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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. Precise Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System

Author

Collaboration, K, Abouzaid, E, Arenton, M, Barker, AR, Barrio, M, Bellantoni, L, Blucher, E, Bock, GJ, Bown, C, Cheu, E, Coleman, R, Corcoran, MD, Cox, B, Erwin, AR, Escobar, CO, Glazov, A, Golossanov, A, Gomes, RA, Gouffon, P, Graham, J, Hamm, J, Hsiung, YB, Jensen, DA, Kessler, R, Kotera, K, LaDue, J, Ledovskoy, A, McBride, PL, Monnier, E, Nguyen, H, Niclasen, R, II, DGP, Prasad, V, Qi, XR, Ramberg, EJ, Ray, RE, Ronquest, M, Roodman, A, Santos, E, Shanahan, P, Shawhan, PS, Slater, W, Smith, D, Solomey, N, Swallow, EC, Taegar, SA, Toale, PA, Tschirhart, R, Wah, YW, Wang, J, White, HB, Whitmore, J, Wilking, MJ, Winstein, B, Winston, R, Worcester, ET, Yamanaka, T, Zimmerman, ED, and Zukanovich, RF

Subjects
High Energy Physics - Experiment (hep-ex), FOS: Physical sciences, High Energy Physics - Experiment
Abstract

We present precise tests of CP and CPT symmetry based on the full dataset of K to pipi decays collected by the KTeV experiment at Fermi National Accelerator Laboratory during 1996, 1997, and 1999. This dataset contains 16 million K to 2pi0 and 69 million K to pi+pi- decays. We measure the direct CP violation parameter Re(epsilon'/epsilon) = (19.2 pm 2.1)x10-4. We find the KL-KS mass difference Deltam = (5270 pm 12)x10^6 hbar/s and the KS lifetime tauS = (89.62 pm 0.05)x10-12 s. We also measure several parameters that test CPT invariance. We find the difference between the phase of the indirect CP violation parameter, epsilon, and the superweak phase, phi_epsilon - phi_SW = (0.40 pm 0.56) degrees. We measure the difference of the relative phases between the CP violating and CP conserving decay amplitudes for K to pi+pi- (phi+-) and for K to 2pi0 (phi00), Delta phi = (0.30 pm 0.35) degrees. From these phase measurements, we place a limit on the mass difference between K0 and K0bar, DeltaM < 4.8 x 10-19 GeV/c^2 at 95% C.L. These results are consistent with those of other experiments, our own earlier measurements, and CPT symmetry., 28 pages, 30 figures; removed extra figure

Published
2010

3. Search for the rare decays K(L)→π0π0μ+μ- and K(L)→π0π0X0→π0π0μ+μ-.

Author

Abouzaid E, Arenton M, Barker AR, Bellantoni L, Blucher E, Bock GJ, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Escobar CO, Glazov A, Golossanov A, Gomes RA, Gouffon P, Hsiung YB, Jensen DA, Kessler R, Kotera K, Ledovskoy A, McBride PL, Monnier E, Nguyen H, Niclasen R, Phillips DG 2nd, Ping H, Ramberg EJ, Ray RE, Ronquest M, Santos E, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Velissaris C, Wah YW, Wang J, White HB, Whitmore J, Wilking MJ, Winston R, Worcester ET, Worcester M, Yamanaka T, Zimmerman ED, and Zukanovich RF

Abstract

The KTeV E799 experiment has conducted a search for the rare decays, K(L)→π(0)π(0)μ(+)μ(-) and K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-), where the X(0) is a possible new neutral boson that was reported by the HyperCP experiment with a mass of (214.3 ± 0.5) MeV/c(2). We find no evidence for either decay. We obtain upper limits of Br(K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-)) < 1.0 × 10(-10) and Br(K(L)→π(0)π(0)μ(+)μ(-)) < 9.2 × 10(-11) at the 90% confidence level. This result rules out the pseudoscalar X(0) as an explanation of the HyperCP result under the scenario that the dsX(0) coupling is completely real.

