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35 results on '"Thomson GB"'

1. Observation of Direct CP Violation in KS,L→ππ Decays

Author

Alavi-Harati, A, Albuquerque, IF, Alexopoulos, T, Arenton, M, Arisaka, K, Averitte, S, Barker, AR, Bellantoni, L, Bellavance, A, Belz, J, Ben-David, R, Bergman, DR, Blucher, E, Bock, GJ, Bown, C, Bright, S, Cheu, E, Childress, S, Coleman, R, Corcoran, MD, Corti, G, Cox, B, Crisler, MB, Erwin, AR, Ford, R, Glazov, A, Golossanov, A, Graham, G, Graham, J, Hagan, K, Halkiadakis, E, Hanagaki, K, Hidaka, S, Hsiung, YB, Jejer, V, Jennings, J, Jensen, DA, Kessler, R, Kobrak, HGE, LaDue, J, Lath, A, Ledovskoy, A, McBride, PL, McManus, AP, Mikelsons, P, Monnier, E, Nakaya, T, Nauenberg, U, Nelson, KS, Nguyen, H, O'Dell, V, Pang, M, Pordes, R, Prasad, V, Qiao, C, Quinn, B, Ramberg, EJ, Ray, RE, Roodman, A, Sadamoto, M, Schnetzer, S, Senyo, K, Shanahan, P, Shawhan, PS, Slater, W, Solomey, N, Somalwar, SV, Stone, RL, Suzuki, I, Swallow, EC, Swanson, RA, Taegar, SA, Tesarek, RJ, Thomson, GB, Toale, PA, Tripathi, A, Tschirhart, R, Wah, YW, Wang, J, White, HB, Whitmore, J, Winstein, B, Winston, R, Wu, J-Y, Yamanaka, T, and Zimmerman, ED

Subjects
Perinatal Period - Conditions Originating in Perinatal Period, Pediatric, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

We have compared the decay rates of KL and KS toΠ+ Π- Π0Π0 final states using a subset of the data from the KTeV experiment (E832) at Fermilab. We find that the direct-CP-violation parameter Re (μ’/μ) is equal to [28.0±3.0(stat)±2.8(syst)]×10-4. This result definitively establishes the existence of CP violation in a decay process. © 1999 The American Physical Society.

Published
1999

2. Observation of direct CP violation in ks, l→ΠΠ decays

Author

Alavi-Harati, A, Albuquerque, IF, Alexopoulos, T, Arenton, M, Arisaka, K, Averitte, S, Barker, AR, Bellantoni, L, Bellavance, A, Belz, J, Ben David, R, Bergman, DR, Blucher, E, Bock, GJ, Bown, C, Bright, S, Cheu, E, Childress, S, Coleman, R, Corcoran, MD, Corti, G, Cox, B, Crisler, MB, Erwin, AR, Ford, R, Glazov, A, Golossanov, A, Graham, G, Graham, J, Hagan, K, Halkiadakis, E, Hanagaki, K, Hidaka, S, Hsiung, YB, Jejer, V, Jennings, J, Jensen, DA, Kessler, R, Kobrak, HGE, La Due, J, Lath, A, Ledovskoy, A, Mc Bride, PL, Mc Manus, AP, Mikelsons, P, Monnier, E, Nakaya, T, Nauenberg, U, Nelson, KS, Nguyen, H, O’dell, V, Pang, M, Pordes, R, Prasad, V, Qiao, C, Quinn, B, Ramberg, EJ, Ray, RE, Roodman, A, Sadamoto, M, Schnetzer, S, Senyo, K, Shanahan, P, Shawhan, PS, Slater, W, Solomey, N, Somalwar, SV, Stone, RL, Suzuki, I, Swallow, EC, Swanson, RA, Taegar, SA, Tesarek, RJ, Thomson, GB, Toale, PA, Tripathi, A, Tschirhart, R, Wah, YW, Wang, J, White, HB, Whitmore, J, Winstein, B, Winston, R, Wu, JY, Yamanaka, T, and Zimmerman, ED

Subjects
Pediatric, Perinatal Period - Conditions Originating in Perinatal Period, General Physics, Physical Sciences, Mathematical Sciences, Engineering
Abstract

We have compared the decay rates of KL and KS toΠ+ Π- Π0Π0 final states using a subset of the data from the KTeV experiment (E832) at Fermilab. We find that the direct-CP-violation parameter Re (μ’/μ) is equal to [28.0±3.0(stat)±2.8(syst)]×10-4. This result definitively establishes the existence of CP violation in a decay process. © 1999 The American Physical Society.

