-
M Ablikim,
M N Achasov,
L An,
Q An,
Z H An,
J Z Bai,
R Baldini,
Y Ban,
J Becker,
N Berger, [......],
S H Zhu,
X L Zhu,
X W Zhu,
Y S Zhu,
Z A Zhu,
J Zhuang,
B S Zou,
J H Zou,
J X Zuo,
P Zweber
[show abstract]
[hide abstract]
ABSTRACT: Using (106±4)×10⁻⁶ ψ(3686) events accumulated with the BESIII detector at the BEPCII e⁺e⁻ collider, we present the first measurement of decays of χ(c1) to vector meson pairs φφ, ωω, and ωφ. The branching fractions are measured to be (4.4±0.3±0.5)×10⁻⁴, (6.0±0.3±0.7)×10⁻⁴, and (2.2±0.6±0.2)×10⁻⁵, for χ(c1)→φφ, ωω, and ωφ, respectively, which indicates that the hadron helicity selection rule is significantly violated in χ(cJ) decays. In addition, the measurement of χ(cJ)→ωφ provides the first indication of the rate of doubly OZI-suppressed χ(cJ) decay. Finally, we present improved measurements for the branching fractions of χ(c0) and χ(c2) to vector meson pairs.
Physical Review Letters 08/2011; 107(9):092001. · 7.37 Impact Factor
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M. Ablikim,
M. N. Achasov,
D. Alberto,
L. An,
Q. An,
Z. H. An,
J. Z. Bai,
R. Baldini,
Y. Ban,
J. Becker, [......],
S. H. Zhu,
X. L. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
J. Zhuang,
B. S. Zou,
J. H. Zou,
J. X. Zuo,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: First measurements of the decays of the three χcJ states to pp̅ K+K- final states are presented. Intermediate ϕ→K+K- and Λ(1520)→pK- resonance states are observed, and branching fractions for χcJ→p̅ K+Λ(1520), Λ(1520)Λ̅ (1520), and ϕpp̅ are reported. We also measure branching fractions for direct χcJ→pp̅ K+K- decays. These are first observations of χcJ decays to unstable baryon resonances and provide useful information about the χcJ states. The experiment uses samples of χcJ mesons produced via radiative transitions from 106×106 ψ′ mesons collected in the BESIII detector at the BEPCII e+e- collider.
Phys. Rev. D. 06/2011; 83(11).
-
M. Ablikim,
M. N. Achasov,
D. Alberto,
L. An,
Q. An,
Z. H. An,
J. Z. Bai,
R. Baldini,
Y. Ban,
J. Becker, [......],
S. H. Zhu,
X. L. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
J. Zhuang,
B. S. Zou,
J. H. Zou,
J. X. Zuo,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: The decays χcJ→γV (V=ϕ, ρ0, ω) are studied with a sample of radiative ψ′→γχcJ events in a sample of (1.06±0.04)×108ψ′ events collected with the BESIII detector. The branching fractions are determined to be: B(χc1→γϕ)=(25.8±5.2±2.3)×10-6, B(χc1→γρ0)=(228±13±22)×10-6, and B(χc1→γω)=(69.7±7.2±6.6)×10-6. The decay χc1→γϕ is observed for the first time. Upper limits at the 90% confidence level on the branching fractions for χc0 and χc2 decays into these final states are determined. In addition, the fractions of the transverse polarization component of the vector meson in χc1→γV decays are measured to be 0.29-0.12-0.09+0.13+0.10 for χc1→γϕ, 0.158±0.034-0.014+0.015 for χc1→γρ0, and 0.247-0.087-0.026+0.090+0.044 for χc1→γω, respectively. The first errors are statistical and the second ones are systematic.
Phys. Rev. D. 06/2011; 83(11).
