Giles Barr: Publications

Search for the decay KS → π0γγ

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 556:3-4 (2003) 105-113

Authors:

A Lai, D Marras, R Batley, A Bevan, RS Dosanjh, TJ Gershon, GE Kalmus, DJ Munday, E Olaiya, MA Parker, T White, SA Wotton, G Barr, G Bocquet, A Ceccucci, T Cuhadar-Dönszelmann, D Cundy, N Doble, V Falaleev, L Gatignon, A Gonidec, B Gorini, G Govi, P Grafström, W Kubischta, A Lacourt, M Lenti, A Norton, S Palestini, B Panzer-Steindel, G Tatishvili, H Taureg, M Velasco, H Wahl, C Cheshkov, P Hristov, V Kekelidze, D Madigojine, N Molokanova, Y Potrebenikov, A Tkatchev, A Zinchenko, I Knowles, C Lazzeroni, V Martin, R Sacco, A Walker, M Contalbrigo, P Dalpiaz, J Duclos, PL Frabetti, A Gianoli, M Martini, L Masetti, F Petrucci, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, HG Becker, M Eppard, H Fox, K Holtz, A Kalter, K Kleinknecht, U Koch, L Köpke, P Lopes da Silva, P Marouelli, I Pellmann, A Peters, B Renk, SA Schmidt, V Schönharting, Y Schué, R Wanke, A Winhart, M Wittgen, JC Chollet, L Fayard, L Iconomidou-Fayard, J Ocariz, G Unal, I Wingerter, G Anzivino, P Cenci, E Imbergamo, P Lubrano, A Mestvirishvili, A Nappi, M Pepe, M Piccini, R Carosi, R Casali, C Cerri, M Cirilli, F Costantini, R Fantechi

Abstract:

A search for the decay KS → π⁰γγ 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 KS beam, an upper limit for the branching ratio BR(KS → π⁰γγ, z ≥ 0.2) < 3.3 x 10^-7 has been obtained at 90% confidence level, where z = m²γγ/mKO². © 2003 Published by Elsevier Science B.V.

Precise measurements of the KS → γγ and KL → γγ decay rates

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 551:1-2 (2003) 7-15

Authors:

A Lai, D Marras, JR Batley, RS Dosanjh, TJ Gershon, GE Kalmus, C Lazzeroni, DJ Munday, E Olaiya, MA Parker, TO White, SA Wotton, R Arcidiacono, G Barr, G Bocquet, A Ceccucci, T Cuhadar-Dönszelmann, D Cundy, N Doble, V Falaleev, L Gatignon, A Gonidec, B Gorini, P Grafström, W Kubischta, A Lacourt, I Mikulec, A Norton, B Panzer-Steindel, G Tatishvili, H Wahl, C Cheshkov, P Hristov, V Kekelidze, D Madigojine, N Molokanova, Y Potrebenikov, A Zinchenko, V Martin, P Rubin, R Sacco, A Walker, M Contalbrigo, P Dalpiaz, J Duclos, PL Frabetti, A Gianoli, M Martini, F Petrucci, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, M Lenti, F Martelli, M Veltri, M Eppard, A Hirstius, K Holtz, K Kleinknecht, U Koch, L Köpke, P Lopes da Silva, P Marouelli, I Mestvirishvili, I Pellmann, A Peters, SA Schmidt, V Schönharting, Y Schué, R Wanke, A Winhart, M Wittgen, JC Chollet, L Fayard, L Iconomidou-Fayard, G Unal, I Wingerter-Seez, G Anzivino, P Cenci, E Imbergamo, P Lubrano, A Mestvirishvili, A Nappi, M Pepe, M Piccini, R Casali, C Cerri, M Cirilli, F Costantini, R Fantechi, L Fiorini, S Giudici, I Mannelli, G Pierazzini, M Sozzi, JB Cheze, M de Beer

Abstract:

The KS → γγ decay rate has been measured with the NA48 detector using a high intensity short neutral beam from the CERN SPS. The measured branching ratio BR(KS → γγ) = (2.78 ± 0.06stat ± 0.04syst) x 10^-6, obtained from 7461 ± 172 KS → γγ events, is significantly higher than the O(p⁴) prediction of chiral perturbation theory. Using a KL beam the ratio Γ(KL → γγ)/Γ(KL → π⁰π⁰π⁰) = (2.81 ± 0.02syst) ×10^-3 has been measured. © 2002 Elsevier Science B.V. All rights reserved.

