-
E. Abouzaid,
M. Arenton,
A. R. Barker,
M. Barrio,
L. Bellantoni,
E. Blucher,
G. J. Bock, C. Bown,
E. Cheu,
R. Coleman, [......],
J. Wang,
H. B. White,
J. Whitmore,
M. J. Wilking,
B. Winstein,
R. Winston,
E. T. Worcester,
T. Yamanaka,
E. D. Zimmerman,
R. F. Zukanovich
[show abstract]
[hide abstract]
ABSTRACT: We present precise tests of CP and CPT symmetry based on the full data set of K→ππ decays collected by the KTeV experiment at Fermi National Accelerator Laboratory during 1996, 1997, and 1999. This data set contains 16×106 K→π0π0 and 69×106 K→π+π- decays. We measure the direct CP violation parameter Re(ϵ′/ϵ)=(19.2±2.1)×10-4. We find the KL-KS mass difference Δm=(5270±12)×106ℏ s-1 and the KS lifetime τS=(89.62±0.05)×10-12 s. We also measure several parameters that test CPT invariance. We find the difference between the phase of the indirect CP violation parameter ϵ and the superweak phase: ϕϵ-ϕSW=(0.40±0.56)°. We measure the difference of the relative phases between the CP violating and CP conserving decay amplitudes for K→π+π- (ϕ+-) and for K→π0π0 (ϕ00): Δϕ=(0.30±0.35)°. From these phase measurements, we place a limit on the mass difference between K0 and K̅ 0: ΔM<4.8×10-19 GeV/c2 at 95% C.L. These results are consistent with those of other experiments, our own earlier measurements, and CPT symmetry.
Phys. Rev. D. 05/2011; 83(9).
-
KTeV Collaboration,
E Abouzaid,
M. Arenton,
A R Barker,
M Barrio,
L Bellantoni,
E Blucher,
G J Bock, C Bown,
E Cheu, [......],
J Wang,
H B White,
J Whitmore,
M. J. Wilking,
B Winstein,
R Winston,
E T Worcester,
T Yamanaka,
E. D. Zimmerman,
R F Zukanovich
[show abstract]
[hide abstract]
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.
10/2010;
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
R F Barbosa,
A R Barker,
M Barrio,
L Bellantoni,
A Bellavance,
E Blucher,
G J Bock, [......],
Y W Wah,
J Wang,
H B White,
J Whitmore,
M Wilking,
B Winstein,
R Winston,
E T Worcester,
T Yamanaka,
R F Zukanovich
[show abstract]
[hide abstract]
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.
Physical Review Letters 07/2004; 93(2):021805. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
R F Barbosa,
A R Barker,
M Barrio,
L Bellantoni,
A Bellavance,
E Blucher, [......],
Y W Wah,
J Wang,
H B White,
J Whitmore,
M Wilking,
B Winstein,
R Winston,
E T Worcester,
T Yamanaka,
R F Zukanovich
[show abstract]
[hide abstract]
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.
Physical Review Letters 04/2003; 90(14):141801. · 7.37 Impact Factor
-
A. Alavi-Harati,
T. Alexopoulos,
M. Arenton,
K. Arisaka,
S. Averitte,
R. F. Barbosa,
A. R. Barker,
M. Barrio,
L. Bellantoni,
A. Bellavance, [......],
R. Tschirhart,
S. E. Turner,
Y. W. Wah,
J. Wang,
H. B. White,
J. Whitmore,
B. Winstein,
R. Winston,
T. Yamanaka,
E. D. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: We present a series of measurements based on KL,S→π+π- and KL,S→π0π0 decays collected in 1996–1997 by the KTeV experiment (E832) at Fermilab. We compare these four K⃗ππ decay rates to measure the direct CP violation parameter Re(ε′/ε)=(20.7±2.8)×10-4. We also test CPT symmetry by measuring the relative phase between the CP violating and CP conserving decay amplitudes for K⃗π+π- (φ+-) and for K⃗π0π0 (φ00). We find the difference between the relative phases to be Δφ≡φ00-φ+-=(+0.39±0.50)°, and the deviation of φ+- from the superweak phase to be φ+--φSW=(+0.61±1.19)°; both results are consistent with CPT symmetry. In addition, we present new measurements of the KL-KS mass difference and KS lifetime: Δm=(5261±15)×106ħs-1 and τS=(89.65±0.07)×10-12s.
