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1. Latest results on rare kaon decays from the NA48/2 experiment at CERN

Author

E. M. Gersabeck, M. C. Petrucci, C. Cerri, N. Doble, Stoyan Stoynev, W. Kubischta, C. Damiani, G. Marel, D. J. Munday, Rainer Wanke, B. Bloch-Devaux, P. Rubin, M. Ziolkowski, Anne Dabrowski, M. Pepe, A. Winhart, M. Holder, E. C. Swallow, E. Imbergamo, G. Bocquet, Yu. Potrebenikov, A. Michetti, Peter Zahariev Hristov, Konrad Kleinknecht, Emmanuel Monnier, M. Markytan, M. Lenti, B. Renk, C. Lazzeroni, P. Marouelli, F. Marchetto, C. Morales Morales, L. Widhalm, D. Coward, Vladimir Kekelidze, V. Falaleev, M. Valdata-Nappi, G. Ruggiero, A. Peters, Evgueni Goudzovski, B. Vallage, Mayda Velasco, W. Baldini, A. Gonidec, E. Iacopini, V. Kozhuharov, G. Collazuol, N. A. Molokanova, Andreas Alexander Maier, K. Eppard, U. Moosbrugger, S. Venditti, Cvetan Valeriev Cheshkov, S. Shkarovskiy, T. Fonseca Martin, J.B. Cheze, G. Lamanna, H. D. Wahl, Luca Fiorini, Nicolo Cartiglia, S. Balev, M. Martini, M. Fidecaro, R. Fantechi, A. Gianoli, M. Scarpa, I. Mannelli, Ivan Mikulec, Milene Calvetti, B. Peyaud, P. F. Dalpiaz, Fabrizio Petrucci, M. Veltri, S. Goy Lopez, G. E. Kalmus, Marco Clemencic, H. Dibon, Leander Litov, A. Norton, Roland Winston, Simone Bifani, M. Shieh, P.L. Frabetti, M. Wache, L. Masetti, Mauro Raggi, I. Polenkevich, D. T. Madigozhin, M. D. Wood, Alan W. Walker, Mark Slater, E. Mazzucato, F. Costantini, Milena Misheva, Jacqueline Batley, A. Ceccucci, Andrea Bizzeti, Michal Szleper, Nicola Cabibbo, P. Cenci, M. Savrie, J. Derre, Roberta Arcidiacono, G. Neuhofer, M. Behler, M. Patel, D.C. Cundy, A.I. Zinchenko, A. Nappi, M. Raggi, Manfred Jeitler, G. Anzivino, G.M. Pierazzini, L. Gatignon, M. Sozzi, S. A. Wotton, L. DiLella, Cristina Biino, S. Giudici, M. Fiorini, and Mauro Piccini

Subjects
Physics, Particle physics, Large Hadron Collider, High Energy Physics::Experiment, Nuclear Physics - Experiment, Particle Physics - Experiment
Abstract

The NA48/2 experiment at CERN reports the first observation of the K->pi0e+e-decay from an exposure of 1.7x10^11 charged kaon decays recorded in 2003-2004. A sample of 4919candidates with 4.9% background contamination allows the determination of the branching ratioin the full kinematic region. The study of the kinematic space shows evidence for a structuredependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated. The most precise measurement of the charged kaon semi-leptonic form factors obtained by NA48/2 with 4.4 million Ke3 and 2.3 million Km3 events collected in 2004 will also be presented.

Published
2021

2. Measurement of the form factors of charged kaon semileptonic decays

Author

V. Kozhuharov, P. Cenci, M. Valdata-Nappi, S. Venditti, M. Shieh, Jacqueline Batley, C. Cerri, G. Collazuol, Manfred Jeitler, J. Derre, N. Doble, U. Moosbrugger, S. Giudici, Roberta Arcidiacono, M. De Beer, Maulik R. Patel, M. Wache, M. Behler, Cristina Lazzeroni, Giuseppe Ruggiero, Rainer Wanke, Augusto Ceccucci, G. Bocquet, Yu. Potrebenikov, Nicola Cabibbo, B. Vallage, M. Slater, C. Cheshkov, A. A. Maier, G. Kalmus, D. T. Madigozhin, S. Goy Lopez, M. Savrie, B. Bloch-Devaux, A. Peters, Lau Gatignon, V. Falaleev, P. L. Frabetti, P. Rubin, E. Imbergamo, E. Mazzucato, A. Norton, Enrico Celeghini, G.M. Pierazzini, Cristina Biino, Ivan Mikulec, F. Costantini, B. Renk, D. Coward, M. Scarpa, Andrea Bizzeti, A. Winhart, M. Szleper, C. Morales Morales, P. F. Dalpiaz, Nicolo Cartiglia, E. C. Swallow, M. D. Wood, M. Veltri, M. Holder, H. Wahl, M. C. Petrucci, Evgueni Goudzovski, E. Iacopini, A. Michetti, Mayda Velasco, I. Polenkevich, M. Ziolkowski, Massimiliano Fiorini, M. Sozzi, M. Fidecaro, A. Nappi, Peter Zahariev Hristov, P. Marouelli, A. I. Zinchenko, C. Damiani, Evelina Gersabeck, Simone Bifani, S. A. Wotton, B. Peyaud, R. Fantechi, Vladimir Kekelidze, L. DiLella, K. Kleinknecht, Anne Dabrowski, A. Gianoli, Leander Litov, W. Baldini, G. Marel, S. Shkarovskiy, M. Markytan, M. Lenti, G. Lamanna, I. Mannelli, Marco Clemencic, Milene Calvetti, R. Winston, M. Pepe, Stoyan Stoynev, A. Gonidec, Giuseppina Anzivino, W. Kubischta, Alan W. Walker, L. Masetti, M. Hita-Hochgesand, E. Monnier, H. Dibon, T. Fonseca Martin, D. J. Munday, Mauro Piccini, S. Balev, N. A. Molokanova, M. Martini, K. Eppard, Mauro Raggi, F. Marchetto, L. Widhalm, A. Cotta Ramusino, G. Neuhofer, D.C. Cundy, F. Petrucci, J.B. Cheze, Luca Fiorini, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and NA48/2

Subjects
Nuclear Theory, S010LQM, S010MSM, Fixed target experiments, Rare decay, K meson, 01 natural sciences, S010LMM, Physics, Particles & Fields, High Energy Physics - Experiment, Economica, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], S010LAM, Nuclear Experiment, Physics, Quantum chromodynamics, form factor, 02 Physical Sciences, Form factor (quantum field theory), semileptonic decay, Kaon, Nuclear & Particles Physics, Fixed target experiments Rare decay, 3. Good health, Rare decay, Nuclear and High Energy Physics, Physical Sciences, Particle Physics - Experiment, Semileptonic decay, Particle physics, S010LPE, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, 0103 physical sciences, S010MVM, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, K: semileptonic decay, 010306 general physics, 01 Mathematical Sciences, S010MVE, S010LLM, Science & Technology, 010308 nuclear & particles physics, hep-ex, High Energy Physics::Phenomenology, Ambientale, K meson, S010LPM, S010LQE, NA48, lcsh:QC770-798, High Energy Physics::Experiment, S010L0
Abstract

A measurement of the form factors of charged kaon semileptonic decays is presented, based on $4.4 \times 10^6$ $K^\pm \to \pi^0 e^\pm \nu_e$ ($K^\pm_{e3}$) and $2.3 \times 10^6$ $K^\pm \to \pi^0 \mu^\pm \nu_{\mu}$ ($K^\pm_{\mu3}$) decays collected in 2004 by the NA48/2 experiment. The results are obtained with improved precision as compared to earlier measurements. The combination of measurements in the $K^\pm_{e3}$ and $K^\pm_{\mu3}$ modes is also presented., Comment: 20 pages , 9 figures, 5 tables

Published
2018

3. MOSCAB: a geyser-concept bubble chamber to be used in a dark matter search

Author

Massimiliano Clemenza, D.C. Cundy, Daniele Cattaneo, R. Podviyanuk, Elisa Ricci, M. Perego, L. Cretara, Massimo Corcione, Gianfranco Caruso, Domenico G. Sorrenti, Giacomo Bruno, F. Chignoli, Antonio Papagni, M. Frullini, A. Santagata, R. Bertoni, A. Pullia, L. Manara, N. Burgio, G. Lucchini, A. Antonicci, M. Maspero, M. Ardid, N. G. Redaelli, R. Mazza, L. Zanotti, Ivan Felis, W. Fulgione, Alessandro Quintino, Antonicci, A., Ardid, M., Bertoni, R., Bruno, G., Burgio, N., Caruso, G., Cattaneo, D., Chignoli, F., Clemenza, M., Corcione, M., Cretara, L., Cundy, D., Felis, I., Frullini, M., Fulgione, W., Lucchini, G., Manara, L., Maspero, M., Mazza, R., Papagni, A., Perego, M., Podviyanuk, R., Pullia, A., Quintino, A., Redaelli, N., Ricci, E., Santagata, A., Sorrenti, D., Zanotti, L., Antonicci, A, Ardid, M, Bertoni, R, Bruno, G, Burgio, N, Caruso, G, Cattaneo, D, Chignoli, F, Clemenza, M, Corcione, M, Cretara, L, Cundy, D, Felis, I, Frullini, M, Fulgione, W, Lucchini, G, Manara, L, Maspero, M, Mazza, R, Papagni, A, Perego, M, Podviyanuk, R, Pullia, A, Quintino, A, Redaelli, N, Ricci, E, Santagata, A, Sorrenti, D, and Zanotti, L

Subjects
Physics - Instrumentation and Detectors, Physics and Astronomy (miscellaneous), Critical phenomena, Dark matter, FOS: Physical sciences, lcsh:Astrophysics, 01 natural sciences, ING-INF/05 - SISTEMI DI ELABORAZIONE DELLE INFORMAZIONI, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Simplicity (photography), lcsh:QB460-466, 0103 physical sciences, Extensive data, Bubble chamber, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Detectors and Experimental Techniques, 010306 general physics, Engineering (miscellaneous), physics.ins-det, Physics, dark matter, bubble chamber, MOSCAB, Series (mathematics), 010308 nuclear & particles physics, hep-ex, Detector, Mechanics, Instrumentation and Detectors (physics.ins-det), Superheating, FIS/01 - FISICA SPERIMENTALE, FISICA APLICADA, lcsh:QC770-798, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE, Particle Physics - Experiment
Abstract

[EN] The MOSCAB experiment (Materia OSCura A Bolle) uses the "geyser technique", a variant of the superheated liquid technique of extreme simplicity. Operating principles of the new dark matter detector and technical solutions of the device are reported in detail. First results obtained in a series of test runs taken in laboratory demonstrate that we have successfully built and tested a geyser-concept bubble chamber that can be used in particle physics, especially in dark matter searches, and that we are ready to move underground for extensive data taking., We gratefully acknowledge support from Istituto Nazionale di Fisica Nucleare (INFN) and Spanish Ministerio de Economia y Competitividad (MINECO), Grants FPA-2015-65150-C3-2-P (MINE-CO/FEDER), and Consolider MultiDark CSD2009-00064. We are grateful to Laboratori Nazionali delGran Sasso (LNGS) for hosting and supporting the MOSCAB project. We thank Massimo Locatelli, Tecnologia Meccanica, Treviolo (BG), Italy, for supporting our project with hard work, competence and passion, and Francesco Boccardo, Vincenzo Caglioti and Dario Menasce for fruitful discussions and their contribution in preparing the manuscript.

Published
2017

4. Neutral pion form factor measurement by the NA62 experiment

Author

Fabrizio Petrucci, A. Gonidec, Leander Litov, A. Romano, G. Collazuol, P.L. Frabetti, M. Scarpa, M. Hita-Hochgesand, Marco Clemencic, V K Semenov, F. Retire, S. Balev, M. Martini, V. Obraztsov, V. Kozhuharov, B. Hallgren, V. Falaleev, I. Mannelli, Rainer Wanke, M. Shieh, M. Zamkovsky, Alan W. Walker, Roberto Piandani, P. Rubin, Jacqueline Batley, Mark Slater, N. A. Molokanova, Peter Zahariev Hristov, F. Marchetto, N. Doble, O. Yushchenko, A. Winhart, L. Widhalm, L. Masetti, A. Peters, K. Eppard, M. Napolitano, G. Dellacasa, Vladimir Kekelidze, Evgueni Goudzovski, Tomas Blazek, E. C. Swallow, U. Moosbrugger, Antonino Sergi, A. Cotta Ramusino, Evgeny Gushchin, S. Movchan, H. D. Wahl, Simone Bifani, M. Fidecaro, F. Ambrosino, Andreas Alexander Maier, P. F. Dalpiaz, M. Moulson, F. Costantini, B. Peyaud, E. Iacopini, M. C. Petrucci, Petra Riedler, Mauro Piccini, P. Marouelli, A. Michetti, Konrad Kleinknecht, Paolo Massarotti, C. Damiani, T. Spadaro, T. Numao, G. D'Agostini, Ivan Mikulec, V. Palladino, Paolo Valente, M. Veltri, D. Coward, Anne Dabrowski, Viacheslav Duk, G. Lamanna, G. Marel, Emilio Leonardi, M. Pepe, M. Valdata-Nappi, M. Ziolkowski, I. Polenkevich, M. D. Wood, Jürgen Engelfried, Emmanuel Monnier, R. Fantechi, A.I. Zinchenko, M. Markytan, M. Lenti, Milene Calvetti, F. Bucci, A. Ceccucci, M. Holder, H. O. Danielsson, Milena Misheva, Andrea Bizzeti, M. Koval, S. Venditti, V. Bolotov, S. A. Wotton, C. Cerri, H. Dibon, Wander Baldini, G. Bocquet, Yu. Potrebenikov, J. Derr, Cristina Lazzeroni, M. Savri, E. Imbergamo, Maulik R. Patel, A. Antonelli, Mauro Raggi, C. Morales Morales, D. Di Filippo, J. B. Chze, S. Shkarovskiy, T. Fonseca Martin, S. Goy Lopez, A. Salamon, M. Serra, A. Norton, Roland Winston, Massimiliano Fiorini, S. Gallorini, V. Kurshetsov, Nicolo Cartiglia, Stoyan Stoynev, W. Kubischta, D. J. Munday, S. Giudici, M. Sozzi, L. DiLella, Cristina Biino, M. De Beer, M. Wache, D. T. Madigozhin, E. Mazzucato, P. Cenci, M. Behler, Roberta Arcidiacono, Michal Szleper, Nicola Cabibbo, B. Bloch-Devaux, G.E. Kalmus, A. Nappi, Mayda Velasco, Cvetan Valeriev Cheshkov, G. Saracino, E. Gersabeck, B. Renk, Manfred Jeitler, A. Gianoli, G.M. Pierazzini, G. Anzivino, A. Fucci, Lidia Fiorini, B. Vallage, L. Gatignon, I. Popov, G. Neuhofer, D.C. Cundy, Nicolas Lurkin, G. Ruggiero, Zamkovsky, Michal, Ambrosino, F., Antonelli, A., Anzivino, G., Arcidiacono, R., Baldini, W., Balev, S., Batley, J. R., Behler, M., Bifani, S., Biino, C., Bizzeti, A., Blazek, T., Bloch-Devaux, B., Bocquet, G., Bolotov, V., Bucci, F., Cabibbo, N., Calvetti, M., Cartiglia, N., Ceccucci, A., Cenci, P., Cerri, C., Cheshkov, C., Chze, J. B., Clemencic, M., Collazuol, G., Costantini, F., Cotta Ramusino, A., Coward, D., Cundy, D., Dabrowski, A., Dagostini, G., Dalpiaz, P., Damiani, C., Danielsson, H., De Beer, M., Dellacasa, G., Derr, J., Dibon, H., Di Filippo, D., Dilella, L., Doble, N., Duk, V., Engelfried, J., Eppard, K., Falaleev, V., Fantechi, R., Fidecaro, M., Fiorini, L., Fiorini, M., Fonseca Martin, T., Frabetti, P. L., Fucci, A., Gallorini, S., Gatignon, L., Gersabeck, E., Gianoli, A., Giudici, S., Gonidec, A., Goudzovski, E., Goy Lopez, S., Gushchin, E., Hallgren, B., Hita-Hochgesand, M., Holder, M., Hristov, P., Iacopini, E., Imbergamo, E., Jeitler, M., Kalmus, G., Kekelidze, V., Kleinknecht, K., Koval, M., Kozhuharov, V., Kubischta, W., Kurshetsov, V., Lamanna, G., Lazzeroni, C., Lenti, M., Leonardi, E., Litov, L., Lurkin, N., Madigozhin, D., Maier, A., Mannelli, I., Marchetto, F., Marel, G., Markytan, M., Marouelli, P., Martini, M., Masetti, L., Massarotti, P., Mazzucato, E., Michetti, A., Mikulec, I., Misheva, M., Molokanova, N., Monnier, E., Moosbrugger, U., Morales Morales, C., Moulson, M., Movchan, S., Munday, D. J., Napolitano, M., Nappi, A., Neuhofer, G., Norton, A., Numao, T., Obraztsov, V., Palladino, V., Patel, M., Pepe, M., Peters, A., Petrucci, F., Petrucci, M. C., Peyaud, B., Piandani, R., Piccini, M., Pierazzini, G., Polenkevich, I., Popov, I., Potrebenikov, Y., Raggi, M., Renk, B., Retire, F., Riedler, P., Romano, A., Rubin, P., Ruggiero, G., Salamon, A., Saracino, G., Savri, M., Scarpa, M., Semenov, V., Sergi, A., Serra, M., Shieh, M., Shkarovskiy, S., Slater, M. W., Sozzi, M., Spadaro, T., Stoynev, S., Swallow, E., Szleper, M., Valdata-Nappi, M., Valente, P., Vallage, B., Velasco, M., Veltri, M., Venditti, S., Wache, M., Wahl, H., Walker, A., Wanke, R., Widhalm, L., Winhart, A., Winston, R., Wood, M. D., Wotton, S. A., Yushchenko, O., Zinchenko, A., and Ziolkowski, M.

Subjects
Physics, History, Particle physics, 02 Physical Sciences, Meson, 010308 nuclear & particles physics, Nuclear Theory, Form factor (quantum field theory), Elementary particle, NA62 experiment, 01 natural sciences, 09 Engineering, Dark photon, Computer Science Applications, Education, Nuclear physics, Physics and Astronomy (all), Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Lepton, Dimensionless quantity
Abstract

The NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion in the time-like region from ∼1 million fully reconstructed π 0 Dalitz decay is presented. The limits on dark photon production in π 0 decays from the earlier kaon experiment at CERN, NA48/2, are also reported.

