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M. Ablikim

Publications and source records attributed to M. Ablikim.

At least 883 records · Page 49Linked to original sources
arXiv2006

Experimental study of $ψ(2S)$ decays to $\K^+ K^- π^+ π^- π^0$ final states

$K^+K^-π^+π^-π^0$ final states are studied using a sample of $14\times10^6$ $ψ(2S)$ decays collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Position Collider. The branching fractions of $ψ(2S)$ decays to $ K^+K^-π^+π^-π^0$, $ωK^+ K^-$, $ωf_0(1710)$, $ K^{\ast}(892)^0 K^- π^+π^0+c.c.$, $K^{\ast}(892)^{+} K^- π^+π^- +c.c.$, $K^{\ast}(892)^{+} K^- ρ^0+c.c.$ and $K^{\ast}(892)^0 K^-ρ^+ + c.c.$ are determined. The first two agree with previous measurements, and the last five are first measurements.

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arXiv2006

Measurement of chi_cJ Decays to 2(pi^+pi^-)ppbar Final States

Using chi_cJ -> 2(π^+π^-) ppbar decays from 14 \times 10^6 psi(2S) events accumulated by the BESII detector at the BEPC, the intermediate states Xi^+Xi^-, Lambda Lambdabar pi^+ pi^-, and K_SK_S p pbar are studied, and their branching ratios or upper limits are measured.

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arXiv2006

Evidence for kappa Meson Production in J/psi -> bar{K}^*(892)^0K^+pi^- Process

Based on 58 million BESII J/psi events, the bar{K}^*(892)^0K^+pi^- channel in K^+K^-pi^+pi^- is studied. A clear low mass enhancement in the invariant mass spectrum of K^+pi^- is observed. The low mass enhancement does not come from background of other J/psi decay channels, nor from phase space. Two independent partial wave analyses have been performed. Both analyses favor that the low mass enhancement is the kappa, an isospinor scalar resonant state. The average mass and width of the kappa in the two analyses are 878 +- 23^{+64}_{-55} MeV/c^2 and 499 +- 52^{+55}_{-87} MeV/c^2, respectively, corresponding to a pole at (841 +- 30^{+81}_{-73}) - i(309 +- 45^{+48}_{-72}) MeV/c^2.

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arXiv2005

Search for psi(3770)\raρπat the BESII detector at the Beijing Electron-Positron Collider

Non-$D\bar{D}$ decay $\psppto \rhopi$ is searched for using a data sample of $(17.3\pm 0.5) pb^{-1}$ taken at the center-of-mass energy of 3.773 GeV by the BESII detector at the BEPC. No $\rhopi$ signal is observed, and the upper limit of the cross section is measured to be $σ(\EETO \rhopi)<6.0 pb$ at 90% C. L. Considering the interference between the continuum amplitude and the $\pspp$ resonance amplitude, the branching fraction of $\pspp$ decays to $ρπ$ is determined to be $\BR(\pspp\raρπ)\in(6.0\times10^{-6}, 2.4\times10^{-3})$ at 90% C. L. This is in agreement with the prediction of the $S$- and $D$-wave mixing scheme of the charmonium states for solving the ``$\rhopi$ puzzle'' between $\jpsi$ and $\psp$ decays.

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arXiv2005

Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons

The branching fractions for the inclusive Cabibbo-favored ~K*0 and Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with the BES-II detector at the BEPC collider. The branching fractions for the decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 -> K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X) < 6.6%.

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arXiv2005

Search for eta_c decays into pi pi and K Bar K

Using 58 million $J/ψ$ events taken with the BESII detector, a search for $eta_{c}$ CP violating decays into $ππ$ and $\bar{K}K$ has been performed. No clear $eta_{c}$ is observed, and upper limits for $B(eta_{c}->ππ)$and $B(eta_{c}->\bar{K} K)$ are given at the 90% confidence level, $B(J/ψ->γη_{c})\times B(eta_{c}->π^{+}π^{-})<1.1\times 10^{-5}$ , $B(J/ψ->γη_{c})\times B(eta_{c}->π^{0}π^{0})<0.71\times 10^{-5}$, $B(J/ψ->γη_{c})\times B(eta_{c}->K^{+}K^{-})<0.96\times 10^{-5}$ and $B(J/ψ->γη_{c})\times B(eta_{c}->{K_{s}}^{0}{K_{s}}^{0})<0.53\times 10^{-5}$.

