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51 results on '"T. Numao"'

1. Search for three body pion decays π+→l+νX

Author

S. Cuen-Rochin, M. Blecher, D. Vavilov, Song Chen, Masaharu Aoki, D. Protopopescu, Y. Igarashi, L. S. Littenberg, P. Gumplinger, A. Sher, Luca Doria, C. Malbrunot, R. E. Mischke, T. Sullivan, Shintaro Ito, D. Vom Bruch, T. Numao, Dave Britton, Alexis A. Aguilar-Arevalo, S. H. Kettell, Douglas Bryman, J. R. Comfort, Leonid Kurchaninov, and Ahmed Hussein

Subjects
Physics, Crystallography, Pion, 010308 nuclear & particles physics, Branching fraction, Full data, High Energy Physics::Phenomenology, 0103 physical sciences, 010306 general physics, Coupling (probability), 01 natural sciences, Boson
Abstract

The three body pion decays π+→l+νX(l=e,μ), where X is a weakly interacting neutral boson, were searched for using the full data set from the PIENU experiment. An improved limit on Γ(π+→e+νX)/Γ(π+→μ+νμ) in the mass range 0

Published
2021

2. Search for heavy neutrinos in \(\pi ^{ + } \to \mu ^{ + }\nu \) decay and status of lepton universality test in the PIENU experiment

Author

T. Numao, Douglas Bryman, Chloé Malbrunot, P. Gumplinger, S. Cuen-Rochin, Dave Britton, Ahmed Hussein, A. Sher, D. Protopopescu, J. R. Comfort, L. S. Littenberg, T. Sullivan, Y. Igarashi, R. E. Mischke, Leonid Kurchaninov, Song Chen, S. Ito, S. H. Kettell, D. Vom Bruch, M. Blecher, Alexis A. Aguilar-Arevalo, Luca Doria, D. Vavilov, Masaharu Aoki, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
Physics, Particle physics, Muon, +muon%2B+neutrino%22">pi+ --> muon+ neutrino, pi: decay, neutrino: heavy: search for, Universality (philosophy), Pontecorvo–Maki–Nakagawa–Sakata matrix, kinetic, energy spectrum, Kinetic energy, Pion, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Neutrino, neutrino: mixing, Order of magnitude, Particle Physics - Experiment, Lepton, experimental results, lepton: universality
Abstract

International audience; In the present work of the PIENU experiment, heavy neutrinos were sought in pion decays \(\pi ^{ + } \to \mu ^{ + }\nu \). No evidence for extra peak was found in the muon kinetic energy spectrum and 90% confidence level upper limits were set on the neutrino mixing matrix \(|U_{\mu i}|^{2}\) in the mass range of 15.7 to 33.8 MeV/c^2, improving an order of magnitude over previous experiments. Current status of lepton universality test is also reported.

Published
2021

3. Search for heavy neutrinos in π → μν decay

Author

T. Numao, Dave Britton, M. Blecher, A. Sher, Y. Igarashi, Douglas Bryman, P. Gumplinger, J. R. Comfort, S. Cuen-Rochin, Alexis A. Aguilar-Arevalo, Leonid Kurchaninov, Song Chen, L. S. Littenberg, Luca Doria, D. Vavilov, R. E. Mischke, Masaharu Aoki, D. Vom Bruch, S. Ito, C. Malbrunot, Ahmed Hussein, S. H. Kettell, D. Protopopescu, and T. Sullivan

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Muon, 010308 nuclear & particles physics, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, High Energy Physics::Phenomenology, Pontecorvo–Maki–Nakagawa–Sakata matrix, 01 natural sciences, lcsh:QC1-999, Pion, 0103 physical sciences, Energy spectrum, High Energy Physics::Experiment, Neutrino, Heavy neutrino, 010306 general physics, Nuclear Experiment, Order of magnitude, lcsh:Physics
Abstract

In the present work of the PIENU experiment, heavy neutrinos were sought in pion decays pi(+) -> mu(+)nu at rest by examining the observed muon energy spectrum for extra peaks in addition to the expected peak for a light neutrino. No evidence for heavy neutrinos was observed. Upper limits were set on the neutrino mixing matrix vertical bar U-mu i vertical bar(2) in the neutrino mass region of 15.7-33.8 MeV/c(2), improving on previous results by an order of magnitude. (C) 2019 The Authors. Published by Elsevier B.V.

Published
2019

4. Improved search for heavy neutrinos in the decay π→eν

Author

L. S. Littenberg, Song Chen, Douglas Bryman, P. Gumplinger, S. H. Kettell, R. E. Mischke, D. Protopopescu, Ahmed Hussein, Y. Igarashi, J. R. Comfort, C. Malbrunot, Alexis A. Aguilar-Arevalo, D. Vom Bruch, S. Ito, D. Vavilov, Leonid Kurchaninov, M. Blecher, Masaharu Aoki, A. Sher, Luca Doria, T. Sullivan, T. Numao, Dave Britton, and S. Cuen-Rochin

Subjects
Physics, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, High Energy Physics::Phenomenology, Spectrum (functional analysis), Pontecorvo–Maki–Nakagawa–Sakata matrix, 01 natural sciences, Spectral line, Positron energy, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Neutrino, 010306 general physics, Order of magnitude
Abstract

A search for massive neutrinos has been made in the decay π+→e+ν. No evidence was found for extra peaks in the positron energy spectrum indicative of pion decays involving massive neutrinos (π→e+νh). Upper limits (90% C.L.) on the neutrino mixing matrix element |Uei|2 in the neutrino mass region 60–135 MeV/c2 were set and are an order of magnitude improvement over previous results.

Published
2018

5. Detector for measuring the π+→e+νe branching fraction

Author

Koji Yamada, S. Ito, A. Sher, P. Gumplinger, Minoru Yoshida, R. E. Mischke, T. Numao, D. Vom Bruch, T. Sullivan, Leonid Kurchaninov, S. Cuen-Rochin, K. Tauchi, G. Sheffer, S. H. Kettell, M. Blecher, L. S. Littenberg, A. Muroi, J. R. Comfort, Y. Igarashi, D. Vavilov, Luca Doria, Masaharu Aoki, Alexis A. Aguilar-Arevalo, C. Malbrunot, Douglas Bryman, Ahmed Hussein, and N. Ito

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Branching fraction, Scintillator, 01 natural sciences, Nuclear physics, Momentum, Crystal, Pion, Positron, 0103 physical sciences, Atomic physics, Decay product, 010306 general physics, Instrumentation
Abstract

The PIENU experiment at TRIUMF is aimed at a measurement of the branching ratio R e / μ = Γ ( ( π + → e + ν e ) + ( π + → e + ν e γ ) ) / Γ ( ( π + → μ + ν μ ) + ( π + → μ + ν μ γ ) ) with precision 0.1 % . Incident pions, delivered at the rate of 60 kHz with momentum 75 MeV/c, were degraded and stopped in a plastic scintillator target. Pions and their decay product positrons were detected with plastic scintillators and tracked with multiwire proportional chambers and silicon strip detectors. The energies of the positrons were measured in a spectrometer consisting of a large NaI(Tl) crystal surrounded by an array of pure CsI crystals. This paper provides a description of the PIENU experimental apparatus and its performance in pursuit of R e / μ .

Published
2015

6. Precision Measurement of the $\pi$$^+$$\rightarrow$$e^+$$\nu$$_e$ Branching Ratio in the PIENU Experiment

Author

A. Husseina, D. Protopopescu, D. Vavilov, Alexis A. Aguilar-Arevalo, Dave Britton, J. R. Comfort, L. Doria, Song Chen, Y. Igarashi, D. Vom Bruch, T. Sullivan, Shintaro Ito, A. Sher, T. Numao, Leonid Kurchaninov, Chloé Malbrunot, Masaharu Aoki, S. H. Kettell, L. S. Littenberg, Douglas Bryman, S. Cuen-Rochin, M. Blecher, P. Gumplinger, and R. E. Mischke

Subjects
Physics, Particle physics, Pion, Branching fraction, Pi, High Energy Physics::Experiment
Abstract

The PIENU experiment at TRIUMF aims to measure the branching ratio of the pion decay modes $R^{\pi}=[{\pi}^+{\rightarrow}e^+{\nu}_e({\gamma})]/[{\pi}^+{\rightarrow}{\mu}^+{\nu}_{\mu}({\gamma})]$ with precision of $

