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B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano,
GP Chen, [......],
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmerspeig-Toeller,
SL Wu,
Z Yu,
H Zobernig,
TMB Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We report branching fraction measurements for exclusive decays of charged and neutral B mesons into two-body final states containing a charmonium meson. We use a sample of 22.72±0.36 million BB̅ events collected between October 1999 and October 2000 with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center. The charmonium mesons considered here are J/ψ, ψ(2S), and χc1, and the light meson in the decay is either a K, K*, or π0.
Physical Review D 02/2013; 65. · 4.56 Impact Factor
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B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano,
GP Chen, [......],
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
H Zobernig,
TMB Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: The B0 and B+ meson lifetimes have been measured in e+e- annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the ϒ(4S) resonance. Events are selected in which one B meson is fully reconstructed in a hadronic final state while the second B meson is reconstructed inclusively. A combined fit to the B0 and the B+ decay time difference distributions yields τB0 = 1.546±0.032(stat)±0.022(syst) ps, τB+ = 1.673±0.032(stat)±0.023(syst) ps, and τB+/τB0 = 1.082±0.026(stat)±0.012(syst).
Physical Review Letters 02/2013; 87(20). · 7.37 Impact Factor
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B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano,
GP Chen, [......],
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
H Zobernig,
TMB Kordich,
H Neal,
BABAR Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We report the result of a search for the rare decay B0→γγ in 426 fb-1 of data, corresponding to 226×106 B0B̅ 0 pairs, collected on the Υ(4S) resonance at the PEP-II asymmetric-energy e+e- collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21-12+13 signal events with a statistical significance of 1.8σ. This corresponds to a branching fraction B(B0→γγ)=(1.7±1.1(stat.)±0.2(syst.))×10-7. Based on this result, we set a 90% confidence level upper limit of B(B0→γγ)<3.2×10-7.
Physical Review D. 01/2011; 83:11.
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B Aubert,
D Boutigny,
J-M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobernig,
T M B Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: The branching fractions of the exclusive decays B0-->K(*0)gamma and B+-->K(*+)gamma are measured from a sample of (22.74+/-0.36)x10(6) BB decays collected with the BABAR detector at the PEP-II asymmetric e(+)e(-) collider. We find B (B0-->K(*0)gamma) = [4.23+/-0.40(stat)+/-0.22(syst)]x10(-5), B(B+-->K(*+)gamma) = [3.83+/-0.62(stat)+/-0.22(syst)]x10(-5) and constrain the CP-violating charge asymmetry to be -0.170<A(CP)(B-->K(*)gamma)<0.082 at 90% C.L.
Physical Review Letters 03/2002; 88(10):101805. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobernig,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: The B(0) and B(+) meson lifetimes have been measured in e(+)e(-) annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the Upsilon(4S) resonance. Events are selected in which one B meson is fully reconstructed in a hadronic final state while the second B meson is reconstructed inclusively. A combined fit to the B(0) and the B(+) decay time difference distributions yields tau(B(0)) = 1.546+/-0.032(stat)+/-0.022(syst) ps, tau(B(+)) = 1.673+/-0.032(stat)+/-0.023(syst) ps, and tau(B(+))/tau(B(0)) = 1.082+/-0.026(stat)+/-0.012(syst).
Physical Review Letters 12/2001; 87(20):201803. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobernig,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the decay amplitudes in B-->J/psiK*(892) channels using 20.7 fb(-1) of data collected at the Upsilon(4S) resonance with the BABAR detector at PEP-II. We measure a P-wave fraction R(perpendicular) = (16.0 +/- 3.2 +/- 1.4)% and a longitudinal polarization fraction (59.7 +/- 2.8 +/- 2.4)%. The measurement of a relative phase that is neither 0 nor pi, phi = 2.50 +/- 0.20 +/-0.08 radians, favors a departure from the factorization hypothesis. Although the decay B-->/psiK(pi) proceeds mainly via K*(892), there is also evidence for K2*(1430) and K(pi) S-wave contributions.
Physical Review Letters 12/2001; 87(24):241801. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobernig,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present a limit on the branching fraction for the decay B0-->gammagamma using data collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric energy e+e- collider. Based on the observation of one event in the signal region, out of a sample of 21.3x10(6) e+e--->Upsilon(4S)-->BB decays, we establish an upper limit on the branching fraction of B(B0-->gammagamma)<1.7x10(-6) at the 90% confidence level. This result substantially improves upon existing limits.