Investigation of KL,S → π+π -e+e- decays

European Physical Journal C 30:1 (2003) 33-49

Authors:

A Lai, D Marras, A Bevan, RS Dosanjh, TJ Gershon, B Hay, GE Kalmus, C Lazzeroni, DJ Munday, MD Needham, E Olaiya, MA Parker, TO White, SA Wotton, G Barr, G Bocquet, A Ceccucci, D Cundy, N Doble, V Falaleev, L Gatignon, A Gonidec, B Gorini, G Govi, P Grafström, W Kubischta, M Lenti, S Luitz, I Mikulec, A Norton, S Palestini, B Panzer-Steindel, H Taureg, M Velasco, H Wahl, C Cheshkov, A Gaponenko, P Hristov, V Kekelidze, D Madigojine, G Tatishvili, Y Potrebenikov, A Zinchenko, I Knowles, V Martin, R Sacco, A Walker, M Contalbrigo, P Dalpiaz, J Duclos, PL Frabetti, A Gianoli, M Martini, L Masetti, F Petrucci, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, M Veltri, HG Becker, M Eppard, H Fox, K Holtz, A Kalter, K Kleinknecht, U Koch, L Köpke, P Lopes da Silva, P Marouelli, I Pellmann, A Peters, SA Schmidt, V Schönharting, Y Schué, R Wanke, A Winhart, M Wittgen, JC Chollet, L Fayard, L Iconomidou-Fayard, J Ocariz, G Unal, I Wingerter-Seez, G Anzivino, P Cenci, E Imbergamo, P Lubrano, A Mestvirishvili, A Nappi, M Pepe, M Piccini, R Casali, C Cerri, M Cirilli, F Costantini, R Fantechi, S Giudici

Abstract:

The KL → π⁺π^-e ⁺e^- and KS → π⁺π ^-e⁺e^- decay modes have been studied in detail using the NA48 detector at the CERN SPS. Based on the data collected during the 1998 and 1999 run periods, a sample of 1162 KL → π ⁺π^-e⁺e^- candidates has been observed with an expected background level of 36.9 events, yielding the branching ratio measurement BR(KL → π⁺π ^-e⁺e^-) = (3.08 ± 0.20) × 10 ^-7. The distribution of events in the sinφ cosφ variable, where φ is the angle between the π⁺π^- and the e⁺e^- decay planes in the kaon centre of mass, is found to exhibit a large CP-violating asymmetry with the value Aφ = (14.2 ± 3.6)%. For the KS → π⁺π ^-e⁺e^- decay channel, 621 candidates have been identified in the 1999 data sample with an estimated background contribution of 0.7 event. The corresponding branching ratio has been determined to be BR(K S → π⁺π^-e⁺e^-) = (4.71 ± 0.32) × 10^-5. The combined value of this measurement with the published 1998 result is BR(KS → π ⁺π^-e⁺e^-) = (4.69 ± 0.30) × 10^-5. No asymmetry is observed in this decay mode. Our results are in good agreement with theoretical predictions based on a phenomenological description of radiative kaon decays. The form factor parameters a1/a2 and g̃M1 in the K L → π⁺π^-e⁺e^- direct emission process as well as the value of the K⁰ charge radius have been extracted from the data.

Precise measurements of the K_s → γγ and K_L → γγ decay rates

PHYSICS LETTERS B 551:1-2 (2003) PII S0370-2693(02)02955-6

Authors:

A Lai, D Marras, JR Batley, RS Dosanjh, TJ Gershon, GE Kalmus, C Lazzeroni, DJ Munday, E Olaiya, MA Parker, TO White, SA Wotton, R Arcidiacono, G Barr, G Bocquet, A Ceccucci, T Cuhadar-Döszelmann, D Cundy, N Doble, V Falaleev, L Gatignon, A Gonidec, B Gorini, P Grafström, W Kubischta, A Lacourt, I Mikulec, A Norton, B Panzer-Steindel, G Tatishvili, H Wahl, C Cheshkov, P Hristov, V Kekelidze, D Madigojine, N Molokanova, Y Potrebenikov, A Zinchenko, V Martin, P Rubin, R Sacco, A Walker, M Contalbrigo, P Dalpiaz, J Duclos, PL Frabetti, A Gianoli, M Martini, E Petrucci, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, M Lenti, F Martelli, M Veltri, M Eppard, A Hirstius, K Holtz, K Kleinknecht, U Koch, L Köpke, PL da Silva, P Marouelli, I Mestvirishvili, I Pellmann, A Peters, SA Schmidt, V Schöharting, Y Schué, R Wanke, A Winhart, M Wittgen, JC Chollet, L Fayard, L Iconomidou-Fayard, G Unal, I Wingerter-Seez, G Anzivino, P Cenci, E Imbergamo, P Lubrano, A Mestvirishvili, A Nappi, M Pepe, M Piccini, R Casali, C Cerri, M Cirilli, F Costantini, R Fantechi, L Fiorini, S Giudici, I Mannelli, G Pierazzini, M Sozzi, JB Cheze, M De Beer, P Debu, F Derue, A Formica, RG de Cassagnac, G Gouge, G Marel, E Mazzucato, B Peyaud, R Turlay, B Vallage, M Holder, A Maier, M Ziolkowski, C Biino, N Cartiglia, F Marchetto, E Menichetti, N Pastrone, J Nassalski, E Rondio, M Szleper, W Wislicki, S Wronka, H Dibon, M Jeitler, M Markytan, G Neuhofer, M Pernicka, A Taurok, L Widhalm

Search for the decay K_S → π⁰ γγ

PHYSICS LETTERS B 556:3-4 (2003) 105-113

Authors:

A Lai, D Marras, R Batley, A Bevan, RS Dosanjh, TJ Gershon, GE Kalmus, DJ Munday, E Olaiya, MA Parker, T White, SA Wotton, G Barr, G Bocquet, A Ceccucci, T Cuhadar-Dönszelmann, D Cundy, N Doble, V Falaleev, L Gatignon, A Gonidec, B Gorini, G Govi, P Grafström, W Kubischta, A Lacourt, M Lenti, A Norton, S Palestini, B Panzer-Steindel, G Tatishvili, H Taureg, M Velasco, H Wahl, C Cheshkov, P Hristov, V Kekelidze, D Madigojine, N Molokanova, Y Potrebenikov, A Tkatchev, A Zinchenko, I Knowles, C Lazzeroni, V Martin, R Sacco, A Walker, M Contalbrigo, P Dalpiaz, J Duclos, PL Frabetti, A Gianoli, M Martini, L Masetti, F Petrucci, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, HG Becker, M Eppard, H Fox, K Holtz, A Kalter, K Kleinknecht, U Koch, L Köpke, PL da Silva, P Marouelli, I Pellmann, A Peters, B Renk, SA Schmidt, V Schnöharting, Y Schué, R Wanke, A Winhart, M Wittgen, JC Chollet, L Fayard, L Iconomidou-Fayard, J Ocariz, G Unal, I Wingerter, G Anzivino, P Cenci, E Imbergamo, P Lubrano, A Mestvirishvili, A Nappi, M Pepe, M Piccini, R Carosi, R Casali, C Cerri, M Cirilli, F Costantini, R Fantechi, S Giudici, I Mannelli, G Pierazzini, M Sozzi, JB Cheze, J Cogan, M De Beer, P Debu, A Formica, RG de Cassagnac, E Mazzucato, B Peyaud, R Turlay, B Vallage, M Holder, A Maier, M Ziolkowski, R Arcidiacono, C Biino, N Cartiglia, R Guida, F Marchetto, E Menichetti, N Pastrone, J Nassalski, E Rondio, M Szleper, W Wislicki, S Wronka, H Dibon, G Fischer, M Jeitler, M Markytan, I Mikulec, G Neuhofer, M Pernicka, A Taurok, L Widhalm

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Giles Barr

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Search for the decay KS → π0γγ

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Precise measurements of the KS → γγ and KL → γγ decay rates

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Abstract:

Investigation of KL,S → π+π -e+e- decays

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Abstract:

Precise measurements of the K_s → γγ and K_L → γγ decay rates

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Search for the decay K_S → π⁰ γγ

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Giles Barr

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Search for the decay KS → π0γγ

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Abstract:

Precise measurements of the KS → γγ and KL → γγ decay rates

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Abstract:

Investigation of KL,S → π+π -e+e- decays

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Abstract:

Precise measurements of the Ks → γγ and KL → γγ decay rates

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Search for the decay KS → π0 γγ

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Precise measurements of the K_s → γγ and K_L → γγ decay rates

Search for the decay K_S → π⁰ γγ