Published
2017

7. Study of π0 Dalitz decays in the NA62 and NA48/2 experiments

Author

A. Salamon, G. Dellacasa, M. Serra, Giuseppe Ruggiero, F. Bucci, Milena Misheva, E. Maurice, Massimiliano Fiorini, S. Gallorini, F. Costantini, R. Fantechi, Vladimir Kekelidze, Lau Gatignon, Cristina Lazzeroni, A. Antonelli, Rainer Wanke, M. Veltri, V. Obraztsov, A. Romano, V. E. Semenov, T. Numao, Emilio Leonardi, O. Yushchenko, V. Kurshetsov, Mauro Piccini, Paolo Massarotti, A. Winhart, H. Wahl, Augusto Ceccucci, Viacheslav Duk, H. O. Danielsson, Andreas Alexander Maier, S. Shkarovskiy, P. Rubin, I. Popov, D. Di Filippo, N. A. Molokanova, K. Eppard, P. F. Dalpiaz, S. Movchan, F. Ambrosino, A. I. Zinchenko, A. Peters, B. Peyaud, E. Iacopini, G. D'Agostini, Petra Riedler, Cristina Biino, V. Palladino, A. Gianoli, M. Napolitano, I. Mannelli, G. Saracino, E. Gersabeck, Paolo Valente, V. Falaleev, Jürgen Engelfried, W. Baldini, D. T. Madigozhin, Leander Litov, Andrea Bizzeti, Roberta Arcidiacono, P.L. Frabetti, A. Fucci, P. Cenci, R. Winston, D. Coward, Mauro Raggi, E. Gushchin, M. Savrie, B. Bloch-Devaux, Yu. Potrebenikov, M. Pepe, B. Hallgren, B. Renk, S. Balev, V. Kozhuharov, M. Sozzi, S. Goy Lopez, M. Moulson, G. Pierazzini, A. Norton, L. DiLella, F. Marchetto, S. Giudici, A. Cotta Ramusino, V. Bolotov, E. Imbergamo, Evgueni Goudzovski, Simone Bifani, M. Lenti, K. Kleinknecht, S. Venditti, G. Collazuol, T. Spadaro, G. Lamanna, Roberto Piandani, F. Petrucci, C. Cerri, N. Doble, Antonino Sergi, Giuseppina Anzivino, M. Hita-Hochgesand, F. Retiere, Maurice, E., Ambrosino, Fabio, Antonelli, A., Anzivino, G., Arcidiacono, R., Baldini, W., Balev, S., Bifani, S., Biino, C., Bizzeti, A., Bloch Devaux, B., Bolotov, V., Bucci, F., Ceccucci, A., Cenci, P., Cerri, C., Collazuol, G., Costantini, F., Cotta Ramusino, A., Coward, D., D'Agostini, G., Dalpiaz, P., Danielsson, H., Dellacasa, G., DI FILIPPO, Domenico, Dilella, L., Doble, N., Duk, V., Engelfried, J., Eppard, K., Falaleev, V., Fantechi, R., Fiorini, M., Frabetti, P. L., Fucci, A., Gallorini, S., Gatignon, L., Gersabeck, E., Gianoli, A., Giudici, S., Goudzovski, E., Goy Lopez, S., Gushchin, E., Hallgren, B., Hita Hochgesand, M., Iacopini, E., Imbergamo, E., Kekelidze, V., Kleinknecht, K., Kozhuharov, V., Kurshetsov, V., Lamanna, G., Lazzeroni, C., Lenti, M., Leonardi, E., Litov, L., Madigozhin, D., Maier, A., Mannelli, I., Marchetto, F., Massarotti, Paolo, Misheva, M., Molokanova, N., Moulson, M., Movchan, S., Napolitano, Marco, Norton, A., Numao, T., Obraztsov, V., Palladino, Vito, Pepe, M., Peters, A., Petrucci, F., Peyaud, B., Piandani, R., Piccini, M., Pierazzini, G., Popov, I., Potrebenikov, Y. u., Raggi, M., Renk, B., Retière, F., Riedler, P., Romano, A., Rubin, P., Ruggiero, G., Salamon, A., Saracino, Giulio, Savrié, M., Semenov, V., Sergi, A., Serra, M., Shkarovskiy, S., Sozzi, M., Spadaro, T., Valente, P., Veltri, M., Venditti, S., Wahl, H., Wanke, R., Winhart, A., Winston, R., Yushchenko, O., and Zinchenko, A.

Subjects
Nuclear and High Energy Physics, Particle physics, dark photon, NA48/2, NA62, π, 0, form factor, dark photon, π0 form factor, Nuclear Theory, Socio-culturale, Electron, NA62 experiment, 01 natural sciences, Dark photon, Nuclear physics, Pion, PE2_2, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Physics, Large Hadron Collider, 010308 nuclear & particles physics, Form factor (quantum field theory), Large sample, π0 form factor, dark photon, π0 form factor, NA48/2, NA62, High Energy Physics::Experiment, Beam (structure)
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

8. Initial results from the PIENU experiment

Author

Tristan Sullivan, T. Sullivan, A. Aguilar-Arevalo, M. Aoki, M. Blecher, D.I Britton, D.A Bryman, D. vom Bruch, S. Chen, J. Comfort, S. Cuen-Rochin, L. Doria, P. Gumplinger, A. Hussein, Y. Igarashi, S. Ito, S.H Kettell, L. Kurchaninov, L.S Littenberg, C. Malbrunot, R.E Mischke, T. Numao, D. Protopopescu, A. Sher, and D. Vavilov

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Branching fraction, Physics beyond the Standard Model, High Energy Physics::Phenomenology, Condensed Matter Physics, 01 natural sciences, Atomic and Molecular Physics, and Optics, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Physical and Theoretical Chemistry, 010306 general physics, Particle Physics - Experiment, Lepton
Abstract

The pion branching ratio, $R_{\pi } = \frac { {\Gamma }(\pi ^{+} \rightarrow e^{+} \nu _{e} + \pi ^{+}\rightarrow e^{+} \nu _{e} \gamma )}{\Gamma (\pi ^{+} \rightarrow \mu ^{+} \nu _{\mu } + \pi ^{+} \rightarrow \mu ^{+} \nu _{\mu } \gamma )}$ , provides a sensitive test of lepton universality and constraints on many new physics scenarios. The theoretical uncertainty on the Standard Model prediction of R π is 0.02 %, a factor of twenty smaller than the experimental uncertainty. The analysis of a subset of data taken by the PIENU experiment will be presented. The result, R π = (1.2344 ± 0.0023(s t a t) ± 0.0019(s y s t)) ⋅ 10−4 [1], is consistent with the Standard Model prediction and represents a 0.1 % constraint on lepton non-universality.

Published
2017

9. 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

10. Study of the K±→π±γγ decay by the NA62 experiment

Author

T. Spadaro, A. Winhart, M. Lenti, O. Yushchenko, Mauro Piccini, A. I. Zinchenko, Paolo Massarotti, P. L. Frabetti, M. Serra, V. Kurshetsov, S. Kholodenko, Konrad Kleinknecht, Evgueni Goudzovski, A. Gianoli, S. Gallorini, C. Cerri, H. O. Danielsson, M. Moulson, V K Semenov, G. Lamanna, D. T. Madigozhin, T. Numao, N. Doble, Viacheslav Duk, S. Shkarovskiy, B. Renk, Rainer Wanke, M. Veltri, V. Bolotov, Fabrizio Petrucci, G. D'Agostini, D. Coward, A. Norton, Roland Winston, A. Fucci, Vladimir Kekelidze, S. Movchan, A. Ceccucci, E. Imbergamo, M. Pepe, F. Ambrosino, S. Balev, Andrea Bizzeti, M. Misheva, D. Di Filippo, Leander Litov, H. D. Wahl, Emilio Leonardi, B. Peyaud, Petra Riedler, W. Baldini, G. Pierazzini, P. F. Dalpiaz, A. Peters, M. Savrie, Simone Bifani, A. Cotta Ramusino, B. Bloch-Devaux, B. Hallgren, V. Obraztsov, G. Dellacasa, Giuseppe Ruggiero, V. Palladino, F. Marchetto, Jürgen Engelfried, A. Salamon, S. Venditti, F. Costantini, N. A. Molokanova, K. Eppard, V. Falaleev, M. Napolitano, I. Mannelli, A. Romano, G. Collazuol, A. A. Maier, P. Valente, F. Bucci, Cristina Lazzeroni, A. Antonelli, Roberto Piandani, M. Hita-Hochgesand, Roberta Arcidiacono, E. Gushchin, F. Retiere, Antonino Sergi, Evelina Gersabeck, R. Fantechi, Cristina Biino, Lau Gatignon, V. Kozhuharov, Mauro Raggi, P. Rubin, P. Cenci, E. Iacopini, M. Sozzi, Yu. Potrebenikov, L. DiLella, Massimiliano Fiorini, S. Giudici, S. Goy Lopez, G. Saracino, and G. Anzivino

Subjects
Physics, Nuclear and High Energy Physics, Particle decay, Pion, Chiral perturbation theory, Nuclear magnetic resonance, Meson, Branching fraction, Hadron, Analytical chemistry, Elementary particle, Dimensionless quantity
Abstract

A study of the dynamics of the rare decay K ± → π ± γ γ has been performed on a sample of 232 decay candidates, with an estimated background of 17.4 ± 1.1 events, collected by the NA62 experiment at CERN in 2007. The results are combined with those from a measurement conducted by the NA48/2 Collaboration at CERN. The combined model-independent branching ratio in the kinematic range z = ( m γ γ / m K ) 2 > 0.2 is B MI ( z > 0.2 ) = ( 0.965 ± 0.063 ) × 10 − 6 , and the combined branching ratio in the full kinematic range assuming a Chiral Perturbation Theory description is B ( K π γ γ ) = ( 1.003 ± 0.056 ) × 10 − 6 . A detailed comparison of the results with the previous measurements is performed.