-
M. Ablikim,
M. N. Achasov,
L. An,
Q. An,
Z. H. An,
J. Z. Bai,
R. Baldini,
Y. Ban,
J. Becker,
N. Berger, [......],
S. H. Zhu,
X. L. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
J. Zhuang,
B. S. Zou,
J. H. Zou,
J. X. Zuo,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: Using samples of 2.25×108 J/ψ events and 1.06×108 ψ′ events collected with the BES III detector, we study the f0(980)→a00(980) and a00(980)→f0(980) transitions in the processes J/ψ→ϕf0(980)→ϕa00(980) and χc1→π0a00(980)→π0f0(980), respectively. Evidence for f0(980)→a00(980) is found with a significance of 3.4σ, while in the case of a00(980)→f0(980) transition, the significance is 1.9σ. Measurements and upper limits of both branching ratios and mixing intensities are determined.
Phys. Rev. D. 02/2011; 83(3).
-
M Ablikim,
M N Achasov,
L An,
Q An,
Z H An,
J Z Bai,
R Baldini,
Y Ban,
J Becker,
N Berger, [......],
S H Zhu,
X L Zhu,
X W Zhu,
Y S Zhu,
Z A Zhu,
J Zhuang,
B S Zou,
J H Zou,
J X Zuo,
P Zweber
[show abstract]
[hide abstract]
ABSTRACT: With a sample of (225.2±2.8)×10(6) J/ψ events registered in the BESIII detector, J/ψ→γπ(+)π(-)η(') is studied using two η(') decay modes: η(')→π(+)π(-)η and η(')→γρ(0). The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20σ. In addition, in the π(+)π(-)η(') invariant-mass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2σ and 6.4σ, respectively. For the X(1835), the angular distribution of the radiative photon is consistent with expectations for a pseudoscalar.
Physical Review Letters 02/2011; 106(7):072002. · 7.37 Impact Factor
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M. Ablikim,
M. N. Achasov,
L. An,
Q. An,
Z. H. An,
J. Z. Bai,
R. Baldini,
Y. Ban,
J. Becker,
N. Berger, [......],
S. H. Zhu,
X. L. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
J. Zhuang,
B. S. Zou,
J. H. Zou,
J. X. Zuo,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: We present a study of the P-wave spin-triplet charmonium χcJ decays (J=0, 1, 2) into π0π0π0π0. The analysis is based on 106×106 ψ′ decays recorded with the BESIII detector at the BEPCII electron positron collider. The decay into the π0π0π0π0 hadronic final state is observed for the first time. We measure the branching fractions B(χc0→π0π0π0π0)=(3.34±0.06±0.44)×10-3, B(χc1→π0π0π0π0)=(0.57±0.03±0.08)×10-3, and B(χc2→π0π0π0π0)=(1.21±0.05±0.16)×10-3, where the uncertainties are statistical and systematical, respectively.
Phys. Rev. D. 01/2011; 83(1).
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M. Ablikim,
M. N. Achasov,
L. An,
Q. An,
Z. H. An,
J. Z. Bai,
R. Baldini,
Y. Ban,
J. Becker,
N. Berger, [......],
S. H. Zhu,
X. L. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
J. Zhuang,
B. S. Zou,
J. H. Zou,
J. X. Zuo,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: The Dalitz plot of η′→ηπ+π- decay is studied using (225.2±2.8)×106 J/ψ events collected with the BESIII detector at the BEPCII e+e- collider. With the largest sample of η′ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/ψ→γη′ is determined to be (4.84±0.03±0.24)×10-3, where the first error is statistical and the second systematic.
Phys. Rev. D. 01/2011; 83(1).