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arXiv2005

Measurement of the branching fractions for $J/ψ\toγπ^0$, $γη$ and $γη^{\prime}$

The decay modes $\jpsi\arγπ^0, γη$ and $γ\etap$ are analyzed using a data sample of 58 million $\jpsi$ decays collected with the BESII detector at BEPC. The branching fractions are determined to be: $Br(\jpsi\arγπ^0)=(3.13^{+0.65}_{-0.44})\times10^{-5}$, $Br(\jpsi\arγη)=(11.23\pm0.89)\times10^{-4}$, and $Br(\jpsi\arγ\etap)=(5.55\pm0.44)\times10^{-3}$, where the errors are combined statistical and systematic errors. The ratio of partial widths $Γ(\jpsi\arγ\etap)/Γ(\jpsi\arγη)$ is measured to be $4.94\pm0.40$, and the singlet-octet pseudoscalar mixing angle of $η-\etap$ system is determined to be $θ_{P}=(-22.08\pm0.81)^{\circ}$.

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arXiv2005

Partial Wave Analysis of $χ_{c0}\toπ^+π^-K^+K^-$

A partial wave analysis of $χ_{c0}\toπ^+π^-K^+K^-$ in $ψ(2S)\toγχ_{c0}$ decay is presented using a sample of 14 million $ψ(2S)$ events accumulated by the BES II detector. The data are fitted to the sum of relativistic covariant tensor amplitudes for intermediate resonant decay modes. From the fit, significant contributions to $χ_{c0}$ decays from the channels $f_0(980)f_0(980)$, $f_0(980)f_0(2200)$, $f_0(1370)f_0(1710)$, $K^*(892)^0\bar K^*(892)^0$, $K^*_0(1430)\bar K^*_0(1430)$, $K^*_0(1430)\bar K^*_2(1430) + c.c.$, and $K_1(1270)K$ are found. Flavor-SU(3)-violating $K_1(1270)-K_1(1400)$ asymmetry is observed. Values obtained for the masses and widths of the resonances $f_0(1710)$, $f_0(2200)$, $f_0(1370)$, and $K^*_0(1430)$ are presented.

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arXiv2005

First observations of $ψ(2S)$ and $χ_{cJ}(1P)$ decays to four-body final states $h^+h^- K^0_S K^0_S$

$χ_{c0}$, $χ_{c1}$, and $χ_{c2}$ decays to $π^+π^-K^0_SK^0_S$ and $K^+K^-K^0_SK^0_S$, as well as $ψ(2S)$ decay to $π^+π^-K^0_SK^0_S$ are presented. The branching fractions of these decay channels are determined using $14\times 10^6$ $ψ(2S)$ events collected at BESII/BEPC. The branching fractions of $χ_{c0},χ_{c2}\to K^0_SK^0_S$ are measured with improved statistical precision.

hep-ex↗
arXiv2005

Observation of a resonance X(1835) in J/ψ--> γπ^+ π^- η^{\prime}

The decay channel J/ψ--> γπ^+ π^- η^{\prime} is analyzed using a sample of 5.8\times 10^7 Jψevents collected with the BESII detector. A resonance, the X(1835), is observed in the π^+ π^- η^{\prime} invariant mass spectrum with a statistical significance of 7.7 σ. A fit with a Breit-Wigner function yields a mass M = 1833.7 \pm 6.1(stat) \pm 2.7(syst) MeV/c^2, a width Γ= 67.7 \pm 20.3(stat) \pm 7.7(syst) MeV/c^2 and a product branching fraction B(J/ψ--> γX) B(X --> π^+ π^- η^{\prime}) = (2.2 \pm 0.4(stat) \pm 0.4(syst)) \times 10^{-4}. The mass and width of the X(1835) are not compatible with any known meson resonance. Its properties are consistent with expectations for the state that produces the strong p\bar{p} mass threshold enhancement observed in the Jψ-->γp \bar{p} process at BESII.

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arXiv2005

Experimental study of \etac decays into vector-vector final states

Using 58 million J/ψevents accumulated with the BES II detector, branching fractions for the η_{c} ->VV decays, η_{c} -> ρρ, η_{c} -> K^{*}{\bar K}^{*}, η_{c} -> ωω, and η_{c} -> ϕϕ, are measured. The branching fractions are Br(η_{c} -> ρρ) = (1.25 \pm 0.37 \pm 0.51) \times 10^{-2}, Br(η_{c} -> \K^{*}{\bar K}^{*}) = (10.4 \pm 2.6\pm 4.3) \times 10^{-3}, Br(η_{c} -> ωω) < 6.3 \times 10^{-3} (90 % CL), and Br(η_{c} -> ϕϕ) = (2.5 \pm 0.5 \pm 0.9) \times 10^{-3}. The process η_{c} -> ωϕis also searched for, and the 90% CL upper limit Br(eta_{c} -> ωϕ) < 1.3 \times 10^{-3} is obtained for this process.