Published
2014

11. Search for massive neutrinos in π + → e + ν e ${\pi }^{+}{\rightarrow }e^{+}{\nu }_{e}$ decay

Author

Luca Doria, S. Cuen-Rochin, P. Gumplinger, Chloé Malbrunot, D. Protopopescu, Ahmed Hussein, T. Sullivan, Douglas Bryman, L. S. Littenberg, T. Numao, A. Sher, R. E. Mischke, J. R. Comfort, Dave Britton, S. H. Kettell, D. Vavilov, D. Vom Bruch, Masaharu Aoki, Alexis A. Aguilar-Arevalo, Y. Igarashi, Leonid Kurchaninov, Song Chen, M. Blecher, and S. Ito

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, 010308 nuclear & particles physics, Branching fraction, Electron, Weak interaction, Condensed Matter Physics, 01 natural sciences, Measure (mathematics), Atomic and Molecular Physics, and Optics, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Sensitivity (control systems), Physical and Theoretical Chemistry, Neutrino, 010306 general physics
Abstract

The PIENU experiment aims to measure the branching ratio of the charged pion decay with precision of < 0.1 %. This measurement is much sensitive to search for massive neutrinos coupled to electrons in ${\pi }^{+}{\rightarrow }e^{+}{\nu }_{e}$ decay. The initial analysis was completed and the upper limit on the neutrino mixing parameter |U e i |2 in the neutrino mass range of 0 to 55 MeV/c 2 was improved by a factor of 1.5, and the sensitivity for the mass range of 68 to 129 MeV/c 2 was improve by a factor of up to 4.

Published
2016

12. Precision Measurements with Pions—Review

Author

T. Numao

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Muon, Pion, Meson, Branching fraction, Hadron, Helicity, Atomic and Molecular Physics, and Optics, Lepton, Dimensionless quantity
Abstract

The branching ratio of pion decays, R e / μ = Γ ( π + → e + ν + e + ν γ ) / Γ ( π + → μ + ν + μ + ν γ ) , has provided the best test of electron-muon universality in weak interactions. While the Standard Model prediction is R e / μ = ( 1.2353 ± 0.0001 ) × 10 − 4 , the existing experimental results, ( 1.2265 ± 0.0056 ) × 10 − 4 (TRIUMF) and ( 1.2346 ± 0.0050 ) × 10 − 4 (PSI), have still orders of magnitude worse uncertainties. Since the decay π + → e + ν is helicity-suppressed, it is extremely sensitive to a presence of pseudo-scalar couplings arising from a wide range of new physics up to a mass scale of 1000 TeV/c2. Two new experiments aiming at a precision level of 0.1 % for R e / μ , as well as related precision measurements of other pion decays, are described.

Published
2011

13. High purity pion beam at TRIUMF

Author

J. Doornbos, N. Ito, Luca Doria, A. Sher, C. Malbrunot, B. Walker, S. H. Kettell, Leonid Kurchaninov, A.H. Hussein, T. Numao, M. Blecher, Glenn M. Marshall, R. Poutissou, J. R. Comfort, Douglas Bryman, K. Yamada, and Alexis A. Aguilar-Arevalo

Subjects
Accelerator Physics (physics.acc-ph), Nuclear and High Energy Physics, Particle physics, Physics - Instrumentation and Detectors, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Momentum, High Energy Physics - Experiment (hep-ex), Pion, Pion beam, Positron, Particle separation, 0103 physical sciences, Calibration, Nuclear Experiment, 010306 general physics, Instrumentation, Physics, 010308 nuclear & particles physics, Instrumentation and Detectors (physics.ins-det), Physics::Accelerator Physics, Physics - Accelerator Physics, High Energy Physics::Experiment, Beam (structure)
Abstract

An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay pi+ --> e+ nu is also described., 5 pages

Published
2009

14. Status of the PIENU experiment at TRIUMF

Author

R. E. Mischke, D. Vom Bruch, Leonid Kurchaninov, S. H. Kettell, Y. Igarashi, J. R. Comfort, T. Sullivan, Luca Doria, Alexis A. Aguilar-Arevalo, Chloé Malbrunot, D. Protopopescu, P. Gumplinger, Douglas Bryman, Ahmed Hussein, S. Ito, S. Cuen-Rochin, T. Numao, Dave Britton, D. Vavilov, Masaharu Aoki, L. S. Littenberg, Song Chen, A. Sher, and M. Blecher

Subjects
Physics, History, Particle physics, Muon, Meson, Branching fraction, Hadron, Computer Science Applications, Education, Nuclear physics, Particle decay, Pion, Particle Physics - Experiment, Lepton, Dimensionless quantity
Abstract

The PIENU experiment at TRIUMF aims to measure the branching ratio of pion decays R = Γ(π(+) → e(+)ν(e) + π(+) → e(+) ν(e)γ)/Γ(π(+)→μ(+)ν(μ) + π(+) → μ(+)ν(μ)γ) with precision

Published
2015

15. Search for the decay K→πν in the momentum region P<195 MeV/c

Author

J. M. Poutissou, S. Ng, P. C. Bergbusch, T. Sasaki, A. J.S. Smith, Y. Yoshimura, R. Poutissou, R. A. McPherson, Takashi Nakano, M. Aoki, J. S. Frank, M. Ardebili, T. Numao, C. Witzig, J. A. Macdonald, L. S. Littenberg, T. Inagaki, Masaaki Kobayashi, Y. Kuno, T. Shinkawa, M. R. Convery, A. Konaka, J. S. Haggerty, M. M. Ito, R. Soluk, J. Mildenberger, F. C. Shoemaker, M. Kuriki, S. Kabe, J. R. Stone, M. V. Diwan, M. Kazumori, T. Sato, A. O. Bazarko, E. W. Blackmore, G. Redlinger, C. Ng, Norihito Muramatsu, K. K. Li, S. Sugimoto, Douglas Bryman, Daniel Robert Marlow, D. E. Jaffe, S. S. Adler, Peter Daniel Meyers, M. S. Atiya, T. F. Kycia, Vivek Jain, P. Kitching, B. Bhuyan, R. C. Strand, I. H. Chiang, S. H. Kettell, and T. K. Komatsubara

Subjects
Momentum, Physics, Nuclear and High Energy Physics, Pion, Branching fraction, Atomic physics, Neutral particle, Event (particle physics), Standard Model
Abstract

We have searched for the decay K + →π + ν ν in the kinematic region with pion momentum below the K + → π + π 0 peak. One event was observed, consistent with the background estimate of 0.73±0.18. This implies an upper limit on B(K + →π + ν ν ) −9 (90% C.L.), consistent with the recently measured branching ratio of 1.57 +1.75 −0.82 ×10 −10 , obtained using the standard model spectrum and the kinematic region above the K + → π + π 0 peak. The same data were used to search for K + → π + X 0 , where X 0 is a weakly interacting neutral particle or system of particles with 150 M X 0 c 2 .

Published
2002

16. Measurement of Direct Photon Emission inK+→π+π0γDecay

Author

M. S. Atiya, J. M. Poutissou, George Redlinger, A. Konaka, L. S. Littenberg, M. Kuriki, S. H. Kettell, T. Inagaki, T. Shinkawa, R. A. McPherson, S. S. Adler, M. Aoki, F. C. Shoemaker, K. K. Li, Douglas Bryman, R. Poutissou, J. R. Stone, Y. Yoshimura, T. Numao, C. Witzig, S. Sugimoto, J. S. Haggerty, R. Soluk, J. A. Macdonald, M. V. Diwan, M. M. Ito, Ewart W. Blackmore, P. D. Meyers, Norihito Muramatsu, T. Nakano, M. Ardebili, Y. Kuno, Motoki Kobayashi, Y. Kishi, S. Kabe, T. Sato, M. R. Convery, P. C. Bergbusch, I-Hung Chiang, T. F. Kycia, James Frank, J. Mildenberger, R. C. Strand, T. K. Komatsubara, and P. Kitching

Subjects
Physics, Meson, Branching fraction, Hadron, Bremsstrahlung, General Physics and Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Kinetic energy, Electromagnetic radiation, Nuclear physics, Particle decay, Pion, High Energy Physics::Experiment, Atomic physics
Abstract

We have performed a measurement of the K + !� + � 0 decay and have observed 2×10 4 events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7 ± 0.8 ± 0.3) × 10 6 in the � + kinetic energy region of 55 to 90 MeV and requires no component due to interference with inner bremsstrahlung.

