Investigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decays
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, yiel...
| मुख्य लेखकों: | , , , , , , , , , , , , , , , , , , , , , , , , |
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| स्वरूप: | Journal article |
| भाषा: | English |
| प्रकाशित: |
2003
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| _version_ | 1826274806429908992 |
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| author | Lai, A Marras, D Bevan, A Dosanjh, R Gershon, T Hay, B Kalmus, G Lazzeroni, C Munday, D Needham, MD Olaiya, E Parker, M White, T Wotton, SA Barr, G Bocquet, G Ceccucci, A Cundy, D Doble, N Falaleev, V Gatignon, L Gonidec, A Gorini, B Govi, G Grafstrom, P |
| author_facet | Lai, A Marras, D Bevan, A Dosanjh, R Gershon, T Hay, B Kalmus, G Lazzeroni, C Munday, D Needham, MD Olaiya, E Parker, M White, T Wotton, SA Barr, G Bocquet, G Ceccucci, A Cundy, D Doble, N Falaleev, V Gatignon, L Gonidec, A Gorini, B Govi, G Grafstrom, P |
| author_sort | Lai, A |
| collection | OXFORD |
| description | 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. |
| first_indexed | 2024-03-06T22:49:01Z |
| format | Journal article |
| id | oxford-uuid:5e2f3341-881e-4bdc-a49d-f2d0225b7c71 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:49:01Z |
| publishDate | 2003 |
| record_format | dspace |
| spelling | oxford-uuid:5e2f3341-881e-4bdc-a49d-f2d0225b7c712022-03-26T17:39:00ZInvestigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decaysJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5e2f3341-881e-4bdc-a49d-f2d0225b7c71EnglishSymplectic Elements at Oxford2003Lai, AMarras, DBevan, ADosanjh, RGershon, THay, BKalmus, GLazzeroni, CMunday, DNeedham, MDOlaiya, EParker, MWhite, TWotton, SABarr, GBocquet, GCeccucci, ACundy, DDoble, NFalaleev, VGatignon, LGonidec, AGorini, BGovi, GGrafstrom, PThe 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. |
| spellingShingle | Lai, A Marras, D Bevan, A Dosanjh, R Gershon, T Hay, B Kalmus, G Lazzeroni, C Munday, D Needham, MD Olaiya, E Parker, M White, T Wotton, SA Barr, G Bocquet, G Ceccucci, A Cundy, D Doble, N Falaleev, V Gatignon, L Gonidec, A Gorini, B Govi, G Grafstrom, P Investigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decays |
| title | Investigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decays |
| title_full | Investigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decays |
| title_fullStr | Investigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decays |
| title_full_unstemmed | Investigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decays |
| title_short | Investigation of K-L,K-s -> pi(+)pi(-)e(+)e(-) decays |
| title_sort | investigation of k l k s gt pi pi e e decays |
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