Published
1999

3. Isotropy of Cosmic Rays beyond 10^{20}  eV Favors Their Heavy Mass Composition.

Author

Abbasi RU, Abe Y, Abu-Zayyad T, Allen M, Arai Y, Arimura R, Barcikowski E, Belz JW, Bergman DR, Blake SA, Buckland I, Cheon BG, Chikawa M, Fujii T, Fujisue K, Fujita K, Fujiwara R, Fukushima M, Furlich G, Globus N, Gonzalez R, Hanlon W, Hayashida N, He H, Hibi R, Hibino K, Higuchi R, Honda K, Ikeda D, Inoue N, Ishii T, Ito H, Ivanov D, Iwasaki A, Jeong HM, Jeong S, Jui CCH, Kadota K, Kakimoto F, Kalashev O, Kasahara K, Kasami S, Kawakami S, Kawata K, Kharuk I, Kido E, Kim HB, Kim JH, Kim JH, Kim SW, Kimura Y, Komae I, Kuzmin V, Kuznetsov M, Kwon YJ, Lee KH, Lubsandorzhiev B, Lundquist JP, Matsumiya H, Matsuyama T, Matthews JN, Mayta R, Mizuno K, Murakami M, Myers I, Lee KH, Nagataki S, Nakai K, Nakamura T, Nishio E, Nonaka T, Oda H, Ogio S, Onishi M, Ohoka H, Okazaki N, Oku Y, Okuda T, Omura Y, Ono M, Oshima A, Oshima H, Ozawa S, Park IH, Park KY, Potts M, Pshirkov MS, Remington J, Rodriguez DC, Rott C, Rubtsov GI, Ryu D, Sagawa H, Saito R, Sakaki N, Sako T, Sakurai N, Sato D, Sato K, Sato S, Sekino K, Shah PD, Shibata N, Shibata T, Shikita J, Shimodaira H, Shin BK, Shin HS, Shinto D, Smith JD, Sokolsky P, Stokes BT, Stroman TA, Takagi Y, Takahashi K, Takamura M, Takeda M, Takeishi R, Taketa A, Takita M, Tameda Y, Tanaka K, Tanaka M, Tanoue Y, Thomas SB, Thomson GB, Tinyakov P, Tkachev I, Tokuno H, Tomida T, Troitsky S, Tsuda R, Tsunesada Y, Udo S, Urban F, Warren D, Wong T, Yamazaki K, Yashiro K, Yoshida F, Zhezher Y, and Zundel Z

Abstract

We report an estimation of the injected mass composition of ultrahigh energy cosmic rays (UHECRs) at energies higher than 10 EeV. The composition is inferred from an energy-dependent sky distribution of UHECR events observed by the Telescope Array surface detector by comparing it to the Large Scale Structure of the local Universe. In the case of negligible extragalactic magnetic fields (EGMFs), the results are consistent with a relatively heavy injected composition at E∼10  EeV that becomes lighter up to E∼100  EeV, while the composition at E>100  EeV is very heavy. The latter is true even in the presence of highest experimentally allowed extragalactic magnetic fields, while the composition at lower energies can be light if a strong EGMF is present. The effect of the uncertainty in the galactic magnetic field on these results is subdominant.

Published
2024
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4. Indications of proton-dominated cosmic-ray composition above 1.6 EeV.