Published
2000

17. Measurement of the Branching Ratio

Author

T. Numao

Subjects
Nuclear physics, Momentum, Physics, Nuclear and High Energy Physics, Pion, Branching fraction, Standard Model
Abstract

Three new events of the decay K + → π + ν ν ¯ have been observed in the pion momentum region 140 P π 199 MeV/c with an estimated background of 0.93 ± 0.17 ( stat ) − 0.24 + 0.32 ( syst ) events. Combining this observation with the previously reported results yields a branching ratio of BR ( K + → π + ν ν ¯ ) = 1.73 − 1.05 + 1.15 × 10 − 10 consistent with the Standard Model prediction.

Published
2009

18. Central tracking chamber with inflated cathode-strip foils

Author

Y. Kuno, R. A. McPherson, R. Soluk, P. Padley, G. Redlinger, T. Numao, Douglas Bryman, C. Lim, and Ewart W. Blackmore

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Muon, Physics::Instrumentation and Detectors, Resolution (electron density), Tracking (particle physics), Cathode, law.invention, Momentum, Pion, law, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics, Instrumentation, Image resolution
Abstract

A new cylindrical low-mass central drift chamber has been constructed for the K + → π + ν ν experiment at BNL (E787). The chamber consists of twelve layers of axial wire cells and six layers of thin cathode-strip foils, four of which are supported by differential gas pressure. The momentum resolution (RMS) for muons and pions in the range 150–250 MeV/c is found to be about 0.9%.

Published
1998

19. Evidence for the DecayK+→π+νν¯

Author

Ewart W. Blackmore, R. A. McPherson, S. H. Kettell, Y. Kuno, P. D. Meyers, J. S. Haggerty, Masaaki Kobayashi, Norihito Muramatsu, M. Kuriki, A. Stevens, A. J.S. Smith, P. C. Bergbusch, J. Roy, R. Poutissou, Stephen L. Adler, R. Soluk, T. Shinkawa, J. M. Poutissou, T. Nakano, T. Sato, J. R. Stone, George Redlinger, L. S. Littenberg, T. Numao, A. Sambamurti, A. O. Bazarko, M. R. Convery, Y. Kishi, J. A. Macdonald, M. Aoki, T. Inagaki, M. V. Diwan, S. Sugimoto, Daniel Robert Marlow, M. Ardebili, M. S. Atiya, Y. Yoshimura, A. Konaka, A. S. Turcot, J. Mildenberger, R. C. Strand, I-H. Chiang, T. K. Komatsubara, F. C. Shoemaker, C. Ng, M. M. Ito, T. F. Kycia, James Frank, P. Padley, P. Kitching, S. Kabe, K. K. Li, Douglas Bryman, and C. Witzig

Subjects
Momentum, Physics, Particle physics, Pion, Branching fraction, General Physics and Astronomy
Abstract

An event consistent with the signature expected for the rare kaon decay ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ has been observed. In the pion momentum region examined, $211lPl230\mathrm{MeV}/c$, the backgrounds are estimated to contribute $0.08\ifmmode\pm\else\textpm\fi{}0.03$ events. If the event is due to ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, the branching ratio is ${4.2}_{\ensuremath{-}3.5}^{+9.7}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$.

Published
1997

20. PIENU experiment at TRIUMF: A sensitive probe of new physics

Author

T. Numao, Dave Britton, S. H. Kettell, Koji Yamada, N. Ito, Song Chen, D. Vavilov, Y. Yoshida, Y. Igarashi, T. Sullivan, C. Malbrunot, A.H. Hussein, Luca Doria, Masaharu Aoki, J. R. Comfort, Alexis A. Aguilar-Arevalo, A. Sher, R. E. Mischke, Douglas Bryman, L. S. Littenberg, Leonid Kurchaninov, P. Gumplinger, S. Ito, A. Sandorfi, D. von Bruch, M. Ding, Y. Kuno, and M. Blecher

Subjects
Nuclear physics, Physics, Particle physics, Effective mass (solid-state physics), Pion, Branching fraction, Physics beyond the Standard Model, High Energy Physics::Experiment, Mass scale, Weak interaction
Abstract

A TRIUMF experiment, PIENU, which aims to measure the branching ratio of pion decays, R = Γ(π→eν+eνγ)/Γ(π→μν+μνγ) to a precision of 0.1% or better is described. Such a measurement provides the best test of electron-muon universality in weak interactions and is sensitive to an effective mass scale of up to 1000 TeV in new physics.

Published
2013

21. Search for the DecayK+→π+νν¯

Author

I. H. Chiang, L. S. Littenberg, S. S. Adler, M. S. Atiya, D. S. Akerib, A. S. Turcot, R. Soluk, K. K. Li, Douglas Bryman, A. Sambamurti, Mats A Selen, A. Stevens, L. Felawka, T. Numao, C. Witzig, Y. Kuno, V. A. Kujala, Robert McPherson, M. M. Ito, M. R. Convery, J. S. Haggerty, T. Nakano, Ewart W. Blackmore, P. Kitching, Daniel Robert Marlow, F. C. Shoemaker, R. C. Strand, A. Konaka, M. Ardebili, R. Poutissou, J. M. Poutissou, T. F. Kycia, A. J.S. Smith, James Frank, W. C. Louis, J. A. Macdonald, P. Padley, J. Roy, and P. D. Meyers

Subjects
Physics, Particle physics, Pion, Overline, Branching fraction, Nuclear Theory, High Energy Physics::Phenomenology, Pi, General Physics and Astronomy, High Energy Physics::Experiment, Limit (mathematics), Nuclear Experiment
Abstract

An upper limit on the branching ratio for the decay $K^+ \! \rightarrow \! \pi^+ \nu \overline{\nu}$ is set at $2.4 \times 10^{-9}$ at the 90\% C.L. using pions in the kinematic region $214~{\rm MeV}/c 0$.

Published
1996

22. Status of Pion Decay Experiments

Author

T Numao

Subjects
Physics, History, Particle physics, 010308 nuclear & particles physics, Branching fraction, 01 natural sciences, Computer Science Applications, Education, Nuclear physics, Experimental uncertainty analysis, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Order of magnitude
Abstract

The branching ratio of pion decays, , has provided a sensitive test of electron-muon universality in weak interactions. The uncertainty of the Standard Model prediction is at a 0.01% level. Although a recent measurement, Re /μ = (1.2344 ± 0.0023(stat) ± 0.0019(syst)) × 10-4, reduced the experimental uncertainty by a factor of two, there is room for improvement by more than an order of magnitude. The status of two experiments at TRIUMF and PSI as well as related pion decay experiments is presented.

Published
2016

23. Measurement of the pion branching ratio at TRIUMF

Author

C. Malbrunot, P. Gumplinger, Alexis A. Aguilar-Arevalo, T. Numao, Makoto Yoshida, D. Vavilov, Dave Britton, J. R. Comfort, Masaharu Aoki, S. Ito, Leonid Kurchaninov, Douglas Bryman, T. Sullivan, L. Littenberg, Y. Igarashi, M. Blecher, Luca Doria, S. Kettell, A. Sher, Song Chen, A.H. Hussein, M. Ding, and Y. Kuno

Subjects
Physics, Nuclear physics, Particle physics, Pion, Branching fraction, Hadron, Weak interaction, Universality (dynamical systems)
Abstract

The branching ratio of pion decays, R = Γ(π+→e+νe+π+→e+νeγ)Γ(π+→μ+νμ+π+→μ+νμγ is one of the most accurately calculated decay processes involving hadrons and has provided one of the most stringent tests of the hypothesis of electron-muon universality in weak interactions. The current experimental branching ratio Rexp = (1.230±0.004)×10−4 is 40 times less precise than the theoretical prediction RSM = 1.2352(1)10−4. The TRIUMF PIENU experiment aims at measuring the pion branching ratio with a precision improved by at least a factor five.

Published
2012

24. Search for massive neutrinos in the decayπ→eν

Author

L. S. Littenberg, A. Sher, C. Malbrunot, T. Sullivan, S. H. Kettell, D. Vavilov, C. Hurst, N. Ito, Luca Doria, R. Poutissou, Song Chen, Masaharu Aoki, Minoru Yoshida, T. Numao, P. Gumplinger, Ahmed Hussein, Leonid Kurchaninov, Y. Igarashi, Douglas Bryman, Koji Yamada, M. Ding, and M. Blecher

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Branching fraction, 01 natural sciences, 7. Clean energy, Massless particle, Nuclear physics, Particle decay, Pion, Antimatter, 0103 physical sciences, High Energy Physics::Experiment, Neutrino, 010306 general physics, Lepton
Abstract

The positron spectrum from the decay ..pi../sup +/..-->..e/sup +/..nu../sub e/ has been examined for evidence of peaks arising from an admixture in the ..nu../sub e/ weak eigenstate of massive neutrinos. Limits on the intensity of such peaks, together with the measured ..pi -->..e..nu.. branching ratio, have been used to derive constraints on the neutrino mixing parameters over the range 4 MeV

Published
2011

25. Search for the decaysK+→π+νν¯andK+→π+X0for150<MX0<250MeV/c2

Author

A. S. Turcot, P. Padley, T. Numao, Daniel Robert Marlow, A. Konaka, R. C. Strand, A. Stevens, Peter Daniel Meyers, J. A. Macdonald, L. S. Littenberg, Mats A Selen, M. M. Ito, J. Roy, R. Poutissou, D. S. Akerib, I-Hung Chiang, J. M. Poutissou, W. C. Louis, Y. Kuno, M. S. Atiya, Ewart W. Blackmore, R. Soluk, J. S. Haggerty, F. C. Shoemaker, L. Felawka, A. Sambamurti, K. K. Li, A. J.S. Smith, Douglas Bryman, P. Kitching, T. F. Kycia, and James Frank

Subjects
Physics, Antiparticle, Particle physics, Particle decay, Crystallography, Pion, Meson, Branching fraction, Hadron, Elementary particle, Boson
Abstract

A search for the decays ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ and ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{X}^{0}$, where ${X}^{0}$ is any weakly interacting neutral particle or system of neutral particles with $150l{M}_{{X}^{0}}l250$ MeV/${\mathit{c}}^{2}$, was performed in the pion kinematic region below the ${K}_{\ensuremath{\pi}2}({K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0})$ peak. An upper limit on $B({K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}})$ is set at 1.7 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}8}$ (90% C.L.) and $B({K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{X}^{0})$ is restricted to the ${10}^{\ensuremath{-}7}$ level or lower. Limits are also set for the production of ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ through scalar or tensor interactions at 1.8 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}8}$ and 1.0 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}8}$ (90% C.L.), respectively.

