, E. Czerwinski, E. Dane, V. De Leo, E. De Lucia, G. De Robertis, A. De Santis, A. Di Domenico, C. Di Donato, R. Di Salvo, D. Domenici, O. Erriquez, G. Fanizzi, A. Fantini, G. Felici, S. Fiore, P. Franzini, A. Gajos, P. Gauzzi, G. Giardina, S. Giovannella, E. Graziani, F. Happacher, L. Heijkenskjold, B. Hoistad, L. Iafolla, M. Jacewicz, T. Johansson, K. Kacprzak, A. Kupsc, J. Lee-Franzini, B. Leverington, F. Loddo, S. Loffredo, G. Mandaglio, M. Martemianov, M. Martini, M. Mascolo, R. Messi, S. Miscetti, G. Morello, D. Moricciani, P. Moskal, F. Nguyen, A. Palladino, A. Passeri, V. Patera, I. Prado Longhi, A. Ranieri, C. F. Redmer, P. Santangelo, I. Sarra, M. Schioppa, B. Sciascia, M. Silarski, C. Taccini, L. Tortora, G. Venanzoni, W. Wislicki, M. Wolke, J. Zdebik
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4 pages, Proceedings of the 48th Rencontres de Moriond "QCD and High Energy Interactions", La Thuile, Italy, March 9-16, 2013
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 contribution includes brief description of results of recent analysis of the KLOE data aimed at (i) the search for the dark matter boson, (ii) determination of the hadronic and light-by-light contributions to the g-2 muon anomaly and (iii) tests of QCD anomalies.
The KLOE Collaboration completed the full data taking on March 2006, acquiring 2.5 fb ^ -1 at the peak of the ϕand other 240 pb ^ -1 off-peak. A new Collaboration is working on a new project, called KLOE-2, to refine and extend the KLOE physics program. We present here some preliminary and published results from the KLOE Collaboration on the pseudoscalar ηmeson and the study of γγprocesses, that are among the main points of the KLOE-2 physics program.
The measurement of the $σ(e^+e^-\rightarrow π^+π^-)$ cross section allows to determine the pion form factor $| F_π|^2$ and the two pion contribution to the muon anomaly $a_μ$. Such a measurement has been performed with the KLOE detector at $DAΦNE$, the Frascati $ϕ$-factory.The preliminary results on the combination of the last analysis (KLOE12) with two previous published (KLOE08, KLOE10) will be presented in the following.
The KLOE experiment at the DA$Φ$NE $ϕ$-factory has performed a new precise measurement of the pion form factor using Initial State Radiation events. Results based on an integrated luminosity of 240 pb$^{-1}$ and extraction of the $ππ$ contribution to $a_μ$ in the mass range $0.35< M^2_{ππ}<0.95$ GeV$^2$ are presented. The new value of $a^{ππ}_μ$ has smaller statistical and systematic error and is consistent with the KLOE published value (confirming the current disagreement between the Standard Model prediction for $a_μ$ and the measured value).
The KLOE experiment at the $ϕ-factory$ DA$Φ$NE in Frascati is the first to have employed Initial State Radiation (ISR) to precisely determine the $e^+e^-\toπ^+π^-(γ)$ cross section below 1 GeV. Such a measurement is particularly important to test the Standard Model (SM) calculation for the $(g-2)$ of the muon, where a long standing 3$σ$ discrepancy is observed. I will review the ISR activity in KLOE in the last 18 years from the measurement of the hadronic cross section to the first direct determination of the time-like complex running $α(s)$ in the region below 1 GeV.
The basic motivation of the KLOE-2 experiment is the test of fundamental symmetries and Quantum Mechanics coherence of the neutral kaon system, and the search for phenomena beyond the Standard Model in the hadronic and leptonic decays of ground-state mesons. Perspectives for experimentation by means of the KLOE-2 apparatus equipped with the inner tracker, new scintillation calorimeters, and the gamma-gamma taggers at the DA\$Phi$NE electron-positron collider upgraded in luminosity and energy are presented.
The goal of the KLOE-2 experiment operating at the upgraded DAΦNE e+e-collider is to collect an integrated luminosity of about 20 fb-1 during 3-4 years of running. Measurements using the KLOE-2 apparatus equipped with the inner tracker, new scintillation calorimeters and tagging detectors for gamma-gamma physics will allow to refine and extend the KLOE program on kaon physics and tests of fundamental symmetries as well as the quantum interferometry. Here the latest results from KLOE data analysis and perspectives at KLOE-2 are presented.
