Search

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 K0K‾0 pairs produced at a ϕ-factory.A data sample collected by the KLOE experiment at DAΦNE corresponding to an integrated luminosity of about 1.7 fb−1 is analysed to study the Δt distributions of the ϕ→KSKL→π+π−π±e∓ν and ϕ→KSKL→π±e∓ν3π0 processes, with Δt the difference of the kaon decay times. A comparison of the measured Δt distributions in the asymptotic region Δt≫τS 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.

Abstract The ratio R $$ \mathcal{R} $$ = 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. Data control samples of K L → πeν decays are used to evaluate signal selection efficiencies. With 49647±316 signal events we measure R $$ \mathcal{R} $$ = (1.0421 ± 0.0066stat ± 0.0075syst) × 10 −3. The combination with our previous measurement gives R $$ \mathcal{R} $$ = (1.0338 ± 0.0054stat ± 0.0064syst) × 10 −3. From this value we derive the branching fraction B $$ \mathcal{B} $$ (K S → πeν) = (7.153 ± 0.037stat ± 0.044syst) × 10 −4 and f +(0)|V us | = 0.2170 ± 0.009.

Abstract The quantum interference between the decays of entangled neutral kaons is studied in the process ϕ → KSKL → 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 the quantum coherence of the entangled kaon pair state, and to search for tiny decoherence and CPT $$ \mathcal{CPT} $$ violation effects, which may be justified in a quantum gravity framework. The analysed data sample was collected with the KLOE detector at DAΦNE, the Frascati ϕ-factory, and corresponds to an integrated luminosity of about 1.7 fb −1, i.e. to about 1.7 × 109 ϕ → KSKL decays produced. From the fit of the observed ∆t distribution, being ∆t the difference of the kaon decay times, the decoherence and CPT $$ \mathcal{CPT} $$ 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 $$ \mathcal{CPT} $$ 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.

Abstract 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 the branching fraction at 90% confidence level is determined to be ℬ(η → π + π − ) < 4.9 × 10 −6, which is approximately three times smaller than the previous KLOE result. From the combination of these two measurements we get ℬ(η → π + π − ) < 4.4 × 10 −6 at 90% confidence level.

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 variables and by a time-of-flight measurement. Signal efficiencies are evaluated with data control samples of KL→πμν decays. A fit to the reconstructed muon mass distribution finds 7223±180 signal events. Normalising to the KS→π+π− decay events the result for the branching fraction is B(KS→πμν)=(4.56±0.11stat±0.17syst)×10−4. It is the first measurement of this decay mode and the result allows an independent determination of |Vus| and a test of the lepton-flavour universality. Keywords: e+e− collisions, K0 meson, Semileptonic decay

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 ratio ε2=α′/α between the dark coupling constant and the fine structure constant of 3×10−6–2×10−7 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−→π+π−γISR events. The combined 90% CL limit increases the sensitivity especially in the ρ–ω interference region and excludes ε2 greater than (13−2)×10−7. For dark photon masses greater than 600 MeV the combined limit is lower than 8 ×10−7 resulting more stringent than present constraints from other experiments. Keywords: e+e− Collisions, Dark forces, Gauge vector boson, Upper limits

Abstract Using 1.63 fb−1 of integrated luminosity collected by the KLOE experiment about 7 × 104 K S → π ± e ∓ ν decays have been reconstructed. The measured value of the charge asymmetry for this decay is A S = (−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 A S = (−3.8 ± 5.0stat ± 2.6syst) × 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.

Abstract 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 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(e + e − → π + π −γ(γ)). 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 μ π + π − = 489.8 ± 1.7 stat ± 4.8 s y s × 10 − 10 $$ {a}_{\mu}^{\pi^{+}{\pi}^{-}}=\left(489.8\pm {1.7}_{\mathrm{stat}}\pm {4.8}_{\mathrm{sys}}\right)\times {10}^{-10} $$ . Data vectors and covariance matrices are available at http://www.lnf.infn.it/kloe/ppg/ ppg_2017/ppg_2017.html .

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, we studied the process e+e−→Uγ, 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, ε2, at 10−6–10−4 in the 5–520 MeV/c2 mass range.

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 DAΦNE. 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 2mμ

We have studied the vector to pseudoscalar conversion decay ϕ→ηe+e−, with η→π0π0π0, with the KLOE detector at DAΦNE. 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. Keywords: e+e− collisions, Conversion decay, Transition form factor

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. Keywords: e+e− experiments, Kaon decays