-
M Ablikim,
M N Achasov,
L An,
Q An,
Z H An,
J Z Bai,
R Baldini,
Y Ban,
J Becker,
N Berger, [......],
S H Zhu,
X L Zhu,
X W Zhu,
Y S Zhu,
Z A Zhu,
J Zhuang,
B S Zou,
J H Zou,
J X Zuo,
P Zweber
[show abstract]
[hide abstract]
ABSTRACT: The decays ψ'→γπ(0), γη and γη' are studied using data collected with the BESIII detector at the BEPCII e(+)e(-) collider. The processes ψ'→γπ(0) and ψ'→γη are observed for the first time with signal significances of 4.6σ and 4.3σ, respectively. The branching fractions are determined to be B(ψ'→γπ(0))=(1.58±0.40±0.13)×10(-6), B(ψ'→γη)=(1.38±0.48±0.09)×10(-6), and B(ψ'→γη')=(126±3±8)×10(-6), where the first errors are statistical and the second ones systematic.
Physical Review Letters 12/2010; 105(26):261801. · 7.37 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Previous studies have demonstrated that merlin acts as a tumor suppressor by blocking Ras-mediated signaling. However, the mechanism by which merlin controls cell proliferation has remained obscure. Here we show that merlin deficient tumors exhibited loss of p21, concomitant with elevated CDKs/cyclin D1 levels in sporadic vestibular schwannomas (VS) from clinic patients. Likewise, silencing of merlin gene expression in the cell lines resulted in down-regulation of p21. Furthermore, we find that merlin-enhanced p21 protein stability, rather than increased RNA accumulation, was responsible for the elevated p21 levels. Interestingly, p21 was required to maintain merlin levels and the inhibitory effect of merlin on Ras signaling was partially overridden by knockdown of p21. Consistent with the observation that over-expression of merlin arrested cell growth at G1-phase, the current study indicates that merlin exerts its antiproliferative effect, at least in part, by maintaining p21 expression, and loss of p21 is a prominent feature of merlin deficient schwannomas.
Neuroscience 09/2010; 170(1):149-55. · 3.38 Impact Factor
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M Ablikim,
M N Achasov,
L An,
Q An,
Z H An,
J Z Bai,
Y Ban,
N Berger,
J M Bian,
I Boyko, [......],
K J Zhu,
Q M Zhu,
X W Zhu,
Y S Zhu,
Z A Zhu,
J Zhuang,
B S Zou,
J H Zou,
J X Zuo,
P Zweber
[show abstract]
[hide abstract]
ABSTRACT: We present measurements of the charmonium state h(c)(1P(1)) made with 106x10(6) psi' events collected by BESIII at BEPCII. Clear signals are observed for psi'-->pi0 h(c) with and without the subsequent radiative decay h(c)-->gamma eta(c). First measurements of the absolute branching ratios B(psi'-->pi0 h(c)) = (8.4+/-1.3+/-1.0) x 10(-4) and B(h(c)-->gamma eta(c)) = (54.3+/-6.7+/-5.2)% are presented. A statistics-limited determination of the previously unmeasured h(c) width leads to an upper limit Gamma(h(c))<1.44 MeV (90% confidence). Measurements of M(h(c)) = 3525.40+/-0.13+/-0.18 MeV/c2 and B(psi'-->pi0 h(c)) x B(h(c)-->gamma eta(c)) = (4.58+/-0.40+/-0.50) x 10(-4) are consistent with previous results.
Physical Review Letters 04/2010; 104(13):132002. · 7.37 Impact Factor
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M. Ablikim,
M. N. Achasov,
L. An,
Q. An,
Z. H. An,
J. Z. Bai,
Y. Ban,
N. Berger,
J. M. Bian,
I. Boyko, [......],
K. J. Zhu,
Q. M. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
J. Zhuang,
B. S. Zou,
J. H. Zou,
J. X. Zuo,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: The decay channel Ψ' → π+π-
J/Ψ(J/Ψ → γpbar p) is studied using a sample of 1.06
× 108 Ψ' events collected by the BESIII experiment
at BEPCII. A strong enhancement at threshold is observed in the pbar p
invariant mass spectrum. The enhancement can be fitted with an S-wave
Breit-Wigner resonance function with a resulting peak mass of M =
1861+6-13
(stat)+7-26 (syst)
MeV/c2 and a narrow width that is Γ < 38
MeV/c2 at the 90% confidence level. These results are
consistent with published BESII results. These mass and width values do
not match with well established mesons.
