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Liu, C.

Publications and source records attributed to Liu, C..

At least 199 records · Page 11
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DOE OSTI2014

Evidence for semileptonic B - → p p ¯ ℓ - ν ¯ ℓ decays

Evidence for the semileptonic baryonic decay B - → p p ¯ ℓ - ν ¯ ℓ ( ℓ = e , μ ), based on a data sample of 772 million B B ¯ pairs collected at the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy electron-positron collider is collected. A neural-network based hadronic B -meson tagging method is used in this study. The branching fraction of B - → p p ¯ ℓ - ν ¯ ℓ is measured to be ( 5. 8 - 2.1 + 2.4 (stat) ± 0.9 (syst) ) × 10 - 6 with a significance of 3.2 σ , where lepton universality is assumed. We also estimate the corresponding upper limit: B ( B - → p p ¯ ℓ - ν ¯ ℓ ) < 9.6 × 10 - 6 at the 90% confidence level. This measurement helps constrain the baryonic transition form factor in B decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Measurement of the decays B s 0 → J / ψ Φ ( 1020 ) , B s 0 → J / ψ f 2 ' ( 1525 ) and B s 0 → J / ψ K + K – at Belle

In this paper, we report a measurement of the branching fraction of the decay B s 0 → J / ψ Φ ( 1020 ) , evidence and a branching fraction measurement for B s 0 → J / ψ f 2 ' ( 1525 ) , and the determination of the total B s 0 → J / ψ K + K – branching fraction, including the resonant and non-resonant contributions to the K+K– channel. We also determine the S-wave contribution within the Φ(1020) mass region. The absolute branching fractions are B[ B s 0 → J / ψ Φ ( 1020 ) ] = (1.25 ± 0.07(stat) ± 0.08(syst) ± 0.22(fs)) × 10 –3 , B[ B s 0 → J / ψ f 2 ' ( 1525 ) ] = (0.26 ± 0.06(stat) ± 0.02(syst) ± 0.05(fs)) × 10 –3 and B[ B s 0 → J / ψ K + K – ] = (1.01 ± 0.09(stat) ± 0.10(syst) ± 0.18(fs)) × 10 –3 , where the last systematic error is due to the branching fraction of bb¯→ B$^{(*)}_{s}$B$^{(*)}_{s}$. The branching fraction ratio is found to be B[ B s 0 → J / ψ f 2 ' ( 1525 ) ]/B[ B s 0 → J / ψ Φ ( 1020 ) ] = (21.5 ± 4.9(stat) ± 2.6(syst)). All results are based on a 121.4 fb –1 data sample collected at the Υ(5S) resonance by the Belle experiment at the KEKB asymmetric-energy e + e – collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

High-statistics study of $K^0_S$ pair production in two-photon collisions

We report a high-statistics measurement of the differential cross section of the process $γγ → K^0_S K^0_S$ in the range 1.05 GeV $≤ W ≤$ 4.00 GeV, where $W$ is the center-of-mass energy of the colliding photons, using 972 fb -1 of data collected with the Belle detector at the $KEKB$ asymmetric-energy $e^+ e^-$ collider operated at and near the $Υ$-resonance region. The differential cross section is fitted by parameterized S-, D 0 - , D 2 - , G 0 - and G 2 -wave amplitudes. In the D 2 wave, the $f_2$(1270), $a_2$(1320) and $f^\prime_2$(1525) are dominant and a resonance, the $f_2$(2200), is also present. The $f_0$(1710) and possibly the $f_0$(2500) are seen in the $S$ wave. The mass, total width and product of the two-photon partial decay width and decay branching fraction to the $K\overline{K}$ state $Γ_{γγ}(ΒK\overline{K})$ are extracted for the $f^\prime_2$(1525), $f_0$(1710), $f_2$(2200) and $f_0$(2500). The destructive interference between the $f_2$(1270) and $a_2$(1320) is confirmed by measuring their relative phase. The parameters of the charmonium states $Χ_{c0}$ and $Χ_{c2}$ are updated. Possible contributions from the $Χ_{c0}(2P)$ and $Χ_{c2}(2P)$ states are discussed. A new upper limit for the branching fraction of the $P-$ and $CP-$violating decay channel $η_c → K^0_S K^0_S$ is reported. The detailed behavior of the cross section is updated and compared with $QCD$-based calculations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Measurement of the C P violation parameters in B 0 → π + π - decays