Published
2011
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4. Determination of the parity of the neutral pion via its four-electron decay.

Author

Abouzaid E, Arenton M, Barker AR, Bellantoni L, Blucher E, Bock GJ, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Escobar CO, Glazov A, Golossanov A, Gomes RA, Gouffon P, Hsiung YB, Jensen DA, Kessler R, Kotera K, Ledovskoy A, McBride PL, Monnier E, Nguyen H, Niclasen R, Phillips DG 2nd, Ramberg EJ, Ray RE, Ronquest M, Santos E, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Wah YW, Wang J, White HB, Whitmore J, Wilking MJ, Winstein B, Winston R, Worcester ET, Yamanaka T, Zimmerman ED, and Zukanovich RF

Abstract

We present a new determination of the parity of the neutral pion via the double Dalitz decay pi0-->e+e-e+e-. Our sample, which consists of 30,511 candidate decays, was collected from KL-->pi0pi0pi0 decays in flight at the KTeV-E799 experiment at Fermi National Accelerator Laboratory. We confirm the negative pi0 parity and place a limit on scalar contributions to the pi0-->e+e-e+e- decay amplitude of less than 3.3% assuming CPT conservation. The pi0gamma*gamma* form factor is well described by a momentum-dependent model with a slope parameter fit to the final state phase-space distribution. Additionally, we have measured the branching ratio of this mode to be B(pi0-->e+e-e+e-)=(3.26+/-0.18)x10(-5).

Published
2008
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5. Search for lepton-flavor-violating decays of the neutral kaon.

Author

Abouzaid E, Arenton M, Barker AR, Bellantoni L, Bellavance A, Blucher E, Bock GJ, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Escobar CO, Glazov A, Golossanov A, Gomes RA, Gouffon P, Hsiung YB, Jensen DA, Kessler R, Kotera K, Ledovskoy A, McBride PL, Monnier E, Nguyen H, Niclasen R, Ii DG, Ping H, Ramberg EJ, Ray RE, Ronquest M, Santos E, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Wah YW, Wang J, White HB, Whitmore J, Wilking MJ, Winstein B, Winston R, Wolfe C, Worcester ET, Worcester M, Yamanaka T, Zimmerman ED, and Zukanovich RF

Abstract

The Fermilab KTeV experiment has searched for lepton-flavor-violating decays of the K(L) meson in three decay modes. We observe no events in the signal region for any of the modes studied, and we set the following upper limits for their branching ratios at the 90% C.L.: BR(K(L) --> pi(0) micro(+/-) e(-/+)) <7.6 x 10(-11); BR(K(L) --> pi(0)pi(0) micro(+/-) e(-/+)) <1.7 x 10(-10); BR(pi(0) --> micro(+/-) e(-/+)) <3.6 x 10(-10). This result represents a factor of 82 improvement in the branching ratio limit for K(L) --> pi(0) micro(+/-) e(-/+) and is the first reported limit for K(L) --> pi(0)pi(0) micro(+/-) e(-/+).

Published
2008
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6. First observation of K{L}-->pi{+/-}e{-/+}nue{+}e{-}.

Author

Abouzaid E, Arenton M, Barker AR, Bellantoni L, Blucher E, Bock GJ, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Escobar CO, Glazov A, Golossanov A, Gomes RA, Gouffon P, Hsiung YB, Jensen DA, Kessler R, Kotera K, Ledovskoy A, McBride PL, Monnier E, Nelson KS, Nguyen H, Niclasen R, Phillips DG 2nd, Ping H, Ramberg EJ, Ray RE, Ronquest M, Santos E, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Velissaris C, Wah YW, Wang J, White HB, Whitmore J, Wilking MJ, Winstein B, Winston R, Worcester ET, Worcester M, Yamanaka T, Zimmerman ED, and Zukanovich RF