Published
1993

26. Search for the DecayK+→π+νν¯

Author

Ewart W. Blackmore, Y. Kuno, W. C. Louis, T. F. Kycia, K. K. Li, Douglas Bryman, L. Felawka, M. M. Ito, J. S. Haggerty, I-Hung Chiang, A. S. Turcot, James Frank, A. J.S. Smith, Daniel Robert Marlow, F. C. Shoemaker, P. Padley, A. Konaka, Mats A Selen, A. Sambamurti, M. S. Atiya, P. Kitching, J. Roy, R. Soluk, R. C. Strand, P. D. Meyers, T. Numao, A. Stevens, J. M. Poutissou, L. S. Littenberg, D. S. Akerib, R. Poutissou, and J. A. Macdonald

Subjects
Physics, Semileptonic decay, Particle physics, Meson, Branching fraction, Particle model, General Physics and Astronomy, Massless particle, Combinatorics, Particle decay, Pion, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Pi, Neutral particle, Bar (unit)
Abstract

An upper limit on the branching ratio for the decay [ital K][sup +][r arrow][pi][sup +][nu][bar [nu]] is set at 7.5[times]10[sup [minus]9] (90% C.L.) using the kinematic region above the [ital K][sub [pi]2]([ital K][sup +][r arrow][pi][sup +][pi][sup 0]) peak. When combined with our result from below the [ital K][sub [pi]2] peak, we obtain the limit 5.2[times]10[sup [minus]9]. An upper limit of 1.7[times]10[sup [minus]9] is also found on the branching ratio for decays of the form [ital K][sup +][r arrow][pi][sup +][ital X0] where [ital X][sup 0] is any massless, weakly interacting neutral particle. Limits are also set for cases where [ital M][sub [ital X]][sup 0][gt]0.

Published
1993

27. Measurement of theK+→π0μ+νμγbranching ratio

Author

Y. Yoshimura, T. Nomura, Vivek Jain, M. M. Ito, P. Kitching, C. Witzig, K. Shimada, James Frank, M. Kuriki, J. R. Stone, A. Konaka, T. Shinkawa, P. C. Bergbusch, Yoichi Tamagawa, S. Sugimoto, J. Mildenberger, R. C. Strand, T. K. Komatsubara, A. O. Bazarko, I. H. Chiang, T. Shimoyama, Song Chen, Y. Kuno, S. H. Kettell, T. Fujiwara, M. Miyajima, T. Tsunemi, Masaaki Kobayashi, C. Ng, K. K. Li, Douglas Bryman, M. V. Diwan, J. Hu, R. Poutissou, S. Kabe, S. Ng, T. Inagaki, Ewart W. Blackmore, J. M. Poutissou, T. Numao, J. A. Macdonald, F. C. Shoemaker, T. Sato, L. S. Littenberg, P. D. Meyers, Norihito Muramatsu, G. Redlinger, S. S. Adler, J. S. Haggerty, T. Nakano, and D. E. Jaffe

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Muon, Branching fraction, Astrophysics::High Energy Astrophysical Phenomena, Particle decay, Pion, Antimatter, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Energy (signal processing), Dimensionless quantity
Abstract

A measurement of the decay K{sup +{yields}{pi}0{mu}+{nu}}{sub {mu}{gamma}}has been performed with the E787 detector at Brookhaven National Laboratory. Forty events were observed in the signal region with the background expectation of (16.5{+-}2.7) events. The branching ratio was measured to be (1.58{+-}0.46(stat.){+-}0.08(syst.))x10{sup -5} in the kinematic region E{sub {gamma}>}30 MeV and {theta}{sub {mu}{gamma}>}20 deg., where E{sub {gamma}}is the energy of the emitted photon and {theta}{sub {mu}{gamma}}is the angle between the muon and the photon in the K{sup +} rest frame. The results were consistent with theoretical predictions.

Published
2010

28. PRECISE TESTS OF e-μ UNIVERSALITY

Author

T. Numao

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, Branching fraction, Hadron, General Physics and Astronomy, Astronomy and Astrophysics, Elementary particle, Universality (dynamical systems), Nuclear physics, Particle decay, Pion, Boson
Abstract

The status of experimental tests of electron-muon universality in weak interactions is reviewed. The average of the new measurements of the π+→e+ν branching ratio, R ave =Γ(π→eν+π→eνγ)/Γ(π→μν+π→μνγ)=(1.2312±0.0037)×10−4, is consistent with standard model calculations R th =(1.234±0.001)×10−4 and confirms the hypothesis of electron-muon universality at the 0.2% level.

Published
1992

29. Search for the decayπ0→γ+X

Author

P. Kitching, J. S. Haggerty, K. K. Li, Daniel Robert Marlow, L. Felawka, Douglas Bryman, Mats A Selen, R. Poutissou, A. J.S. Smith, T. F. Kycia, J. M. Poutissou, Y. Kuno, A. Konaka, Ewart W. Blackmore, T. Numao, R. C. Strand, W. C. Louis, J. A. Macdonald, J. Roy, M. M. Ito, A. Sambamurti, J. S. Frank, F. C. Shoemaker, M. S. Atiya, A. J. Stevens, I. H. Chiang, A. S. Turcot, P. Padley, L. S. Littenberg, D. S. Akerib, and P. D. Meyers

Subjects
Physics, Nuclear physics, Pion, Branching fraction, General Physics and Astronomy, Elementary particle, Neutral vector, Two-body problem, Three-body problem, Neutral particle, Upper and lower bounds
Abstract

A search for the decay π 0 →γX, where X is any long-lived weakly interacting neutral vector particle with mass smaller than the neutral pion mass, was performed using neutral pions tagged by K + →π + π 0 . A 90%-C.L. upper limit for the branching ratio of the two-body decay B(π 0 →γX)

Published
1992

30. Further Search for the DecayK+→π+νν¯

Author

S. Adler, M. S. Atiya, I-H. Chiang, M. V. Diwan, J. S. Frank, J. S. Haggerty, V. Jain, S. H. Kettell, T. F. Kycia, K. K. Li, L. S. Littenberg, C. Ng, R. C. Strand, C. Witzig, M. Kazumori, T. K. Komatsubara, M. Kuriki, N. Muramatsu, A. Otomo, S. Sugimoto, T. Inagaki, S. Kabe, M. Kobayashi, Y. Kuno, T. Sato, T. Shinkawa, Y. Yoshimura, Y. Kishi, T. Nakano, T. Sasaki, M. Ardebili, A. O. Bazarko, M. R. Convery, M. M. Ito, D. R. Marlow, R. A. McPherson, P. D. Meyers, F. C. Shoemaker, A. J. S. Smith, J. R. Stone, M. Aoki, P. C. Bergbusch, E. W. Blackmore, D. A. Bryman, A. Konaka, J. A. Macdonald, J. Mildenberger, T. Numao, P. Padley, J.-M. Poutissou, R. Poutissou, G. Redlinger, P. Kitching, and R. Soluk

Subjects
Physics, Antiparticle, Particle decay, Particle physics, Pion, Meson, Branching fraction, Hadron, General Physics and Astronomy, Neutrino, Lepton
Abstract

A search for additional evidence for the rare kaon decay K+-->pi(+)nunu; has been made with a new data set comparable in sensitivity to the previous exposure that produced a single event. No new events were found in the pion momentum region examined, 211 pi(+)nunu;) = 1.5(+3.4)(-1.2)x10(-10).