Phys. Rev. D. 01/2003; 67(1).
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
R F Barbosa,
A R Barker,
M Barrio,
L Bellantoni,
A Bellavance, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 11/2002; 89(21):211801. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
R F Barbosa,
A R Barker,
M Barrio,
L Bellantoni,
A Bellavance, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 08/2002; 89(7):072001. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
R F Barbosa,
A R Barker,
M Barrio,
L Bellantoni,
A Bellavance, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 06/2002; 88(18):181601. · 7.37 Impact Factor
-
A. Alavi-Harati,
T. Alexopoulos,
M. Arenton,
K. Arisaka,
S. Averitte,
R. F. Barbosa,
A. R. Barker,
M. Barrio,
L. Bellantoni,
A. Bellavance, [......],
R. Tschirhart,
S. E. Turner,
Y. W. Wah,
J. Wang,
H. B. White,
J. Whitmore,
B. Winstein,
R. Winston,
T. Yamanaka,
E. D. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: We present a new measurement of the branching ratio of the decay KL→π±e∓νeγ(Ke3γ) with respect to KL→π±e∓νe(Ke3), and the first study of the photon energy spectrum in this decay. We find BR(Ke3γ,Eγ*>30MeV, θeγ*>20°)/BR(Ke3)=0.908±0.008(stat)-0.012+0.013(syst)%. Our measurement of the spectrum is consistent with inner bremsstrahlung as the only source of photons in Ke3γ.
Phys. Rev. D. 11/2001; 64(11).
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
R F Barbosa,
A R Barker,
M Barrio,
L Bellantoni,
A Bellavance, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 09/2001; 87(13):132001. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
R F Barbosa,
A R Barker,
M Barrio,
L Bellantoni,
A Bellavance, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 09/2001; 87(11):111802. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
A R Barker,
L Bellantoni,
A Bellavance,
J Belz,
R Ben-David, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 08/2001; 87(7):071801. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
A R Barker,
L Bellantoni,
A Bellavance,
J Belz,
R Ben-David, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 06/2001; 86(24):5425-9. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
A R Barker,
L Bellantoni,
A Bellavance,
J Belz,
R Ben-David, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 04/2001; 86(15):3239-43. · 7.37 Impact Factor
-
A Alavi-Harati,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
A R Barker,
L Bellantoni,
A Bellavance,
J Belz,
R Ben-David, [......],
R Tschirhart,
S E Turner,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 02/2001; 86(5):761-4. · 7.37 Impact Factor
-
A Alavi-Harati,
I F Albuquerque,
T Alexopoulos,
M Arenton,
K Arisaka,
S Averitte,
A R Barker,
L Bellantoni,
A Bellavance,
J Belz, [......],
A Tripathi,
R Tschirhart,
Y W Wah,
J Wang,
H B White,
J Whitmore,
B Winstein,
R Winston,
T Yamanaka,
E D Zimmerman
[show abstract]
[hide abstract]
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.
Physical Review Letters 02/2001; 86(3):397-401. · 7.37 Impact Factor
-
A. Alavi-Harati,
I. F. Albuquerque,
T. Alexopoulos,
M. Arenton,
K. Arisaka,
S. Averitte,
A. R. Barker,
L. Bellantoni,
A. Bellavance,
J. Belz, [......],
A. Tripathi,
R. Tschirhart,
Y. W. Wah,
J. Wang,
H. B. White,
J. Whitmore,
B. Winstein,
R. Winston,
T. Yamanaka,
E. D. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: We have observed the decay KL→μ+μ-γγ at the KTeV experiment at Fermilab. This decay presents a formidable background to the search for new physics in KL→π0μ+μ-. The 1997 data yielded a sample of 4 signal events, with an expected background of 0.155±0.081 events. The branching ratio is B (KL→μ+μ-γγ)=[10.4-5.9+7.5 (stat)±0.7 (syst)]×10-9 with mγγ>~1 MeV/c2, consistent with a QED calculation which predicts (9.1±0.8)×10-9.