Published
2017

5. A new measurement of the K±→π±γγ decay at the NA48/2 experiment

Author

Fabrizio Petrucci, B. Vallage, Lau Gatignon, Cristina Biino, G. Neuhofer, A. Winhart, M. Sozzi, L. DiLella, Massimiliano Fiorini, Leander Litov, S. Giudici, T. Fonseca Martin, E. Monnier, P. Cenci, D.C. Cundy, Nicola Cabibbo, C. Cheshkov, V. Kozhuharov, R. Fantechi, M. Veltri, A. I. Zinchenko, D.J. Munday, Milene Calvetti, W. Kubischta, M. Savrie, Marco Clemencic, Nicolo Cartiglia, M. Pepe, I. Polenkevich, B. Bloch-Devaux, N. Doble, M. D. Wood, Enrico Celeghini, Mauro Piccini, A. Ceccucci, I. Mannelli, A. Gianoli, P. Hristov, Evelina Gersabeck, G.E. Kalmus, M. Szleper, A. Peters, Andrea Bizzeti, M. De Beer, H. Dibon, Wander Baldini, Cristina Lazzeroni, F. Marchetto, A. Cotta Ramusino, A. Dabrowski, Ivan Mikulec, L. Widhalm, S. Goy Lopez, J.B. Cheze, J. Derre, M. C. Petrucci, Mauro Raggi, A. Norton, Roland Winston, C. Morales Morales, M. Behler, Roberta Arcidiacono, A. A. Maier, F. Costantini, G. Ruggiero, E. Imbergamo, Luca Fiorini, M. Ziolkowski, S. Stoynev, L. Masetti, Mayda Velasco, A. Gonidec, P. Rubin, C. Cerri, M. Wache, Vladimir Kekelidze, P. Marouelli, D. T. Madigozhin, U. Moosbrugger, G. Collazuol, M. Markytan, M. Lenti, E. Iacopini, H. D. Wahl, M. Fidecaro, G.M. Pierazzini, E. Mazzucato, B. Peyaud, P. F. Dalpiaz, M.W. Slater, G. Lamanna, M. Shieh, B. Renk, C. Damiani, J. R. Batley, M. Scarpa, G. Bocquet, Yu. Potrebenikov, Evgueni Goudzovski, S. Balev, M. Martini, Alan W. Walker, V. Falaleev, A. Nappi, Manfred Jeitler, G. Anzivino, N. A. Molokanova, K. Eppard, P. L. Frabetti, Konrad Kleinknecht, A. Michetti, M. Valdata-Nappi, M. Holder, S. Venditti, S. A. Wotton, Maulik R. Patel, Simone Bifani, Rainer Wanke, E. C. Swallow, D. Coward, and G. Marel

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle decay, Pion, Chiral perturbation theory, Meson, Branching fraction, Hadron, Analytical chemistry, Radioactive decay, Dimensionless quantity
Abstract

The NA48/2 experiment at CERN collected two data samples with minimum bias trigger conditions in 2003 and 2004. A measurement of the rate and dynamic properties of the rare decay K ± → π ± γ γ from these data sets based on 149 decay candidates with an estimated background of 15.5 ± 0.7 events is reported. The model-independent branching ratio in the kinematic range z = ( m γ γ / m K ) 2 > 0.2 is measured to be B MI ( z > 0.2 ) = ( 0.877 ± 0.089 ) × 10 − 6 , and the branching ratio in the full kinematic range assuming a particular Chiral Perturbation Theory description to be B ( K π γ γ ) = ( 0.910 ± 0.075 ) × 10 − 6 .

Published
2014

6. Measurement of the branching ratio of the decay Ξ0→Σ+μ−ν¯μ

Author

Milene Calvetti, H. Dibon, G.M. Pierazzini, L. Gatignon, G. Ruggiero, A. Gonidec, Cristina Lazzeroni, P. F. Dalpiaz, M. De Beer, S. Giudici, G. Collazuol, T. Fonseca Martin, Mauro Piccini, E. Monnier, G. Bocquet, Yu. Potrebenikov, D.J. Munday, Nicolo Cartiglia, Manfred Jeitler, M. Scarpa, G. Neuhofer, D.C. Cundy, A. Winhart, Rainer Wanke, H. Wahl, Nadia Pastrone, R. Sacco, A. Hirstius, G. Anzivino, G. Gouge, Simone Bifani, M. Behler, Marco Clemencic, M. Pepe, P. Marouelli, B. Panzer-Steindel, M. Veltri, P. Debu, E. Iacopini, R. Winston, S. Wotton, A. Maier, N. Doble, Vladimir Kekelidze, P. Cenci, E. C. Swallow, N. A. Molokanova, P. Grafström, W. Baldini, K. Eppard, Cristina Biino, M. Ziolkowski, P. Rubin, P. Lubrano, M. Holder, A. Nappi, D. T. Madigozhin, A. Peters, Evgueni Goudzovski, F. Costantini, I. Mannelli, M. Sozzi, S. Stoynev, L. Widhalm, S. Goy Lopez, Roberta Arcidiacono, U. Koch, W. Wislicki, U. Moosbrugger, M. Martini, A. Norton, M. Patel, W. Kubischta, Konrad Kleinknecht, G. Marel, M.W. Slater, A. Zinchenko, L. Masetti, Ivan Mikulec, E. Menichetti, E. Mazzucato, P. Hristov, J. R. Batley, E. Imbergamo, B. Peyaud, C. Cheshkov, V. Kozhuharov, M. Eppard, V. Falaleev, M. Savrie, F. Marchetto, A. Michetti, G.E. Kalmus, C. Cerri, B. Vallage, Fabrizio Petrucci, A. Ceccucci, Andrea Bizzeti, Leander Litov, P.L. Frabetti, A. Gianoli, Alan W. Walker, C. Morales Morales, M. Valdata, A. Dabrowski, M. C. Petrucci, Mayda Velasco, M. Markytan, M. Lenti, J.B. Cheze, G. Lamanna, Luca Fiorini, and R. Fantechi

Subjects
Physics, Nuclear and High Energy Physics, Meson, 010308 nuclear & particles physics, Branching fraction, Hadron, Analytical chemistry, Elementary particle, 01 natural sciences, Nuclear physics, 0103 physical sciences, 010306 general physics, Boson, Dimensionless quantity
Abstract

From the 2002 data taking with a neutral kaon beam extracted from the CERN-SPS, the NA48/1 experiment observed 97 Ξ 0 → Σ + μ − ν ¯ μ candidates with a background contamination of 30.8 ± 4.2 events. From this sample, the BR ( Ξ 0 → Σ + μ − ν ¯ μ ) is measured to be ( 2.17 ± 0.32 stat ± 0.17 syst ) × 10 − 6 .

Published
2013

7. SEARCH FOR THE DECAY K(S)-]PI(0)E+E

Author

B. Renk, B. Panzer, J. Schueller, Lydia Iconomidou-Fayard, P. Mayer, L. Bertanza, Harsha Blumer, E. Auge, Laurent Serin, M. Rost, M. Holder, O. Perdereau, I. Mannelli, R. Carosi, Arthur Schaffer, D.C. Cundy, A. Wagner, H. Wahl, Peter Buchholz, A. Bigi, D. Coward, Ken Peach, V.M. Marzulli, M. Calvetti, H. G. Sander, G.M. Pierazzini, Daniel Fournier, H. Rohrer, A. Nappi, R. Werthenbach, L. Gatignon, Paolo Calafiura, A. Kreutz, R. Casali, H.N. Nelson, G.D. Barr, N. Doble, Konrad Kleinknecht, R. Hagelberg, and R. Heinz

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Mass spectrum, CP violation
Abstract

The full data set of the experiment NA31 at CERN has been used to search for the decay Ks→π0e+e-. The rate of this decay may be used to determine the magnitude of the state mixing contribution to the CP violating amplitude of the decay KL→π0e+e-. No candidate events for the decayKs→π0e+- were seen. This leads to a branching ratio upper limit of 1.1 × 10-6 at the 90% confidence level. © 1993.

Published
2016

8. Search for the decay KL → π0π0γ

Author

Konrad Kleinknecht, J. Scheidt, O. Perdereau, Arthur Schaffer, Niels Doble, P. Mayer, D. Coward, A. Bigi, B. Renk, Paolo Calafiura, G.M. Pierazzini, Lydia Iconomidou-Fayard, H. D. Wahl, L. Bertanza, G.D. Barr, V.M. Marzulli, A. Wagner, M. Holder, L. Gatignon, R. Carosi, T. Beier, E. Augé, D.C. Cundy, I. Mannelli, A. Kreutz, R. Werthenbach, Laurent Serin, A. Nappi, J. Staeck, R. Heinz, R. Hagelberg, H. Blümer, M. Calvetti, R. Casali, C. Cerri, H.N. Nelson, Peter Buchholz, M. Rost, H. G. Sander, P. Grafström, Ken Peach, Daniel Fournier, and H. Rohrer

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle decay, Particle physics, Photon, Branching fraction, Signal region, Elementary particle, Upper and lower bounds
Abstract

Data from the NA31 experiment at CERN have been used for a search for the decay mode K L → π 0 π 0 γ . After all cuts, three events remain in the signal region with an estimated background of 2.2 ± 0.9 events. The upper limit for the branching ratio of K L → π 0 π 0 γ is 5.6 × 10 −6 at the 90% confidence level.

Published
2016

9. Search for the decay KS → π0γγ

Author

R.S. Dosanjh, M. Wittgen, J. Cogan, M. De Beer, T.J. Gershon, H. D. Wahl, G. Govi, W. Kubischta, E. Rondio, T. Cuhadar-Dönszelmann, Peter Zahariev Hristov, Anton Taurok, K. Holtz, Rainer Wanke, B. Peyaud, C. Cheshkov, N. A. Molokanova, M. Markytan, M. Lenti, D. J. Munday, Vladimir Kekelidze, G. Graziani, G. Neuhofer, A. Nappi, Lau Gatignon, A. Tkatchev, Nadia Pastrone, J.-C. Chollet, P. F. Dalpiaz, B. Panzer-Steindel, P. Cenci, E. Iacopini, P. Grafström, R. Turlay, I.G. Knowles, Konrad Kleinknecht, V. Falaleev, S. Giudici, I. Mannelli, D.C. Cundy, M. Contalbrigo, M. Pepe, S. Wronka, Y. Schué, B. Vallage, Benedetto Gorini, D. Marras, R. Fantechi, A. Maier, M. Eppard, G. Fischer, Milene Calvetti, L. Köpke, D. Madigojine, U. Koch, Manfred Jeitler, C. Cerri, R. Carosi, A. Lai, Andrea Formica, A. Winhart, A. Peters, Nicolo Cartiglia, A. Kalter, S. A. Wotton, Michael Andrew Parker, P.L. Frabetti, Louis Fayard, Mauro Piccini, F. Marchetto, A. Norton, J. Duclos, H. Dibon, Michal Szleper, Niels Doble, E. Olaiya, I. Pellmann, G. Unal, H. Fox, G. Anzivino, P. Debu, L. Widhalm, F. Costantini, E. Mazzucato, Roberta Arcidiacono, M. Sozzi, R. Sacco, B. Renk, A. Lacourt, Augusto Ceccucci, G. Pierazzini, J. Nassalski, T. O. White, W. Wislicki, V. Schönharting, M. Pernicka, Alan W. Walker, P. Lopes da Silva, L. Masetti, Sandro Palestini, A. Gonidec, A. I. Zinchenko, Lydia Iconomidou-Fayard, M. Holder, P. Marouelli, M. Cirilli, G. Collazuol, F. Petrucci, A. Gianoli, M. Savrie, C. Lazzeroni, R. Granier de Cassagnac, Roberto Guida, R. Casali, G. Tatishvili, G. Bocquet, Yu. Potrebenikov, G. Kalmus, R. J. Batley, H.G. Becker, Cristina Biino, Ivan Mikulec, J.B. Cheze, P. Lubrano, S.A. Schmidt, Victoria Jane Martin, E. Imbergamo, Mayda Velasco, H. Taureg, Andrea Bizzeti, Michael Ziolkowski, G.D. Barr, M. Martini, J. Ocariz, I. Wingerter, Alexi Mestvirishvili, Adrian John Bevan, and E. Menichetti

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, 010308 nuclear & particles physics, Branching fraction, 0103 physical sciences, Detector, Limit (mathematics), 010306 general physics, 01 natural sciences, Beam (structure)
Abstract

A search for the decay K S → π 0 γγ has been made using the NA48 detector at the CERN SPS. Using data collected in 1999 during a 40-hour run with a high-intensity K S beam, an upper limit for the branching ratio BR ( K S → π 0 γγ , z ⩾0.2) −7 has been obtained at 90% confidence level, where z = m γγ 2 / m K 0 2 .

Published
2016

10. Observation of the decay KL→π0γγ

Author

Arthur Schaffer, M. Calvetti, A. Nappi, M. Rost, Ken Peach, Daniel Fournier, H. Rohrer, R. Carosi, N. Doble, H.N. Nelson, I. Harrus, P. Mayer, J. van der Lans, R. Fantechi, C. Cerri, D.C. Cundy, P. Calafiura, G. Zech, G. Quast, R. Heinz, L. Bertanza, H.G. Sander, R. Casali, B. Panzer, G. Kesseler, H. Blümer, Konrad Kleinknecht, M. Holder, Ph. Heusse, A. Kreutz, W. Weihs, A. Bigi, A. M. Lutz, Laurent Serin, G.M. Pierazzini, V. Gibson, B. Renk, Lydia Iconomidou-Fayard, R. Werthenbach, L. Gatignon, P. Grafström, D. Coward, R. Black, H. Burkhardt, O. Perdereau, I. Mannelli, J. Muir, D. J. Candlin, E. Augé, G.D. Barr, R. Hagelberg, and H. D. Wahl

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Angular distribution, Branching fraction, Theoretical models, Atomic physics
Abstract

The decay mode K L → π 0 γγ has been observed with a signal of 21 events and an expected background of 1.5±0.9 events. A branching ratio for decays with invariant γγ masses above 280 MeV of (2.1±0.6)×10 −6 is calculated. This result is compared with the values estimated from theoretical models and has implications for the CP conserving contribution to K L → π 0 e + e − decay.

Published
2016

11. Measurement of K-e3(0) form factors

Author

S.A. Schmidt, G. Bocquet, Yu. Potrebenikov, I. Mannelli, D. Marras, E. Imbergamo, G.M. Pierazzini, Rainer Wanke, P. Debu, Michael Andrew Parker, M. Sozzi, H. Taureg, M. Ziolkowski, V. Schönharting, M. Pepe, P. Lubrano, Nadia Pastrone, G. D'Agostini, S. A. Wotton, M. Cirilli, A. Nappi, J. C. Chollet, B. Panzer-Steindel, J. Ocariz, B. Renk, P. Lopes da Silva, L. Gatignon, M. Martini, P. F. Dalpiaz, H.G. Becker, I.G. Knowles, Fabrizio Petrucci, G. Neuhofer, N. Doble, T.J. Gershon, I. Wingerter-Seez, A. Ceccucci, Ivan Mikulec, M. Pernicka, S. Giudici, Michal Szleper, S. Wronka, Andrea Bizzeti, D.C. Cundy, F. Martelli, A. Peters, Louis Fayard, Lydia Iconomidou-Fayard, P. Marouelli, F. Marchetto, Y. Schué, G. Graziani, Adrian John Bevan, H. Fox, M. Wittgen, G.D. Barr, J. Cogan, T.O. White, E. Iacopini, G. Unal, L. Widhalm, Benedetto Gorini, M. Eppard, V. Falaleev, L. Bertanza, A. Lacourt, S. Stoynev, Manfred Jeitler, Leander Litov, P. Grafström, Cristina Biino, M. Savrie, Alexi Mestvirishvili, I. Pellmann, R. Sacco, J. Duclos, G. Anzivino, Wojciech Wislicki, J.B. Cheze, Vladimir Kekelidze, G.E. Kalmus, A. Gonidec, Rodolfo Carosi, H. D. Wahl, R. Fantechi, P.L. Frabetti, G. Govi, C. Cerri, G. Collazuol, B. Peyaud, Milene Calvetti, R. Turlay, B. Hay, B. Vallage, W. Kubischta, Cristina Lazzeroni, M. Veltri, U. Koch, A. Winhart, G. Fischer, M. Markytan, M. Lenti, H. Dibon, Anton Taurok, Mauro Piccini, A. Norton, E. Menichetti, M. De Beer, Konrad Kleinknecht, Alan W. Walker, N. A. Molokanova, K. Eppard, D.J. Munday, J. Nassalski, Nicolo Cartiglia, Sandro Palestini, E. Olaiya, E. Mazzucato, A. I. Zinchenko, A. Gianoli, R. Granier de Cassagnac, Victoria Jane Martin, Mayda Velasco, E. Rondio, T. Cuhadar-Dönszelmann, R.S. Dosanjh, D. Madigojine, A. Lai, Andrea Formica, C. Cheshkov, P. Cenci, A. Kalter, Roberta Arcidiacono, R. Casali, M. Contalbrigo, F. Costantini, A. Maier, P. Hristov, L. Köpke, and M. Holder

Subjects
Physics, Semileptonic decay, Nuclear and High Energy Physics, Meson, Scalar (mathematics), Hadron, SEMI-LEPTONIC DECAYS, RADIATIVE-CORRECTIONS, TENSOR INTERACTIONS, MONTE-CARLO, KAONS, Form factor (quantum field theory), Zero (complex analysis), Dalitz plot, Weak interaction, NO, Atomic physics, Particle Physics - Experiment
Abstract

The semi-leptonic decay of the neutral K meson $K^{0}_{L} \to \pi^{\pm}e^{\mp}\nu (K_{e3})$, was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector $(f_{+}(q^{2}))$, scalar $(f_{S})$ and tensor $(f_{T})$ interactions were measured. The linear slope of the vector form factor $\lambda_{+} = 0.0284 \pm 0.0007 \pm 0.0013$ and values for the ratios $|f_{S}/f_{+}(0)|=0.015^{+0.007}_{-0.010} \pm 0.012$ and $|f_{T}/f_{+}(0)|=0.05^{+0.03}_{-0.04} \pm 0.03$ were obtained. The values for $f_{S}$ and for $f_{T}$ are consistent with zero. Assuming only vector-axial vector couplings, $\lambda_{+} = 0.02888 \pm 0.0004 \pm 0.0011$ and a good fit consistent with pure V-A couplings were obtained. Alternatively a fit to a dipole form factor yields a pole mass of $M = 859 \pm 18$ MeV, consistent with the $K^{*}(892)$ mass. The semileptonic decay of the neutral K meson, KL0→π±e∓ν ( Ke3 ), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f+(q2)) , scalar ( fS ) and tensor ( fT ) interactions were measured. The linear slope of the vector form factor λ+=0.0284±0.0007±0.0013 and values for the ratios |fS/f+(0)|=0.015−0.010+0.007±0.012 and |fT/f+(0)|=0.05−0.04+0.03±0.03 were obtained. The values for fS and fT are consistent with zero. Assuming only vector–axial-vector couplings, λ+=0.0288±0.0004±0.0011 and a good fit consistent with pure V–A couplings were obtained. Alternatively, a fit to a dipole form factor yields a pole mass of M=859±18 MeV , consistent with the K*(892) mass. The semileptonic decay of the neutral K meson, KL -> pi e nu (Ke3), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f_+(q^2)), scalar (f_S) and tensor (f_T) interactions were measured. The linear slope of the vector form factor lambda_+ = 0.0284+-0.0007+-0.0013 and values for the ratios |f_S/f_+(0)| = 0.015^{+0.007}_{-0.010}+-0.012 and |f_T/f_+(0)| = 0.05^{+0.03}_{-0.04}+-0.03 were obtained. The values for f_S and f_T are consistent with zero. Assuming only Vector-Axial vector couplings, lambda_+ = 0.0288+-0.0004+-0.0011 and a good fit consistent with pure V-A couplings were obtained. Alternatively, a fit to a dipole form factor yields a pole mass of M = 859+-18 MeV, consistent with the K^*(892) mass.