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arXiv2005

Obervation of χ_{cJ}--> omega omega decays

Decays of $χ_{c0,2}\ar\ww$ are observed for the first time using a sample of $14.0\times 10^6$ $ψ(2S)$ events collected with the BESII detector. The branching ratios are determined to be ${\cal B}(χ_{c0}\ar \ww)=(2.29\pm 0.58\pm 0.41)\times 10^{-3}$ and ${\cal B}(χ_{c2}\ar\ww)=(1.77\pm 0.47\pm 0.36)\times 10^{-3}$, where the first errors are statistical and the second systematic. The significances of the two signals are $4.4σ$ and $4.7σ$, respectively.

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arXiv2005

First Measurements of eta_c Decaying into K^+K^-2(pi^+pi^-) and 3(pi^+pi^-)

The decays of eta_c to K^+K^-2(pi^+pi^-) and 3(pi^+pi^-) are observed for the first time using a sample of 5.8X10^7 J/ψevents collected by the BESII detector. The product branching fractions are determined to be B(J/ψ-->gamma eta_c)*B(eta_c-->K^+K^-pi^+pi^-pi^+pi^-)=(1.21+-0.32+- 0.23)X10^{-4}$,B(J/ψ-->gamma eta_c)*B(eta_c-->K^{*0}\bar{K}^{*0}pi^+pi^-)= (1.29+-0.43+-0.32)X10^{-4}$, and (J/ψ-->gamma eta_c)* B(eta_c-->pi^+pi^-pi^+pi^-pi^+pi^-)= (2.59+-0.32+-0.48)X10^{-4}. The upper limit for eta_c-->phi pi^+pi^-pi^+pi^- is also obtained as B(J/ψ-->gamma eta_c)*B(eta_c--> phi pi^+pi^-pi^+pi^-)< 6.03 X10^{-5} at the 90% confidence level.

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arXiv2005

Observation of the decay $\psip\rar\kstark$

Using 14 million $ψ(2S)$ events collected with the BESII detector, branching fractions of $\psip\rar\kstarkpm$ and $\kstarknn$ are determined to be: $\calB(\psip\rar\kstarkpm)=(2.9^{+1.3}_{-1.7}\pm0.4)\times 10^{-5}$ and $\calB(\psip\rar\kstarknn)=(13.3^{+2.4}_{-2.7}\pm1.9)\times 10^{-5}$. The results confirm the violation of the "12%" rule for these two decay channels with higher precision. A large isospin violation between the charged and neutral modes is observed.

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arXiv2005

Precise measurement of spin-averaged chi_{cJ}(1P) mass using photon conversions in psi(2S) -> gamma chi_{cJ}

Using photon conversions to e^+e^- pairs, the energy spectrum of inclusive photons from psi(2S) radiative decays is measured by BESII at the Beijing Electron-Positron Collider. The chi_{cJ}(1P) states (J=0,1,2) are clearly observed with energy resolution between 2.3 to 3.8 MeV, and their masses and the spin-averaged chi_{cJ} mass are determined to be M_{chi_{c0}}=3414.21\pm 0.39 \pm 0.27, M_{chi_{c1}}=3510.30\pm 0.14\pm 0.16, M_{chi_{c2}}=3555.70\pm 0.59 \pm 0.39 and M(^3P_{cog})=3524.85\pm 0.32 \pm 0.30 MeV/c^2.

hep-ex↗
arXiv2005

Measurement of the branching fractions of psi(2S) -> 3(pi+pi-) and J/psi -> 2(pi+pi-)

Using data samples collected at sqrt(s) = 3.686GeV and 3.650GeV by the BESII detector at the BEPC, the branching fraction of psi(2S) -> 3(pi+pi-) is measured to be [4.83 +- 0.38(stat) +- 0.69(syst)] x 10^-4, and the relative branching fraction of J/psi -> 2(pi+pi-) to that of J/psi -> mu+mu- is measured to be [5.86 +- 0.19(stat) +- 0.39(syst)]% via psi(2S) -> (pi+pi-)J/psi, J/psi -> 2(pi+pi-). The electromagnetic form factor of 3(pi+pi-) is determined to be 0.21 +- 0.02 and 0.20 +- 0.01 at sqrt(s) = 3.686GeV and 3.650GeV, respectively.

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