Phys. Rev. D. 10/2000; 62(11).
-
A. Alavi-Harati,
I. F. Albuquerque,
T. Alexopoulos,
M. Arenton,
K. Arisaka,
S. Averitte,
A. R. Barker,
L. Bellantoni,
A. Bellavance,
J. Belz, [......],
R. Tschirhart,
Y. W. Wah,
J. Wang,
H. B. White,
J. Whitmore,
B. Winstein,
R. Winston,
J.-Y. Wu,
T. Yamanaka,
E. D. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: We report on a search for the decay
KL-->π0νν¯, carried out as a part
of E799-II, a rare KL decay experiment at Fermilab. Within
the standard model, the
KL-->π0νν¯ decay is dominated by
direct CP violating processes, and thus an observation of the decay
implies confirmation of direct CP violation. No events were observed,
and we set an upper limit for the branching ratio of
KL-->π0νν¯ to be < 5.9
×10-7 at the 90% confidence level.
Physical review D: Particles and fields 03/2000; 61(7):72006.
-
A. Alavi-Harati,
I. F. Albuquerque,
T. Alexopoulos,
M. Arenton,
K. Arisaka,
S. Averitte,
A. R. Barker,
L. Bellantoni,
A. Bellavance,
J. Belz, [......],
R. Tschirhart,
Y. W. Wah,
J. Wang,
H. B. White,
J. Whitmore,
B. Winstein,
R. Winston,
J.-Y. Wu,
T. Yamanaka,
E. D. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: We report on a search for the decay KL→π0νν̅ , carried out as a part of E799-II, a rare KL decay experiment at Fermilab. Within the standard model, the KL→π0νν̅ decay is dominated by direct CP violating processes, and thus an observation of the decay implies confirmation of direct CP violation. No events were observed, and we set an upper limit for the branching ratio of KL→π0νν̅ to be <5.9×10-7 at the 90% confidence level.
Phys. Rev. D. 03/2000; 61(7).
-
E. Cheu,
S.A. Taegar,
J. Wang,
K. Arisaka,
J. Jennings,
W. Slater,
A.K. Tripathi,
H.G. Kobrak,
R.A. Swanson,
E. Blucher, [......],
P.A. Toale,
J. Wu,
L. Bellantoni,
R. Ben-David,
G.J. Bock,
S. Childress,
R. Coleman,
M.B. Crisler,
R. Ford,
Hsiung
[show abstract]
[hide abstract]
ABSTRACT: We report on two null searches, one for the spontaneous appearance of [pi][sup +][pi][sup [minus]] pairs, another for a single [pi][sup 0] , consistent with the decay of a long-lived neutral particle into hadrons and an unseen neutral particle. For the lowest level gluon-gluino bound state, known as the R[sup 0] , we exclude the decays R[sup 0][r arrow][pi][sup +][pi][sup [minus]] [tilde [gamma]] and R[sup 0][r arrow][pi][sup 0][tilde [gamma]] for the masses of R[sup 0] and [tilde [gamma]] in the theoretically allowed range. In the most interesting R[sup 0] mass range, [le]3 GeV/c[sup 2] , we exclude R[sup 0] lifetimes from 3[times]10[sup [minus]10] sec to as high as 10[sup [minus]3] sec , assuming perturbative QCD production for the R[sup 0] . [copyright] [ital 1999] [ital The American Physical Society]
Physical Review Letters 08/1999; 83:11. · 7.37 Impact Factor