Published
2016

12. First measurement of the rate K0L → πμνγ

Author

C Siman, J.P. Matheys, R. Wilhelm, G.D. Barr, Julien Cogan, B. Panzer-Steindel, Sandro Palestini, R. Turlay, Michael Ziolkowski, J.B. Cheze, P. Lubrano, V. Fanti, U. Koch, W. Kubischta, A. Michetti, M. Calvetti, C. Cerri, D. J. Munday, J. Scheidt, R. Fantechi, P. F. Dalpiaz, B. Vallage, M. Bender, J. C. Chollet, Cinzia Talamonti, Augusto Ceccucci, P.L. Frabetti, P Maas, S. Schanne, Paolo Calafiura, H.G. Becker, S. Giudici, H. Dibon, O. Boyle, A. Gianoli, R. Casali, P. Hristov, T. O. White, H. Parsons, R. Carosi, A. Lai, M. Martini, Alan W. Walker, Andrea Formica, S. Crépé, M. Pepe, Cristina Biino, Ivan Mikulec, L. Bertolotto, F Rossi, B. Peyaud, Benedetto Gorini, D. Schinzel, L. Köpke, H. Blümer, G. Pierazzini, P. Buchholz, M. Savrie, M. Sozzi, E. Menichetti, I Schwarze, Lau Gatignon, Mayda Velasco, G. Tatichvili, H. Taureg, Manfred Jeitler, M.G Setzu, M. De Beer, G Fischer, A. Tkatchev, G Oakland, D. Coward, F. Costantini, T Beier, Louis Fayard, F. Marchetto, Niels Doble, I Kojevnikov, A. Norton, Konrad Kleinknecht, P. Cenci, L. Musa, J. Duclos, Fabrizio Petrucci, G. Anzivino, Aniello Nappi, J. Schmidt, A. Kalter, P. Grafström, G. Unal, I. Potrebenikov, Vladimir Kekelidze, G. Govi, J. Bremer, Anton Taurok, Andrea Bizzeti, P. Debu, Lydia Iconomidou-Fayard, E. Mazzucato, M. Porcu, Roberta Arcidiacono, I. Augustin, V. Marzulli, S.F Takach, A. Gonidec, M. Holder, M. Pernicka, C. Ebersberger, R.W. Moore, Ken Peach, B Hay, M. Markytan, M. Lenti, O. Zeitnitz, F. Leber, O. Steinkamp, G. Kesseler, N.E Mc Kay, G. Neuhofer, Wolfgang Funk, D.C. Cundy, J. Ocariz, B. Renk, O. Vossnack, I. Mannelli, S. Luitz, G. Bocquet, Michael Andrew Parker, and V. Schönharting

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Large Hadron Collider, Branching fraction, Photon detector, NA48 experiment, Calorimeter
Abstract

In a preliminary version of the NA48 experiment at the CERN SPS, in which an iron-scintillator sandwich calorimeter was used as a photon detector, the ratio of K L → πμνγ and K L → πμν decays was measured. The branching ratio BR(K L →πμνγ, E γ ∗ ≥30 MeV )/(K L → πμν ) is found to be (2.08±0.17 +0.16 −0.21 )×10 −3 , where the first error is statistical and the second systematic. The result is in agreement with theoretical predictions.

Published
2016

13. Observation of the decay Ks → 2γ and measurement of the decay rates KL → 2γ and KS → 2γ

Author

R. Carosi, G. Quast, M. Hassan, A. Bigi, I. Mannelli, G. Kesseler, Ian Shipsey, J. Muir, D. J. Candlin, N. Doble, D.C. Cundy, L. Bertanza, G. Dietrich, H. D. Wahl, B. Renk, Konrad Kleinknecht, Arthur Schaffer, H. G. Sander, H. Burkhardt, M. Holder, R. Chase, E. Massa, Peter Clarke, D. Heyland, M. Corti, C. Youngman, P. Steffen, R. Hagelberg, A. M. Lutz, Ph Heusse, W. Heinen, B. Panzer, R. Black, A. Nappi, W. Weihs, G. M. Pierazzini, Ken Peach, J. Steinberger, E. Auge, L. Gatignon, W. Stephenson, Clemens Becker, C. Cerri, M. Calvetti, J. van der Lans, M. Kasemann, H. Blümer, B. Pijlgroms, M. Rost, G. Zech, Daniel Fournier, H. Taureg, R. Casali, and T. Miczaika

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences
Abstract

The decay rates of K L → 2γ and K S → 2γ have been measured at the CERN SPS. The results are Γ (K L →2 γ )/ χ (K L →2 π 0 )=0.632±0.004±0.008 and Γ (K S →2 γ )/ Γ (K L →2 γ )=2.3 ±1.0±0.4. This is the first observation of K S →2γ decays.

Published
2016

14. Searches for lepton number violation and resonances in $K^\pm \to \pi \mu \mu$ decays with the NA48/2 experiment

Author

N. A. Molokanova, K. Eppard, M. Wache, C. Cerri, A. Nappi, D. T. Madigozhin, E. M. Gersabeck, S. Venditti, E. Mazzucato, V. Kozhuharov, B. Bloch-Devaux, Peter Zahariev Hristov, N. Doble, M. De Beer, P. Cenci, Anne Dabrowski, M. Pepe, C. Morales Morales, Marco Clemencic, Vladimir Kekelidze, M. Sozzi, S. A. Wotton, M. Shieh, M. Holder, Andreas Alexander Maier, Simone Bifani, E. Iacopini, A. Michetti, C. Damiani, A. Gonidec, B. Vallage, L. DiLella, M. Behler, M. Scarpa, G. Bocquet, Mark Slater, Fabrizio Petrucci, H. D. Wahl, G. Collazuol, Giuseppe Ruggiero, Mayda Velasco, J. Derre, Leander Litov, Konrad Kleinknecht, M. Fidecaro, M. Patel, Jacqueline Batley, G.M. Pierazzini, P.L. Frabetti, B. Peyaud, A. Peters, F. Costantini, Cvetan Valeriev Cheshkov, Roberta Arcidiacono, Emmanuel Monnier, D. Coward, Rainer Wanke, P. Rubin, R. Fantechi, M. Valdata-Nappi, I. Mannelli, Alan W. Walker, P. F. Dalpiaz, G. E. Kalmus, F. Marchetto, Manfred Jeitler, Milene Calvetti, Michal Szleper, R. Marchevski, Nicola Cabibbo, I. Polenkevich, L. Widhalm, M. Ziolkowski, A. Gianoli, M. Savrie, M. D. Wood, Cristina Biino, A. Winhart, U. Moosbrugger, P. Marouelli, Ivan Mikulec, E. Imbergamo, H. Dibon, E. C. Swallow, G. Anzivino, Stoyan Stoynev, W. Kubischta, L. Masetti, L. Gatignon, A.I. Zinchenko, D. J. Munday, B. Renk, S. Giudici, Mauro Raggi, Yu Potrebenikov, G. Marel, S. Balev, M. Martini, G. Neuhofer, A. Ceccucci, A. Cotta Ramusino, Andrea Bizzeti, W. Baldini, D.C. Cundy, V. Falaleev, M. Veltri, J.B. Cheze, G. Lamanna, S. Goy Lopez, Luca Fiorini, A. Norton, Roland Winston, Nicolo Cartiglia, Evgueni Goudzovski, T. Fonseca Martin, Mauro Piccini, C. Lazzeroni, K. Massri, M. Markytan, M. Lenti, M. Fiorini, and M. C. Petrucci

Subjects
Physics, Range (particle radiation), Particle physics, Large Hadron Collider, Branching fraction, High Energy Physics::Phenomenology, High Energy Physics::Experiment, Lepton number, Charged particle, Particle Physics - Experiment, Large sample, Lepton
Abstract

The NA48/2 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2003-2004. An upper limit of $8.6 \times 10^{-11}$ at 90~$\%$~CL is set on the branching ratio of the lepton number violating decay $K^\pm \rightarrow \pi^{\mp} \mu^{\pm} \mu^{\pm}$. Searches for two-body resonances like heavy neutral leptons and inflatons in the $K^\pm \rightarrow \pi \mu \mu$ decays in the accessible range of masses and lifetimes are also presented.

Published
2016

15. New measurement of the K±→π+π−e±ν (Ke4) decay branching ratio and hadronic form factors

Author

Cvetan Valeriev Cheshkov, Stoyan Stoynev, W. Kubischta, A. Gianoli, Simone Bifani, M. Scarpa, M. Markytan, M. Lenti, D. J. Munday, G. Ruggiero, P. Rubin, S. Venditti, A.I. Zinchenko, V. Falaleev, Ivan Mikulec, M. Wache, E. Iacopini, S. Balev, M. Martini, D. T. Madigozhin, M. Sozzi, E. Monnier, A. Gonidec, S. A. Wotton, L. DiLella, B. Renk, Konrad Kleinknecht, E. Mazzucato, Mauro Piccini, Massimiliano Fiorini, E. Gersabeck, M. C. Petrucci, D. Coward, M. Valdata-Nappi, R. Fantechi, A. Peters, Peter Zahariev Hristov, G. Collazuol, Milene Calvetti, Manfred Jeitler, Vladimir Kekelidze, C. Morales Morales, Jacqueline Batley, P. Cenci, Wood, S. Giudici, A. Cotta Ramusino, Mayda Velasco, M. Veltri, S. Goy Lopez, H. Dibon, M. Ziolkowski, J. Derre, I. Mannelli, A. Norton, Roland Winston, G. Lamanna, C. Lazzeroni, G. Anzivino, G.M. Pierazzini, Roberta Arcidiacono, Mauro Raggi, G. Marel, U. Moosbrugger, J.B. Cheze, A. Michetti, F. Marchetto, Rainer Wanke, Fabrizio Petrucci, Cristina Biino, V. Kozhuharov, P. Marouelli, E. Imbergamo, Luca Fiorini, L. Widhalm, B. Vallage, Leander Litov, L. Masetti, P.L. Frabetti, Mark Slater, W. Baldini, A. Winhart, L. Gatignon, Alan W. Walker, E. C. Swallow, Anne Dabrowski, G. Neuhofer, Nicolo Cartiglia, M. Pepe, F. Costantini, M. Holder, N. A. Molokanova, A. Nappi, D.C. Cundy, K. Eppard, G. Bocquet, Yu. Potrebenikov, T. Fonseca Martin, M. Patel, Marco Clemencic, I. Polenkevich, M. De Beer, M. Behler, A. Ceccucci, Andrea Bizzeti, Michal Szleper, Evgueni Goudzovski, Nicola Cabibbo, H. D. Wahl, M. Fidecaro, B. Peyaud, M. Savrie, B. Bloch-Devaux, G.E. Kalmus, C. Cerri, N. Doble, C. Damiani, M. Shieh, P. F. Dalpiaz, and A. A. Maier

Subjects
Normalization (statistics), Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, 010308 nuclear & particles physics, Branching fraction, Scattering, Hadron, Form factor (quantum field theory), 01 natural sciences, Nuclear physics, 0103 physical sciences, Pi, Relative precision, 010306 general physics
Abstract

A sample of more than one million K±→π+π−e±ν ( Ke4 ) decay candidates with less than one percent background contamination has been collected by the NA48/2 experiment at the CERN SPS in 2003–2004, allowing a detailed study of the decay properties. The branching ratio, inclusive of Ke4γ decays, is measured to be BR(Ke4)=(4.257±0.016exp±0.031ext)×10−5 with a total relative error of 0.8% . This measurement complements the study of S- and P-wave hadronic form factors by assigning absolute values to the relative hadronic form factors obtained earlier in a simultaneous analysis of the ππ scattering lengths conducted on the same data sample. The overall form factor normalization fs=5.705±0.017exp±0.031ext is obtained with a total relative precision of 0.6% .

Published
2012

16. New measurement of the K±→π±μ+μ− decay

Author

A. Gonidec, G. Collazuol, Milene Calvetti, H. Dibon, H. D. Wahl, Nicola Cabibbo, C. Cheshkov, V. Kozhuharov, Mauro Raggi, M. Fidecaro, M. Savrie, B. Bloch-Devaux, B. Peyaud, E. Iacopini, M. Sozzi, D. Coward, G. Neuhofer, F. Marchetto, G.E. Kalmus, S. A. Wotton, L. Widhalm, M. De Beer, D.C. Cundy, Massimiliano Fiorini, Wood, Vladimir Kekelidze, Fabrizio Petrucci, G. Bocquet, Yu. Potrebenikov, G. Marel, Rainer Wanke, N. Doble, A. Winhart, P. Rubin, A. Nappi, M. Pepe, Simone Bifani, M. Markytan, M. Lenti, B. Vallage, M. Behler, W. Kubischta, E. C. Swallow, C. Lazzeroni, Leander Litov, J.B. Cheze, Evgueni Goudzovski, D. J. Munday, M. Holder, I. Mannelli, Luca Fiorini, Cristina Biino, M. Veltri, S. Goy Lopez, A. Ceccucci, A. Peters, Andrea Bizzeti, A. Norton, Roland Winston, Ivan Mikulec, A. I. Zinchenko, A. A. Maier, V. Falaleev, C. Cerri, E. Marinova, M. Scarpa, Enrico Celeghini, A. Dabrowski, G.M. Pierazzini, T. Fonseca Martin, Maulik R. Patel, Mauro Piccini, M. C. Petrucci, L. Masetti, A. Gianoli, C. Damiani, M. Ziolkowski, Konrad Kleinknecht, Manfred Jeitler, S. Stoynev, P. Marouelli, S. Giudici, B. Renk, M. Valdata-Nappi, G. Anzivino, Alan W. Walker, M. Shieh, S. Balev, M. Martini, W. Baldini, P. L. Frabetti, M. Wache, Nicolo Cartiglia, D. T. Madigozhin, A. Michetti, E. Mazzucato, N. A. Molokanova, K. Eppard, Marco Clemencic, C. Morales Morales, Mayda Velasco, I. Polenkevich, Mark Slater, M. Szleper, E. Imbergamo, F. Costantini, L. Di Lella, P. F. Dalpiaz, S. Venditti, G. Lamanna, U. Moosbrugger, A. Cotta Ramusino, E. Monnier, Lau Gatignon, P. Cenci, Jacqueline Batley, G. Ruggiero, P. Hristov, J. Derre, Roberta Arcidiacono, and R. Fantechi

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle decay, Antiparticle, Muon, Pion, Meson, Branching fraction, Analytical chemistry, Lepton, Dimensionless quantity
Abstract

A sample of 3120 K ± → π ± μ + μ − decay candidates with ( 3.3 ± 0.7 ) % background contamination has been collected by the NA48/2 experiment at the CERN SPS, allowing a detailed study of the decay properties. The branching ratio was measured to be BR = ( 9.62 ± 0.25 ) × 10 − 8 . The form factor W ( z ) , where z = ( M μ μ / M K ) 2 , was parameterized according to several models. In particular, the slope of the linear form factor W ( z ) = W 0 ( 1 + δ z ) was measured to be δ = 3.11 ± 0.57 . Upper limits of 2.9 × 10 − 2 and 2.3 × 10 − 2 on possible charge asymmetry and forward–backward asymmetry were established at 90% CL. An upper limit BR ( K ± → π ∓ μ ± μ ± ) 1.1 × 10 − 9 was established at 90% CL for the rate of the lepton number violating decay.

Published
2011

17. New precise measurements of the and decay asymmetries

Author

S. Stoynev, E. Monnier, R. Sacco, U. Moosbrugger, Nadia Pastrone, M. Valdata, M. Calvetti, B. Vallage, N. A. Molokanova, K. Eppard, M. C. Petrucci, Roberta Arcidiacono, D. T. Madigozhin, G. Ruggiero, Marco Clemencic, R. Fantechi, P. F. Dalpiaz, A. Maier, F. Costantini, E. Mazzucato, A. Winhart, T. Fonseca Martin, Mauro Piccini, E. Imbergamo, C. Cerri, P. Lubrano, A. Michetti, A. Nappi, H. Dibon, Anne Dabrowski, Lau Gatignon, M. Pepe, M. Ziolkowski, M. Markytan, B. Panzer-Steindel, G. Neuhofer, C. Morales Morales, M. Lenti, Leander Litov, G. Lamanna, E. Menichetti, D.C. Cundy, M. De Beer, A. Ceccucci, Andrea Bizzeti, Cristina Biino, P. Cenci, P.L. Frabetti, S. Goy Lopez, F. Marchetto, Jacqueline Batley, Manfred Jeitler, L. Widhalm, Mayda Velasco, E. Iacopini, H. D. Wahl, P. Grafström, M. Holder, F. Petrucci, P. Rubin, M. Scarpa, M. Behler, U. Koch, G. Pierazzini, Alan W. Walker, W. Wislicki, B. Peyaud, G. Bocquet, Yu. Potrebenikov, G. Anzivino, A. Gonidec, A. I. Zinchenko, M. Sozzi, G. Gouge, A. Hirstius, S. A. Wotton, C. Cheshkov, S. Giudici, J.B. Cheze, M. Savrie, C. Lazzeroni, M. Slater, A. Gianoli, Niels Doble, D.J. Munday, Evgueni Goudzovski, I. Mannelli, L. Fiorini, L. Masetti, V. Falaleev, M. Veltri, A. Norton, Roland Winston, Nicolo Cartiglia, P. Marouelli, W. Baldini, Konrad Kleinknecht, P. Debu, G. Collazuol, G. Marel, Maulik R. Patel, M. Martini, M. Eppard, W. Kubischta, Rainer Wanke, E. C. Swallow, G. Kalmus, A. Peters, Ivan Mikulec, Peter Zahariev Hristov, and Vladimir Kekelidze

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Hadron, Hyperon, Gamma ray, Elementary particle, Fermion, 01 natural sciences, Nuclear physics, Baryon, Particle decay, 0103 physical sciences, 010306 general physics, Radioactive decay
Abstract

The decay asymmetries of the weak radiative hyperon decays Ξ 0 → Λ γ and Ξ 0 → Σ 0 γ have been measured with high precision using data of the NA48/1 experiment at CERN. From about 52 000 Ξ 0 → Λ γ and 15 000 Ξ 0 → Σ 0 γ decays, we obtain for the decay asymmetries α Ξ 0 → Λ γ = − 0.704 ± 0.019 stat ± 0.064 syst and α Ξ 0 → Σ 0 γ = − 0.729 ± 0.030 stat ± 0.076 syst , respectively. These results are in good agreement with previous experiments, but more precise.

Published
2010

18. Empirical parameterization of the K±→π±π0π0 decay Dalitz plot

Author

E. Monnier, A. Winhart, A. Nappi, C. Lazzeroni, B. Renk, T. Fonseca Martin, M. Holder, Mauro Piccini, F. Costantini, P. L. Frabetti, A. Michetti, Jacqueline Batley, Peter Zahariev Hristov, B. Vallage, S. Bifani, G.M. Pierazzini, Vladimir Kekelidze, M. Slater, M. Szleper, Cristina Biino, I. Polenkevich, J.B. Cheze, A. Cotta Ramusino, A. A. Maier, Luca Fiorini, I. Mannelli, A. Ceccucci, Andrea Bizzeti, C. Damiani, A. I. Zinchenko, P. Rubin, M. D. Wood, M. Sozzi, C. Cheshkov, E. Imbergamo, Massimiliano Fiorini, Nicolo Cartiglia, A. Peters, S. A. Wotton, Manfred Jeitler, S. Balev, M. Martini, H. D. Wahl, M. Fidecaro, A. Gianoli, Ivan Mikulec, N. Doble, U. Moosbrugger, Stoyan Stoynev, B. Peyaud, L. DiLella, Lau Gatignon, Nicola Cabibbo, W. Kubischta, M. Scarpa, G. Anzivino, M. Savrie, P. Cenci, G. Lamanna, B. Bloch-Devaux, D. J. Munday, M. Veltri, A. Dabrowski, S. Goy Lopez, G.E. Kalmus, M. Shieh, M. C. Petrucci, J. Derre, A. Norton, Roland Winston, M. De Beer, Roberta Arcidiacono, C. Cerri, M. Wache, D. T. Madigozhin, S. Giudici, M. Behler, E. Marinova, P. Marouelli, G. Neuhofer, E. Mazzucato, P. F. Dalpiaz, Konrad Kleinknecht, W. Baldini, D.C. Cundy, M. Pepe, V. Falaleev, C. Morales Morales, D. Coward, Mayda Velasco, M. Valdata-Nappi, Marco Clemencic, S. Venditti, M. Markytan, M. Lenti, Maulik R. Patel, F. Marchetto, L. Widhalm, G. Ruggiero, A. Gonidec, G. Collazuol, G. Marel, Rainer Wanke, A. J. Culling, E. C. Swallow, Fabrizio Petrucci, Leander Litov, Alan W. Walker, N. A. Molokanova, K. Eppard, Evgueni Goudzovski, Lucia Masetti, E. Iacopini, R. Fantechi, Milene Calvetti, H. Dibon, Mauro Raggi, M. Ziolkowski, G. Bocquet, Yu. Potrebenikov, and V. Kozhuharov

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Scattering, Monte Carlo method, Dalitz plot, 01 natural sciences, Pion, Isospin, 0103 physical sciences, Quasinormal mode, High Energy Physics::Experiment, Invariant mass, Anomaly (physics), Nuclear Experiment, 010306 general physics
Abstract

As first observed by the NA48/2 experiment at the CERN SPS, the π0π0 invariant mass (M00) distribution from K±→π±π0π0 decay shows a cusp-like anomaly at M00=2m+, where m+ is the charged pion mass. An analysis to extract the ππ scattering lengths in the isospin I=0 and I=2 states, a0 and a2, respectively, has been recently reported. In the present work the Dalitz plot of this decay is fitted to a new empirical parameterization suitable for practical purposes, such as Monte Carlo simulations of K±→π±π0π0 decays.