Chinese Physics C. 03/2010; 34:421-426.
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M. Ablikim,
M. N. Achasov,
L. An,
Q. An,
Z. H. An,
J. Z. Bai,
Y. Ban,
N. Berger,
J. M. Bian,
I. Boyko, [......],
K. J. Zhu,
Q. M. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
J. Zhuang,
B. S. Zou,
J. H. Zou,
J. X. Zuo,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: Using a sample of 1.06×108 ψ′ decays collected by the BESIII detector, χc0 and χc2 decays into π0π0 and ηη are studied. The branching fraction results are Br(χc0→π0π0)=(3.23±0.03±0.23±0.14)×10-3, Br(χc2→π0π0)=(8.8±0.2±0.6±0.4)×10-4, Br(χc0→ηη)=(3.44±0.10±0.24±0.2)×10-3, and Br(χc2→ηη)=(6.5±0.4±0.5±0.3)×10-4, where the uncertainties are statistical, systematic due to this measurement, and systematic due to the branching fractions of ψ′→γχcJ. The results provide information on the decay mechanism of χc states into pseudoscalars.
Phys. Rev. D. 03/2010; 81(5).
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M. Ablikim,
J. Z. Bai,
Y. Bai,
Y. Ban,
X. Cai,
H. F. Chen,
H. S. Chen,
H. X. Chen,
J. C. Chen,
Jin Chen, [......],
L. Zhou,
K. J. Zhu,
Q. M. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
Z. L. Zhu,
B. A. Zhuang,
B. S. Zou,
BES Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of
J/ψ→ηK*0K¯ decay in a J/ψ
sample of 58 million events collected with the BESII detector. The
branching fraction is determined to be
(1.15±0.13±0.22)×10-3. The selected
signal event sample is further used to search for the Y(2175) resonance
through J/ψ→ηY(2175),
Y(2175)→K*0K¯. No evidence of a signal
is seen. An upper limit of
Br(J/ψ→ηY(2175))ṡBr(Y(2175)→K*0K¯)<2.52×10-4
is set at the 90% confidence level.
Physics Letters B 01/2010; 685:27-32. · 3.95 Impact Factor
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M. Ablikim,
J. Z. Bai,
Y. Bai,
Y. Ban,
X. Cai,
H. F. Chen,
H. S. Chen,
H. X. Chen,
J. C. Chen,
Jin Chen, [......],
B. Zhong,
L. Zhou,
K. J. Zhu,
Q. M. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
Z. L. Zhu,
B. A. Zhuang,
B. S. Zou
[show abstract]
[hide abstract]
ABSTRACT: Based on a sample of 58×106J/ψ decays collected with the BESII detector at the BEPC, the Λ̅ decay parameter αΛ̅ for Λ̅ →p̅ π+ is measured using about 9000 J/ψ→ΛΛ̅ →pp̅ π+π- decays. A fit to the joint angular distributions yields αΛ̅ (Λ̅ →p̅ π+)=-0.755±0.083±0.063, where the first error is statistical, and the second systematic.
Phys. Rev. D. 01/2010; 81(1).
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The 18th International Conference on Geoinformatics: GIScience in Change, Geoinformatics 2010, Peking University, Beijing, China, June, 18-20, 2010; 01/2010
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[show abstract]
[hide abstract]
ABSTRACT: ZnO thin films were grown on Si (1 1 1) substrates by pulsed laser deposition (PLD) at various laser repetition frequency in order to investigate the structural and optical properties of the films. The optical properties of the films were studied by photoluminescence spectra using a 325 nm He-Cd laser. The structural properties of the films were investigated by XRD measurement. The results suggest that films grown at 5 Hz have excellent UV emission and high-quality crystallinity. Laser repetition frequency can affect the structural and optical properties obviously. In addition, the thickness of all samples is about 200 nm and is not as expected that the film thickness was in direct proportion to laser repetition frequency. The authors think that one laser pulse is not corresponding to one growth instantaneousness. There is a growth ambience containing essential components and partial pressure in the work cavity. (C) 2010 Elsevier Ltd. All rights reserved.