Published
2000

31. Measurement of the K+ → π+ ν anti-ν decay at Fermilab

Author

Herman B. White, Sergei Striganov, Shaomin Chen, Mingming Ding, Jurgen Engelfried, A.H. Hussein, Zhe Wang, David E. Jaffe, Jaap Doornbos, Yuri Kudenko, Roberto Carosi, J. R. Comfort, T. Numao, Oleg Mineev, J. L. Ritchie, Douglas Bryman, A. Sher, Artur Shaykhiev, Laurie Littenberg, L. Doria, David C. Christian, Mike Syphers, D. Vavilov, Robert Tschirhart, S. H. Kettell, D. A. Jensen, Andreas Kronfeld, and Leo Bellantoni

Subjects
Nuclear physics, Physics, Particle physics, Particle decay, Pion, law, Particle accelerator, Fermilab, Neutrino, law.invention
Published
2009

32. Study of the decayK+→π+νν¯in the momentum region140<Pπ<199 MeV/c

Author

I. H. Chiang, Y. Yoshimura, O. V. Mineev, S. H. Kettell, S. Sugimoto, Tamaki Yoshioka, Norihito Muramatsu, J. Ives, E. J. Ramberg, V. A. Mukhin, T. Numao, A. Kushnirenko, V. Obraztsov, L. S. Littenberg, J. Hu, M. V. Diwan, M. M. Khabibullin, B. Lewis, T. Nakano, S. V. Petrenko, J. A. Macdonald, B. Bassalleck, Yu. G. Kudenko, T. Sato, T. Tsunemi, D. E. Jaffe, J. Mildenberger, R. Tschirhart, R. C. Strand, M. Miyajima, A. N. Khotjantsev, K. Mizouchi, A. P. Kozhevnikov, T. K. Komatsubara, Yoichi Tamagawa, Song Chen, Ewart W. Blackmore, T. Shinkawa, N. V. Yershov, D. V. Vavilov, T. Sekiguchi, Takashi Nomura, D. I. Patalakha, T. Fujiwara, A. Konaka, Masaaki Kobayashi, A. V. Artamonov, I. A. Christidi, Zhe Wang, R. Poutissou, Masaharu Nomachi, B. Viren, P. Kitching, B. Bhuyan, S. Kabe, K. K. Li, L. G. Landsberg, Douglas Bryman, P. S. Cooper, James Frank, George Redlinger, and K. Omata

Subjects
Physics, Nuclear and High Energy Physics, Particle decay, Particle physics, Pion, Meson, Branching fraction, Hadron, Elementary particle, Dimensionless quantity, Lepton
Abstract

Experiment E949 at Brookhaven National Laboratory has observed three new events consistent with the decay ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ in the pion momentum region $140l{P}_{\ensuremath{\pi}}l199\text{ }\text{ }\mathrm{MeV}/c$ in an exposure of $1.71\ifmmode\times\else\texttimes\fi{}{10}^{12}$ stopped kaons with an estimated total background of $0.93\ifmmode\pm\else\textpm\fi{}0.17(\mathrm{stat}{)}_{\ensuremath{-}0.24}^{+0.32}(\mathrm{syst})$ events. This brings the total number of observed ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ events to seven. Combining this observation with previous results, assuming the pion spectrum predicted by the standard model, results in a branching ratio of $\mathcal{B}({K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}})=({1.73}_{\ensuremath{-}1.05}^{+1.15})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$. An interpretation of the results for alternative models of the decay ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}+nothing$ is also presented.

Published
2009

33. Upper limit on the branching ratio for the decayπ0→νν¯

Author

Daniel Robert Marlow, Georges Azuelos, Ewart W. Blackmore, R. C. Strand, T. Numao, W. C. Louis, L. S. Littenberg, Mats A Selen, J. Roy, I. H. Chiang, A. J. Stevens, T. F. Kycia, D. S. Akerib, Y. Kuno, R. Poutissou, Peter Daniel Meyers, L. Felawka, K. K. Li, Douglas Bryman, J. S. Frank, J. A. Macdonald, J. S. Haggerty, P. Padley, A. J.S. Smith, M. S. Atiya, P. Kitching, F. C. Shoemaker, J. M. Poutissou, and M. M. Ito

Subjects
Physics, Particle decay, Antiparticle, Pion, Meson, Branching fraction, General Physics and Astronomy, High Energy Physics::Experiment, Atomic physics, Weak interaction, Energy (signal processing), Lepton
Abstract

An experimental upper limit on the branching ratio for the decay {pi}{sup 0}{r arrow}{nu}{bar {nu}} is set at 8.3{times}10{sup {minus}7} (90% C.L.). This decay is forbidden if neutrinos are purely left handed. The limit also applies to any decays of the {pi}{sup 0} to weakly interacting neutrals.

Published
1991

34. New Measurement of theK+→π+νν¯Branching Ratio

Author

A. Kushnirenko, J. Ives, T. Numao, E. J. Ramberg, Tamaki Yoshioka, Ewart W. Blackmore, J. A. Macdonald, T. Tsunemi, B. Bassalleck, K. K. Li, Song Chen, Y. Yoshimura, J. Mildenberger, R. Poutissou, Douglas Bryman, R. C. Strand, A. P. Kozhevnikov, T. K. Komatsubara, Yoichi Tamagawa, D. E. Jaffe, A. V. Artamonov, I. A. Christidi, T. Shinkawa, D. I. Patalakha, N. V. Yershov, O. V. Mineev, T. Sekiguchi, A. N. Khotjantsev, George Redlinger, K. Mizouchi, T. Nomura, A. Konaka, R. Tschirhart, Zhe Wang, I. H. Chiang, K. Omata, S. H. Kettell, T. Fujiwara, Norihito Muramatsu, V. Obraztsov, M. M. Khabibullin, M. V. Diwan, Masaaki Kobayashi, V. A. Mukhin, L. S. Littenberg, Yu. G. Kudenko, S. Sugimoto, T. Sato, J. Hu, James Frank, Masaharu Nomachi, B. Lewis, T. Nakano, M. Miyajima, S. V. Petrenko, P. Kitching, P. S. Cooper, B. Viren, B. Bhuyan, S. Kabe, D. V. Vavilov, and L. G. Landsberg

Subjects
Physics, Nuclear physics, Particle decay, Pair production, Pion, Meson, Branching fraction, Hadron, General Physics and Astronomy, Dimensionless quantity, Lepton
Abstract

Three events for the decay K+-->pi+ nunu have been observed in the pion momentum region below the K+-->pi+pi0 peak, 140 pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction.

Published
2008

35. Measurement of theK+→π+νν¯branching ratio

Author

V. Obraztsov, M. M. Khabibullin, M. Ardebili, A. V. Artamonov, T. Numao, A. Konaka, S. S. Adler, P. S. Cooper, A. Kushnirenko, I. H. Chiang, Song Chen, S. H. Kettell, James Frank, A. O. Bazarko, M. Kuriki, K. Omata, J. A. Macdonald, B. Bassalleck, M. S. Atiya, T. Sekiguchi, J. Mildenberger, R. C. Strand, A. P. Kozhevnikov, T. K. Komatsubara, T. Sato, Ewart W. Blackmore, O. V. Mineev, M. Aoki, M. R. Convery, Masaharu Nomachi, P. D. Meyers, D. E. Jaffe, Y. Yoshimura, Yoichi Tamagawa, B. Viren, T. Shinkawa, Norihito Muramatsu, K. Mizouchi, M. Kazumori, George Redlinger, P. Kitching, B. Bhuyan, L. S. Littenberg, F. C. Shoemaker, M. Miyajima, Tamaki Yoshioka, J. R. Stone, V. A. Mukhin, J. Hu, Masaaki Kobayashi, N. V. Yershov, B. Lewis, T. Nakano, S. V. Petrenko, K. K. Li, A. N. Khotjantsev, Douglas Bryman, Y. Kuno, A. P. Ivashkin, Takashi Nomura, Daniel Robert Marlow, T. Fujiwara, S. Kabe, R. Poutissou, E. J. Ramberg, M. M. Ito, T. Tsunemi, D. I. Patalakha, S. Sugimoto, V. V. Anisimovsky, D. V. Vavilov, R. A. McPherson, I. A. Christidi, L. G. Landsberg, R. Tschirhart, J. S. Haggerty, A. J.S. Smith, T. Inagaki, M. V. Diwan, and Yu. G. Kudenko

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Particle decay, Crystallography, Pion, Meson, Branching fraction, Hadron, Elementary particle, Lepton, Dimensionless quantity
Abstract

Experiment E949 at Brookhaven National Laboratory studied the rare decay K{sup +}-->pi{sup +} nu{ovr {nu}} and other processes with an exposure of 1.77 x 10{sup 12} k{sup +}'s. The data were analyzed using a blind analysis technique yielding one candidate event with an estimated background of 0.30 {+-} 0.03 events. Combining this result with the observation of two candidate events by the predecessor experiment E787 gave the branching ratio B(K{sup +}-->pi{sup +} nu{ovr {nu}}) = (1.47{sub -0.89}{sup +1.30}) x 10{sup -10}, consistent with the standard model prediction of (0.74 {+-} 0.20) x 10{sup -10}. This is a more detailed report of results previously published [V.V. Anisimovsky et al., Phys. Rev. Lett. 93, 031801 (2004)].