Published
2010

19. Measurement of the polarization of the Ξ0 (Ξ0¯) hyperon beam by the NA48/1 experiment

Author

M. Sozzi, C. Morales Morales, S. A. Wotton, W. Kubischta, G. Neuhofer, Cristina Biino, U. Moosbrugger, Ivan Mikulec, Niels Doble, D. J. Munday, Mayda Velasco, Rainer Wanke, A. Gonidec, P. Debu, D.C. Cundy, Marco Clemencic, A. Maier, Leander Litov, M. De Beer, E. Iacopini, Jacqueline Batley, G. Collazuol, H. D. Wahl, P.L. Frabetti, Nadia Pastrone, P. Grafström, Nicolo Cartiglia, G. Pierazzini, E. C. Swallow, D. T. Madigozhin, U. Koch, A. Winhart, Evgueni Goudzovski, T. Fonseca Martin, Mauro Piccini, B. Peyaud, P. Rubin, E. Mazzucato, Alan W. Walker, A. Peters, M. Eppard, R. Fantechi, Vladimir Kekelidze, Mark Slater, M. Markytan, M. Lenti, N. A. Molokanova, M. Holder, M. Martini, F. Petrucci, K. Eppard, Konrad Kleinknecht, M. Behler, E. Imbergamo, V. Falaleev, H. Dibon, A. I. Zinchenko, M. Savrie, R. Sacco, B. Panzer-Steindel, G. Bocquet, Yu. Potrebenikov, A. Gianoli, F. Costantini, G. Marel, F. Marchetto, M. Patel, Michael Ziolkowski, A. Michetti, L. Widhalm, M. Scarpa, M. Valdata, A. Dabrowski, W. Wislicki, M. C. Petrucci, A. Hirstius, S. Stoynev, E. Menichetti, G. Lamanna, E. Monnier, G. Ruggiero, C. Cheshkov, M. Pepe, G.E. Kalmus, C. Lazzeroni, P. Lubrano, A. Nappi, C. Cerri, A. Ceccucci, Andrea Bizzeti, Manfred Jeitler, G. Anzivino, I. Mannelli, G. Gouge, L. Fiorini, L. Masetti, S. Giudici, B. Vallage, P. F. Dalpiaz, J.B. Cheze, P. Hristov, Roberta Arcidiacono, M. Calvetti, Lau Gatignon, P. Cenci, M. Veltri, S. Goy Lopez, A. Norton, Roland Winston, P. Marouelli, and W. Baldini

Subjects
Physics, Nuclear and High Energy Physics, Meson, Proton, 010308 nuclear & particles physics, Hadron, Hyperon, 7. Clean energy, 01 natural sciences, Xi baryon, Nuclear physics, Baryon, Pion, 0103 physical sciences, 010306 general physics, Nucleon
Abstract

A total of 368 415 Ξ 0 → Λ π 0 and 31 171 Ξ 0 ¯ → Λ ¯ π 0 were selected from data recorded in the NA48/1 experiment during 2002 data taking. From this sample, the polarization of Ξ 0 and Ξ 0 ¯ hyperons was measured to be P Ξ 0 = − 0.102 ± 0.012 (stat) ± 0.008 (syst) and P Ξ 0 ¯ = − 0.01 ± 0.04 (stat) ± 0.008 (syst) . The dependence of P Ξ 0 on the Ξ 0 transverse momentum with respect to the primary proton beam is also presented. With the same data sample, the ratio of Ξ 0 ¯ and Ξ 0 fluxes in proton collisions at 400 GeV / c on a beryllium target was measured.

Published
2009

20. First observation and measurement of the decay K±→π±e+e−γ

Author

Rainer Wanke, R. Fantechi, A. Ceccucci, Andrea Bizzeti, Marco Clemencic, F. Costantini, C. Cerri, I. Polenkevich, M. D. Wood, Milene Calvetti, G. Ruggiero, G.M. Pierazzini, J. Derre, I. Mannelli, A. Gonidec, B. Vallage, E. C. Swallow, P. Rubin, Roberta Arcidiacono, H. D. Wahl, M. Fidecaro, Evgueni Goudzovski, N. Doble, H. Dibon, G. Collazuol, S. Balev, M. Martini, R. Winston, B. Peyaud, L. Masetti, D. Coward, Cristina Lazzeroni, J.B. Cheze, M. Scarpa, T. Fonseca Martin, M. Holder, Mauro Raggi, B. Renk, Mauro Piccini, P. Hristov, Luca Fiorini, A.J. Culling, E. Marinova, E. Monnier, G. Neuhofer, D.J. Munday, G. Marel, A. Winhart, Nicola Cabibbo, W. Kubischta, M. Shieh, C. Cheshkov, V. Kozhuharov, D.C. Cundy, S. Stoynev, Nicolo Cartiglia, M. Pepe, Cristina Biino, Ivan Mikulec, Lau Gatignon, M. Savrie, E. Iacopini, A. A. Maier, P. F. Dalpiaz, P. Marouelli, B. Bloch-Devaux, P. Cenci, C. Handel, M. Veltri, F. Marchetto, C. Damiani, M.W. Slater, L. Widhalm, Manfred Jeitler, W. Baldini, G.E. Kalmus, V. Falaleev, A. Zinchenko, M. Ziolkowski, M. De Beer, G. Anzivino, J. R. Batley, A. Peters, S. Goy Lopez, A. Norton, M. Behler, G. Bocquet, Yu. Potrebenikov, A. Nappi, S. Wotton, Vladimir Kekelidze, S. Giudici, M. Sozzi, L. DiLella, M. Wache, Massimiliano Fiorini, D. T. Madigozhin, E. Mazzucato, C. Morales Morales, Mayda Velasco, M. Markytan, M. Lenti, A. Gianoli, Enrico Celeghini, A. Dabrowski, M. C. Petrucci, Maulik R. Patel, Konrad Kleinknecht, M. Valdata-Nappi, F. Martelli, M. Szleper, Simone Bifani, U. Moosbrugger, E. Imbergamo, A. Cotta Ramusino, G. Lamanna, Fabrizio Petrucci, Leander Litov, Alan W. Walker, P. L. Frabetti, A. Michetti, N. A. Molokanova, and K. Eppard

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Chiral perturbation theory, Meson, 010308 nuclear & particles physics, Branching fraction, Hadron, Analytical chemistry, 01 natural sciences, Nuclear physics, Particle decay, Pion, 0103 physical sciences, 010306 general physics, Dimensionless quantity
Abstract

Using the full data set of the NA48/2 experiment, the decay K ± → π ± e + e − γ is observed for the first time, selecting 120 candidates with 7.3 ± 1.7 estimated background events. With K ± → π ± π D 0 as normalisation channel, the branching ratio is determined in a model-independent way to be Br ( K ± → π ± e + e − γ , m e e γ > 260 MeV / c 2 ) = ( 1.19 ± 0.12 stat ± 0.04 syst ) × 10 −8 . This measured value and the spectrum of the e + e − γ invariant mass allow a comparison with predictions of chiral perturbation theory.

Published
2008

21. Measurement of the Dalitz plot slope parameters of the K±→π±π+π− decay

Author

Enrico Celeghini, P. Marouelli, Leander Litov, A. Dabrowski, S. Giudici, M. C. Petrucci, B. Vallage, M. Sozzi, G. Ruggiero, M. Holder, Michael Ziolkowski, A. Peters, F. Petrucci, Alan W. Walker, E. Imbergamo, M. Savrie, Augusto Ceccucci, G. Bocquet, Yu. Potrebenikov, Cristina Biino, Ivan Mikulec, P. L. Frabetti, Lau Gatignon, S. Stoynev, F. Martelli, J.B. Cheze, M. Lenti, A. Michetti, E. Marinova, I. Mannelli, C. Lazzeroni, F. Costantini, G. Neuhofer, Nicolo Cartiglia, Vladimir Kekelidze, P. Cenci, M. Calvetti, A. Winhart, T. Fonseca Martin, Mauro Piccini, D.C. Cundy, C. Damiani, S. Balev, Marco Clemencic, M. Markytan, M. De Beer, Mark Slater, L. DiLella, M. Fidecaro, N. A. Molokanova, Maulik R. Patel, A. Cotta Ramusino, P. Hristov, S. A. Wotton, B. Peyaud, Evgueni Goudzovski, B. Renk, K. Eppard, Massimiliano Fiorini, V. Falaleev, M. Behler, A. Nappi, J. Derre, G. Lamanna, Nicola Cabibbo, Roberta Arcidiacono, C. Cheshkov, V. Kozhuharov, Andrea Bizzeti, B. Bloch-Devaux, G.E. Kalmus, P. Rubin, N. Doble, I. Polenkevich, Simone Bifani, M. D. Wood, Jacqueline Batley, C. Cerri, M. Veltri, Konrad Kleinknecht, M. Valdata-Nappi, Manfred Jeitler, R. Fantechi, D. Coward, H. Dibon, Wander Baldini, G. Anzivino, Mauro Raggi, G. Pierazzini, G. Marel, E. Iacopini, P. F. Dalpiaz, M. Wache, D. T. Madigozhin, E. Mazzucato, Rainer Wanke, A. J. Culling, E. C. Swallow, C. Morales Morales, H. Wahl, Mayda Velasco, A. I. Zinchenko, A. Gianoli, A. Gonidec, U. Moosbrugger, G. Collazuol, S. Goy Lopez, A. Maier, A. Norton, Roland Winston, W. Kubischta, E. Monnier, L. Fiorini, D. J. Munday, M. Pepe, M. Szleper, F. Marchetto, L. Widhalm, M. Scarpa, M. Martini, M. Shieh, and L. Masetti

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Dalitz plot, Particle Data Group, Atomic physics, Order of magnitude
Abstract

The distribution of the K ± → π ± π + π − decays in the Dalitz plot has been measured by the NA48/2 experiment at the CERN SPS with a sample of 4.71 × 10 8 fully reconstructed events. With the standard Particle Data Group parameterization the following values of the slope parameters were obtained: g = ( − 21.134 ± 0.017 ) % , h = ( 1.848 ± 0.040 ) % , k = ( − 0.463 ± 0.014 ) % . The quality and statistical accuracy of the data have allowed an improvement in precision by more than an order of magnitude, and are such as to warrant a more elaborate theoretical treatment, including pion–pion rescattering, which is in preparation.

Published
2007

22. Measurement of Kμ30 form factors

Author

M. Sozzi, P. Debu, M. Cirilli, G. Fischer, S. A. Wotton, Konrad Kleinknecht, H. D. Wahl, E. Iacopini, H.G. Becker, P. Grafström, P. Lubrano, B. Peyaud, Anton Taurok, M. Eppard, A. Winhart, Nadia Pastrone, Benedetto Gorini, Cristina Biino, Ivan Mikulec, J. C. Chollet, V. Kekelidze, S.A. Schmidt, I.G. Knowles, B. Vallage, Milene Calvetti, Manfred Jeitler, I. Wingerter-Seez, H. Taureg, S. Wronka, H. Fox, R. Turlay, M. Wittgen, A. Lacourt, J. Cogan, A. Kalter, A. Gonidec, M. Markytan, H. Dibon, T.O. White, G. Unal, G. Collazuol, J. Duclos, G. Anzivino, A. Peters, Adrian John Bevan, E. Rondio, J. Ocariz, G. Graziani, G.D. Barr, C. Cheshkov, R. Fantechi, I. Mannelli, L. Gatignon, T.J. Gershon, Roberta Arcidiacono, Andrea Bizzeti, M. Lenti, B. Renk, G. Bocquet, Wojciech Wislicki, B. Panzer-Steindel, D. Madigozhin, R. Casali, M. De Beer, J.B. Cheze, U. Koch, A. Nappi, V. Falaleev, M. Piccini, Michael Ziolkowski, M. Contalbrigo, A. Zinchenko, Alexi Mestvirishvili, Louis Fayard, T. Cuhadar-Dönszelmann, R. Wanke, R.S. Dosanjh, R. Bernhard, N. Doble, L. Widhalm, Cristina Lazzeroni, A. Ceccucci, S. Stoynev, M. Martini, B. Hay, A. Maier, P. Hristov, A. Lai, I. Pellmann, S. Giudici, Andrea Formica, Giuseppe Ruggiero, D.J. Munday, Michal Szleper, A. Norton, J. Nassalski, L. Köpke, C. Cerri, E. Imbergamo, M. Pernicka, M. Savrie, E. Menichetti, F. Costantini, M. Pepe, G.E. Kalmus, G. D'Agostini, G. Govi, Nicolo Cartiglia, P. Cenci, Michael Andrew Parker, W. Kubischta, P. F. Dalpiaz, V. Schönharting, M. Holder, M. Veltri, G.M. Pierazzini, P. Lopes da Silva, Lydia Iconomidou-Fayard, P. Marouelli, L. Bertanza, G. Neuhofer, R. Carosi, D.C. Cundy, Y. Schué, R. Sacco, A. Gianoli, R. Granier de Cassagnac, E. Olaiya, Yu. Potrebenikov, E. Mazzucato, F. Petrucci, Victoria Jane Martin, Mayda Velasco, Sandro Palestini, F. Marchetto, N. A. Molokanova, K. Eppard, Leander Litov, P.L. Frabetti, Alan W. Walker, and D. Marras

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 0103 physical sciences, Form factor (quantum field theory), Dalitz plot, NA48 experiment, 010306 general physics, 01 natural sciences
Abstract

This Letter reports on a new high precision measurement of the form factors of the K L → π ± μ ∓ ν μ decay. The data sample of about 2.3 × 10 6 events was recorded in 1999 by the NA48 experiment at CERN. Studying the Dalitz plot density we measured a linear, λ + ′ = ( 20.5 ± 2.2 stat ± 2.4 syst ) × 10 −3 , and a quadratic, λ + ″ = ( 2.6 ± 0.9 stat ± 1.0 syst ) × 10 −3 term in the power expansion of the vector form factor. No evidence was found for a second order term for the scalar form factor; the linear slope was determined to be λ 0 = ( 9.5 ± 1.1 stat ± 0.8 syst ) × 10 −3 . Using a linear fit our results were: λ + = ( 26.7 ± 0.6 stat ± 0.8 syst ) × 10 −3 and λ 0 = ( 11.7 ± 0.7 stat ± 1.0 syst ) × 10 −3 . A pole fit of the form factors yields: m V = ( 905 ± 9 stat ± 17 syst ) MeV / c 2 and m S = ( 1400 ± 46 stat ± 53 syst ) MeV / c 2 .

Published
2007

23. Measurements of charged kaon semileptonic decay branching fractions K±→π0μ±ν and K±→π0e±ν and their ratio

Author

G. Ruggiero, G.M. Pierazzini, Evgueni Goudzovski, A. Gonidec, Peter Zahariev Hristov, G. Collazuol, Fabrizio Petrucci, V. Falaleev, Manfred Jeitler, G. Anzivino, P. F. Dalpiaz, B. Vallage, Cristina Biino, M. Fiorini, L. Gatignon, M. Scarpa, Mayda Velasco, Leander Litov, Enrico Celeghini, A.I. Zinchenko, A. Dabrowski, M. Sozzi, R. Fantechi, Maulik R. Patel, M. C. Petrucci, E. Monnier, A. Winhart, Jacqueline Batley, T. Fonseca Martin, Cvetan Valeriev Cheshkov, F. Marchetto, Mauro Piccini, S. A. Wotton, Milene Calvetti, L. Widhalm, G. Marel, M. De Beer, U. Moosbrugger, L. DiLella, A. Gianoli, Alan W. Walker, A. Cotta Ramusino, I. Mannelli, Rainer Wanke, H. Dibon, A. Peters, M. Markytan, M. Lenti, Konrad Kleinknecht, E. Marinova, M. Wache, D. T. Madigozhin, G. Neuhofer, Ivan Mikulec, M. Holder, Mauro Raggi, J. Derre, E. Mazzucato, N. A. Molokanova, D.C. Cundy, K. Eppard, Stoyan Stoynev, M. Behler, D. Coward, M. Valdata-Nappi, W. Kubischta, E. C. Swallow, G. Lamanna, M. Szleper, L. Masetti, Roberta Arcidiacono, D. J. Munday, M. Pepe, E. Iacopini, S. Giudici, Luca Fiorini, J. B. Cheze, B. Renk, G. Bocquet, E. Imbergamo, S. Balev, M. Martini, P. L. Frabetti, P. Rubin, Simone Bifani, P. Cenci, C. Morales, A. Michetti, Nicola Cabibbo, V. Kozhuharov, C. Lazzeroni, M. Savrie, M. Ziolkowski, V. Kekelidze, M. Shieh, H. D. Wahl, M. Fidecaro, B. Peyaud, A. Ceccucci, B. Bloch-Devaux, A. A. Maier, Andrea Bizzeti, F. Martelli, Nicolo Cartiglia, M. Veltri, S. Goy Lopez, A. Norton, Roland Winston, P. Marouelli, W. Baldini, I. Polenkevich, M. D. Wood, N. Doble, Mark Slater, F. Costantini, C. Damiani, C. Cerri, and Marco Clemencic

Subjects
semileptonic kaon decays, CKM matrix, Semileptonic decay, Particle physics, Physics and Astronomy (miscellaneous), kaon decay, BRANCHING FRACTION, Branching (polymer chemistry), NO, High Energy Physics - Experiment, mesoni K, Nuclear physics, decadimenti, MONTE-CARLO, RADIATIVE-CORRECTIONS, PHOTOS, Pi, Kaon decays, Engineering (miscellaneous), Physics, Science & Technology, Unitarity, Cabibbo–Kobayashi–Maskawa matrix, PHYSICS, PARTICLES & FIELDS, semileptonic decay, semileptonic kaon decays, CKM matrix, Physical Sciences
Abstract

Measured ratios of decay rates for Ke3/K2\pi, K\mu3/K2\pi and K\mu3/Ke3 are presented. These measurements are based on K^+- decays collected in a dedicated run in 2003 by the NA48/2 experiment at CERN. The results obtained are Ke3/K2\pi = 0.2470 +/- 0.0009 (stat) +/- 0.0004 (syst) and K\mu3/K2\pi = 0.1637 +/- 0.0006 (stat) +/- 0.0003 (syst). Using the PDG average for the K^+- -> \pi^+-\pi^0 normalisation mode, both values are found to be larger than the current values given by the Particle Data Book and lead to a larger magnitude of the |V_{us}| CKM element than previously accepted. When combined with the latest Particle Data Book value of |V_{ud}|, the result is in agreement with unitarity of the CKM matrix. In addition, a new measured value of K\mu3/Ke3 = 0.663 +/- 0.003(stat) +/- 0.001(syst) is compared to the semi-empirical predictions based on the latest form factor measurements., Comment: 20 pages, 5 tables, 10 figures. Published in European Physical Journal C 50 2 (2007), contains erratum submitted to European Physical Journal C