Kaon physics can test new-physics effects in leptonic or semileptonic decays. A unitarity test of the first row of the CKM mixing matrix is obtained from the precision measurements of Kl3 widths for K{\pm}, KL, and (unique to KLOE) KS. The KLOE measurement of RK = Γ(Ke2)/Γ(Kμ2) with an accuracy at the % level, aims at finding evidence of deviations from the SM prediction induced by lepton-flavor violation new-physics effects.
The phi-factory DAPHNE offers a possibility to select pure kaon beams, charged and neutral ones. In particular, neutral kaons from phi->KS KL are produced in pairs and the detection of a KS (KL) tags the presence of a KL (KS). This allows to perform precise measurements of kaon properties by means of KLOE detector. Another advantage of a phi-factory consists in fact that the neutral kaon pairs are produced in a pure quantum state (J^(PC) = 1^(--)), which allowsto investigate CP and CPT symmetries via quantum interference effects, as well as the basic principles of quantum mechanics.A review of…
The KLOE experiment at the DA$Φ$NE $ϕ$-factory performed precise studies of charged and neutral kaon physics, low energy QCD, as well as tests of CP and CPT invariance. For the new run the KLOE has been upgraded by adding new tagger systems for the $γγ$ physics, the inner tracking chamber and two calorimeters in the final focusing region. We are also improving on kaon identification techniques, in particular algorithms for the $K_S$ meson tagging. In this article we discuss the impact of the improved tagging procedure on studies of the $K_S$ decays.
The KLOE-2 experiment at the INFN Laboratori Nazionali di Frascati (LNF) is currently taking data at the upgraded $e^{+}e^{-}$ DAFNE collider. Present Run II follows a~development phase to assess the feasibility of a long term acquisition program, Run I, which successfully ended in July 2015 with 1 fb$^{-1}$ integrated luminosity collected in less than eight months. KLOE-2 represents the continuation of the KLOE experiment with a new physics program. The KLOE detector has undergone several upgrades including state-of-the-art cylindrical GEM Inner Tracker, electron-positron taggers for the $γγ$…
In this paper we discuss the recent finalized analyses by the KLOE experiment at DA$Φ$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 ${ K^+} \rightarrow π^+π^-π^+(γ)$. We also present the status of an ongoing analysis aiming to precisely measure the $K^{\pm} $ mass.
The KLOE results on the measurement of the transition form factors of the eta and pi0 mesons in phi Dalitz decays are presented, and the determination of the Gamma(eta->gamma gamma) in gamma gamma processes is also reported. The prospects for gamma gamma physics of the new data-taking, started in November 2014 with the upgraded detector, are reviewed.
The KLOE-2 experiment at the INFN Laboratori Nazionali di Frascati (LNF) completed its data-taking at the $e^+ e^-$ DA$Φ$NE collider, which implements an innovative collision scheme based on a crab-waist configuration, and achieved the integrated luminosity of more than 5 fb$^-1$. KLOE-2 represents the continuation of KLOE with an upgraded detector and an extended physics program which includes, among the main topics, neutral kaon interferometry and test of discrete symmetries . Entangled neutral kaon pairs produced at DA$Φ$NE are a unique tool to test discrete symmetries and quantum coherence…
The precision measurement of the $dσ(e^+e^- \rightarrow μ^+μ^- γ)/d\sqrt{s}$ cross section with the photon emitted in the initial state with the KLOE detector has been used to measure the running of the QED coupling constant $α(s)$ in the energy range 0.6 $< \sqrt{s} <$ 0.975 GeV in the time-like region. We were able to achieve a significance of the hadronic contribution to the running of $α(s)$ of more than 5$σ$ with a clear contribution of the $ρ- ω$ resonances to the photon propagator. The real and imaginary part of the shift $Δα$ to the running has been estracted and a fit of the real part…
A short review of two measurements recently published by KLOE/KLOE-2 collaborations is presented. Namely the most stringent limits of the CPT-violating parameters Delta a_mu for neutral kaons, and the absolute branching ratio of K+ --> pi+pi-pi+(gamma) decay. In addition a discussion of starting KLOE-2 project is performed.
