-
B. Aubert,
D. Boutigny,
J.-M. Gaillard,
A. Hicheur,
Y. Karyotakis,
J. P. Lees,
P. Robbe,
V. Tisserand,
A. Palano,
A. Pompili, [......],
F. Di Lodovico,
Y. Pan,
R. Prepost,
I. J. Scott,
S. J. Sekula,
J. H. von Wimmersperg-Toeller,
S. L. Wu,
Z. Yu,
T. M. B. Kordich,
H. Neal
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of time-dependent CP-violating asymmetries in neutral B meson decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. The data sample consists of 29.7 fb-1 recorded at the Υ(4S) resonance and 3.9 fb-1 off resonance. One of the neutral B mesons, which are produced in pairs at the Υ(4S), is fully reconstructed in the CP decay modes J/ψKS0, ψ(2S)KS0, χc1KS0, J/ψK*0 (K*0→KS0π0) and J/ψKL0, or in flavor-eigenstate modes involving D(*)π/ρ/a1 and J/ψK*0 (K*0→K+π-). The flavor of the other neutral B meson is tagged at the time of its decay, mainly with the charge of identified leptons and kaons. A neural network tagging algorithm is used to recover events without a clear lepton or kaon tag. The proper time elapsed between the decays is determined by measuring the distance between the decay vertices. Wrong-tag probabilities, the time-difference resolution function, and the B0-B0 oscillation frequency Δmd are measured with a sample of about 6350 fully-reconstructed B0 decays in hadronic flavor-eigenstate modes. A maximum-likelihood fit to this flavor eigenstate sample finds Δmd=0.516±0.016(stat)±0.010(syst)ps-1. The value of the asymmetry amplitude sin2β is determined from a simultaneous maximum-likelihood fit to the time-difference distribution of the flavor-eigenstate sample and about 642 tagged B0 decays in the CP-eigenstate modes. We find sin2β=0.59±0.14(stat)±0.05(syst), demonstrating that CP violation exists in the neutral B meson system. We also determine the value of the CP violation parameter |λ|=0.93±0.09(stat)±0.03(syst), which is consistent with the expectation of |λ|=1 for no direct CP violation.
Physical Review D 02/2013; 66(3). · 4.56 Impact Factor
-
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
-
BABAR Collaboration,
B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano, [......], R Liu,
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
TMB Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: New measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the Υ(4S) resonance are presented. Using 20.8 fb-1 of data on the Υ(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the Υ(4S) mass. The branching fractions ΣB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ΣB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.
Physical Review D 02/2013; 65(9). · 4.56 Impact Factor
-
BABAR Collaboration,
B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano, [......],
F Di Lodovico,
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
TMB Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: Flavor oscillations of neutral B mesons have been studied in e+e- annihilation data collected with the BABAR detector at center-of-mass energies near the ϒ(4S) resonance. The data sample used for this purpose consists of events in which one B0 meson is reconstructed in a hadronic decay mode, while the flavor of the recoiling B0 is determined with a tagging algorithm that exploits the correlation between the flavor of the heavy quark and the charges of its decay products. From the time development of the observed mixed and unmixed final states, we determine the B0-B̅ 0 oscillation frequency Δmd to be 0.516±0.016(stat)±0.010(syst) ps-1.
Physical Review Letters 02/2013; 88(22). · 7.37 Impact Factor
-
BABAR Collaboration,
B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano, [......],
F Di Lodovico,
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
S L Wu,
Z Yu,
TMB Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We search for direct CP violation in charmless hadronic B decays observed in a sample of about 22.7 million BB̅ pairs collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e+e- collider. We measure the following charge asymmetries: ACP(B±→η′K±)=-0.11±0.11±0.02, ACP(B±→ωπ±)=-0.01 - 0.31 + 0.29±0.03, ACP(B±→φK±)=-0.05±0.20±0.03, ACP(B±→φK*±)=-0.43 - 0.30 + 0.36±0.06, and ACP(B0→φK*0)=0.00±0.27±0.03.