Physical Review Letters 12/2001; 87(24):241803. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobernig,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present the results of searches for B decays to charmless two-body final states containing eta(') or omega mesons, based on 20.7 fb(-1) of data collected with the BABAR detector. We find the branching fractions Beta(B(+)-->eta(')K(+)) = (70+/-8+/-5) x 10(-6), Beta(B(0)-->eta(')K(0)) = (42(+13)(-11) +/- 4) x 10(-6), and Beta(B(+)-->omega pi(+)) = (6.6(+2.1)(-1.8) +/- 0.7) x 10(-6), where the first error quoted is statistical and the second is systematic. We give measurements of four additional modes for which the 90% confidence level upper limits are Beta(B(+)-->eta(')pi(+)) < 12 x 10(-6), Beta(B(+)-->omega K(+)) < 4 x 10(-6), Beta(B(0)-->omega K(0)) < 13 x 10(-6), and Beta(B(0)-->omega pi(0)) < 3 x 10(-6).
Physical Review Letters 11/2001; 87(22):221802. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobering,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present measurements, based on a sample of approximately 23x10(6) BB pairs, of the branching fractions and a search for CP-violating charge asymmetries in charmless hadronic decays of B mesons into two-body final states of kaons and pions. We find the branching fractions B(B0-->pi(+)pi(-)) = (4.1+/-1.0+/-0.7)x10(-6), B(B0-->K+pi(-)) = (16.7+/-1.6+/-1.3)x10(-6), B(B+-->K+pi(0)) = (10.8(+2.1)(-1.9)+/-1.0)x10(-6), B(B+-->K0pi(+)) = (18.2(+3.3)(-3.0)+/-2.0)x10(-6), B(B0-->K0pi(0)) = (8.2(+3.1)(-2.7)+/-1.2)x10(-6). We also report 90% confidence level upper limits for B meson decays to the pi(+)pi(0), K+K-, and K0K+ final states. In addition, charge asymmetries have been found to be consistent with zero, where the statistical precision is in the range of +/-0.10 to +/-0.18, depending on the decay mode.
Physical Review Letters 10/2001; 87(15):151802. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobering,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We have observed the decays B--> phiK and phiK(*) in a sample of over 45 million B mesons collected with the BABAR detector at the PEP-II collider. The measured branching fractions are B(B+--> phiK+) = (7.7(+1.6)(-1.4)+/-0.8)x10(-6), B(B0--> phiK0) = (8.1(+3.1)(-2.5)+/-0.8)x10(-6), B(B+--> phiK(*+)) = (9.7(+4.2)(-3.4)+/-1.7)x10(-6), and B(B0--> phiK(*0)) = (8.7(+2.5)(-2.1)+/-1.1)x10(-6). We also report the upper limit B(B+--> phipi(+))<1.4x10(-6) ( 90% C.L.).
Physical Review Letters 10/2001; 87(15):151801. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobernig,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: The production of J/psi mesons in continuum e(+)e(-) annihilations has been studied with the BABAR detector at energies near the Upsilon(4S) resonance. The mesons are distinguished from J/psi production in B decays through their center-of-mass momentum and energy. We measure the cross section e(+)e(-)-->J/psi X to be 2.52+/-0.21+/-0.21 pb. We set a 90% C.L. upper limit on the branching fraction for direct Upsilon(4S)-->J/psi X decays at 4.7 x 10(-4).
Physical Review Letters 10/2001; 87(16):162002. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
J M Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano,
G P Chen, [......],
J Nielsen,
Y Pan,
R Prepost,
I J Scott,
S J Sekula,
J H von Wimmersperg-Toeller,
S L Wu,
H Zobernig,
T M Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.
Physical Review Letters 09/2001; 87(9):091801. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
I De Bonis,
J M Gaillard,
A Jeremie,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano, [......],
Y Pan,
R Prepost,
I J Scott,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Zobernig,
T M Kordich,
T B Moore,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23x10(6) Upsilon(4S)-->BbarB decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events in which one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta = 0.34+/-0.20 (stat)+/-0.05 (syst).
Physical Review Letters 03/2001; 86(12):2515-22. · 7.37 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: We report the design and fabrication of an 805 MHz RF cavity with
beryllium (Be) windows for a muon cooling experiment. The cavity
resembles closely to a cylindrical pillbox cavity with the conventional
beam iris covered by thin Be foils to enhance on-axis accelerating
fields. The Be windows are bolted to the cavity body to allow for easy
replacement and testing for different windows. The cavity is to be
installed within a super-conducting solenoid with magnetic field up to 5
Tesla, and tested at high RF power
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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J. Corlett,
M.A. Green,
N. Hartman,
A. Ladran,
D. Li,
R. MacGill,
R. Rimmer,
A. Moretti,
T. Jurgens,
N. Holtkamp,
E. Black,
D. Summers, M. Booke
[show abstract]
[hide abstract]
ABSTRACT: We present a status report on the research and development of
high-gradient normal-conducting RF structures for the ionization cooling
of rations in a neutrino factory or muon collider. High-gradient RF
structures are required in regions enclosed in strong focussing
solenoidal magnets, precluding the application of superconducting RF
technology. We propose using linear accelerating structures, with
individual cells electromagnetically isolated, to achieve the required
gradients of over 15 MV/m at 201 MHz and 30 MV/m at 805 MHz. Each cell
will be powered independently, and cell length and drive phase adjusted
to optimise shunt impedance of the assembled structure. This efficient
design allows for relatively small field enhancement on the structure
walls, and an accelerating field approximately 1.7 times greater than
the peak surface field. The electromagnetic boundary of each cell may be
provided by a thin Be sheet, or an assembly of thin-walled metal tubes.