Published
2008

36. Search for the decayK+→π+νν¯

Author

J. S. Haggerty, A. J.S. Smith, R. Poutissou, Ewart W. Blackmore, P. Padley, W. C. Louis, Selen, F. C. Shoemaker, T. Numao, Georges Azuelos, A. Stevens, J. A. Macdonald, Daniel Robert Marlow, Atiya, J. M. Poutissou, M. M. Ito, L. Felawka, P. Kitching, T. F. Kycia, James Frank, R. C. Strand, P. D. Meyers, L. S. Littenberg, D. S. Akerib, I-Hung Chiang, Y. Kuno, J. Roy, K. K. Li, and Douglas Bryman

Subjects
Semileptonic decay, Physics, Particle physics, Crystallography, Particle decay, Pion, Meson, Branching fraction, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Hadron, General Physics and Astronomy, Elementary particle, Particle identification
Abstract

An upper limit on the branching ratio for the decay {ital K}{sup +}{r arrow}{pi}{sup +}{nu}{bar {nu}} is set at 3.4{times}10{sup {minus}8} (90% C.L.). In addition, a 90%-C.L. upper limit of 6.4{times}10{sup {minus}9} is set on the branching ratio for decays of the form {ital K}{sup +}{r arrow}{pi}{sup +}{ital X}{sup 0}, where {ital X}{sup 0} is any massless, weakly interacting neutral particle. Limits are also set for the case where {ital M}{sub {ital X}{sup 0}}{gt}0.

Published
1990

37. Search for Free Decay of Negative Pions in Water and Light Materials

Author

J. M. Poutissou, R. Gearhart, Yu. Efremenko, T. C. Awes, W. Bugg, V. Cianciolo, Yu. I. Davydov, S. Ovchinnikov, S. Berridge, and T. Numao

Subjects
Physics, High Energy Physics - Experiment (hep-ex), Nuclear and High Energy Physics, Particle physics, Pion, chemistry, Analytical chemistry, FOS: Physical sciences, chemistry.chemical_element, Production (computer science), Beryllium, Neutrino, High Energy Physics - Experiment
Abstract

We report on a search for the free-decay component of {pi}{sup -} stopped in water and light materials. A nonzero value of this would be an indication of anomalous {nu}{sub e} contamination to the {nu}{sub e} and {nu}{sub {mu}} production at stopped-pion neutrino facilities. No free-decay component of {pi}{sup -} was observed in water, Beryllium, and Aluminum, for which upper limits were established at 8.2x10{sup -4}, 3.2x10{sup -3}, and 7.7x10{sup -3}, respectively.

Published
2006

38. Improved Measurement of theK+→π+νν¯Branching Ratio

Author

K. K. Li, T. Numao, K. Mizouchi, P. S. Cooper, J. A. Macdonald, Takashi Nakano, Douglas Bryman, E. J. Ramberg, Masaharu Nomachi, B. Bassalleck, S. Sugimoto, V. V. Anisimovsky, Yoichi Tamagawa, R. Poutissou, Tamaki Yoshioka, O. V. Mineev, N. V. Yershov, T. Nomura, T. Tsunemi, D. V. Vavilov, R. Tschirhart, L. G. Landsberg, Y. Yoshimura, J. S. Frank, I. A. Christidi, N. Muramatsu, A. Kushnirenko, Ewart W. Blackmore, D. I. Patalakha, George Redlinger, A. N. Khotjantsev, A. Konaka, T. Shinkawa, V. Obraztsov, T. Fujiwara, A. V. Artamonov, M. V. Diwan, B. Bhuyan, J. Hu, S. Kabe, M. Miyajima, M. M. Khabibullin, Yu. G. Kudenko, T. Sato, T. Sekiguchi, K. Omata, L. S. Littenberg, I. H. Chiang, S. H. Kettell, Masaaki Kobayashi, Shaomin Chen, A. P. Ivashkin, B. Viren, V. A. Mukhin, B. Lewis, S. V. Petrenko, D. E. Jaffe, J. Mildenberger, R. C. Strand, A. P. Kozhevnikov, T. K. Komatsubara, and P. Kitching

Subjects
Physics, Momentum, Nuclear physics, Particle physics, Pion, Branching fraction, Pi, General Physics and Astronomy, Value (computer science), National laboratory
Abstract

An additional event near the upper kinematic limit for K+ to pi+ nu nubar has been observed by Experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+ to pi+ nu nubar)= 1.47 (+1.30, - 0.89) x 10-10 based on three events observed in the pion momentum region 211

Published
2004

39. Further Evidence for the DecayK+→π+νν¯

Author

Vivek Jain, J. R. Stone, P. Kitching, Yoichi Tamagawa, G. Redlinger, J. Hu, M. Kuriki, J. Mildenberger, R. C. Strand, I. H. Chiang, Shaomin Chen, Y. Yoshimura, T. K. Komatsubara, S. H. Kettell, K. Shimada, S. Ng, S. S. Adler, J. S. Frank, J. S. Haggerty, Ewart W. Blackmore, P. C. Bergbusch, C. Witzig, T. Shinkawa, T. Shimoyama, M. Miyajima, K. K. Li, Takashi Nakano, Douglas Bryman, A. Konaka, T. Inagaki, T. Sato, M. V. Diwan, Motoki Kobayashi, A. O. Bazarko, S. Sugimoto, Y. Kuno, S. Kabe, T. Numao, J. A. Macdonald, F. C. Shoemaker, J. M. Poutissou, L. S. Littenberg, P. D. Meyers, Norihito Muramatsu, R. Poutissou, C. Ng, and M. M. Ito

Subjects
Physics, Particle physics, Pion, Branching fraction, Pi, General Physics and Astronomy, Sensitivity (control systems)
Abstract

Additional evidence for the rare kaon decay ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, $211lPl229\mathrm{MeV}/c$, bringing the total for the combined data set to two. Including all data taken, the backgrounds were estimated to contribute $0.15\ifmmode\pm\else\textpm\fi{}0.05$ events. The branching ratio is $B({K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}){\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.57}_{\ensuremath{-}0.82}^{+1.75}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$.

Published
2002

40. Improved search for massive neutrinos inπ+→e+νdecay

Author

Shama Ahmad, M. S. Dixit, D. I. Britton, J. M. Poutissou, T. Numao, J. A. Macdonald, R. A. Burnham, P. Kitching, E. T. H. Clifford, A. Olin, Y. Kuno, and Douglas Bryman

Subjects
Physics, Antiparticle, Particle physics, Particle decay, Pion, Meson, Branching fraction, High Energy Physics::Phenomenology, High Energy Physics::Experiment, Elementary particle, Neutrino, Lepton
Abstract

Evidence of massive neutrinos was sought in the ${\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{e}^{+}\ensuremath{\nu}$ decay spectrum with the background from the $\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\mu}\ensuremath{\rightarrow}e$ decay chain highly suppressed. Upper limits (90% C.L.) were set on the neutrino mixing parameter ${|{U}_{\mathrm{ei}}|}^{2}l{10}^{\ensuremath{-}7}$ in the mass region $50l{m}_{\ensuremath{\nu}}l130$ MeV/${\mathit{c}}^{2}$.

Published
1992

41. New pi + lifetime measurement

Author

J. A. Macdonald, M. C. Fujiwara, Glenn M. Marshall, A. Olin, and T. Numao

Subjects
Physics, Crystallography, Particle physics, Muon, Pion, Computer Science::Information Retrieval, Pi, High Energy Physics::Experiment, Nuclear Experiment, Time spectrum, Spectral line
Abstract

A time spectrum of surface muons from the decay {pi}{sup +}{r_arrow}{mu}{sup +}{nu} ({ital P}{sub {mu}}{sup +}=30 MeV/{ital c}) was measured using a secondary beam channel as a spectrometer, yielding the pion lifetime {tau}{sub {pi}}=26.0231{plus_minus}0.0050 (stat){plus_minus}0.0084(syst) ns.

Published
1995

42. The PIENU experiment at TRIUMF : a sensitive probe for new physics

Author

Makoto Yoshida, Koji Yamada, J. Doornbos, Chloé Malbrunot, T. Numao, N. Ito, Dave Britton, Alexis A. Aguilar-Arevalo, C. Hurst, Song Chen, A.H. Hussein, P. Gumplinger, A. Sher, J. R. Comfort, Leonid Kurchaninov, D. Vavilov, Douglas Bryman, Masaharu Aoki, Luca Doria, Y. Igarashi, M. Ding, S. Kettell, L. Littenberg, Y. Kuno, T. Sullivan, M. Blecher, and R. Poutissou

Subjects
Physics, History, Particle physics, Meson, Branching fraction, Physics beyond the Standard Model, Elementary particle, Computer Science Applications, Education, Nuclear physics, Pseudoscalar, Particle decay, Pion, Lepton
Abstract

Study of rare decays is an important approach for exploring physics beyond the Standard Model (SM). The branching ratio of the helicity suppressed pion decays, R = , is one of the most accurately calculated decay process involving hadrons and has so far provided the most stringent test of the hypothesis of electron-muon universality in weak interactions. The branching ratio has been calculated in the SM to better than 0.01% accuracy to be RSM = 1.2353(1) × 10 . The PIENU experiment at TRIUMF, which started taking physics data in September 2009, aims to reach an accuracy five times better than the previous experiments, so as to confront the theoretical calculation at the level of ±0.1%. If a deviation from the RSM is found, "new physics" beyond the SM, at potentially very high mass scales (up to 1000 TeV), could be revealed. Alternatively, sensitive constraints on hypotheses can be obtained for interactions involving pseudoscalar or scalar interactions. So far, 4 million π+ → e+ νe ue events have been accumulated by PIENU. This paper will outline the physics motivations, describe the apparatus and techniques designed to achieve high precision and present the latest results.