Physical Review D 02/2013; 65(5):051101. · 4.56 Impact Factor
-
BABAR Collaboration,
B Aubert,
D Boutigny,
JM Gaillard,
A Hicheur,
Y Karyotakis,
JP Lees,
P Robbe,
V Tisserand,
A Palano, [......],
F Di Lodovico,
Y Pan,
R Prepost,
IJ Scott,
SJ Sekula,
JH von Wimmersperg-Toeller,
SL Wu,
Z Yu,
TMB Kordich,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of time-dependent CP-violating asymmetries in neutral B meson decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. The data sample consists of 29.7 fb-1 recorded at the Υ(4S) resonance and 3.9 fb-1 off resonance. One of the neutral B mesons, which are produced in pairs at the Υ(4S), is fully reconstructed in the CP decay modes J/ψKS0, ψ(2S)KS0, χc1KS0, J/ψK*0 (K*0→KS0π0) and J/ψKL0, or in flavor-eigenstate modes involving D(*)π/ρ/a1 and J/ψK*0 (K*0→K+π-). The flavor of the other neutral B meson is tagged at the time of its decay, mainly with the charge of identified leptons and kaons. A neural network tagging algorithm is used to recover events without a clear lepton or kaon tag. The proper time elapsed between the decays is determined by measuring the distance between the decay vertices. Wrong-tag probabilities, the time-difference resolution function, and the B0-B0 oscillation frequency Δmd are measured with a sample of about 6350 fully-reconstructed B0 decays in hadronic flavor-eigenstate modes. A maximum-likelihood fit to this flavor eigenstate sample finds Δmd=0.516±0.016(stat)±0.010(syst)ps-1. The value of the asymmetry amplitude sin2β is determined from a simultaneous maximum-likelihood fit to the time-difference distribution of the flavor-eigenstate sample and about 642 tagged B0 decays in the CP-eigenstate modes. We find sin2β=0.59±0.14(stat)±0.05(syst), demonstrating that CP violation exists in the neutral B meson system. We also determine the value of the CP violation parameter |λ|=0.93±0.09(stat)±0.03(syst), which is consistent with the expectation of |λ|=1 for no direct CP violation.
Physical Review D 02/2013; 66(3). · 4.56 Impact Factor
-
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.
-
[show abstract]
[hide abstract]
ABSTRACT: A dynamic dead-time controller based on a novel dead-time detector for synchronous buck DC-DC converters is proposed. With this controller, the dead time of power converters can be dynamically optimised under any load condition. A voltage mode buck converter with this controller has been designed using Chartered 0.35 ¿m CMOS process. Experimental results show that the power efficiency can be improved by 6.5% with the proposed technique.
Electronics Letters 02/2010; · 0.96 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Wireless Sensor Networks (WSNs) which utilise IEEE 802.15.4 technology offer the potential for low cost deployment and maintenance compared with conventional wired sensor networks, enabling effective and efficient condition monitoring of aged civil engineering infrastructure. We will address wireless propagation for a below to above ground scenario where one of the wireless nodes is located in a below ground fire hydrant chamber to permit monitoring of the local water distribution network. Frequency Diversity (FD) is one method that can be used to combat the damaging effects of multipath fading and so improve the reliability of radio links. However, no quantitative investigation concerning the potential performance gains from the use of FD at 2.4 GHz is available for the outlined scenario. In this paper, we try to answer this question by performing accurate propagation measurements using modified and calibrated off-the-shelf 802.15.4 based sensor nodes. These measurement results are also compared with those obtained from simulations that employ our Modified 2D Finite-Difference Time-Domain (FDTD) approach.
Antennas & Propagation Conference, 2009. LAPC 2009. Loughborough; 12/2009
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[show abstract]
[hide abstract]
ABSTRACT: Two nanopower CMOS sub-bandgap references have been designed with the Chartered 0.35 mum CMOS process, which generate two precise voltages of 96.6 and 108.9 mV with minimal temperature coefficients of 11.4 and 9.2 ppm/degC, respectively. Both circuits operate properly with a supply voltage down to 1.1 V and a supply current below 26 nA. The power supply rejection ratio for each circuit without any filtering capacitor at 100 Hz and 10 MHz is lower than 60 and 40 dB, respectively.
Electronics Letters 07/2009; · 0.96 Impact Factor
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Energy Sources Part A Recovery Utilization and Environmental Effects 05/2009; Part A(Vol. 31):646-656. · 0.71 Impact Factor
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B Aubert,
R Barate,
D Boutigny,
F Couderc,
Y Karyotakis,
J P Lees,
V Poireau,
V Tisserand,
A Zghiche,
E Grauges, [......], R Liu,
B Mellado,
A Mihalyi,
Y Pan,
R Prepost,
P Tan,
J H von Wimmersperg-Toeller,
S L Wu,
Z Yu,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B-->Kpipigamma in the range m(Kpipi)<1.8 GeV/c(2). We reconstruct four final states: K(+)pi(-)pi(+)gamma, K(+)pi(-)pi(0)gamma, K(S)(0)pi(-)pi(+)gamma, and K(S)(0)pi(+)pi(0)gamma, where K(S)(0)-->pi(+)pi(-). Using 232 x 10(6) e(+)e(-)-->BB events recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy storage ring, we measure the branching fractions B(B(+)-->K(+)pi(-)pi(+)gamma)=[2.95+/-0.13(stat)+/-0.20(syst)] x 10(-5), B(B(0)-->K(+)pi(-)pi(0)gamma)=[4.07+/-0.22(stat)+/-0.31(syst)] x 10(-5), B(B(0)-->K(0)pi(+)pi(-)gamma)=[1.85+/-0.21(stat)+/-0.12(syst)] x 10(-5), and B(B(+)-->K(0)pi(+)pi(0)gamma)=[4.56+/-0.42(stat)+/-0.31(syst)] x 10(-5).