Use of thin, low-Z materials will allow passage of the muon beams
without significant deterioration in beam quality due to scattering.
R&D in design and analysis of robust structures that will operate
under large electric and magnetic fields and RF current heating are
discussed, including the experimental program based in a high-power test
laboratory developed for this purpose
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano,
GP Chen, [......],
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
H Zobernig,
TMB Kordich,
H Neal,
BABAR Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We present a limit on the branching fraction for the decay B0→γγ using data collected at the ϒ(4S) resonance with the BABAR detector at the PEP-II asymmetric energy e+e- collider. Based on the observation of one event in the signal region, out of a sample of 21.3×106 e+e-→ϒ(4S)→BB̅ decays, we establish an upper limit on the branching fraction of B(B0→γγ)<1.7×10-6 at the 90% confidence level. This result substantially improves upon existing limits.
Physical Review Letters 01/2001; 87. · 7.37 Impact Factor
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B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano,
GP Chen, [......],
W Orejudos,
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
H Zobernig,
BABAR Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We have observed the decays B→φK and φK* in a sample of over 45 million B mesons collected with the BABAR detector at the PEP-II collider. The measured branching fractions are B(B+→φK+) = (7.7-1.4+1.6±0.8)×10-6, B(B0→φK0) = (8.1-2.5+3.1±0.8)×10-6, B(B+→φK*+) = (9.7-3.4+4.2±1.7)×10-6, and B(B0→φK*0) = (8.7-2.1+2.5±1.1)×10-6. We also report the upper limit B(B+→φπ+)<1.4×10-6 ( 90% C.L.).
Physical Review Letters 01/2001; 87:7. · 7.37 Impact Factor
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J Allison,
K Baird,
R J Barlow,
J M Bauer,
R Bernet, M Booke,
C K Bowdery,
T Brandt,
A Brooks,
J Brose, [......],
P. Vidal,
R Waldi,
D. Walz, R Wang,
M Weaver,
W J Wisniewski,
C R Wuest,
D S Yan,
Y Xue,
R Y Zhu
[show abstract]
[hide abstract]
ABSTRACT: The design and construction of the BaBar electromagnetic calorimeter are reviewed. Recent results on the expected sensitivity of the CsI(TI) to radiation damage are discussed. The performance of the calorimeter in the first PEP-II run is presented. Particular emphasis is placed on operational experience and the measured degradation due to radiation damage. Correlation of radiation damage with the dose recorded in a novel large-scale array of radiation sensitive FETs are presented. The consequences for the long-term performance of a CsI(TI) calorimeter operating in a high background environment are discussed
Nuclear Science Symposium, 1999. Conference Record. 1999 IEEE; 02/1999
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B. Bolen, M. Booke,
L. Cremaldi,
J. Reidy,
E. Tarkovsky,
W. Bugg,
A. Gordeev,
Yu. Efremenko,
Yu. Kamyshkov,
D. Onoprienko,
A. Savin,
K. Shmakov,
S. Chae,
H. Cohn,
F. Plasil,
M. Rennich,
C. Wynn
[show abstract]
[hide abstract]
ABSTRACT: We studied the characteristics of scintillating tiles with
wavelength shifting fiber readout. The focus of this work has been
directed toward the design and development of the Scintillating Barrel
Calorimeter - the copper-scintillator tail catcher device - for the GEM
detector at the SSC. However, these studies are applicable as well to
the design of the hadron calorimeter for the Compact Muon Solenoid
detector proposed for the Large Hadron Collider at CERN. We report on
the results of light yield, response uniformity and timing measurements
for tile-fiber configurations
Nuclear Science Symposium and Medical Imaging Conference, 1994., 1994 IEEE Conference Record;
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BABAR Collaboration,
B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
J P Lees,
P Robbe,
V Tisserand,
A Palano, [......],
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
H Zobernig,
TMB Kordich,
H Neal