The most recent results from the KLOE experiment are presented, covering: the measurement of the running fine-structure constant alpha_em,the Dalitz plot measurement of eta to pi+pi-pi0, the search of a U boson, tests of discrete symmetries and quantum coherence. The KLOE-2 Collaboration will take data until mid 2018 aiming to collect 5 inversed fb increasing the data set, in order to produce new precision measurements and continue studies of fundamental symmetries and New Physics.
Kaon decay studies seeking new-physics (NP) effects in leptonic (K_l2) or semileptonic (K_l3) decays are discussed. A unitarity test of the first row of the CKM mixing matrix is obtained from the KLOE precision measurements of Kl3 widths for K^+-, K_L, and (unique to KLOE) K_S, complemented with the absolute branching ratio for the K_mu2 decay. KLOE results lead to constraints for NP models and can probe possible charged Higgs exchange contribution in SM extensions with two Higgs doublets. The main focus in the present document is set on a new measurement of R_K=Gamma(K_e2)/Gamma(K_mu2) with a…
We present recent results obtained by the KLOE-2 Collaboration at the DAPHNE e+e- collider. The first class of results concerns search for dark forces at the scale of 1 GeV in associated production of gamma and the U boson, in search for the Higgsstrahlung and in possible decays of phi into eta and U. The second is in neutral kaon physics, on testing the CPT and Lorentz invariance, and on search for quantum decoherence effects in entangled pairs of kaons. The third class of results concerns precision measurements in hadronic physics at low energy where transition form factors of phi to pseudos…
Prospective presentation is given for the experimental program of the KLOE-2 Collaboration, to be performed using the DA$Φ$NE $e^+e^-$ collider upgraded in luminosity. Data with the total luminosity of 25 fb$^{-1}$ are aimed to be collected in 3 years. Major modifications of the accelerator and the spectrometer are described. The KLOE-2 physics program contains: CKM unitarity and lepton universality tests, $γγ$ physics, search for quantum decoherence and testing CPT conservation, low-energy QCD, rare kaon decays, physics of $η$ and $η^\prime$, structure of low-mass scalars, contribution of vac…
One of the basic motivations of the KLOE-2 and WASA-at-COSY experiments is the test of fundamental symmetries and the search for phenomena beyond the Standard Model in the hadronic and leptonic decays of ground-state mesons and in particular in decays of the $η$ meson. At COSY these mesons are produced in collisions of proton or deuteron beam with hydrogen or deuterium pellet target, and at DA$Φ$NE $η$ mesons originate from radiative decays of $ϕ$ meson or from the fusion of virtual gamma quanta exchanged between colliding electrons and positrons. This contribution includes brief description o…
We have updated our evaluation of the hadronic contribution to the running of the QED fine structure constant using the recent precise measurements of the e+e- annihilation at the center-of-mass (c.m.s.) energy region between 2.6 and 3.65 GeV performed by the BES collaboration. In the low energy region, around the rho resonance, we include the recent measurements from the BABAR, CDM-2, KLOE and SND collaborations. We obtain Delta alpha (5)_had (s) = 0.02750 +/- 0.00033 at s = m_Z^2.
The processes $e^+e^-\to e^+e^-X$, with $X$ being either the $η$ meson or $π^0π^0$, are studied at DA$Φ$NE, with $e^+e^-$ beams colliding at $\sqrt{s}\simeq1$ GeV, below the $ϕ$ resonance peak. The data sample is from an integrated luminosity of 240 pb$^{-1}$, collected by the KLOE experiment without tagging of the outgoing $e^+e^-$. Preliminary results are presented on the observation of the $γγ\toη$ process, with both $η\toπ^+π^-π^0$ and $η\toπ^0π^0π^0$ channels, and the evidence for $γγ\toπ^0π^0$ production at low $π^0π^0$ invariant mass.