Published
2007

24. Measurement of the ratio Γ(KL→π+π−)/Γ(KL→π±e∓ν) and extraction of the CP violation parameter |η+−

Author

P. Debu, T. Cuhadar-Dönszelmann, Sandro Palestini, R.S. Dosanjh, S. A. Wotton, M. Wittgen, Benedetto Gorini, J. Cogan, Rainer Wanke, Manfred Jeitler, P. F. Dalpiaz, H. D. Wahl, T.J. Gershon, A. Gaponenko, J. Duclos, M. Veltri, G. Anzivino, B. Peyaud, Michal Szleper, G.D. Barr, G. Fischer, Anton Taurok, Nadia Pastrone, Vladimir Kekelidze, A. Norton, G.M. Pierazzini, C. Cheshkov, B. Vallage, R. Fantechi, Fabrizio Petrucci, M. Savrie, A. I. Zinchenko, A. Kalter, Konrad Kleinknecht, Nicolo Cartiglia, Michael Andrew Parker, J. C. Chollet, Leander Litov, P.L. Frabetti, E. Menichetti, G.E. Kalmus, A. Peters, V. Schönharting, Milene Calvetti, A. Nappi, J. Ocariz, H. Taureg, I.G. Knowles, H.G. Becker, A. Gianoli, B. Renk, R. Granier de Cassagnac, R. Turlay, M. Pepe, Cristina Biino, Ivan Mikulec, Roberto Guida, Alan W. Walker, D.J. Munday, J. Nassalski, G. D'Agostini, F. Martelli, Augusto Ceccucci, Roberta Arcidiacono, S. Giudici, G. Govi, M. De Beer, P. Lopes da Silva, M. Pernicka, H. Dibon, B. Hay, Andrea Bizzeti, S. Wronka, W. Kubischta, N. A. Molokanova, Lydia Iconomidou-Fayard, P. Marouelli, Louis Fayard, F. Marchetto, G. Graziani, Michael Ziolkowski, K. Eppard, M. Holder, Victoria Jane Martin, U. Koch, D. Marras, A. Winhart, L. Widhalm, I. Mannelli, Mayda Velasco, Alexi Mestvirishvili, M. Eppard, Mauro Piccini, Wojciech Wislicki, P. Lubrano, V. Falaleev, M. Sozzi, S. Stoynev, G. Tatishvili, L. Bertanza, E. Rondio, E. Olaiya, A. Gonidec, D. T. Madigozhin, Lau Gatignon, S.A. Schmidt, M. Cirilli, Cristina Lazzeroni, Niels Doble, G. Collazuol, C. Cerri, A. Tkatchev, I. Pellmann, E. Mazzucato, T.O. White, G. Unal, M. Martini, R. Sacco, M. Markytan, M. Lenti, G. Bocquet, Yu. Potrebenikov, E. Iacopini, P. Cenci, E. Imbergamo, G. Neuhofer, M. Contalbrigo, P. Grafström, I. Wingerter-Seez, A. Maier, P. Hristov, R. Carosi, D.C. Cundy, L. Köpke, A. Lai, Andrea Formica, Adrian John Bevan, Y. Schué, F. Costantini, J.B. Cheze, B. Panzer-Steindel, H. Fox, and A. Lacourt

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Photon emission, 010308 nuclear & particles physics, Branching fraction, 0103 physical sciences, Extraction (chemistry), Analytical chemistry, NA48 experiment, CP violation, 010306 general physics, 01 natural sciences
Abstract

We present a measurement of the ratio of the decay rates Γ ( K L → π + π − ) / Γ ( K L → π ± e ∓ ν ) , denoted as Γ K 2 π / Γ K e 3 . The analysis is based on data taken during a dedicated run in 1999 by the NA48 experiment at the CERN SPS. Using a sample of 47 000 K 2 π and five million K e 3 decays, we find Γ K 2 π / Γ K e 3 = ( 4.835 ± 0.022 stat . ± 0.016 syst . ) × 10 −3 . From this we derive the branching ratio of the CP violating decay K L → π + π − and the CP violation parameter | η + − | . Excluding the CP conserving direct photon emission component K L → π + π − γ , we obtain the results BR ( K L → π + π − ) = ( 1.941 ± 0.019 ) × 10 −3 and | η + − | = ( 2.223 ± 0.012 ) × 10 −3 .

Published
2007

25. Measurement of the branching ratios of the decays Ξ0→Σ+e−ν¯e and Ξ0¯→Σ+¯e+νe

Author

P. F. Dalpiaz, C. Morales Morales, U. Moosbrugger, M. Valdata, B. Panzer-Steindel, R. Fantechi, Konrad Kleinknecht, A. Dabrowski, C. Cheshkov, A. Maier, M. C. Petrucci, Michael Ziolkowski, G.E. Kalmus, M. De Beer, M. Behler, G. Ruggiero, Mayda Velasco, Nicolo Cartiglia, M. Patel, H. Dibon, Wander Baldini, Jacqueline Batley, S. Stoynev, V. Falaleev, Mark Slater, C. Cerri, E. Menichetti, D. T. Madigozhin, Nadia Pastrone, G. Pierazzini, B. Vallage, M. Sozzi, Leander Litov, E. Mazzucato, H. D. Wahl, Evgueni Goudzovski, J.B. Cheze, W. Kubischta, Augusto Ceccucci, P. Debu, P.L. Frabetti, F. Costantini, A. I. Zinchenko, G. Collazuol, D. J. Munday, E. Iacopini, M. Eppard, B. Peyaud, Cristina Biino, Ivan Mikulec, A. Peters, A. Gianoli, M. Holder, P. Grafström, M. Markytan, F. Petrucci, C. Lazzeroni, M. Veltri, Lau Gatignon, M. Savrie, M. Martini, G. Bocquet, Yu. Potrebenikov, Alan W. Walker, I. Mannelli, M. Calvetti, Andrea Bizzeti, Vladimir Kekelidze, A. Winhart, G. Marel, L. Masetti, Rainer Wanke, T. Fonseca Martin, F. Marchetto, A. Michetti, E. C. Swallow, Mauro Piccini, P. Cenci, N. A. Molokanova, K. Eppard, R. Sacco, G. Neuhofer, S. Giudici, D.C. Cundy, M. Lenti, P. Hristov, S. A. Wotton, U. Koch, Niels Doble, G. Lamanna, Marco Clemencic, E. Imbergamo, Roberta Arcidiacono, P. Rubin, S. Goy Lopez, A. Norton, Roland Winston, E. Monnier, L. Fiorini, M. Pepe, A. Gonidec, L. Widhalm, M. Scarpa, W. Wislicki, P. Marouelli, Manfred Jeitler, G. Anzivino, G. Gouge, P. Lubrano, A. Nappi, and A. Hirstius

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Cabibbo–Kobayashi–Maskawa matrix, 0103 physical sciences, Sigma, Particle Data Group, 010306 general physics, Branching (polymer chemistry), 01 natural sciences
Abstract

From 56 days of data taking in 2002, the NA48/1 experiment observed 6316 Ξ 0 → Σ + e − ν ¯ e candidates (with the subsequent Σ + → p π 0 decay) and 555 Ξ 0 ¯ → Σ + ¯ e + ν e candidates with background contamination of 215 ± 44 and 136 ± 8 events, respectively. From these samples, the branching ratios BR ( Ξ 0 → Σ + e − ν ¯ e ) = ( 2.51 ± 0.03 stat ± 0.09 syst ) × 10 −4 and BR ( Ξ 0 ¯ → Σ + ¯ e + ν e ) = ( 2.55 ± 0.14 stat ± 0.10 syst ) × 10 −4 were measured allowing the determination of the CKM matrix element | V us | = 0.209 −0.028 +0.023 . Using the Particle Data Group average for | V us | obtained in semileptonic kaon decays, we measured the ratio g 1 / f 1 = 1.20 ± 0.05 of the axial-vector to vector form factors.

Published
2007

26. Search for the dark photon in π0 decays

Author

Enrico Celeghini, C. Damiani, H. D. Wahl, A. A. Maier, P. Marouelli, M. Fidecaro, E. Imbergamo, U. Moosbrugger, A. Dabrowski, B. Peyaud, M. C. Petrucci, W. Baldini, E. Monnier, G. Bocquet, V. Falaleev, M. Piccini, N. Doble, N. A. Molokanova, K. Eppard, Cristina Lazzeroni, D. Coward, I. Mannelli, L. Gatignon, M. Markytan, S. Venditti, D.J. Munday, Nicolo Cartiglia, P. L. Frabetti, V. Kekelidze, M. Scarpa, Giuseppe Ruggiero, M. Shieh, S. A. Wotton, G. Pierazzini, S. Stoynev, Milene Calvetti, A. Norton, M. Szleper, F. Marchetto, A. Michetti, A. Ceccucci, M. Pepe, G. Marel, P. Hristov, M. Veltri, Evelina Gersabeck, A. Cotta Ramusino, Maulik R. Patel, M. De Beer, Evgueni Goudzovski, S. Goy Lopez, Roland Winston, J.B. Cheze, H. Dibon, W. Kubischta, A. Gonidec, A. Winhart, T. Fonseca Martin, M. Holder, G. Collazuol, Luca Fiorini, F. Costantini, Konrad Kleinknecht, Andrea Bizzeti, R. Fantechi, P. F. Dalpiaz, M. Lenti, M. Valdata-Nappi, P. Cenci, Leander Litov, Mauro Raggi, M. Ziolkowski, G. Lamanna, S. Balev, M. Martini, J. Derre, Alan W. Walker, Roberta Arcidiacono, Marco Clemencic, E. Iacopini, E. C. Swallow, I. Polenkevich, M. D. Wood, L. Widhalm, M. Behler, Simone Bifani, Massimiliano Fiorini, M.W. Slater, A. Peters, A. Zinchenko, Cristina Biino, Ivan Mikulec, R. Wanke, J. R. Batley, Nicola Cabibbo, C. Cheshkov, V. Kozhuharov, M. Sozzi, M. Savrie, L. DiLella, B. Bloch-Devaux, G.E. Kalmus, A. Nappi, A. Gianoli, B. Vallage, M. Wache, C. Cerri, B. Renk, Yu. Potrebenikov, D. Madigozhin, P. Rubin, Manfred Jeitler, S. Giudici, G. Anzivino, E. Mazzucato, L. Masetti, F. Petrucci, C. Morales Morales, Mayda Velasco, G. Neuhofer, and D.C. Cundy

Subjects
Nuclear and High Energy Physics, Dark matter, KAON DECAYS, Socio-culturale, Astronomy & Astrophysics, 01 natural sciences, Dark photon, dark matter, High Energy Physics - Experiment, Physics, Particles & Fields, Nuclear physics, 0202 Atomic, Molecular, Nuclear, Particle And Plasma Physics, 0103 physical sciences, dark matter, meson decays, 010306 general physics, DETECTOR, Physics, Nuclear and High Energy Physics, dark photon, photon, pion, neutral pion, neutral pion, Range (particle radiation), Large Hadron Collider, Science & Technology, 010308 nuclear & particles physics, photon, Dark Photon, pion, meson decays, Nuclear & Particles Physics, lcsh:QC1-999, Physics, Nuclear, Physical Sciences, dark photon, Fotone, High Energy Physics::Experiment, Particle Physics - Experiment, lcsh:Physics
Abstract

A sample of $1.69\times 10^7$ fully reconstructed $\pi^0\to\gamma e^+e^-$ decay candidates collected by the NA48/2 experiment at CERN in 2003--2004 is analysed to search for the dark photon ($A'$) production in the $\pi^0\to\gamma A'$ decay followed by the prompt $A'\to e^+e^-$ decay. No signal is observed, and an exclusion region in the plane of the dark photon mass $m_{A'}$ and mixing parameter $\varepsilon^2$ is established. The obtained upper limits on $\varepsilon^2$ are more stringent than the previous limits in the mass range $9~{\rm MeV}/c^2, Comment: Revised version accepted for publication in Physics Letter B

Published
2015

27. A measurement of the CP-conserving component of the decay KS0→π+π−π0

Author

Konrad Kleinknecht, G.M. Pierazzini, P. F. Dalpiaz, Augusto Ceccucci, W. Wislicki, L. Widhalm, Rainer Wanke, P. Debu, C. Cerri, M. Patel, W. Kubischta, S. A. Wotton, A. I. Zinchenko, Nadia Pastrone, N. A. Molokanova, U. Moosbrugger, A. Gianoli, B. Vallage, G. Graziani, K. Eppard, C. Cheshkov, M. Holder, G. Bocquet, Yu. Potrebenikov, E. C. Swallow, A. Peters, G. Ruggiero, Marco Clemencic, M. Wache, D.J. Munday, Andrea Bizzeti, P. Rubin, Roberta Arcidiacono, L. Masetti, M. Savrie, D. T. Madigozhin, A. Gonidec, V. Falaleev, Michael Ziolkowski, Nicolo Cartiglia, E. Menichetti, R. Sacco, G. Collazuol, E. Mazzucato, Cristina Lazzeroni, S. Stoynev, G. Neuhofer, P. Marouelli, E. Monnier, F. Marchetto, M. De Beer, I. Mannelli, D.C. Cundy, J.B. Cheze, A. Michetti, C. Morales Morales, S. Giudici, B. Panzer-Steindel, M. Pepe, M. Martini, Fabrizio Petrucci, Luca Fiorini, A. Maier, H. D. Wahl, P. Hristov, F. Costantini, M. Scarpa, Leander Litov, Manfred Jeitler, B. Peyaud, M. Behler, M. Veltri, P.L. Frabetti, M. Sozzi, S. Goy Lopez, Mayda Velasco, G. Marel, A. Norton, Roland Winston, G. Anzivino, Alan W. Walker, G. Gouge, D. Gurev, M. Eppard, Niels Doble, A. Hirstius, Evgueni Goudzovski, Lau Gatignon, A. Nappi, P. Cenci, Cristina Biino, Ivan Mikulec, M. Valdata, F. Martelli, Vladimir Kekelidze, E. Iacopini, P. Grafström, R. Fantechi, Milene Calvetti, H. Dibon, Wander Baldini, U. Koch, A. Winhart, T. Fonseca Martin, Mauro Piccini, M.W. Slater, J. R. Batley, M. Markytan, M. Lenti, A. Dabrowski, M. C. Petrucci, G. Lamanna, P. Lubrano, and E. Imbergamo

Subjects
Physics, Nuclear and High Energy Physics, Angular momentum, Amplitude, Chiral perturbation theory, 010308 nuclear & particles physics, Component (thermodynamics), Quantum mechanics, 0103 physical sciences, Pi, Perturbation theory, 010306 general physics, 01 natural sciences
Abstract

The NA48 Collaboration has measured the amplitude of the CP-conserving component of the decay K S 0 → π + π − π 0 relative to K L 0 → π + π − π 0 . For the characteristic parameter λ , the values Re λ = 0.038 ± 0.010 and Im λ = − 0.013 ± 0.007 have been extracted. These values agree with earlier measurements and with theoretical predictions from chiral perturbation theory.

Published
2005

28. Measurement of the KL→e+e−e+e− decay rate

Author

M. Wittgen, Rainer Wanke, J. Cogan, T. Çuhadar, J. C. Chollet, U. Koch, M. Markytan, M. Lenti, I.G. Knowles, A. Winhart, G. Tatishvili, Mauro Piccini, S. Giudici, R. Fantechi, S. Wronka, I. Wingerter-Seez, Milene Calvetti, Nicolo Cartiglia, R.S. Dosanjh, Michael Andrew Parker, G.M. Pierazzini, G. Govi, N. A. Molokanova, A. Kalter, M. Eppard, H. D. Wahl, P. Lubrano, Adrian John Bevan, T.O. White, W. Kubischta, B. Hay, G. Unal, Vladimir Kekelidze, K. Eppard, H. Dibon, I. Mannelli, S.A. Schmidt, E. Rondio, B. Peyaud, V. Schönharting, Roberta Arcidiacono, E. Imbergamo, G. Graziani, P. F. Dalpiaz, Fabrizio Petrucci, Nadia Pastrone, R. Casali, H. Taureg, R. Turlay, D. Marras, Augusto Ceccucci, P.L. Frabetti, B. Vallage, M. Contalbrigo, I. Melzer-Pellmann, Alexi Mestvirishvili, J. Ocariz, T.J. Gershon, M. Sozzi, Benedetto Gorini, C. Cheshkov, A. I. Zinchenko, Louis Fayard, J.B. Cheze, F. Marchetto, B. Renk, V. Falaleev, Manfred Jeitler, H.G. Becker, Alan W. Walker, A. Gianoli, Sandro Palestini, E. Iacopini, A. Maier, P. Hristov, J. Duclos, G. Anzivino, M. Cirilli, Niels Doble, Andrea Bizzeti, Cristina Biino, Ivan Mikulec, A. Peters, Konrad Kleinknecht, Luca Fiorini, R. Granier de Cassagnac, G. Neuhofer, P. Grafström, G. Bocquet, Yu. Potrebenikov, Michael Ziolkowski, G.D. Barr, D.C. Cundy, G. Lamanna, D. Madigojine, M. Holder, C. Cerri, L. Widhalm, M. Pernicka, L. Köpke, Victoria Jane Martin, Y. Schué, A. Lai, Andrea Formica, Mayda Velasco, P. Debu, E. Olaiya, Lau Gatignon, F. Costantini, G. Ruggiero, A. Nappi, E. Mazzucato, S. A. Wotton, R. Sacco, Michal Szleper, Wojciech Wislicki, A. Gonidec, Cristina Lazzeroni, M. Savrie, P. Cenci, G. Collazuol, G. Fischer, E. Menichetti, Anton Taurok, G.E. Kalmus, M. De Beer, M. Martini, M. Pepe, G. D'Agostini, M.D. Needham, A. Norton, D.J. Munday, J. Nassalski, H. Fox, P. Lopes da Silva, Lydia Iconomidou-Fayard, P. Marouelli, A. Lacourt, and B. Panzer-Steindel

Subjects
Physics, Nuclear and High Energy Physics, Meson, Branching fraction, Analytical chemistry, Atomic physics, Positron annihilation
Abstract

The decay rate of the long-lived neutral K meson into the e + e − e + e − final state has been measured with the NA48 detector at the CERN SPS. Using data collected in 1998 and 1999, a total of 200 events has been observed with negligible background. This observation corresponds to a branching ratio of Br ( K L → e + e − e + e − ) = ( 3.30 ± 0.24 stat ± 0.23 syst ± 0.10 norm ) × 10 −8 .