Author

Abbasi RU, Abu-Zayyad T, Al-Seady M, Allen M, Amman JF, Anderson RJ, Archbold G, Belov K, Belz JW, Bergman DR, Blake SA, Brusova OA, Burt GW, Cannon C, Cao Z, Deng W, Fedorova Y, Finley CB, Gray RC, Hanlon WF, Hoffman CM, Holzscheiter MH, Ivanov D, Hughes G, Hüntemeyer P, Ivanov D, Jones BF, Jui CC, Kim K, Kirn MA, Loh EC, Liu J, Lundquist JP, Maestas MM, Manago N, Marek LJ, Martens K, Matthews JA, Matthews JN, Moore SA, O'Neill A, Painter CA, Perera L, Reil K, Riehle R, Roberts M, Rodriguez D, Sasaki N, Schnetzer SR, Scott LM, Sinnis G, Smith JD, Sokolsky P, Song C, Springer RW, Stokes BT, Stratton S, Thomas SB, Thomas JR, Thomson GB, Tupa D, Zech A, and Zhang X

Abstract

We report studies of ultrahigh-energy cosmic-ray composition via analysis of depth of air shower maximum (X(max)), for air shower events collected by the High-Resolution Fly's Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d/d[log(E)] of 47.9+/-6.0(stat)+/-3.2(syst) g/cm2/decade for energies between 1.6 and 63 EeV, and are consistent with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which the galactic-to-extragalactic transition is the cause of the energy spectrum ankle at 4x10(18) eV.

Published
2010
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5. First observation of the Greisen-Zatsepin-Kuzmin suppression.

Author

Abbasi RU, Abu-Zayyad T, Allen M, Amman JF, Archbold G, Belov K, Belz JW, Ben Zvi SY, Bergman DR, Blake SA, Brusova OA, Burt GW, Cannon C, Cao Z, Connolly BC, Deng W, Fedorova Y, Finley CB, Gray RC, Hanlon WF, Hoffman CM, Holzscheiter MH, Hughes G, Hüntemeyer P, Jones BF, Jui CC, Kim K, Kirn MA, Loh EC, Maestas MM, Manago N, Marek LJ, Martens K, Matthews JA, Matthews JN, Moore SA, O'Neill A, Painter CA, Perera L, Reil K, Riehle R, Roberts M, Rodriguez D, Sasaki N, Schnetzer SR, Scott LM, Sinnis G, Smith JD, Sokolsky P, Song C, Springer RW, Stokes BT, Thomas SB, Thomas JR, Thomson GB, Tupa D, Westerhoff S, Wiencke LR, Zhang X, and Zech A

Abstract

The High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10(19) eV, consistent with the expected cutoff energy. We observe the ankle of the cosmic-ray energy spectrum as well, at an energy of 4 x 10(18) eV. We describe the experiment, data collection, and analysis and estimate the systematic uncertainties. The results are presented and the calculation of the statistical significance of our observation is described.

Published
2008
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6. Measurement of the flux of ultrahigh energy cosmic rays from monocular observations by the High Resolution Fly's Eye experiment.

Author

Abbasi RU, Abu-Zayyad T, Amann JF, Archbold G, Bellido JA, Belov K, Belz JW, Bergman DR, Cao Z, Clay RW, Cooper MD, Dai H, Dawson BR, Everett AA, Fedorova YA, Girard JH, Gray RC, Hanlon WF, Hoffman CM, Holzscheiter MH, Hüntemeyer P, Jones BF, Jui CC, Kieda DB, Kim K, Kirn MA, Loh EC, Manago N, Marek LJ, Martens K, Martin G, Matthews JA, Matthews JN, Meyer JR, Moore SA, Morrison P, Moosman AN, Mumford JR, Munro MW, Painter CA, Perera L, Reil K, Riehle R, Roberts M, Sarracino JS, Sasaki M, Schnetzer SR, Shen P, Simpson KM, Sinnis G, Smith JD, Sokolsky P, Song C, Springer RW, Stokes BT, Taylor SF, Thomas SB, Thompson TN, Thomson GB, Tupa D, Westerhoff S, Wiencke LR, VanderVeen TD, Zech A, and Zhang X

Abstract

We have measured the cosmic ray spectrum above 10(17.2) eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode. We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors. We fit the spectrum to a model consisting of galactic and extragalactic sources.