Vacuum. 01/2010; 85(3):397-399.
-
M. Ablikim,
J. Z. Bai,
Y. Bai,
Y. Ban,
X. Cai,
H. F. Chen,
H. S. Chen,
H. X. Chen,
J. C. Chen,
Jin Chen, [......],
L. Zhou,
K. J. Zhu,
Q. M. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
Z. L. Zhu,
B. A. Zhuang,
B. S. Zou,
BES Collaboration
[show abstract]
[hide abstract]
ABSTRACT: Based on a sample of 58×106J/ψ decays collected
with the BESII detector at the BEPC, the Λ¯ decay parameter
αΛ¯ for
Λ¯→p¯π+ is measured using about 9000
J/ψ→ΛΛ¯→pp¯π+π-
decays. A fit to the joint angular distributions yields
αΛ¯(Λ¯→p¯π+)=-0.755±0.083±0.063,
where the first error is statistical, and the second systematic.
Physical review D: Particles and fields 12/2009; 81(1):12003.
-
M. Ablikim,
J. Z. Bai,
Y. Bai,
Y. Ban,
X. Cai,
H. F. Chen,
H. S. Chen,
H. X. Chen,
J. C. Chen,
Jin Chen, [......],
B. Zhong,
L. Zhou,
K. J. Zhu,
Q. M. Zhu,
X. W. Zhu,
Y. S. Zhu,
Z. A. Zhu,
Z. L. Zhu,
B. A. Zhuang,
B. S. Zou
[show abstract]
[hide abstract]
ABSTRACT: Using a sample of 58 million J/ψ events collected with the BESII detector at the BEPC, more than 100 000 J/ψ→pp̅ π0 events are selected, and a detailed partial wave analysis is performed. The branching fraction is determined to be Br(J/ψ→pp̅ π0)=(1.33±0.02±0.11)×10-3. A long-sought missing N*, first observed in J/ψ→pn̅ π-, is observed in this decay too, with mass and width of 2040-4+3±25 MeV/c2 and 230-8+8±52 MeV/c2, respectively. Its spin-parity favors 3/2+. The masses, widths, and spin parities of other N* states are obtained as well.
Phys. Rev. D. 09/2009; 80(5).
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[show abstract]
[hide abstract]
ABSTRACT: Using first-principles calculations, we investigate the electronic structure of CoSb3 compound by considering the spin–orbit interaction. Within the framework of Boltzmann theory, the transport coefficient (power factor) is evaluated as a function of chemical potential assuming a rigid-band picture and constant relaxation time. It is found that appropriate n-type doping in the compound may be better than p-type doping to enhance the power factor. Our theoretical calculations give a plausible guide on how to optimize the thermoelectric performance of this compound, and the upper limit of its ZT value is estimated.
Journal of Physics D Applied Physics 05/2009; 42(11):115403. · 2.54 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The electronic structures of half-Heusler compounds TiNiSn and TiCoSb are investigated by using the full-potential linearized augmented plane-wave method. When the spin-orbital coupling is included in the calculations, there is only a slight change in the energy band structures. The transport coefficients (Seebeck coefficient, electrical conductivity, and power factor) are then calculated within the Boltzmann theory, and further evaluated as a function of chemical potential assuming a rigid band picture. Our calculations offer a valuable insight on how to improve the thermoelectric performance of these two compounds.
Journal of Applied Physics 02/2009; · 2.17 Impact Factor