Physical Review Letters 05/2007; 98(21):211804. · 7.37 Impact Factor
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B. Aubert,
R. Barate,
M. Bona,
D. Boutigny,
F. Couderc,
Y. Karyotakis,
J. P. Lees,
V. Poireau,
V. Tisserand,
A. Zghiche, [......],
B. Mellado,
A. Mihalyi,
A. K. Mohapatra,
Y. Pan,
M. Pierini,
R. Prepost,
P. Tan,
S. L. Wu,
Z. Yu,
H. Neal
[show abstract]
[hide abstract]
ABSTRACT: We report on a study of inclusive B- and B̅ 0 meson decays to D0X, D̅ 0X, D+X, D-X, Ds+X, Ds-X, Λc+X, Λ̅ c-X, based on a sample of 231×106 BB̅ events recorded with the BABAR detector at the Υ(4S) resonance. Events are selected by completely reconstructing one B and searching for a reconstructed charm particle in the rest of the event. From the measured branching fractions of these decays, we infer the number of charm and anticharm particles per B̅ decay, separately for charged and neutral parents. We derive the total charm yield per B- decay, nc-=1.208±0.023±0.040-0.029+0.035, and per B̅ 0 decay, nc0=1.203±0.030±0.034-0.035+0.044 where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties. We also present the charm momentum distributions measured in the B̅ rest frame.
Phys. Rev. D. 04/2007; 75(7).
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B Aubert,
R Barate,
M Bona,
D Boutigny,
F Couderc,
Y Karyotakis,
J P Lees,
V Poireau,
V Tisserand,
A Zghiche, [......],
B Mellado,
A Mihalyi,
A K Mohapatra,
Y Pan,
M Pierini,
R Prepost,
P Tan,
S L Wu,
Z Yu,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: Using 230.2 fb-1 of e+e- annihilation data collected with the BABAR detector at and near the peak of the Upsilon(4S) resonance, 489+/-55 events containing the pure leptonic decay Ds+-->micro;+numicro have been isolated in charm-tagged events. The ratio of partial widths Gamma(D+-->micro+numicro)/Gamma(Ds+-->phipi+) is measured to be 0.143+/-0.018+/-0.006 allowing a determination of the pseudoscalar decay constant fDs=(283+/-17+/-7+/-14) MeV. The errors are statistical, systematic, and from the Ds+-->phipi+ branching ratio, respectively.
Physical Review Letters 04/2007; 98(14):141801. · 7.37 Impact Factor
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B Aubert,
R Barate,
M Bona,
D Boutigny,
F Couderc,
Y Karyotakis,
J P Lees,
V Poireau,
V Tisserand,
A Zghiche, [......],
B Mellado,
A Mihalyi,
A K Mohapatra,
Y Pan,
M Pierini,
R Prepost,
P Tan,
S L Wu,
Z Yu,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of decays B{0}-->D{s}{(*)+}pi- and B{0}-->D{s}{(*)-}K+ in a sample of 230 x 10(6) Upsilon(4S)-->BB[over] events recorded with the BABAR detector at the SLAC PEP-II asymmetric-energy e+ e- storage ring. We measure the branching fractions B(B{0}-->D{s}{+}pi-)=(1.3+/-0.3(stat)+/-0.2(syst))x10(-5), B(B{0}-->D{s}{-} K+)=(2.5+/-0.4(stat)+/-0.4(syst))x10(-5), B(B{0}-->D{s}{*+}pi-)=(2.8+/-0.6(stat)+/-0.5(syst))x10(-5), and B(B{0}-->D{s}{*-}K+)=(2.0+/-0.5(stat)+/-0.4(syst))x10(-5). The significances of the measurements to differ from zero are 5, 9, 6, and 5 standard deviations, respectively. This is the first observation of B{0}-->D{s}{+}pi-, B{0}-->D{s}{*+}pi-, and B{0}-->D{s}{*-}K+ decays.