Published
2004
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7. Measurement of decay parameters for Xi- --> Lambda pi- decay.

Author

Chakravorty A, Diehl HT, Duryea J, Guglielmo G, Heller K, Ho PM, James C, Johns K, Kaplan DM, Longo MJ, Luk KB, Rameika R, Rubin HA, Teige S, Thomson GB, and Zou Y

Abstract

Based on 1.35 x 10(6) polarized Xi(-) events, we measure the parameter phi(Xi) to be -1.61 degrees +/-2.66 degrees +/-0.37 degrees for the Xi(-)-->Lambda pi(-) decay. New results for the parameters beta(Xi) and gamma(Xi) are also presented. Assuming that the CP-violating phase difference is negligible, we deduce the strong phase difference between the P-wave and S-wave amplitudes of the Lambda pi final state to be 3.17 degrees +/-5.28 degrees +/-0.73 degrees, reducing the uncertainty in estimating the level of CP violation in Xi-hyperon decay.

Published
2003
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8. Search for the KL-->pi 0 pi 0 e+e- decay in the KTeV experiment.

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barbosa RF, Barker AR, Barrio M, Bellantoni L, Bellavance A, Belz J, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pordes R, Prasad V, Qi XR, Quinn B, Ramberg EJ, Ray RE, Roodman A, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

The recent discovery of a large CP violating asymmetry in KL-->pi+pi-e+e- mode has prompted us to seach for the associated KL-->pi 0 pi 0 e+e- decay mode in the KTeV-E799 experiment at Fermilab. In 2.7 x 10(11) K(L) decays, one candidate event has been observed with an expected background of 0.3 event, resulting in an upper limit for the KL-->pi 0 pi 0 e+e- branching ratio of 6.6 x 10(-9) at the 90% C.L.

Published
2002
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9. Radiative decay width measurements of neutral kaon excitations using the primakoff effect.

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barbosa RF, Barker AR, Barrio M, Bellantoni L, Bellavance A, Belz J, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Cunha A, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Medvigy D, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pordes R, Prasad V, Qi XR, Quinn B, Ramberg EJ, Ray RE, Roodman A, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We use K(L)'s in the 100-200 GeV energy range to produce 147 candidate events of the axial vector pair K1(1270)-K1(1400) in the nuclear Coulomb field of a Pb target and determine the radiative widths Gamma(K1(1400)-->K0+gamma)=280.8+/-23.2(stat)+/-40.4(syst) keV and Gamma(K1(1270)-->K0+gamma)=73.2+/-6.1(stat)+/-28.3(syst) keV. These first measurements appear to be lower than the quark-model predictions. We also place upper limits on the radiative widths for K(*)(1410) and K(*)(2)(1430) and find that the latter is vanishingly small in accord with SU(3) invariance in the naive quark model.

Published
2002
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10. Measurement of the K(L) charge asymmetry.

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barbosa RF, Barker AR, Barrio M, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Qi XR, Quinn B, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We present a measurement of the charge asymmetry delta(L) in the mode K(L)-->pi(+/-)e(-/+)nu based on 298 x 10(6) analyzed decays. We measure a value of delta(L) = [3322+/-58(stat)+/-47(syst)]x10(-6), in good agreement with previous measurements and 2.4 times more precise than the current best published result. The result is used to place more stringent limits on CPT and DeltaS = DeltaQ violation in the neutral kaon system.

Published
2002
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11. First measurement of form factors of the decay Xi(0) --> Sigma(+)e(-)nu macro(e).

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barbosa RF, Barker AR, Barrio M, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Qi XR, Quinn B, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We present the first measurement of the form factor ratios g(1)/f(1) (direct axial vector to vector), g(2)/f(1) (second class current), and f(2)/f(1) (weak magnetism) for the decay Xi(0)-->Sigma(+)e(-)nu macro(e) using the KTeV (E799) beam line and detector at Fermilab. From the Sigma(+) polarization measured with the decay Sigma(+)-->p pi(0) and the e(-)-nu; correlation, we measure g(1)/f(1) to be 1.32+/-(0.21)(0.17)(stat)+/-0.05(syst), assuming the SU(3)(f) (flavor) values for g(2)/f(1) and f(2)/f(1). Our results are all consistent with exact SU(3)(f) symmetry.