Published
2011

43. Search for a light Higgs boson in the decayK+→π+H, H→μ+μ−

Author

T. Numao, Mats A Selen, R. Poutissou, F. C. Shoemaker, R. C. Strand, J. M. Poutissou, Peter Daniel Meyers, I. H. Chiang, J. S. Frank, Y. Kuno, J. A. Macdonald, J. Roy, T. F. Kycia, M. S. Atiya, W. C. Louis, A. J. Stevens, Georges Azuelos, J. S. Haggerty, A. J.S. Smith, Daniel Robert Marlow, K. K. Li, Douglas Bryman, M. M. Ito, P. Padley, L. S. Littenberg, D. S. Akerib, Ewart W. Blackmore, P. Kitching, L. Felawka, and Michael Hildreth

Subjects
Physics, Particle decay, Particle physics, Crystallography, Pion, Muon, Meson, Branching fraction, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Hadron, Higgs boson, General Physics and Astronomy, Elementary particle
Abstract

An upper limit on the branching ratio of the decay {ital K}{sup +}{r arrow}{pi}{sup +}H, {ital H}{r arrow}{mu}{sup +}{mu}{sup {minus}} is set at 1.5{times}10{sup {minus}7} at the 90% confidence level, for a Higgs-boson mass in the interval 220{lt}{ital m}{sub {ital H}}{lt}320 MeV/{ital c}{sup 2}. In addition, 90%-confidence-level upper limits on the branching ratios of the decays {ital K}{sup +}{r arrow}{pi}{sup +}{mu}{sup +}{mu}{sup {minus}} and {ital K}{sup +}{r arrow}{mu}{sup +}{nu}{mu}{sup +}{mu}{sup {minus}} are set at 2.3{times}10{sup {minus}7} and 4.1{times}10{sup {minus}7}, respectively.

Published
1989

44. Measurements of Cross Sections for Pion Absorption by Nuclei

Author

K. Masutani, K. Nakai, T. Kobayashi, Tatsuo Shibata, T. Numao, and J. Chiba

Subjects
Physics, Nuclear reaction, Light nucleus, Range (particle radiation), Aluminium-27, Nuclear Theory, General Physics and Astronomy, Nuclear physics, Pion, Absorption (logic), Isotopes of gold, Atomic physics, Nuclear Experiment, Energy (signal processing)
Abstract

Cross sections for true absorption by nuclei (Al, Ti, Cu, Sn, Au) of pions (${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$) in the energy range from 20 to 280 MeV were measured by a new method of detecting nuclear $\ensuremath{\gamma}$ rays following the reaction. The incident-energy dependence of the cross sections in the low-energy region (${T}_{\ensuremath{\pi}}l50$ MeV) was well reproduced by an optical-model calculation, while the higher-energy part seems to indicate complex mechanisms of pion absorption.

Published
1980

45. New Measurement of theπ→eνBranching Ratio

Author

D. Berghofer, T. Numao, A. Olin, Douglas Bryman, R. Dubois, J. A. Macdonald, M. S. Dixit, B. Olaniyi, J. M. Poutissou, and B. C. Robertson

Subjects
Physics, Nuclear physics, Particle decay, Antiparticle, Pion, Positron, Meson, Branching fraction, Hadron, Pi, Analytical chemistry, General Physics and Astronomy
Abstract

A new measurement of the ..pi -->..e..nu.. branching ratio yields GAMMA(..pi -->..e..nu..+..pi -->..e..nu gamma..)/GAMMA(..pi --> mu nu..+..pi --> mu nu.. ..gamma..) = (1.218 +- 0.014) x 10/sup -4./ The measured value is in good agreement with the standard-model prediction incorporating electron-muon universality.

Published
1983

46. A cylindrical drift chamber for the measurement of K to pi nu nu decay

Author

T. Numao, Y. Kuno, Douglas Bryman, Ewart W. Blackmore, Nadeem A. Khan, Shama Ahmad, and J.V. Cresswell

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Meson, Physics::Instrumentation and Detectors, Particle detector, Nuclear physics, Particle decay, Pion, Nuclear Energy and Engineering, Antimatter, Measuring instrument, High Energy Physics::Experiment, Electrical and Electronic Engineering, Lepton
Abstract

A cylindrical drift chamber has been constructed for the study of a rare kaon decay. A description is given of the design and construction of the chamber. Data from two prototype chambers and initial results from the final chamber are presented. >

Published
1988

47. A low-momentum π-μ channel at the KEK 12 GeV proton synchrotron

Author

T. Kobayashi, Osamu Hashimoto, T. Numao, H. Hirabayashi, K. Nakai, M. Taino, H. Hamagaki, S. Kurokawa, Akira Yamamoto, T. Yamazaki, J. Chiba, and Tatsuo Shibata

Subjects
Physics, Proton, Nuclear Theory, Proton Synchrotron, General Medicine, Pulse (physics), Momentum, Nuclear physics, Pion, Quadrupole, Physics::Accelerator Physics, Channel (broadcasting), Nuclear Experiment, Beam (structure)
Abstract

A low-momentum secondary beam channel for pion-and muon-experiments has been constructed at the KEK proton synchrotron. Pions produced at 90° to the 12 GeV primary proton beam are extracted with a simple beam optics of two quadrupole doublets and a single 45° bending magnet. The large angle extraction resulted in a good π/e ratio of more than 80% for p π > 150 MeV/ c . The maximum available pion intensity for p π = 200 MeV/ c is 10 7 /pulse. The channel can be used parasitically to other high-energy experiments. The design of the channel, results of the performance tests and some experiments using the channel are described.

Published
1981

48. Measurement of thepi→eνbranching ratio

Author

A. Olin, B. Olaniyi, J. M. Poutissou, J. A. Macdonald, T. Numao, M. S. Dixit, R. Dubois, and Douglas Bryman

Subjects
Physics, Nuclear physics, Particle decay, Pion, Meson, Branching fraction, Electroweak interaction, Hadron, Analytical chemistry, Elementary particle, Lepton
Abstract

A measurement of the ..pi -->..e..nu.. branching ratio using a NaI(Tl) spectrometer yields a value GAMMA((..pi -->..e..nu..)+(..pi -->..e..nu gamma..))/ GAMMA((..pi --> mu nu..)+(..pi --> mu nu gamma..)) = (1. 218 +- 0.014) x 10/sup -4/. The result is consistent with expectations of the standard electroweak theory incorporating electron-muon universality.

Published
1986

49. Constraints on Massive Neutrinos inπ→eνDecay

Author

A. Olin, P. Kitching, T. Numao, Georges Azuelos, Dave Britton, P. Schlatter, Douglas Bryman, E. T. H. Clifford, J. A. Macdonald, M. S. Dixit, B. Olaniyi, and J. M. Poutissou

Subjects
Massless particle, Physics, Nuclear physics, Particle decay, Particle physics, Pion, Meson, Antimatter, General Physics and Astronomy, High Energy Physics::Experiment, Decay chain, Neutrino, Lepton
Abstract

A search has been carried out for the production of neutrinos in the mass range 60 to 130 MeV coupling to the electron in the decay ..pi../sup +/..-->..e/sup +/..nu... The dominant background from the ..pi..-..mu..-e decay chain has been suppressed by use of a new technique leading to more than an order of magnitude greater sensitivity than achieved previously.

Published
1986

50. Searches for Majoron production and other processes associated withπ→eνdecay

Author

P. Kitching, Salahuddin Ahmad, Douglas Bryman, J. A. Macdonald, A. Olin, J. Summhammer, J. M. Poutissou, M. S. Dixit, T. Numao, Dave Britton, Y. Kuno, C. E. Picciotto, and E. T. H. Clifford

Subjects
Nuclear physics, Physics, Particle decay, Antiparticle, Particle physics, Pion, Meson, Branching fraction, High Energy Physics::Phenomenology, Hadron, High Energy Physics::Experiment, Particle identification, Majoron
Abstract

Data from a new study of the decay ..pi -->..e..nu.. are used to place bounds on Majoron-neutrino couplings and to obtain inclusive branching-ratio limits for ..pi -->..e..nu..M, where M is a new particle with a mass in the range 0 to 125 MeV. A limit for the process ..pi../sup +/..-->..e/sup +/..nu nu..nu-bar is also obtained.

Published
1988

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