Published
2005

29. Search for CP violation in K0→3π0 decays

Author

Konrad Kleinknecht, M. Holder, G. Graziani, W. Wislicki, A. Gonidec, M. Wittgen, E. Rondio, Andrea Bizzeti, J. C. Chollet, G. Collazuol, J. Nassalski, P. F. Dalpiaz, V. Falaleev, D. Madigojine, P. Lopes da Silva, Nadia Pastrone, R. Fantechi, I. Pellmann, Benedetto Gorini, G. Bocquet, Yu. Potrebenikov, T.J. Gershon, S. Giudici, T. Cuhadar-Dönszelmann, Milene Calvetti, Augusto Ceccucci, Vladimir Kekelidze, Manfred Jeitler, F. Martelli, A. Lai, Andrea Formica, R.S. Dosanjh, F. Derue, M. Martini, G.D. Barr, B. Vallage, G. Neuhofer, M. Markytan, J. Duclos, G. Anzivino, H. D. Wahl, Lydia Iconomidou-Fayard, M. Lenti, N. A. Molokanova, K. Eppard, P. Marouelli, C. Cerri, D.C. Cundy, G. Gouge, R. Turlay, H. Dibon, G. Marel, B. Peyaud, F. Costantini, Rainer Wanke, U. Koch, A. Peters, Y. Schué, M. Pepe, P. Debu, A. Winhart, C. Cheshkov, Fabrizio Petrucci, Mauro Piccini, G.M. Pierazzini, T.O. White, G. Unal, S. A. Wotton, P. Lubrano, W. Kubischta, B. Panzer-Steindel, P. Rubin, S.A. Schmidt, S. Wronka, Alexi Mestvirishvili, P.L. Frabetti, Nicolo Cartiglia, Michael Ziolkowski, E. Imbergamo, J.B. Cheze, Michael Andrew Parker, Luca Fiorini, Louis Fayard, F. Marchetto, D. Marras, L. Widhalm, E. Iacopini, Alan W. Walker, V. Schönharting, Cristina Biino, Ivan Mikulec, I. Wingerter-Seez, P. Grafström, M. Sozzi, G. Tatishvili, A. Nappi, M. Eppard, J. R. Batley, Massimiliano Fiorini, M. Cirilli, Niels Doble, Michal Szleper, R. Sacco, A. Lacourt, M. Savrie, E. Menichetti, G.E. Kalmus, M. De Beer, Roberta Arcidiacono, R. Casali, M. Veltri, Lau Gatignon, A. Norton, P. Cenci, M. Contalbrigo, A. Maier, P. Hristov, L. Köpke, D.J. Munday, Victoria Jane Martin, E. Olaiya, Cristina Lazzeroni, E. Mazzucato, A. I. Zinchenko, M. Pernicka, A. Gianoli, R. Granier de Cassagnac, A. Hirstius, Anton Taurok, I. Mestvirishvili, and I. Mannelli

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Amplitude, 010308 nuclear & particles physics, Branching fraction, 0103 physical sciences, Pi, CP violation, 010306 general physics, Lifetime distribution, 01 natural sciences
Abstract

Using data taken during the year 2000 with the NA48 detector at the CERN SPS, a search for the CP violating decay K S → 3 π 0 has been performed. From a fit to the lifetime distribution of about 4.9 million reconstructed K 0 / K ¯ 0 → 3 π 0 decays, the CP violating amplitude η 000 = A ( K S → 3 π 0 ) / A ( K L → 3 π 0 ) has been found to be Re ( η 000 ) = − 0.002 ± 0.011 ± 0.015 and Im ( η 000 ) = − 0.003 ± 0.013 ± 0.017 . This corresponds to an upper limit on the branching fraction of Br ( K S → 3 π 0 ) 7.4 × 10 −7 at 90% confidence level. The result is used to improve knowledge of Re ( e ) and the CPT violating quantity Im ( δ ) via the Bell–Steinberger relation.

Published
2005

30. Observation of the rare decay KS→π0μ+μ−

Author

S Goy-Lopez, G. Kalmus, Cristina Biino, Nadia Pastrone, Ivan Mikulec, M. Markytan, M. Lenti, A. Peters, P. Rubin, Mauro Piccini, T. Fonseca Martin, C. Cerri, M. Valdata, Peter Zahariev Hristov, G. Ruggiero, Vladimir Kekelidze, Marco Clemencic, A. Gonidec, E. Iacopini, G. Collazuol, N. Doble, R. Sacco, A.I. Zinchenko, P. Grafström, M. Holder, P. Lubrano, M. C. Petrucci, G. Bocquet, Yu. Potrebenikov, Roberta Arcidiacono, R. Fantechi, G.M. Pierazzini, U. Koch, Milene Calvetti, E. Imbergamo, E. Monnier, H. Dibon, Wander Baldini, H. D. Wahl, Mayda Velasco, L. Gatignon, G. Neuhofer, Nicolo Cartiglia, Cristina Lazzeroni, Anne Dabrowski, M. Pepe, Cvetan Valeriev Cheshkov, Manfred Jeitler, D.C. Cundy, P. F. Dalpiaz, J.B. Cheze, F. Costantini, M. Ziolkowski, A. Gianoli, B. Peyaud, N. A. Molokanova, Luca Fiorini, J. Duclos, K. Eppard, G. Anzivino, G. Lamanna, V. Kozhuharov, F. Marchetto, D. T. Madigozhin, L. Widhalm, E. Mazzucato, W. Wislicki, G. Gouge, I. Mannelli, A. A. Maier, M. W. Slater, L. Masetti, S. Giudici, A. Hirstius, G. Marel, Rainer Wanke, Fabrizio Petrucci, P. Cenci, Leander Litov, Jacqueline Batley, U. Moosbrugger, P.L. Frabetti, B. Vallage, Alan W. Walker, Evgueni Goudzovski, M. Sozzi, Michal Szleper, A. Michetti, S. A. Wotton, M. Savrie, D. Gurev, E. Menichetti, A. Ceccucci, Andrea Bizzeti, A. Nappi, M. De Beer, B. Panzer-Steindel, M. Behler, M. Scarpa, M. Martini, G. Graziani, V. Falaleev, A. Winhart, E. C. Swallow, P. Marouelli, C. Morales Morales, P. Debu, Stoyan Stoynev, W. Kubischta, M. Eppard, D. J. Munday, M. Veltri, A. Norton, Roland Winston, Maulik R. Patel, F. Martelli, and Konrad Kleinknecht

Subjects
mesoni K, decadimenti rari, Physics, Nuclear and High Energy Physics, Large Hadron Collider, 010308 nuclear & particles physics, Branching fraction, Form factor (quantum field theory), 01 natural sciences, Nuclear physics, 0103 physical sciences, Pi, CP violation, Matrix element, 010306 general physics
Abstract

A search for the decay KS→π0μ+μ−KS→π0μ+μ− has been made by the NA48/1 Collaboration at the CERN SPS accelerator. The data were collected during 2002 with a high-intensity KSKS beam. Six events were found with a background expectation of 0.22−0.11+0.18 events. Using a vector matrix element and unit form factor, the measured branching ratio is B(KS→π0μ+μ−)=[2.9−1.2+1.5(stat)±0.2(syst)]×10−9.

Published
2004

31. Measurement of the Ξ0→Λγ decay asymmetry and branching fraction

Author

G. Tatishvili, Lau Gatignon, D. Marras, A. Tkatchev, M. Sozzi, Benedetto Gorini, P. Cenci, M. Cirilli, Niels Doble, G. Govi, M. De Beer, Manfred Jeitler, M. Holder, A. Kalter, Roberta Arcidiacono, R. Casali, W. Kubischta, M. Contalbrigo, E. Olaiya, J. Duclos, A. Winhart, P. Debu, A. Maier, G. Anzivino, P. Hristov, Mauro Piccini, L. Köpke, P. F. Dalpiaz, I. Wingerter-Seez, T.O. White, G. Unal, S. A. Wotton, Rainer Wanke, Nadia Pastrone, C. Cheshkov, E. Mazzucato, T.J. Gershon, Adrian John Bevan, A. Gaponenko, G.D. Barr, H. Fox, R. Turlay, B. Vallage, M. Markytan, M. Lenti, M. Pepe, G. D'Agostini, Nicolo Cartiglia, A. I. Zinchenko, A. Lacourt, Michael Andrew Parker, F. Martelli, E. Rondio, J. C. Chollet, M. Martini, I.G. Knowles, Alexi Mestvirishvili, Augusto Ceccucci, E. Iacopini, J.B. Cheze, A. Peters, D. Madigojine, S. Giudici, A. Gianoli, N. A. Molokanova, T. Cuhadar-Dönszelmann, K. Eppard, P. Grafström, A. Nappi, A. Gonidec, R. Granier de Cassagnac, Roberto Guida, G.M. Pierazzini, R.S. Dosanjh, G. Collazuol, Konrad Kleinknecht, H.G. Becker, Cristina Biino, Ivan Mikulec, S. Wronka, V. Schönharting, G. Graziani, R. Fantechi, M. Wittgen, Michal Szleper, B. Hay, J. Cogan, V. Falaleev, I. Pellmann, Milene Calvetti, M. Savrie, H. Dibon, P. Lubrano, B. Panzer-Steindel, S.A. Schmidt, E. Menichetti, G. Neuhofer, Sandro Palestini, G.E. Kalmus, Louis Fayard, R. Carosi, F. Marchetto, D.C. Cundy, Vladimir Kekelidze, L. Widhalm, A. Lai, Andrea Formica, Y. Schué, E. Imbergamo, F. Costantini, Victoria Jane Martin, M. Eppard, R. Sacco, G. Bocquet, Yu. Potrebenikov, U. Koch, Mayda Velasco, M. Veltri, A. Norton, G. Fischer, Anton Taurok, D.J. Munday, J. Nassalski, P. Lopes da Silva, Lydia Iconomidou-Fayard, P. Marouelli, L. Bertanza, M. Pernicka, Wojciech Wislicki, J. Ocariz, B. Renk, Cristina Lazzeroni, H. D. Wahl, B. Peyaud, I. Mannelli, Michael Ziolkowski, H. Taureg, Andrea Bizzeti, C. Cerri, Fabrizio Petrucci, P.L. Frabetti, and Alan W. Walker

Subjects
Physics, Particle physics, Nuclear and High Energy Physics, Large Hadron Collider, Branching fraction, media_common.quotation_subject, iperoni Xi0, Hyperon, Radiative decay, NA48 experiment, Asymmetry, Nuclear physics, decadimenti radiativi, Radiative transfer, media_common
Abstract

In data taken with the NA48 experiment at the CERN SPS in 1999, 730 candidates of the weak radiative hyperon decay Ξ0→Λγ have been found with an estimated background of 58±8 events. From these events the Ξ0→Λγ decay asymmetry has been determined to α(Ξ0→Λγ)=-0.78±0.18stat±0.06 syst, which is the first evidence of a decay asymmetry in Ξ 0→Λγ. The branching fraction of the decay has been measured to be Br(Ξ0→Λγ)=(1.16±0.05 stat±0.06syst)×10-3. © 2004 Elsevier B.V. All rights reserved.

Published
2004
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32. Investigation of $K_\mathrm{L,S} \rightarrow \pi^+ \pi^{-} e^+ e^{-}$ decays

Author

Benedetto Gorini, J.P. Matheys, Manfred Jeitler, Victoria Jane Martin, M. De Beer, J. Duclos, G. Anzivino, Michael Ziolkowski, T. Cuhadar-Dönszelmann, G. Kalmus, H.G. Becker, Mayda Velasco, Cristina Biino, Ivan Mikulec, M. Wittgen, I. Augustin, Vladimir Kekelidze, G. Neuhofer, E. Iacopini, M. Pernicka, M. Veltri, M. Contalbrigo, A. Winhart, P. Grafström, M. Cirilli, O. Vossnack, Wolfgang Funk, Mauro Piccini, R. Carosi, T.J. Gershon, D.C. Cundy, A. Gaponenko, A. Hirstius, Paolo Calafiura, A. Norton, A. I. Zinchenko, S. Luitz, A. Lai, Nadia Pastrone, M. Sozzi, Augusto Ceccucci, A. Gianoli, K. Holtz, I. Mannelli, J.B. Cheze, R. Granier de Cassagnac, Michal Szleper, Roberto Guida, Y. Schué, R. Casali, R. Fantechi, B. Hay, L. Köpke, Frederic Derue, D. Coward, D. Marras, M. Savrie, Cristina Lazzeroni, G. Fischer, A. Peters, Milene Calvetti, H. D. Wahl, E. Menichetti, D. Schinzel, C. Cheshkov, G.D. Barr, G. Unal, Michael Bender, A. Kalter, M. Martini, J. Nassalski, U. Koch, A. Nappi, Anton Taurok, H. Bluemer, Louis Fayard, F. Marchetto, S. A. Wotton, R.S. Dosanjh, Roberta Arcidiacono, P. Lopes da Silva, H. Taureg, Lydia Iconomidou-Fayard, A L Tkachev, P. Marouelli, H. Dibon, L. Bertanza, R. Turlay, L. Widhalm, G. Tatishvili, M. Markytan, Niels Doble, Adrian John Bevan, M. Lenti, E. Rondio, A. Bigi, B. Peyaud, Lau Gatignon, G. Graziani, R. Sacco, J.-C. Chollet, Andrea Bizzeti, I. Wingerter-Seez, G. Pierazzini, V. Falaleev, P Z Khristov, I.G. Knowles, W. Wislicki, E. Mazzucato, G. Govi, P. Cenci, S. Giudici, W. Kubischta, S. Wronka, P. Lubrano, P. Debu, S.A. Schmidt, M. Scarpa, D. J. Munday, E. Imbergamo, Alexi Mestvirishvili, J. Ocariz, J. G. Cogan, F. Martelli, M. Holder, M. Pepe, G. D'Agostini, D. Madigojine, Konrad Kleinknecht, I. Pellmann, F. Costantini, G. Bocquet, Yu. Potrebenikov, A. Gonidec, G. Collazuol, A. Maier, Matthew Needham, M. Eppard, Nicolo Cartiglia, Michael Andrew Parker, Rainer Wanke, P. F. Dalpiaz, V. Schönharting, B. Vallage, Jacqueline Batley, C. Cerri, E. Olaiya, H. Fox, A. Lacourt, B. Panzer-Steindel, Fabrizio Petrucci, P.L. Frabetti, T. O. White, H. Parsons, Alan W. Walker, Sandro Palestini, A. Formica, and N. A. Molokanova

Subjects
Nuclear physics, Physics, Particle physics, Angular distribution, Large Hadron Collider, Physics and Astronomy (miscellaneous), Angular correlation, Charge radius, Pi, NA48 experiment, Engineering (miscellaneous)
Published
2003

33. Detailed study of the K ± → π 0 π 0 e ± ν (K e4 00 ) decay properties

Author

W. Kubischta, G.M. Pierazzini, D. J. Munday, E. Iacopini, M. Scarpa, Enrico Celeghini, P. L. Frabetti, E. Monnier, A. Dabrowski, Cristina Lazzeroni, Manfred Jeitler, R. Fantechi, Rainer Wanke, M. C. Petrucci, Marco Clemencic, Milene Calvetti, M. Holder, G. Anzivino, A. Michetti, A. Ceccucci, F. Marchetto, P. Rubin, Nicolo Cartiglia, S. Venditti, Fabrizio Petrucci, Andrea Bizzeti, H. Dibon, U. Moosbrugger, A. Winhart, Leander Litov, Cristina Biino, T. Fonseca Martin, L. Widhalm, M. Shieh, Mauro Piccini, Mauro Raggi, C. Damiani, S. Stoynev, E. C. Swallow, G. Neuhofer, Maulik R. Patel, A. A. Maier, M. Sozzi, A. Nappi, G. Bocquet, S. A. Wotton, Jacqueline Batley, D.C. Cundy, H. D. Wahl, L. DiLella, Massimiliano Fiorini, V. Falaleev, D. Coward, Alan W. Walker, M. Fidecaro, B. Peyaud, M. Szleper, I. Polenkevich, M. Slater, M. D. Wood, P. Hristov, N. A. Molokanova, Evelina Gersabeck, K. Eppard, S. Balev, M. Martini, S. Giudici, J.B. Cheze, C. Cerri, Evgueni Goudzovski, M. Ziolkowski, N. Doble, Luca Fiorini, Giuseppe Ruggiero, G. Marel, P. Marouelli, W. Baldini, F. Costantini, M. Veltri, S. Goy Lopez, A. Norton, Roland Winston, Simone Bifani, M. Markytan, M. Lenti, Lau Gatignon, M. Pepe, B. Vallage, Konrad Kleinknecht, E. Imbergamo, M. Valdata-Nappi, P. Cenci, A. Gonidec, G. Collazuol, P. F. Dalpiaz, J. Derre, A. Cotta Ramusino, M. Gersabeck, Roberta Arcidiacono, Vladimir Kekelidze, M. Wache, G. Lamanna, D. T. Madigozhin, G. Kalmus, A. Peters, Ivan Mikulec, M. De Beer, Yu. Potrebenikov, E. Mazzucato, M. Behler, A. I. Zinchenko, A. Gianoli, Nicola Cabibbo, C. Cheshkov, V. Kozhuharov, M. Savrie, B. Bloch-Devaux, I. Mannelli, C. Morales Morales, L. Masetti, B. Renk, and Mayda Velasco

Subjects
Physics, Nuclear and High Energy Physics, Branching fraction, Fixed target experiments, Flavor physics, Rare decay, Plane (geometry), Hadron, Form factor (quantum field theory), kaon decay, semileptonic decay, Distribution (mathematics), Radiative transfer, Invariant mass, Atomic physics, Order of magnitude
Abstract

A sample of 65210 K ± → π 0 π 0 e ± ν (K e4 00 ) decay candidates with 1% background contamination has been collected in 2003-2004 by the NA48/2 collaboration at the CERN SPS. A study of the differential rate provides the first measurement of the hadronic form factor variation in the plane (M 2 , M 2 ) and brings evidence for a cusp-like structure in the distribution of the squared π 0 π 0 invariant mass around $$ 4{m}_{\pi^{+}}^2 $$ . Exploiting a model independent description of this form factor, the branching ratio, inclusive of radiative decays, is obtained using the K ± → π 0 π 0 π ± decay mode as normalization. It is measured to be BR(K e4 00 ) = (2.552 ± 0.010stat ± 0.010syst ± 0.032ext) × 10−5, which improves the current world average precision by an order of magnitude while the 1.4% relative precision is dominated by the external uncertainty from the normalization mode. A comparison with the properties of the corresponding mode involving a π + π − pair (K e4 + − ) is also presented.

Published
2014

34. Observation of the decay KS→π+π−e+e−

Author

C. Cheshkov, U. Koch, G. Govi, W. Kubischta, E. Iacopini, P. Grafström, G. Bocquet, Yu. Potrebenikov, Nadia Pastrone, A. Winhart, A. Lai, Mauro Piccini, B. Vallage, P. Debu, R. Fantechi, Andrea Formica, Lydia Iconomidou-Fayard, Milene Calvetti, J. C. Chollet, I. Mannelli, A. Nappi, M. Eppard, I.G. Knowles, Michal Szleper, M. Savrie, E. Menichetti, R.S. Dosanjh, F. Costantini, G.E. Kalmus, Sandro Palestini, M. De Beer, P. Lubrano, H. Dibon, S. Giudici, Giacomo Graziani, A. Peters, S. Wronka, M. Wittgen, M. Holder, Benedetto Gorini, S.A. Schmidt, D. Marras, R. Turlay, S. A. Wotton, M. Contalbrigo, K. Holtz, J. Cogan, Manfred Jeitler, M. Sozzi, M. Bender, G.D. Barr, Wojciech Wislicki, E. Imbergamo, H. D. Wahl, E. Olaiya, J. Duclos, D.J. Munday, G. Anzivino, J. Nassalski, Michael Andrew Parker, M. Cirilli, N. A. Molokanova, J. Ocariz, Niels Doble, B. Renk, P. F. Dalpiaz, P. Hristov, E. Rondio, I. Pellmann, E. Mazzucato, I. Augustin, G. Fischer, M. Pepe, G. D'Agostini, T.O. White, G. Unal, T.J. Gershon, M.D. Needham, B. Peyaud, Anton Taurok, B. Hay, R. Sacco, Fabrizio Petrucci, L. Köpke, A. Gonidec, Augusto Ceccucci, V. Schönharting, M. Markytan, M. Lenti, P.L. Frabetti, G. Collazuol, J.B. Cheze, Vladimir Kekelidze, Victoria Jane Martin, G.M. Pierazzini, G. Tatishvili, Lau Gatignon, Mayda Velasco, Michael Ziolkowski, A. Mestvirishvili, A. Tkatchev, M. Martini, H. Parsons, Louis Fayard, F. Marchetto, Alan W. Walker, A. I. Zinchenko, Konrad Kleinknecht, P. Cenci, H. Taureg, H.G. Becker, H. Blümer, A. Gianoli, C. Lazzeroni, A. Kalter, R. Granier de Cassagnac, Cristina Biino, Ivan Mikulec, G. Neuhofer, S. Crépé, V. Falaleev, R. Carosi, D. Madigojine, Luciano Musa, M. Pernicka, Roberta Arcidiacono, D.C. Cundy, Andrea Bizzeti, R. Casali, A. Norton, Y. Schué, B. Panzer-Steindel, H. Fox, A. Lacourt, C. Cerri, I. Wingerter-Seez, and Adrian John Bevan

Subjects
mesoni K, decadimenti rari, Physics, Nuclear physics, Nuclear and High Energy Physics, Branching fraction, Bremsstrahlung, NA48 experiment
Abstract

We present the first observation of the decay KS→π+π−e+e− based upon the data collected in 1998 by the NA48 experiment at CERN. We have identified a clean sample of 56 events with negligible background contamination. Using KL→π+π−π0D decays as normalization sample, the branching ratio is measured to be BR(KS→π+π−e+e−)=[4.5±0.7(stat)±0.4(syst)]×10−5. This result is in good agreement with the theoretical expectations from the mechanism of inner bremsstrahlung.