Published
2001
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12. Branching ratio measurement of the decay K(L) --> e(+)e(-)mu(+)mu(-).

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barbosa RF, Barker AR, Barrio M, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Quinn B, Qi XR, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We have collected a 43 event sample of the decay K(L)-->e(+)e(-)mu(+)mu(-) with negligible backgrounds and measured its branching ratio to be (2.62+/-0.40+/-0.17)x10(-9). We see no evidence for CP violation in this decay. In addition, we set the 90% confidence upper limit on the combined branching ratios for the lepton flavor violating decays K(L)-->e(+/-)e(+/-)mu(-/+)mu(-/+) at B(K(L)-->e(+/-)e(+/-)mu(-/+)mu(-/+))< or =1.23x10(-10), assuming a uniform phase space distribution.

Published
2001
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13. Measurement of the branching ratio and form factor of K(L)-->mu(+)mu(-)gamma.

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barker AR, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Quinn B, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We report on the analysis of the rare decay K(L)-->mu(+)mu(-)gamma the 1997 data from the KTeV experiment at Fermilab. A total of 9327 candidate events are observed with 2.4% background, representing a factor of 40 increase in statistics over the current world sample. We find that B(K(L)-->mu(+)mu(-)gamma) = (3.62 +/- 0.04(stat) +/- 0.08(syst)) x 10(-7). The form factor parameter alpha(K*) is measured to be alpha(K*) = -0.160(+0.026)(-0.028). In addition, we make the first measurement of the parameter alpha from the D'Ambrosio-Isidori-Portolés form factor, finding alpha = -1.54 +/- 0.10. In that model, this alpha measurement limits the Cabibbo-Kobayashi-Maskawa parameter rho>-0.2.

Published
2001
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14. Measurements of the rare decay K(L) --> e(+)e(-)e(+)e(-).

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barker AR, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Quinn B, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We observe 441 K(L)-->e(+)e(-)e(+)e(-) candidate events with a background of 4.2 events and measure B(K(L)-->e(+)e(-)e(+)e(-)) = [3.72+/-0.18(stat)+/-0.23(syst)]x10(-8) in the KTeV/E799II experiment at Fermilab. Using the distribution of the angle between the planes of the e(+)e(-) pairs, we measure the CP parameters beta(CP) = -0.23+/-0.09(stat)+/-0.02(syst) and gamma(CP) = -0.09+/-0.09(stat)+/-0.02(syst). We also present the first detailed study of the e(+)e(-) invariant mass spectrum in this decay mode.

Published
2001
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15. Measurement of the branching ratio and asymmetry of the decay Xi degrees -->Sigma degrees gamma.

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barker AR, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Quinn B, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Suzuki I, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We have studied the rare weak radiative hyperon decay Xi degrees -->Sigma degrees gamma in the KTeV experiment at Fermilab. We have identified 4045 signal events over a background of 804 events. The dominant Xi degrees -->Lambdapi degrees decay, which was used for normalization, is the only important background source. An analysis of the acceptance of both modes yields a branching ratio of B(Xi degrees -->Sigma degrees gamma)/B(Xi degrees -->Lambdapi degrees ) = (3.34+/-0.05+/-0.09)x10(-3). By analyzing the final state decay distributions, we have also determined that the Sigma degrees emission asymmetry parameter for this decay is alpha(XiSigma) = -0.63+/-0.09.

Published
2001
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16. Study of the K(0)(L) --> pi(+)pi(-)gamma Direct Emission Vertex.