Abstract

This Letter is the first report of the K{L}-->pi{+/-}e{-/+}nue{+}e{-} decay. Based on 19 208+/-144 events, we determine the branching fraction, B(K{L}-->pi{+/-}e{-/+}nue{+}e{-}M&#95;{e{+}e{-}}>5 MeV/c{2},E{e{+}e{-}}{*}>30 MeV)=(1.285+/-0.041)x10{-5}, and Gamma(K{e3ee}M{e{+}e{-}}>5 MeV/c{2})/Gamma(K{e3})=[4.57+/-0.04(stat)+/-0.14(syst)]x10{-5}. This ratio agrees with a theoretical prediction based on chiral perturbation theory (ChPT) calculated to O(p{4}). The measured kinematical distributions agree with those predicted by just ChPT O(p{4}), but show significant disagreement with ones predicted by leading-order ChPT.

Published
2007
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7. Measurements of the decay KL-->e+ e- gamma.

Author

Abouzaid E, Arenton M, Barker AR, Bellantoni L, Blucher E, Bock GJ, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Glazov A, Golossanov A, Hsiung YB, Jensen DA, Kessler R, Kobrak HG, Kotera K, LaDue J, Ledovskoy A, McBride PL, Monnier E, Nguyen H, Niclasen R, Ramberg EJ, Ray RE, Ronquest M, Shields J, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Wah YW, Wang J, White HB, Whitmore J, Wilking MJ, Winston R, Worcester ET, Yamanaka T, and Zimmerman ED

Abstract

The E799-II (KTeV) experiment at Fermilab has collected 83 262 K(L)-->e+ e- gamma(gamma) events above a background of 79 events. We measure a decay width, normalized to the K(L)-->pi0pi0pi(D)0 (pi0-->gammagamma, pi0-->gammagamma, pi(D0-->e+ e- gamma(gamma)) decay width, of Gamma(K(L)-->e+e-gamma(gamma))/Gamma(K(L)-->pi0pi0pi(D)0)=(1.3302+/-0.0046(stat)+/-0.0102(syst)) x 10(-3). We also measure parameters of two K(L)gamma*gamma form factor models. In the Bergström-Massó-Singer parametrization, we find Calpha(K*)= -0.517 +/- 0.030(stat) +/- 0.022(syst). We separately fit for the first parameter of the D'Ambrosio-Isidori-Portolés model and find alpha(DIP)= -1.729 +/- 0.043(stat) +/- 0.028(syst).

Published
2007
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8. Measurement of the K0 charge radius and a CP-violating asymmetry and a search for CP-violating E1 direct photon emission in the rare decay KL--> pi+ pi- e+ e-.

Author

Abouzaid E, Arenton M, Barker AR, Bellantoni L, Bellavance A, Blucher E, Bock GJ, Cheu E, Coleman R, Corcoran MD, Corti G, Cox B, Erwin AR, Escobar CO, Glazov A, Golossanov A, Gomes RA, Gouffon P, Hanagaki K, Hsiung YB, Huang H, Jensen DA, Kessler R, Kotera K, Ledovskoy A, McBride PL, Monnier E, Nelson KS, Nguyen H, Niclasen R, Ping H, Qi XR, Ramberg EJ, Ray RE, Ronquest M, Santos E, Shields J, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Velissaris C, Wah YW, Wang J, White HB, Whitmore J, Wilking M, Winstein B, Winston R, Worchester ET, Worchester M, Yamanaka T, Zimmerman ED, and Zukanovich RF