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

CYGNO is an international collaboration with the aim of operating a Image 3 optical time projection chamber (TPC) for directional Dark Matter (DM) searches and solar neutrino spectroscopy, to be deployed at the Laboratori Nazionali del Gran Sasso (LNGS). A Image 1/Image 2 (60/40) mixture is used, along with a triple Gas Electron Multiplier (GEM) cascade to amplify the ionisation signal. The scintillation produced in the electron avalanches is read out using a scientific complementary metal–oxide–semiconductor (sCMOS) camera. This solution has proven to provide very high sensitivity to interactions in the few Image 4 energy range. The inclusion of a hydrogen-based gas will offer an even lighter target, resulting in a more efficient energy transfer in a DM particle collision, and consequently, a lower detection threshold. Additionally, longer track lengths of light nuclear recoils are easier to detect with a clearer direction. However, the addition of such gas will contribute to quenching the scintillation, jeopardizing the TPC performance. In this work, we demonstrate the feasibility of adding 1% to 5% isobutane to the Image 1/Image 2 (60/40) mixture by measuring the respective absolute scintillation yield output. The overall scintillation produced in the charge avalanches is not drastically suppressed by quenching due to the isobutane addition. The presence of Penning transfer from excited He atoms to isobutane molecules increases the number of electrons in the avalanches, partially compensating for the loss of scintillation due to quenching. For the highest applied GEM voltage, the total number of photons produced in the avalanche per Image 4 deposited in the absorption region presents a decrease of only a factor of about three, from 2.30(20)×104 to 8.2(4)×103 Image 5, as the isobutane content increases from 0 to 5%. The quantification of the visible component of the scintillation shows that isobutane quenches both visible and ultraviolet (UV) photons emitted by Image 1/Image 2.

Abstract MicroRNAs (miRNAs) hold great promise in cancer research. The use of appropriate reference miRNAs for normalization of qPCR data is crucial for accurate expression analysis. We present here analysis and verification of current data, proposing a workflow strategy for identification of reference miRNAs in colorectal cancer (CRC). We performed a systematic review of studies aimed to identify stable reference miRNAs in CRC through high-throughput screening. Among the candidate miRNAs selected from the literature we excluded those predicted to target oncogenes or tumor suppressor gene. We then assessed the expression levels of the remaining candidates in exosomes, plasma and tissue samples from CRC patients and healthy controls. The expression stability was evaluated by box-plot, ∆Cq analysis, NormFinder and BestKeeper statistical algorithms. The effects of normalisers on the relative quantification of the oncogenic miR-1290 was also assessed. Our results consistently showed that different combinations of miR-520d, miR-1228 and miR-345 provided the most stably expressed reference miRNAs in the three biological matrices. We identified suitable reference miRNAs for future miRNA expression studies in exosomes plasma and tissues CRC samples. We also provided a novel conceptual framework that overcome the need of performing ex novo identification of suitable reference genes in single experimental systems.

We have measured the running of the effective QED coupling constant α(s) in the time-like region 0.6

Background: The objective of this study was to determine the effectiveness of the group program "parent management training" to reduce the symptoms of external disorders of children affected by attention deficit/hyperactivity disorder (ADHD). Methods: The method was semi-experimental design with pretest, posttest, control group, and follow-up was two months. Statistical population were all parents of children with ADHD in the Alborz province, who had referred from 2010 to clinic of childhood and adolescence disorders’ Dr. Maryam Dalili, and had records there. Among them 30 children aged 3-10 and their parents were selected by sampling and matched with regard to research criteria and were randomly divided into two groups of 15 people. Research tool was Rutter`s behavioral assessment questionnaire 1964 that was performed in both groups in pretest, posttest and follow-up. The Management training program for parents of Barkely 1987, included 9 session one-hour, once a week was presented to parents of experimental group, and the control group received no intervention. Data were analyzed by using one-way intra group covariance analysis. Results: Results showed that parents management training significantly has reduced the behavioral disorders symptoms and external signs including aggression, impulsivity, hyperactivity and anxiety in children with ADHA compared with the control group and pretest stage. Conclusion: Parent management training can be an effective method to treat the external symptoms of children with ADHA, and this method can be used in combination with other treatments that are performed about these children, such as drug therapy, behavioral therapy and so on.

The aim of this study is to examine the effect of self-instruction techniques on reading performance of students with medium dyslexic and depression symptoms . From a sample of the students of the third and forth grades of public primary schools, 32 students were randomly selected and assigned to the two experimental and control groups. The experiment group practiced the self-instruction techniques for 12 sessions, while the students in the control group continued their ordinary school activities. In the experiment group the students' parents (i.e. mother) were also trained for six sessions to help their children at home. The data were evaluated through covariance analysis. The results indicated that the self-instruction techniques are effective on the improvement of reading performance of students and the reduction of depression symptoms. After 5 months, the results of follow up studies revealed that although student marks in the experiment group have decreased to some extent, the difference between experiment and control groups is significant.

As an ex post facto research, it aimed to study the effects of similarity and dissimilarity of introversion/ extroversion personality characteristics of married couples on their marital satisfaction. The sample studied composed 207 married couples who lived together. The research instruments were Eysench's 57 item personality scale, Enrich's 47 marital satisfaction questionnaire, and researcher made informative questionnaire. Couples filled the questionnaires first and then they were divided into sixteen different groups according to the similarity or dissimilarity of their introversion / extroversion personality characteristics. Data were collected and descriptive statistics was used for data analysis. One way Anova and LSD test were used to determine the significance of means difference. In the light of previous research and five hypotheses of the present research the following results were obtained which can be used in pre and post marriage counseling: 1) The highest degree of marital Satisfaction was observed among couples composed of a moderate introvert / extrovert and an introvert partner. 2) The second highest degree of marital satisfaction belonged to the married couples who were both normal extroverts. 3) The third highest degree of marital satisfaction was observed among married couples who were excessive introverts or a moderate person and an excessive introvert. 4) The degree of marital satisfaction of an introvert female married to an extrovert male fell in the fourth category. 5) The degree of marital satisfaction of an introvert females married to an excessive extrovert male 6) The least degree of marital satisfaction was observed among an extrovert female married to an introvert male.