Published
2000

35. Measurement of the decay rate and form factor parameter in the decay KL→e+e−γ

Author

H.G. Becker, Cristina Biino, Ivan Mikulec, Vladimir Kekelidze, R. Turlay, M. Holder, D. Marras, G. Fischer, A. Gonidec, A. I. Zinchenko, Michael Ziolkowski, S. Luitz, I. Potrebenikov, Anton Taurok, G. Collazuol, M. Sozzi, S. A. Wotton, E. Iacopini, G. Govi, Konrad Kleinknecht, S. Schanne, A. Gianoli, Paolo Calafiura, Matthew Needham, B. Vallage, P. Grafström, R.W. Moore, I. Mannelli, J. Nassalski, R. Granier de Cassagnac, A. Lai, Andrea Formica, G. Kesseler, J.B. Cheze, M. Cirilli, Niels Doble, W. Kubischta, Michal Szleper, O. Boyle, P. F. Dalpiaz, A. Nappi, P. Hristov, P. Lubrano, P. Debu, R. Fantechi, H. D. Wahl, Giacomo Graziani, A. Mestvirishvili, M. Savrie, U. Koch, A. Winhart, Louis Fayard, G. Neuhofer, F. Marchetto, J. C. Chollet, F. Costantini, D. J. Munday, Milene Calvetti, H. Blümer, L. Köpke, M. Bender, I.G. Knowles, P. Buchholz, E. Menichetti, A. Kalter, B. Peyaud, M. Martini, Lydia Iconomidou-Fayard, D. Schinzel, J. Scheidt, B. Hay, Victoria Jane Martin, W. Wislicki, Michael Andrew Parker, S. Giudici, M. De Beer, E. Rondio, H. Dibon, J. Ocariz, Roberta Arcidiacono, G.D. Barr, H. Taureg, B. Renk, Augusto Ceccucci, S. Wronka, Mayda Velasco, V. Fanti, I. Wingerter, V. Schönharting, G. Tatishvili, O. Vossnack, Lau Gatignon, Benedetto Gorini, G. Unal, M. Porcu, A. Tkatchev, M. Pepe, D. Coward, Manfred Jeitler, J.P. Matheys, C. Cerri, J. Schmidt, Luciano Musa, G. Bocquet, I. Augustin, K.N. Moore, J. Duclos, Andrea Bizzeti, P. Cenci, J. Bremer, G. Anzivino, A. Norton, M. Pernicka, C. Ebersberger, G. Wirrer, D. Vattolo, S. Crépé, E. Mazzucato, M. Markytan, M. Lenti, H. Fox, A. Lacourt, R. Wilhelm, B. Panzer-Steindel, Fabrizio Petrucci, P.L. Frabetti, T. O. White, H. Parsons, Sandro Palestini, A. Michetti, Wolfgang Funk, R. Carosi, D.C. Cundy, Y. Schué, G.M. Pierazzini, M. Wittgen, and J. Cogan

Subjects
Pseudoscalar, Physics, Nuclear physics, Nuclear and High Energy Physics, Amplitude, Meson, Branching fraction, Form factor (quantum field theory), Alpha (ethology), Relative strength
Abstract

The decay rate of the neutral K meson KL→e+e−γ has been measured with the NA48 detector at the CERN SPS. A total of 6864 events has been observed with an estimated background of 10 events. The branching ratio is Γ(KL→e+e−γ)/Γ(KL→all) = (1.06±0.02stat±0.02sys±0.04calc)×10−5. The parameter α K ∗ describing the relative strength of the two contributing amplitudes to this decay through intermediate pseudoscalar or vector mesons was measured to be α K ∗ =−0.36±0.06stat±0.02sys.

Published
1999

36. A 40 MHz pipelined trigger for K/sup 0//spl rarr/2/spl pi//sup 0/ decays for the CERN NA48 experiment

Author

G. Neuhofer, P. Kapusta, P. Calafiura, F. Formenti, C. Avanzini, Ivan Mikulec, Benedetto Gorini, M. Markytan, Manfred Jeitler, D. Rizzi, D.C. Cundy, Michael Ziolkowski, B. Hallgren, F. Laico, O. Vossnack, G. Pierazzini, M. Velasco, G. Laverrière, M Porcu, H. D. Wahl, G.D. Barr, W. Iwanski, F. Rossi, F. Costantini, M. Sozzi, H. Dibon, M. Cirilli, Fabio Morsani, G. Magazza, M. Pernicka, G. Fischer, Anton Taurok, and Raffaele Tripiccione

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Krypton, NA48 experiment, chemistry.chemical_element, Particle accelerator, STRIPS, law.invention, Calorimeter, Nuclear physics, Nuclear Energy and Engineering, chemistry, law, Nuclear electronics, CP violation, Electrical and Electronic Engineering
Abstract

A first level trigger system based on a 40 MHz digital pipeline has been developed for the CERN NA48 experiment, aiming at measuring CP violation in K/sup 0//spl rarr/2/spl pi/ decays. The outputs of the 13340 cells of the 10 m/sup 3/ liquid krypton calorimeter are summed into 64 X and 64 Y projection strips and continuously digitised with 40 MHz FADCs. This information is used to reconstruct at each clock cycle and for the two calorimeter projections, the number of clusters, the impact time of each of them (with a precision of about 3 ns), their total energy and the first and second moments of the energy distribution. Based on the quantities listed above, a programmable look-up table system subsequently computes online the longitudinal position of the kaon decay vertex and performs an event selection. The system is described.

Published
1998

37. Measurement of the decay KL→e+e−γγ

Author

M. Holder, I. Mannelli, R. Carosi, G.M. Pierazzini, L. Gatignon, R. Hagelberg, O. Perdereau, A. Bigi, M. Calvetti, Ken Peach, R. Werthenbach, Arthur Schaffer, D. Coward, D.C. Cundy, A. Kreutz, B. Renk, A. Beisser, Daniel Fournier, H. G. Sander, J. Scheidt, G.D. Barr, R. Fantechi, H. Rohrer, H. Blümer, Konrad Kleinknecht, P. Buchholz, E. Augé, Paolo Calafiura, M.G. Setzu, R. Casali, F. Leber, F. Scheerer, A. Wagner, A. Nappi, N. Doble, P. Grafström, Laurent Serin, J. Staeck, Lydia Iconomidou-Fayard, L. Bertanza, V.M. Marzulli, H. D. Wahl, and T. Beier

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Branching fraction, Full data
Abstract

The full data set of the NA31 experiment at CERN has been used to analyse the decay mode KOL → e+ e-γγ. A signal of 47 events has been observed with an estimated background of 6.9 events. The total number of kaon decays in the decay volume was determined to be (2.1 ± 0.1stat) · 109. This corresponds to a branching ratio of (8.0 ± 1.5+1.4-1.2)· 10-7. © 1998 Published by Elsevier Science B.V.

Published
1998

38. Recent results and prospects on kaon physics at CERN

Author

Augusto Ceccucci, H. Wahl, V. Bolotov, B. Renk, Tommaso Spadaro, Mayda Velasco, M. Sozzi, E. Imbergamo, P. Rubin, P. F. Dalpiaz, S. Movchan, F. Ambrosino, S. A. Wotton, E. Iacopini, L. DiLella, F. Bucci, Andreas Alexander Maier, V. Obraztsov, G. Lamanna, Milena Misheva, D. Di Filippo, G. Marel, V. E. Semenov, J.B. Cheze, A. Cotta Ramusino, Cvetan Valeriev Cheshkov, A. I. Zinchenko, Cristina Lazzeroni, O. Yushchenko, Luca Fiorini, Antonino Sergi, A. Antonelli, I. Mannelli, A. Gianoli, N. Doble, Milene Calvetti, Cristina Biino, Ivan Mikulec, G. DʼAgostini, R. Winston, Mauro Piccini, M. Holder, V. Palladino, D. Coward, Paolo Massarotti, V. Kurshetsov, Evgueni Goudzovski, A. Peters, Emmanuel Monnier, P. Cenci, Roberto Piandani, L. Masetti, Rainer Wanke, Jacqueline Batley, M. Markytan, M. Lenti, H. Dibon, G. Neuhofer, M. Wache, Jürgen Engelfried, V. Falaleev, M. Shieh, M. Valdata-Nappi, M. Scarpa, Viacheslav Duk, D. T. Madigozhin, Peter Zahariev Hristov, C. Cerri, A. Winhart, H. O. Danielsson, F. Petrucci, Mauro Raggi, E. Mazzucato, E. C. Swallow, R. Fantechi, U. Moosbrugger, Vladimir Kekelidze, C. Morales Morales, B. Vallage, P. Marouelli, M. C. Petrucci, Simone Bifani, M. Hita-Hochgesand, T. Numao, Stoyan Stoynev, W. Baldini, W. Kubischta, G. Bocquet, Yu. Potrebenikov, D. J. Munday, D.C. Cundy, S. Balev, M. Martini, K. Kleinknecht, S. Goy Lopez, A. Salamon, M. Serra, A. Norton, Massimiliano Fiorini, S. Gallorini, S. Venditti, G. Collazuol, F. Retiere, C. Damiani, Nicolo Cartiglia, I. Popov, M. Ziolkowski, V. Kozhuharov, G.M. Pierazzini, A. Fucci, M. De Beer, M. Veltri, Emilio Leonardi, I. Polenkevich, M. D. Wood, M. Behler, Mark Slater, Michal Szleper, G. Dellacasa, Giuseppe Ruggiero, Nicola Cabibbo, M. Savrie, B. Bloch-Devaux, F. Costantini, Lau Gatignon, J. Derre, M. Patel, Roberta Arcidiacono, S. Shkarovskiy, T. Fonseca Martin, E. Gushchin, Marco Clemencic, A. Gonidec, A. Romano, Leander Litov, P.L. Frabetti, M. Pepe, B. Hallgren, Paolo Valente, Alan W. Walker, M. Moulson, Andrea Bizzeti, F. Marchetto, A. Michetti, L. Widhalm, M. Fidecaro, N. A. Molokanova, B. Peyaud, K. Eppard, Petra Riedler, G. E. Kalmus, M. Napolitano, E. M. Gersabeck, Anne Dabrowski, G. Saracino, Manfred Jeitler, S. Giudici, G. Anzivino, A. Nappi, and Ambrosino, Fabio

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle decay, Particle physics, Large Hadron Collider, Meson, Hadron, Elementary particle, Fermion, NA62 experiment, Atomic and Molecular Physics, and Optics, Lepton
Abstract

A review of recent experimental results on charged kaon decays from NA48/2 and NA62 collaborations is given, together with a description of the NA62 experiment to study the ultra-rare decay K + → π + ν ν ¯ starting in fall 2014.

Published
2013

39. Measurement of the branching ratio of the double Dalitz decayK L →e+e−e+e− and the CP parity of theK L -meson

Author

O. Perdereau, Arthur Schaffer, D. Coward, G.M. Pierazzini, Ken Peach, M. Holder, P. Grafström, A. Kreutz, Konrad Kleinknecht, L. Gatignon, R. Casali, R. Carosi, Daniel Fournier, H. Rohrer, G.D. Barr, R. Heinz, I. Mannelli, Lydia Iconomidou-Fayard, R. Hagelberg, A. Wagner, L. Bertanza, H. G. Sander, D.C. Cundy, A. Nappi, J. Scheidt, M. Calvetti, F. Leber, M. Rost, H. D. Wahl, Laurent Serin, B. Renk, J. Staeck, V.M. Marzulli, T. Beier, Paolo Calafiura, Peter Buchholz, N. Doble, C. Cerri, H. Blümer, R. Werthenbach, E. Augé, and P. Mayer

Subjects
Physics, Particle physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), Meson, Branching fraction, Nuclear Theory, Parity (physics), Elementary particle, Nuclear physics, High Energy Physics::Experiment, Quantum field theory, Nuclear Experiment, Engineering (miscellaneous)
Abstract

Data from the NA31 experiment at CERN have been used to measure the branching ratio of the double Dalitz decay of the long-lived neutral kaon. Eight events have been found with negligible background. The measured distribution of the angle between the planes of the two e+e--pairs favours a CP=-1 state for the long-lived neutral kaon. © 1995 Springer-Verlag.

Published
1995

40. Search for the decay KL → 3γ

Author

R. Heinz, Laurent Serin, I. Mannelli, M. Rost, J. Staeck, A. Kreutz, R. Hagelberg, J. Scheidt, H. G. Sander, F. Leber, B. Renk, H. Blümer, Ken Peach, N. Doble, D.C. Cundy, G.D. Barr, Konrad Kleinknecht, V.M. Marzulli, Paolo Calafiura, M. Holder, E. Augé, R. Carosi, R. Casali, F. Scheerer, Daniel Fournier, H. Rohrer, G.M. Pierazzini, Peter Buchholz, M. Calvetti, T. Beier, P. Grafström, O. Perdereau, Arthur Schaffer, D. Coward, R. Werthenbach, C. Cerri, L. Gatignon, H. D. Wahl, A. Nappi, A. Wagner, Lydia Iconomidou-Fayard, and L. Bertanza

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Distribution (mathematics), Branching fraction
Abstract

Data from the NA31 experiment at the CERN SPS have been used for the first search for the decay mode KL → 3γ. Seven events have been found with an estimated background of 6.7 ± 1.5 events. The corresponding upper limit for the branching ratio is Γ(K L → 3γ) Γ(K L → all ) = 2.4 × 10 −7 at the 90% confidence level, assuming a phase-space decay distribution.

Published
1995

41. A test of chiral perturbation theory from the measurement of the decay KS → γγ

Author

H. G. Sander, A. Nappi, M. Calvetti, M. Rost, P. Grafström, O. Perdereau, Arthur Schaffer, D.C. Cundy, D. Coward, J. Scheidt, A. Kreutz, M. Punturo, Paolo Calafiura, V.M. Marzulli, A. Wagner, I. Mannelli, C. Cerri, T. Beier, R. Hagelberg, F. Leber, M. Holder, G.M. Pierazzini, R. Carosi, H. D. Wahl, Lydia Iconomidou-Fayard, R. Casali, Peter Buchholz, L. Gatignon, B. Renk, G.D. Barr, L. Bertanza, F. Scheerer, N. Doble, Konrad Kleinknecht, Ken Peach, Daniel Fournier, E. Augé, H. Blümer, R. Werthenbach, Laurent Serin, and J. Staeck

Subjects
Physics, Nuclear physics, Systematic error, Nuclear and High Energy Physics, Particle physics, Chiral perturbation theory, Branching fraction
Abstract

Data from NA31 experiment at CERN have been used to measure the decay KS → γγ. From 69 candidate events of the type K0 → γγ, 52 events can be attributed to KL → γγ and one event is expected from background processes. The ratio of the relative decay widths R = Γ(KS → γγ)Γ(KL → γγ) is measured to be R = 2.2 ± 1.0(stat.) ± 0.3(syst.) ± 0.2(ext.) where the external systematic error is due to the experimental uncertainty in the branching ratio of the decay KL → γγ. This translates into a branching ratio of BR(KS → γγ) = (2.2 ± 1.1) × 10−6. If these data are combined with the published data from an earlier data taking period with the same experiment, the ratio R is determined to be R = 2.35 ± 0.75(stat.) ± 0.4(syst.) + 7.5 · (1 − BR(KL → γγ)5.86 × 10−4) where the last term accounts for the dependence on the measured KL → γγ branching ratio. The corresponding branching ratio for KS → γγ is BR(KS → γγ) = (2.4 ± 0.9) × 10−6. The measurement is a sensitive test of chiral perturbation theory and in good agreement with theoretical predictions.

Published
1995

42. Performance of an electromagnetic liquid krypton calorimeter

Author

D. Schiuma, G. Viehhauser, W. Seidl, D. Schinzel, G. Linser, C. Cerri, P. Lubrano, B. Hallgren, L. Piemontese, A. Lacourt, J. Kekelidze, A. Norton, Sandro Palestini, Benedetto Gorini, C. E. Wulz, M. Markytan, N. Doble, A. Kalinin, P. Cenci, M. Martini, G. Neuhofer, Cristina Biino, A. Gianoli, J. Duclos, D.C. Cundy, H. Taureg, D. Coward, R. Fantechi, V. Marzulli, P. Calafiura, M. Pepe, P. Debu, E. Mazzucato, A. Migliori, V. Fanti, Peter Buchholz, A. Ceccucci, A. Kreutz, E. Griesmayer, M. Pernicka, G. Laverrière, H. D. Wahl, P. Lariccia, F. Leber, B. Peyaud, G. Kesseler, I. Mannelli, G.D. Barr, L. Gatignon, A. Gonidec, T. Taurok, R. Turlay, M. Savrie, F. Laico, Y. Kozhevnikov, and T. Stemmler

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Muon, Calorimeter (particle physics), Physics::Instrumentation and Detectors, Krypton, Detector, chemistry.chemical_element, Electron, Nuclear physics, chemistry, High Energy Physics::Experiment, Detectors and Experimental Techniques, Nuclear Experiment, Instrumentation, Image resolution, Noise (radio)
Abstract

A prototype electromagnetic calorimeter containing 180 litres of liquid krypton has been tested in electron and muon beams at the CERN SPS. The main features of this detector are its active shower medium, a granularity of 2 cm with tower readout, and the use of the initial current readout technique with an effective shaping time of about 60 ns. An energy resolution for electrons of 4.1% √E[ GeV ] with a constant term of 0.4% and a noise contribution of 50 MeV has been achieved. The calorimeter has a spatial resolution of 4.5 mm √E[ GeV ] with a constant term of 0.3 mm and a time resolution of about 0.5 ns for energies larger than 10 GeV.