Physical Review Letters 02/2007; 98(8):081801. · 7.37 Impact Factor
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B Aubert,
R Barate,
M Bona,
D Boutigny,
F Couderc,
Y Karyotakis,
J P Lees,
V Poireau,
V Tisserand,
A Zghiche, [......],
B Mellado,
A Mihalyi,
A K Mohapatra,
Y Pan,
M Pierini,
R Prepost,
P Tan,
S L Wu,
Z Yu,
H Neal
[show abstract]
[hide abstract]
ABSTRACT: A search for charmed baryons decaying to D(0)p reveals two states: the Lambdac(2880)+ baryon and a previously unobserved state at a mass of [2939.8+/-1.3(stat)+/-1.0(syst)] MeV/c2 and with an intrinsic width of [17.5+/-5.2(stat)+/-5.9(syst)] MeV. Consistent and significant signals are observed for the K(-)pi(+) and K(-)pi(+)pi(-)pi(+) decay modes of the D0 in 287 fb(-1) annihilation data recorded by the BABAR detector at a center-of-mass energy of 10.58 GeV. There is no evidence in the D+p spectrum of doubly charged partners. The mass and intrinsic width of the Lambdac(2880)+ baryon and relative yield of the two baryons are also measured.
Physical Review Letters 02/2007; 98(1):012001. · 7.37 Impact Factor
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B. Aubert,
R. Barate,
D. Boutigny,
F. Couderc,
Y. Karyotakis,
J. P. Lees,
V. Poireau,
V. Tisserand,
A. Zghiche,
E. Grauges, [......],
B. Mellado,
A. Mihalyi,
A. K. Mohapatra,
Y. Pan,
M. Pierini,
R. Prepost,
P. Tan,
S. L. Wu,
Z. Yu,
H. Neal
[show abstract]
[hide abstract]
ABSTRACT: We measure the dependence of B̅ 0→D*+e-ν̅ e on the decay angles and momentum transfer. The data sample consists of ∼86×106 BB̅ -pairs accumulated on the Υ(4S) resonance by the BABAR detector at the asymmetric e+e- collider PEP-II. We specify the three form factors by two ratios R1 and R2, and by a single parameter ρ2 characterizing the polynomial representing hA1, the function which describes the momentum-transfer dependence of the form factor A1. We determine R1, R2, and ρ2 using an unbinned maximum likelihood fit to the full decay distribution. The results are R1=1.396±0.060±0.035±0.027, R2=0.885±0.040±0.022±0.013, and ρ2=1.145±0.059±0.030±0.035. The stated uncertainties are the statistical from the data, statistical from the size of the Monte Carlo sample and the systematic uncertainty, respectively. In addition, based on this measurement, we give an updated value for the CKM matrix element |Vcb|.
Phys. Rev. D. 11/2006; 74(9).
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B. Aubert,
R. Barate,
D. Boutigny,
F. Couderc,
Y. Karyotakis,
J. P. Lees,
V. Poireau,
V. Tisserand,
A. Zghiche,
E. Grauges, [......], R. Liu,
B. Mellado,
A. Mihalyi,
Y. Pan,
R. Prepost,
P. Tan,
J. H. von Wimmersperg-Toeller,
S. L. Wu,
Z. Yu,
H. Neal
Physical review D: Particles and fields 10/2006; 74(9):99903.
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B. Aubert,
R. Barate,
M. Bona,
D. Boutigny,
F. Couderc,
Y. Karyotakis,
J. P. Lees,
V. Poireau,
V. Tisserand,
A. Zghiche, [......],
B. Mellado,
A. Mihalyi,
A. K. Mohapatra,
Y. Pan,
M. Pierini,
R. Prepost,
P. Tan,
S. L. Wu,
Z. Yu,
H. Neal
[show abstract]
[hide abstract]
ABSTRACT: We present measurements of branching fractions of B0 decays
to multibody final states containing protons, based on
232×106 Υ(4S)→BB¯ decays collected
with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory.
We measure the branching fractions
B(B0→D¯0pp¯)=(1.13±0.06±0.08)×10-4,
B(B0→D¯*0pp¯)=(1.01±0.10±0.09)×10-4,
B(B0→D-pp¯π+)=(3.38±0.14±0.29)×10-4,
and
B(B0→D*-pp¯π+)=(4.81±0.22±0.44)×10-4
where the first error is statistical and the second systematic. We
present a search for the charmed pentaquark state,
Θc(3100) observed by H1 and put limits on the branching
fraction
B(B0→Θcp¯π+)×B(Θc→D*-p)<14×10-6
and
B(B0→Θcp¯π+)×B(Θc→D-p)<9×10-6.
Upon investigation of the decay structure of the above four
B0 decay modes, we see an enhancement at low pp¯ mass
and deviations from phase-space in the D¯p¯ and D¯p
invariant mass spectra.
Physical review D: Particles and fields 08/2006; 74(5):51101.