Abstract

Using the complete KTeV data set of 5,241 candidate K(L)--> pi(+) pi(-) e(+) e(-) decays (including an estimated background of 204 +/- 14 events), we have measured the coupling g(CR)= 0.163 +/- 0.0149(stat) +/- 0.023(syst) of the CP conserving charge radius process and from it determined a K(0) charge radius of = [-0.077 +/- 0.007(stat) +/- 0.011(syst)]fm(2). We have determined a first experimental upper limit of 0.04 (90% C.L.) /g(e1)/ / /g(M1)/ of the couplings for the E1 and M1 direct photon emission processes. We also report the measurement of /g(M1)/ including a vector form factor /g(M1)/(1 + (a(1)/a(2))/((M(2)(p)-(M(2)(k))= 2M(K)E(gamma*)), where vector /g(M1)/= 1.11+/- 0.12(stat) +/- 0.08(syst) and a(1)/a(2) = [-0.744 +/- 0.027(stat) +/- 0.032(syst)] GeV(2)/c(2). Finally, a CP-violating asymmetry of [13.6 +/- 1.4(stat) +/- 1.5(syst)]% in the CP and T odd angle phi between the decay planes of the e(+) e(-) and pi(+) pi(-) pairs in the K(L) center of mass is reported.

Published
2006
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9. Observation of the decay xi0 --> sigma+ mu- nu(mu).

Author

Abouzaid E, Alexopoulos T, Arenton M, Barbosa RF, Barker AR, Bellantoni L, Bellavance A, Blucher E, Bock GJ, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Escobar CO, Glazov A, Golossanov A, Gomes RA, Gouffon P, Hanagaki K, Hsiung YB, Huang H, Jensen DA, Kessler R, Kotera K, LaDue J, Ledovskoy A, McBride PL, Monnier E, Nelson KS, Nguyen H, Niclasen R, Ping H, Prasad V, Qi XR, Ramberg EJ, Ray RE, Ronquest M, Santos E, Shields J, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Velissaris C, Wah YW, Wang J, White HB, Whitmore J, Wilking M, Winstein B, Winston R, Worcester ET, Worcester M, Yamanaka T, Zimmerman ED, and Zukanovich RF

Abstract

The xi0 muon semileptonic decay has been observed for the first time with nine identified events using the KTeV beam line and detector at Fermilab. The decay is normalized to the xi0 beta decay mode and yields a value for the ratio of decay rates gamma(xi0 --> sigma+ mu- nu(mu))/gamma(xi0 --> sigma+ e- nu(e)) of [1.8(-0.5)(+0.7)(stat) +/- 0.2(syst)] x 10(-2). This is in agreement with the SU(3) flavor symmetric quark model.

Published
2005
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10. A determination of the Cabibbo-Kobayashi-Maskawa parameter |V us| using KL decays.

Author

Alexopoulos T, Arenton M, Barbosa RF, Barker AR, Bellantoni L, Bellavance A, Blucher E, Bock GJ, Cheu E, Childress S, Coleman R, Corcoran MD, Cox B, Erwin AR, Ford R, Glazov A, Golossanov A, Graham J, Hamm J, Hanagaki K, Hsiung YB, Huang H, Jejer V, Jensen DA, Kessler R, Kobrak HG, Kotera K, LaDue J, Ledovskoy A, McBride PL, Monnier E, Nelson KS, Nguyen H, Niclasen R, Prasad V, Qi XR, Ramberg EJ, Ray RE, Ronquest M, Santos E, Shanahan P, Shields J, Slater W, Smith D, Solomey N, Swallow EC, Toale PA, Tschirhart R, Wah YW, Wang J, White HB, Whitmore J, Wilking M, Winstein B, Winston R, Worcester ET, Yamanaka T, and Zimmerman ED

Abstract

We present a determination of the Cabibbo-Kobayashi-Maskawa parameter |V(us)| based on new measurements of the six largest K(L) branching fractions and semileptonic form factors by the KTeV (E832) experiment at Fermilab. We find |V(us)|=0.2252+/-0.0008(KTeV)+/-0.0021(ext), where the errors are from KTeV measurements and from external sources. We also use the measured branching fractions to determine the CP violation parameter |eta(+-)|=(2.228+/-0.005(KTeV)+/-0.009(ext))x10(-3).

