6,683 research outputs found

    Results on CP Violation from the NA48 experiment at CERN

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    In this article the current status and latest results of the NA48 experiment at CERN are given. We present in more details the analysis performed for the Re(e'/e) measurement with the combined statistics accumulated during the 1998 and 1999 data periods. Reviewing the NA48 rare decay program, we select to underline the new results on the branching ratio and the A_v factor for the decay KL->pi0gg and the KL->pi+pi-e+e- CP violating decay. This article is the contribution to the Proceedings of the Lepton-Photon Conference held in Roma, July 23-29 2001.Comment: 13 pages, 11 figures, contribution to the Lepton-Photon 2001 Conference Proceedings -ne

    Recent CP violation and |Vus_{us}| measurements from the NA48 experiment

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    Results from recent analyses of the NA48 experiment at CERN are compared with other experiments and confronted with theoretical predictions to provide constraints on the CKM matrix and on CP Violation. The observable eta+- is related to the parameters of indirect and direct CPV (eta+- = epsilon + epsilon'). |eta+-| has been determined by measuring the ratio of decay rates: Gamma(K_L to pi+pi-)/Gamma(K_L to pi e nu), using an NA48 run with a dedicated pure high-intensity K_L beam. The main objective of NA48/2 has been to search for direct CP violation by high precision measurement of the asymmetry A_g = (g+ - g-)/(g+ + g-) of the linear slope parameter g in the Dalitz plot of K+- to 3pi decays. The final results from all data samples are summarised and discussed. The decay rates R(Ke3/K2pi), R(Kmu3/K2pi) and R(Kmu3/Ke3) have been measured with charged K decays from special data samples with a low bias trigger in the NA48/2 experiment. Using the latest PDG average for the (K+- to pi+- pi0) normalisation channel, the Ke3 and Kmu3 branching fractions are then used as input to deduce the CKM matrix element Vus

    Motor games for learning fundamental motor skills

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    Active Initiation Guidelines recommend that children up to age 5 years engage in daily physical activity to develop basic motor skills for health-related fitness. However, many entering kindergarten today have low motor skills and many more are predicted to have lower motor coordination skills tomorrow. Recent studies suggest that children who do not adequately develop their movement skills and fitness levels in early childhood will fail to progress them later in life. This chapter presents a literature review of motor competence in young children and suggests game playing as a means for preschoolers to learn fundamental motor skills in locomotor and object control skills

    Coherent radiation of atoms and a channeling particle

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    New mechanism of radiation emitted at channeling of a relativistic particle in a crystal is studied. Superposition of coherent radiation of the atoms in a crystal lattice which are excited by a channeling particle and radiation of the channeling particle itself is considered. It is shown that coherent radiation of the chain of oscillating atoms forms a resonance peak on the background of radiation of the channeling particle.Comment: 7 pages, 4 figure

    A Strategy analysis for genetic association studies with known inbreeding

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    Background: Association studies consist in identifying the genetic variants which are related to a specific disease through the use of statistical multiple hypothesis testing or segregation analysis in pedigrees. This type of studies has been very successful in the case of Mendelian monogenic disorders while it has been less successful in identifying genetic variants related to complex diseases where the insurgence depends on the interactions between different genes and the environment. The current technology allows to genotype more than a million of markers and this number has been rapidly increasing in the last years with the imputation based on templates sets and whole genome sequencing. This type of data introduces a great amount of noise in the statistical analysis and usually requires a great number of samples. Current methods seldom take into account gene-gene and gene-environment interactions which are fundamental especially in complex diseases. In this paper we propose to use a non-parametric additive model to detect the genetic variants related to diseases which accounts for interactions of unknown order. Although this is not new to the current literature, we show that in an isolated population, where the most related subjects share also most of their genetic code, the use of additive models may be improved if the available genealogical tree is taken into account. Specifically, we form a sample of cases and controls with the highest inbreeding by means of the Hungarian method, and estimate the set of genes/environmental variables, associated with the disease, by means of Random Forest. Results: We have evidence, from statistical theory, simulations and two applications, that we build a suitable procedure to eliminate stratification between cases and controls and that it also has enough precision in identifying genetic variants responsible for a disease. This procedure has been successfully used for the betathalassemia, which is a well known Mendelian disease, and also to the common asthma where we have identified candidate genes that underlie to the susceptibility of the asthma. Some of such candidate genes have been also found related to common asthma in the current literature. Conclusions: The data analysis approach, based on selecting the most related cases and controls along with the Random Forest model, is a powerful tool for detecting genetic variants associated to a disease in isolated populations. Moreover, this method provides also a prediction model that has accuracy in estimating the unknown disease status and that can be generally used to build kit tests for a wide class of Mendelian diseases

    Intrinsic Charm Contribution to Double Quarkonium Hadroproduction

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    Double J/ψJ/\psi production has been observed by the NA3 collaboration in πN\pi N and pNp N collisions with a cross section of the order of 20-30 pb. The ψψ\psi \psi pairs measured in π−\pi^- nucleus interactions at 150 and 280 GeV/c/c are observed to carry an anomalously large fraction of the projectile momentum in the laboratory frame, xψψ≥0.6x_{\psi \psi} \geq 0.6 at 150 GeV/c/c and ≥0.4\geq 0.4 at 280 GeV/c/c. We postulate that these forward ψψ\psi \psi pairs are created by the materialization of Fock states in the projectile containing two pairs of intrinsic cc‾c \overline c quarks. We calculate the overlap of the charmonium states with the ∣u‾dcc‾cc‾⟩|\overline u d c \overline c c \overline c \rangle Fock state as described by the intrinsic charm model and find that the π−N→ψψ\pi^- N \rightarrow \psi \psi longitudinal momentum and invariant mass distributions are both well reproduced. We also discuss double J/ψJ/\psi production in pNpN interactions and the implications for other heavy quarkonium production channels in QCD.Comment: Revtex, APS style, 7 pages, 3 figures in uuencoded fil

    The simultaneous long- and short-lived neutral kaon beams for experiment NA48

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    Simultaneous, nearly-collinear beams of long- and short-lived neutral kaons are an essential feature of the precision CP-violation experiment NA48 *) at the SPS. The present report describes the design and performance of these beams in relation to the requirements of the experiment

    The simultaneous and nearly-collinear K0K^{0} beams for experiment NA48

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    A system of simultaneous and nearly-collinear beams of long- and short-lived neutral kaons has been installed and extensively studied. These beams form an integral part of the NA48 experiment at the CERN SPS, which aims to study direct CP-violation. The beam splitting is achieved by a novel application of a bent silicon crystal. The principles and design of these beams, as well as their performance are described
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