Published
1994

43. Measurement of the direct emission and interference terms and search for CP violation in the decay K-+/- -> pi(+/-)pi(0)gamma

Author

R. Fantechi, M. Sozzi, S. A. Wotton, Milene Calvetti, Michael Ziolkowski, L. DiLella, H. Dibon, Mauro Raggi, A. Winhart, G. Ruggiero, Manfred Jeitler, N. A. Molokanova, A. A. Maier, K. Eppard, T. Fonseca Martin, Mauro Piccini, J.B. Cheze, A. Gonidec, S. Giudici, G. Anzivino, Luca Fiorini, G. Collazuol, I. Polenkevich, M. D. Wood, C. Morales Morales, P. Rubin, M. Szleper, P. L. Frabetti, J. Derre, G. Neuhofer, Jacqueline Batley, G. Bocquet, Yu. Potrebenikov, E. Iacopini, G. Kalmus, A. Peters, A. Ceccucci, Roberta Arcidiacono, Andrea Bizzeti, A. Michetti, C. Damiani, M. Holder, Cristina Biino, Ivan Mikulec, M. Slater, Lau Gatignon, Fabrizio Petrucci, P. Marouelli, Mayda Velasco, A. Nappi, P. F. Dalpiaz, B. Renk, H. D. Wahl, Leander Litov, D.C. Cundy, M. Fidecaro, M. Shieh, Stoyan Stoynev, W. Kubischta, P. Cenci, M. Wache, B. Peyaud, F. Marchetto, Evgueni Goudzovski, D. T. Madigozhin, D. J. Munday, M. Markytan, M. Lenti, L. Widhalm, Lucia Masetti, U. Moosbrugger, F. Costantini, B. Vallage, Peter Zahariev Hristov, Alan W. Walker, E. Mazzucato, E. Monnier, W. Baldini, Massimiliano Fiorini, A. I. Zinchenko, M. Pepe, Nicolo Cartiglia, A. Gianoli, Enrico Celeghini, Cristina Lazzeroni, C. Cerri, A. Dabrowski, M. C. Petrucci, E. Marinova, G.M. Pierazzini, N. Doble, C. Cheshkov, Marco Clemencic, I. Mannelli, G. Lamanna, V. Kekelidze, M. Veltri, S. Goy Lopez, A. Norton, Roland Winston, M. Scarpa, Nicola Cabibbo, V. Kozhuharov, M. Savrie, B. Bloch-Devaux, M. De Beer, M. Behler, A. Cotta Ramusino, E. Imbergamo, V. Falaleev, S. Balev, M. Martini, S. Venditti, Maulik R. Patel, Rainer Wanke, Simone Bifani, E. C. Swallow, Konrad Kleinknecht, D. Coward, M. Valdata-Nappi, G. Marel, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and NA48/2

Subjects
Particle physics, Meson, Physics and Astronomy (miscellaneous), DIRECT PHOTON-EMISSION, RADIATIVE KAON DECAYS, DETECTOR, Hadron, interference, Elementary particle, CP violation, Kaon decay, NA48 2 collaboration, 01 natural sciences, charged K meson, High Energy Physics - Experiment, Particle decay, Pion, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Kaon decays, Nuclear Experiment, 010306 general physics, Engineering (miscellaneous), K meson decay, Physics, 010308 nuclear & particles physics, Branching fraction, 3. Good health, High Energy Physics::Experiment, Atomic physics, Dimensionless quantity
Abstract

We report on the measurement of the direct emission (DE) and interference (INT) terms of the K\pm -> \pi\pm\pi^0 g decay by the NA48/2 experiment at the CERN SPS. From the data collected during 2003 and 2004 about 600k such decay candidates have been selected. The relative amounts of DE and INT with respect to the internal bremsstrahlung (IB) contribution have been measured in the range 0, Comment: 17 pages, 8 figures

Published
2010

44. The NA48 liquid krypton prototype calorimeter

Author

P. Schilly, M. Debeer, D. Schiuma, A. Kreutz, D. Schinzel, P. Wicht, I. Mannelli, A. Lacourt, H. Taureg, G. Linser, V.M. Marzulli, L. Gatignon, R. Carosi, G. Kesseler, M. Pernicka, M. Markytan, P. Debu, W. Seidl, G. Gennaro, A. Bigi, G.M. Pierazzini, G.D. Barr, C. Cerri, Anton Taurok, G. Viehhauser, P. Calafiura, D. Coward, Peter Buchholz, B. Hallgren, Niels Doble, H. D. Wahl, L. Bertanza, B. Peyaud, G. Neuhofer, C.-E. Wulz, D. Bederede, D.C. Cundy, M. Mast, R. Casali, B. Gorini, F. Sergiampietri, R. Fantechi, G. Laverrière, A. Gonidec, and E. Griesmayer

Subjects
Physics, Nuclear and High Energy Physics, Calorimeter (particle physics), Physics::Instrumentation and Detectors, Krypton, Resolution (electron density), NA48 experiment, chemistry.chemical_element, Nuclear physics, chemistry, Homogeneous, Cathode ray, CP violation, High Energy Physics::Experiment, Instrumentation, Energy (signal processing)
Abstract

The NA48 experiment for a precision measurement of the CP violation parameter ϵ′ ϵ in K 0 → 2 π decays will require a fast electromagnetic calorimeter with excellent energy and time resolution. A quasi homogeneous calorimeter using liquid krypton and a fast readout with 40 MHz FADCs is proposed. A prototype with 400 kg of liquid krypton was built and tested in an electron beam. Results for the energy, space and time resolution of this prototype are given.

Published
1992

45. A measurement of the decay KL→π0γγ

Author

I. Mannelli, B. Panzer, M. Rost, Konrad Kleinknecht, M. Holder, H.H. Nelson, O. Perdereau, Arthur Schaffer, R. Hagelberg, R. Carosi, A. Wagner, Laurent Serin, B. Renk, I. Harrus, P. Grafström, G.D. Barr, Lydia Iconomidou-Fayard, L. Bertanza, R. Werthenbach, A. Kreutz, V.M. Marzulli, H. D. Wahl, D.C. Cundy, M. Calvetti, R. Casali, P. Mayer, R. Heinz, A. Nappi, Niels Doble, G.M. Pierazzini, Peter Buchholz, H. Blümer, A. Bigi, L. Gatignon, D. Coward, E. Auge, Paolo Calafiura, Ken Peach, Daniel Fournier, and H. Rohrer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Chiral perturbation theory, Meson, 010308 nuclear & particles physics, Branching fraction, Elementary particle, 7. Clean energy, 01 natural sciences, Nuclear physics, Particle decay, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, 010306 general physics, Boson
Abstract

The full data set of the experiment NA31 at CERN has been used to analyse the decay mode KL→π0γγ. A signal of 63 events has been observed with an estimated background of 6.0±1.7 events, corresponding to a branching ratio of (1.7±0.3)×10−6 consistent with our previous result based on partial statistics. The invariant mass spectrum of the two photons is found to be consistent with chiral perturbation theory, and the decay is dominated by the J = 0 two photon state.

Published
1992

46. Observation of the decay KLO→ e+e−ep+e−

Author

B. Renk, H. D. Wahl, B. Panzer, V. Gibson, M. Calvetti, J. van der Lans, G. Zech, A. Bigi, D.C. Cundy, D. Coward, I. Mannelli, G.M. Pierazzini, D. J. Candlin, M. Holder, M. Rost, A. Kreutz, R. Heinz, L. Gatignon, R. Casali, H.G. Sander, H.N. Nelson, R. Carosi, G.D. Barr, O. Perdereau, Paolo Calafiura, Arthur Schaffer, Niels Doble, G. Grafström, R. Hagelberg, C. Cerri, P. Mayer, Lydia Iconomidou-Fayard, G. Quast, L. Bertanza, A. Wagner, Ken Peach, Ph. Heusse, Daniel Fournier, H. Rohrer, A. Nappi, E. Augé, Konrad Kleinknecht, H. Blümer, R. Werthenbach, I. Harrus, Laurent Serin, and R. Fantachi

Subjects
Physics, Nuclear and High Energy Physics, Branching fraction, Theoretical models, Atomic physics
Abstract

Two events with the characteristic of the decay K L O → e + e − e − have been observed with a negligible expected background from which a branching ratio of (4±3)×10 −8 is derived. This result is consistent with values estimated from theoretical models based on the double internal conventional of the decay K L O → γγ .

Published
1991

47. Measurement of the rate of the decay KL→e+e−γ and observation of a form factor in this decay

Author

H. D. Wahl, P. Calafiura, R. Heinz, Ken Peach, R. Hagelberg, H.G. Sander, I. Harrus, V. Gibson, R.L. Chase, H. Blümer, R. Fantechi, Daniel Fournier, H. Rohrer, R. Black, Arthur Schaffer, B. Panzer, A. Kreutz, Konrad Kleinknecht, L. Gatignon, C. Cerri, I. Mannelli, W. Weihs, G.D. Barr, H.N. Nelson, N. Doble, P. Grafström, M. Calvetti, M. Rost, R. Casali, A. Bigi, B. Renk, R. Werthenbach, D. Coward, J. van der Lans, G. Zech, G. Kesseler, R. Carosi, G.M. Pierazzini, Lydia Iconomidou-Fayard, D.C. Cundy, J. Muir, D. J. Candlin, P. Mayer, M. Holder, Ph. Heusse, H. Burkhardt, E. Augé, G. Quast, and A. Nappi

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Photon, Meson, Branching fraction, Propagator, High Energy Physics::Experiment, Large sample
Abstract

A large sample of Dalitz decays, K L → e + e − γ , has been observed. The branching ratio is Γ(K L →e + e − γ) Γ(K L → all )=(9.2±0.5±0.5)×10 −6 in good agreement with theoretical predictions. We observe an enhancement at high masses in the distribution of the invariant electron-positron pair mass, compared to the distribution expected from QED. This excess is interpreted as being due to virtual mesons contributing to the photon propagator.

Published
1990

48. Determination of the relative decay rate

Author

Jacqueline Batley, Nicolo Cartiglia, G. Ruggiero, B. Panzer-Steindel, M. C. Petrucci, M. Sozzi, U. Moosbrugger, Mark Slater, Fabrizio Petrucci, Evgueni Goudzovski, A. Gonidec, S. A. Wotton, G. Collazuol, Nadia Pastrone, A. A. Maier, M. Ziolkowski, Leander Litov, M. Savrie, E. Menichetti, P.L. Frabetti, M. Markytan, M. Lenti, M. Holder, M. Martini, H. D. Wahl, R. Sacco, P. Rubin, G.E. Kalmus, G. Bocquet, M. Scarpa, Yu. Potrebenikov, S. Giudici, M. De Beer, P. Lubrano, Anne Dabrowski, B. Peyaud, Stoyan Stoynev, Cristina Biino, Ivan Mikulec, M. Pepe, W. Kubischta, G.M. Pierazzini, Mitesh Patel, I. Mannelli, A. Peters, M. Valdata, E. Iacopini, A. Nappi, D. J. Munday, Alan W. Walker, P. Grafström, A. Hirstius, G. Graziani, M. Behler, E. Imbergamo, F. Marchetto, P. Cenci, F. Costantini, P. F. Dalpiaz, C. Lazzeroni, Peter Zahariev Hristov, L. Widhalm, Mayda Velasco, R. Fantechi, L. Masetti, V. Falaleev, W. Wislicki, Vladimir Kekelidze, U. Koch, Milene Calvetti, Mauro Piccini, A. Michetti, J.B. Cheze, Cvetan Valeriev Cheshkov, H. Dibon, Wander Baldini, Luca Fiorini, A. Ceccucci, C. Cerri, Andrea Bizzeti, A. Gianoli, G. Lamanna, N. A. Molokanova, K. Eppard, Manfred Jeitler, L. Gatignon, C. Morales Morales, Konrad Kleinknecht, G. Neuhofer, Rainer Wanke, D. T. Madigozhin, E. Mazzucato, A. Winhart, D.C. Cundy, G. Anzivino, E. C. Swallow, Roberta Arcidiacono, G. Gouge, P. Debu, T. Fonseca Martin, P. Marouelli, Marco Clemencic, N. Doble, M. Eppard, A.I. Zinchenko, E. Monnier, B. Vallage, M. Veltri, S. Goy Lopez, A. Norton, Roland Winston, F. Martelli, and G. Marel

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Kaon decays, Width ratio, Standard Model
Abstract

The decay rate of K S → π e ν relative to the rate of K L → π e ν has been measured by the NA48 Collaboration in a neutral kaon beam originating from 400 GeV proton-Be interactions at the CERN SPS. The result is 0.993 ± 0.026 stat ± 0.022 syst , compatible with 1 in agreement with the Standard Model prediction at tree level. It implies B R ( K S → π e ν ) = ( 7.05 ± 0.18 stat ± 0.16 syst ) × 10 −4 .

Published
2007

49. First observation and branching fraction and decay parameter measurements of the weak radiative decay Xi0 -> Lambda e+ e

Author

Nadia Pastrone, A. Winhart, T. Fonseca Martin, M. Eppard, Mauro Piccini, Fabrizio Petrucci, G. Bocquet, Yu. Potrebenikov, M. Ziolkowski, Leander Litov, P.L. Frabetti, A. Peters, D.J. Munday, Rainer Wanke, Nicolo Cartiglia, Cristina Lazzeroni, Ivan Mikulec, P. Debu, E. Iacopini, M. Valdata, P. Grafström, Alan W. Walker, M.W. Slater, V. Falaleev, S. A. Wotton, P. F. Dalpiaz, M. Pepe, E. Imbergamo, E. C. Swallow, A. Dabrowski, M. Veltri, M. C. Petrucci, J. R. Batley, R. Fantechi, S. Goy Lopez, G. Ruggiero, N. Doble, J.B. Cheze, A. Norton, Roland Winston, M. Patel, Milene Calvetti, U. Moosbrugger, M. Martini, Evgueni Goudzovski, A. Maier, P. Hristov, G. Lamanna, M. Holder, Vladimir Kekelidze, A. Gonidec, N. A. Molokanova, K. Eppard, H. Dibon, Konrad Kleinknecht, A. Hirstius, A. Ceccucci, Andrea Bizzeti, Luca Fiorini, G. Collazuol, W. Kubischta, G. Marel, M. Markytan, M. Lenti, E. Menichetti, P. Marouelli, C. Cerri, S. Stoynev, U. Koch, C. Cheshkov, W. Baldini, F. Marchetto, L. Widhalm, M. Savrie, P. Cenci, H. D. Wahl, G.E. Kalmus, W. Wislicki, M. De Beer, B. Peyaud, Roberta Arcidiacono, M. Behler, A. Michetti, Marco Clemencic, M. Sozzi, F. Costantini, S. Giudici, Cristina Biino, P. Rubin, E. Monnier, C. Morales Morales, Mayda Velasco, D. T. Madigozhin, E. Mazzucato, A. I. Zinchenko, A. Gianoli, I. Mannelli, L. Masetti, B. Panzer-Steindel, P. Lubrano, A. Nappi, Manfred Jeitler, G.M. Pierazzini, G. Anzivino, G. Gouge, L. Gatignon, B. Vallage, R. Sacco, G. Neuhofer, D.C. Cundy, and M. Scarpa

Subjects
Nuclear and High Energy Physics, media_common.quotation_subject, Signal region, Radiative decay, Xi0 hyperon, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Asymmetry, iperoni, acceleratori di particelle, NO, High Energy Physics - Experiment, mesoni K, 0103 physical sciences, 010306 general physics, radiative decay, particelle elementari, media_common, Physics, decadimenti, 010308 nuclear & particles physics, Branching fraction, High Energy Physics::Phenomenology, Bremsstrahlung, High Energy Physics::Experiment, Atomic physics, Particle Physics - Experiment, Conjugate
Abstract

The weak radiative decay Xi0 --> Lambda e+e- has been detected for the first time. We find 412 candidates in the signal region, with an estimated background of 15 +/- 5 events. We determine the branching fraction B(Xi0 --> Lambda e+e-) = [7.6 +/- 0.4(stat) +/- 0.4(syst) +/- 0.2(norm)] x 10^{-6}, consistent with an internal bremsstrahlung process, and the decay asymmetry parameter alpha_{XiLambdaee} = -0.8 +/- 0.2, consistent with that of Xi0 --> Lambda gamma. The charge conjugate reaction Xi0_bar --> Lambda_bar e+e- has also been observed., Comment: 20 pages, 5 figures, 4 tables; revised: 19 pages, 4 figures, 4 tables, after reviewers' comments: 1 figure removed, 1 figure corrected, minor editorial changes; to be published in Phys. Lett. B

Published
2007

50. Search for direct CP violation in the decays K-+/- -> 3 pi(+/-)

Author

Peter Zahariev Hristov, Nicolo Cartiglia, L. DiLella, Enrico Celeghini, L. Masetti, W. Kubischta, A. I. Zinchenko, A. Dabrowski, M. C. Petrucci, D. J. Munday, Simone Bifani, M. Martini, A. Gianoli, M. Fidecaro, M. Holder, E. Monnier, B. Vallage, F. Petrucci, B. Peyaud, M. Savrie, Evgueni Goudzovski, G. Kalmus, Maulik R. Patel, G. Bocquet, Yu. Potrebenikov, N. A. Molokanova, P. Marouelli, A. Peters, M. Calvetti, K. Eppard, L. Fiorini, Cristina Biino, Ivan Mikulec, F. Martelli, P. F. Dalpiaz, J.B. Cheze, M. Shieh, M. Wache, D. T. Madigozhin, I. Polenkevich, Michael Ziolkowski, V. Falaleev, Konrad Kleinknecht, D. Coward, M. Valdata-Nappi, Lau Gatignon, F. Costantini, M. Pepe, M. D. Wood, I. Mannelli, M. Markytan, S. Stoynev, E. Mazzucato, V. Kekelidze, S. Balev, P. Rubin, P. L. Frabetti, M. W. Slater, U. Moosbrugger, N. Doble, M. Sozzi, Augusto Ceccucci, E. Iacopini, G. Marel, G. Lamanna, Rainer Wanke, C. Morales Morales, Jacqueline Batley, Giuseppe Ruggiero, F. Marchetto, Cristina Lazzeroni, C. Damiani, A. Michetti, A. Winhart, T. Fonseca Martin, L. Widhalm, M. Scarpa, C. Cerri, H. Wahl, M. Veltri, Mauro Piccini, Andrea Bizzeti, R. Fantechi, P. Cenci, Mayda Velasco, Leander Litov, A. Gonidec, A. J. Culling, E. C. Swallow, G. Collazuol, B. Renk, A. Cotta Ramusino, H. Dibon, Wander Baldini, Alan W. Walker, E. Imbergamo, Mauro Raggi, G. Pierazzini, J. Derre, G. Neuhofer, Nicola Cabibbo, V. Kozhuharov, M. Lenti, S. Goy Lopez, D.C. Cundy, A. Maier, A. Norton, Roland Winston, Roberta Arcidiacono, S. Giudici, B. Bloch-Devaux, Marco Clemencic, S. A. Wotton, Massimiliano Fiorini, M. De Beer, E. Marinova, M. Szleper, C. Cheshkov, Manfred Jeitler, M. Behler, G. Anzivino, and A. Nappi

Subjects
Particle physics, Nuclear and High Energy Physics, media_common.quotation_subject, Dalitz plot, violazione CP, charged K meson, Asymmetry, NEUTRAL KAON, Nuclear physics, mesoni K, CHARGE ASYMMETRY, PARAMETER, NA48, CP-violation asymmetries, media_common, Physics, Large Hadron Collider, K meson, CP violation, Charge (physics), kaon decay
Abstract

We report a measurement of the direct CP violation asymmetry parameter A g in charged kaon decays K ± → π ± π + π − by the NA48/2 experiment at the CERN SPS. The experiment has been designed not to be limited by systematics in the asymmetry measurement. Using 1.67 × 10 9 such decays collected during the 2003 run, the charge asymmetry in the Dalitz plot linear slope parameter g has been measured to be A g = ( 1.7 ± 2.9 ) × 10 −4 . The precision of the result is limited by the statistics used.

Published
2006

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