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barker AR, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hamm J, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Quinn B, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Shields J, Slater W, Solomey N, Somalwar SV, Stone RL, Suzuki I, Swallow EC, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Turner SE, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We have performed studies of the K(0)(L)-->pi(+)pi(-)gamma direct emission ( DE) and inner Bremsstrahlung ( IB) vertices, based on data collected by KTeV during the 1996 Fermilab fixed target run. We find a(1)/a(2) = -0.737+/-0.034 GeV2 for the DE form-factor parameter in the rho-propagator parametrization, and report on fits of the form factor to linear and quadratic functions as well. We concurrently measure gamma(K(0)(L)-->pi(+)pi(-)gamma,E(*)(gamma)>20 MeV)/gamma(K(0)(L)-->pi(+)pi(-)) = (20.8+/-0.3)x10(-3), and a K(0)(L)-->pi(+)pi(-)gamma DE/(DE+IB) branching ratio of 0.683+/-0.011.

Published
2001
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17. Search for the decay KL --> pi(0)e+e-.

Author

Alavi-Harati A, Albuquerque IF, Alexopoulos T, Arenton M, Arisaka K, Averitte S, Barker AR, Bellantoni L, Bellavance A, Belz J, Ben-David R, Bergman DR, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Childress S, Coleman R, Corcoran MD, Corti G, Cox B, Crisler MB, Erwin AR, Ford R, Fordyce PM, Glazov A, Golossanov A, Graham G, Graham J, Hagan K, Halkiadakis E, Hanagaki K, Hidaka S, Hsiung YB, Jejer V, Jennings J, Jensen DA, Kessler R, Kobrak HG, LaDue J, Lath A, Ledovskoy A, McBride PL, McManus AP, Mikelsons P, Monnier E, Nakaya T, Nelson KS, Nguyen H, O'Dell V, Pang M, Pordes R, Prasad V, Qiao C, Quinn B, Ramberg EJ, Ray RE, Roodman A, Sadamoto M, Schnetzer S, Senyo K, Shanahan P, Shawhan PS, Slater W, Solomey N, Somalwar SV, Stone RL, Suzuki I, Swallow EC, Swanson RA, Taegar SA, Tesarek RJ, Thomson GB, Toale PA, Tripathi A, Tschirhart R, Wah YW, Wang J, White HB, Whitmore J, Winstein B, Winston R, Yamanaka T, and Zimmerman ED

Abstract

We report on a search for the decay KL-->pi(0)e+e- carried out by the KTeV/E799 experiment at Fermilab. This decay is expected to have a significant CP violating contribution and the measurement of its branching ratio could support the Cabibbo-Kobayashi-Maskawa mechanism for CP violation or could point to new physics. Two events were observed in the 1997 data with an expected background of 1.06+/-0.41 events, and we set an upper limit B(KL-->pi(0)e+e-)<5.1 x 10(-10) at the 90% confidence level.

Published
2001
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18. Search for direct CP violation in nonleptonic decays of charged Xi and lambda hyperons

Author

Luk KB, Diehl HT, Duryea J, Guglielmo G, Heller K, Ho PM, James C, Johns K, Longo MJ, Rameika R, Teige S, Thomson GB, and Zou Y

Abstract

A search for direct CP violation in the nonleptonic decays of hyperons has been performed. In comparing the product of the decay parameters, alpha(Xi)alpha(Lambda), in terms of an asymmetry parameter, A(XiLambda), between hyperons and antihyperons in the charged Xi-->Lambdapi and Lambda-->ppi decay sequence, we found no evidence of direct CP violation. The parameter A(XiLambda) was measured to be 0.012+/-0.014.

Published
2000
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19. First evidence for the decay KL-->e+e- micro+ micro-

Author

Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Thomson GB, Zou Y, Arisaka K, Roberts D, Slater W, Spencer MB, Weaver M, Briere RA, Cheu E, Harris DA, Krolak P, McFarland KS, Roodman A, Schwingenheuer B, Somalwar SV, Wah YW, Winstein B, Winston R, Barker AR, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, O'Dell VR, Ramberg E, Tschirhart R, Collins EM, Gollin GD, Nakaya T, and Yamanaka T

Published
1996
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20. New measurement of the CP violation parameter eta +- gamma.