The KLOE detector at the DA$Φ$NE $ϕ$-factory has been operating in two periods from 2001 to 2006 and from 2014 to 2018 collecting a large sample of $ϕ$-meson decays. This allowed to perform precision measurements and studies of fundamental symmetries, and searches of New Physics phenomena. In this overview, the results of KLOE and KLOE-2 Collaborations are presented. The most recent results from the KLOE experiment are discussed, covering: the measurement of the running fine-structure constant $α_{em}$, the Dalitz plot measurement of $η\rightarrow π^+π^-π^0$, the search of a U boson, tests of …
Dark Matter and Dark Energy are two of the most fundamental open questions in physics today. The existence of a light dark-force mediator has been hypothesized as a possible explanation for several unexplained physical phenomena. A new search for this mediator, the dark photon $U$, is underway using data collected with the KLOE detector at DA$Φ$NE. We describe the strategy we will use in our search for a resonant peak in the electron-positron invariant mass spectrum from the process $e^+e^- \to U γ$ with $U \to e^+e^-$. So far we found no evidence for the process and set a preliminary upper li…
The aim of this work was to determine the KS -> 3pi0 decay branching ratio and a modulus of the eta000 parameter, defined as the ratio of amplitudes for KS -> 3 pi0 to KL -> 3pi0 decays, which characterizes the CP symmetry violation in this decay. The measurement has been carried out with the KLOE detector operating at the phi-factory DAFNE in the Italian National Center for Nuclear Physics in Frascati. The KS mesons were identified with high efficiency via registration of these KL mesons which crossed the drift chamber without decaying and then interacted with the KLOE electromagnetic calorim…
I review some of the highlights of results from non-hadron collider flavor experiments shown at the EPS conference in the summer of 2009. These include highlights of the latest results from the BaBar and Belle B-factories, CLEO-c, BES-III, NA48, KTeV, KLOE, NA62, MEG, and mu to e conversion experiments.
The three precision measurements of the cross section $σ\big(e^+e^-\rightarrowπ^+π^-γ(γ)\big)$ 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 $σ\…
The 4.2$σ$ discrepancy between the standard model prediction for the muon anomalous magnetic moment $a_μ$ and the experimental result is accompanied by other anomalies. A crucial input for the prediction is the hadronic vacuum polarization $a_μ^{\rm HVP}$ inferred from $σ_{\rm had} =σ(e^+e^- \to\,$hadrons) data. However, the two most accurate determinations of $σ_{\rm had}$ from KLOE and BaBar disagree by almost 3$\,σ$. Additionally, the combined data-driven result disagrees with the most precise lattice determination of $a_μ^{\rm HVP}$ by $2.1\,σ$. We show that all these discrepancies could b…
A short review of recent results and future prospects in kaon physics is presented. Recent measurements performed at the NA48, NA62, KLOE and KTeV experiments on CP and Lepton Flavour violation and rare decays will be summarised, together with measurements of CKM elements and Chiral Perturbation Theory tests.
We reevaluate the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the $Z$-boson mass. We include newest $e^+e^- \to$ hadrons cross-section data together with a phenomenological fit of the threshold region in the evaluation of the dispersion integrals. The precision in the individual datasets cannot be fully exploited due to discrepancies that lead to additional systematic uncertainty in particular between BABAR and KLOE data in the dominant $π^+π^-$ channel. For the muon $(g-2)/2$, we find for the lowest-ord…
Investigation at a $ϕ$--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$^\prime$ mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for …
Time to Digital Converters (TDCs) are very common devices in particles physics experiments. A lot of "off-the-shelf" TDCs can be employed but the necessity of a custom DAta acQuisition (DAQ) system makes the TDCs implemented on the Field-Programmable Gate Arrays (FPGAs) desirable. Most of the architectures developed so far are based on the tapped delay lines with precision down to 10 ps, obtained with high FPGA resources usage and non-linearity issues to be managed. Often such precision is not necessary; in this case TDC architectures with low resources occupancy are preferable allowing the im…
Patterns of chiral symmetry violation and tests of the conservation of the fundamental C, P and CP symmetries are key physics issues in studies of the pi0, eta and eta' meson decays. These tests include searches for rare or forbidden decays and searches for asymmetries among the decay products in the not-so-rare decays. Some examples for the rare decays are eta-->2pi, eta-->4pi0 (CP tests), decays into an odd number of photons (e.g., eta-->3g) and the decay eta-->pi0e+e- (C tests). The experimental studies of the pi0, eta and eta' meson decays are carried out at four European accelerator resea…
This document reviews the physics program of the KLOE-2 detector at DA$Φ$NE upgraded in energy and provides a simple solution to run the collider above the $ϕ$-peak (up to 2, possibly 2.5 GeV). It is shown how a precise measurement of the multihadronic cross section in the energy region up to 2 (possibly 2.5) GeV would have a major impact on the tests of the Standard Model through a precise determination of the anomalous magnetic moment of the muon and the effective fine-structure constant at the $M_Z$ scale. With a luminosity of about $10^{32}$cm$^{-2}$s$^{-1}$, DA$Φ$NE upgraded in energy can…