Published
2004
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11. Search for the rare decay K(L)-->pi(0)e(+)e(-).

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Barbosa RF, Barker AR, Barrio M, Bellantoni L, Bellavance A, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Escobar CO, Ford R, Glazov A, Golossanov A, Gomes RA, Gouffon P, Graham J, Hamm J, Hanagaki K, Hsiung YB, Huang H, Jejer V, Jensen DA, Kessler R, Kobrak HG, Kotera K, LaDue J, Lai N, Ledovskoy A, McBride PL, Monnier E, Nelson KS, Nguyen H, Ping H, Prasad V, Qi XR, Quinn B, Ramberg EJ, Ray RE, Ronquest M, Santos E, Senyo K, Shanahan P, Shields J, Slater W, Smith DE, Solomey N, Swallow EC, Taegar SA, Tesarek RJ, Toale PA, Tschirhart R, Velissaris C, Wah YW, Wang J, White HB, Whitmore J, Wilking M, Winstein B, Winston R, Worcester ET, Yamanaka T, and Zukanovich RF

Abstract

The KTeV/E799 experiment at Fermilab has searched for the rare kaon decay K(L)-->pi(0)e(+)e(-). This mode is expected to have a significant CP violating component. The measurement of its branching ratio could support the standard model or could indicate the existence of new physics. This Letter reports new results from the 1999-2000 data set. One event is observed with an expected background at 0.99+/-0.35 events. We set a limit on the branching ratio of 3.5x10(-10) at the 90% confidence level. Combining with the previous result based on the data set taken in 1997 yields the final KTeV result: BR(K(L)-->pi(0)e(+)e(-))<2.8x10(-10) at 90% C.L.

Published
2004
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12. Measurements of the Decay KL-->e+ e- mu+ mu-.

Author

Alavi-Harati A, Alexopoulos T, Arenton M, Arisaka K, Barbosa RF, Barker AR, Barrio M, Bellantoni L, Bellavance A, Blucher E, Bock GJ, Bown C, Bright S, Cheu E, Coleman R, Corcoran MD, Cox B, Erwin AR, Escobar CO, Ford R, Glazov A, Golossanov A, Gouffon P, Graham J, Hamm J, Hanagaki K, Hsiung YB, Huang H, Jejer V, Jensen DA, Kessler R, Kobrak HG, Kotera K, LaDue J, Lai N, Ledovskoy A, McBride PL, Monnier E, Nelson KS, Nguyen H, Prasad V, Qi XR, Quinn B, Ramberg EJ, Ray RE, Santos E, Senyo K, Shanahan P, Shields J, Slater W, Solomey N, Swallow EC, Taegar SA, Tesarek RJ, Toale PA, Tripathi A, Tschirhart R, Wah YW, Wang J, White HB, Whitmore J, Wilking M, Winstein B, Winston R, Worcester ET, Yamanaka T, and Zukanovich RF

Abstract

The KTeV experiment at Fermilab has isolated a total of 132 events from the rare decay K(L)-->e+ e- mu+ mu-, with an estimated background of 0.8 events. The branching ratio of this mode is determined to be [2.69+/-0.24(stat)+/-0.12(syst)]x10(-9), with a radiative cutoff of M(2)(ee mu mu)/M(2)(K)>0.95. The first measurement using this mode of the parameter alpha from the D'Ambrosio-Isidori-Portolès (DIP) model of the K(L)gamma*gamma* vertex yields a result of -1.59+/-0.37, consistent with values obtained from other decay modes. Because of the limited statistics, no sensitivity is found to the DIP parameter beta. We use this decay mode to set limits on CP and lepton violation.

Published
2003
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13. 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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14. 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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15. 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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16. 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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17. 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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18. 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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19. 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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20. 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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21. 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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22. 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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