Author

Matthews JN, Gu P, Haas P, Hogan WP, Kim SK, Myung SS, Schnetzer S, Somalwar SV, Thomson GB, Zou Y, Barker AR, Briere RA, Cheu E, Harris DA, Makoff G, McFarland KS, Roodman A, Schwingenheuer B, Wah YW, Winstein B, Winston R, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, Ramberg E, Tschirhart R, Yamanaka T, Collins EM, and Gollin GD

Published
1995
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21. CPT tests in the neutral kaon system.

Author

Schwingenheuer B, Briere RA, Barker AR, Cheu E, Gibbons LK, Harris DA, Makoff G, McFarland KS, Roodman A, Wah YW, Winstein B, Winston R, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, Ramberg E, Tschirhart R, Yamanaka T, Collins EM, Gollin GD, Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Somalwar SV, Thomson GB, and Zou Y

Published
1995
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22. Measurement of the Branching Ratio and Form Factor of KL--> micro+ micro- gamma.

Author

Spencer MB, Arisaka K, Roberts D, Slater W, Weaver M, Briere RA, Cheu E, Harris DA, Krolak P, McFarland KS, Roodman A, Schwingenheuer B, Somalwar SV, Wah YW, Winstein B, Winston R, Barker AR, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, Ramberg E, Tschirhart R, Collins EM, Gollin GD, Nakaya T, Yamanaka T, Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Thomson GB, and Zou Y

Published
1995
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23. Measurement of the branching ratio of KL-->e+e- gamma gamma.

Author

Nakaya T, Yamanaka T, Arisaka K, Roberts D, Slater W, Weaver M, Briere RA, Cheu E, Harris DA, McFarland KS, Roodman A, Schwingenheuer B, Somalwar SV, Wah YW, Winstein B, Winston R, Barker AR, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, Ramberg E, Tschirhart R, Collins EM, Gollin GD, Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Thomson GB, and Zou Y

Published
1994
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24. Limit on the branching ratio of KL--> pi 0 nu nu -bar.

Author

Weaver M, Arisaka K, Roberts D, Slater W, Briere RA, Cheu E, Harris DA, Roodman A, Schwingenheuer B, Wah YW, Winstein B, Winston R, Barker AR, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonia J, Ford R, Hsiung YB, Jensen DA, McFarland KS, Ramberg E, Tschirhart R, Collins EM, Gollin GD, Nakaya T, Yamanaka T, Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Somalwar SV, Thomson GB, and Zou Y

Published
1994
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25. Measurement of the branching ratio and a study of CP for the leptonic decay KL-->e+e-e+e-

Author

Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Thomson GB, Zou Y, Arisaka K, Roberts D, Slater W, Weaver M, Briere RA, Cheu E, Harris DA, McFarland KS, Roodman A, Schwingenheuer B, Somalwar SV, Wah YW, Winstein B, Winston R, Barker AR, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, Ramberg E, Tschirhart R, Collins EM, Gollin GD, Nakaya T, and Yamanaka T

Published
1994
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26. Limit on the branching ratio of KL--> pi 0e+e-

Author

Harris DA, Briere RA, Cheu E, Makoff G, McFarland KS, Roodman A, Schwingenheuer B, Somalwar SV, Wah YW, Winstein B, Winston R, Arisaka K, Roberts D, Slater W, Weaver M, Barker AR, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, Ramberg E, Tschirhart R, Collins EM, Gollin GD, Nakaya T, Yamanaka T, Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Thomson GB, and Zou Y

Published
1993
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27. Measurement of the branching ratio of pi 0-->e+e- from pi 0's produced by KL--> pi 0 pi 0 pi 0 decays in flight.

Author

McFarland KS, Briere RA, Cheu E, Harris DA, Makoff G, Roodman A, Schwingenheuer B, Somalwar SV, Wah YW, Winstein B, Winston R, Arisaka K, Roberts D, Slater W, Weaver M, Barker AR, Swallow EC, Bock GJ, Coleman R, Crisler M, Enagonio J, Ford R, Hsiung YB, Jensen DA, Ramberg E, Tschirhart R, Collins EM, Gollin GD, Nakaya T, Yamanaka T, Gu P, Haas P, Hogan WP, Kim SK, Matthews JN, Myung SS, Schnetzer S, Thomson GB, and Zou Y

Published
1993
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