We present a measurement of the charge-parity ( C P ) violating parameters in B 0 → π + π - decays. The results are obtained from the final data sample containing 772 × 10 6 B B ¯ pairs collected at the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider. We obtain the C P violation parameters A C P ( B 0 → π + π - ) = + 0.33 ± 0.06 ( stat ) ± 0.03 ( syst ) , S C P ( B 0 → π + π - ) = - 0.64 ± 0.08 ( stat ) ± 0.03 ( syst ) , where A C P and S C P represent the direct and mixing-induced C P asymmetries in B 0 → π + π - decays, respectively. Using an isospin analysis including results from other Belle measurements, we find 23.8 ° < Φ 2 < 66.8 ° is disfavored at the 1 σ level, where Φ 2 is one of the three interior angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle related to B u , d decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Experimental constraints on the spin and parity of the Z ( 4430 ) +

We perform a full amplitude analysis of B 0 -> ψ' K + π - decays, with ψ' -> μ + μ - or e + e - , to constrain the spin and parity of the Z(4430) - . The J P =1 + hypothesis is favored over the 0 - , 1 - , 2 - and 2 + hypotheses at the levels of 3.4 σ, 3.7 σ, 4.7 σ and 5.1 σ, respectively. The analysis is based on a 711 fb -1 data sample that contains 772x10 6 $B$$\bar{B}$ pairs, collected at the Y(4S) resonance by the Belle detector at the asymmetric-energy e + e - collider KEKB.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

First observation of Cabibbo-suppressed Ξ c 0 decays

We report the first observation of the Cabibbo-suppressed decays $\Xi^0_c$→$\Xi^-K^+$, $\Xi_c^0\to\Lambda K^+ K^-$ and $\Xi^0_c→ΛΦ$, using a data sample of 711 fb -1 collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We measure the ratios of branching fractions to be $\frac{{\cal B}(\Xi_c^0\to \Xi^- K^+)}{{\cal B}(\Xi^0_c\to\Xi^-\pi^+)}=(2.75\pm 0.51\pm 0.25)\times 10^{-2}$, $\frac{{\cal B}(\Xi_c^0\to\Lambda K^+ K^-)}{{\cal B}(\Xi_c^0\rightarrow\Xi^- \pi^+)}=(2.86\pm 0.61\pm 0.24)\times 10^{-2}$ and $\frac{{\cal B}(\Xi_c^0\to \Lambda\phi)}{{\cal B}(\Xi^0_c\to\Xi^-\pi^+)}=(3.43\pm 0.58\pm 0.32)\times 10^{-2}$, where the first uncertainty is statistical and the second is systematic.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Measurement of the wrong-sign decay D 0 → K + π - π + π -

A measurement of the rate for the "wrong-sign" decay $D^0 → K^+ π^- π^+ π^-$ relative to that for the "right-sign" decay $D^0 → K^- π^+ π^+ π^-$ is presented. Using 791 fb -1 of data collected with the Belle detector, we obtain a branching fraction ratio of $R_{WS}$ = [0.324 ± 0.008 (stat) ± 0.007 (sys)]%. Multiplying this ratio by the world average value for the branching fraction $B(D^0 → K^- π^+ π^+ π^-)$ gives a branching fraction $B(D^0 → K^+ π^- π^+ π^-$) = (2.61 ± 0.06 $^{+0.09}_{-0.08}$) x 10 -4 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Measurement of exclusive Υ ( 1 S ) and Υ ( 2 S ) decays into vector-pseudoscalar final states

Using samples of 102 million $Υ(1S)$ and 158 million $Υ(2S)$ events collected with the Belle detector, we study exclusive hadronic decays of these two bottomonium resonances to $K^0_sK^+ \pi^-$ and charge-conjugate (c.c.) states, $π^+π^-π^0π^0$, and $π^+π^-π^0$, and to the two-body Vector-Pseudoscalar $(K^*(892)^0\bar{K}^0+c.c.$, $K^*(892)^-K^++c.c.$, $ωπ^0$, and $ρπ$) final states. For the first time, signals are observed in the modes $Υ(1S)$ → $K^0_sK^+\pi^- + c.c.$, $π^+π^-π^0π^0$, and $Υ(2S)$→$π^+π^-π^0π^0$, and evidence is found for the modes $Υ(1S)$→$π^+π^-π^0$, $K^*(892)^0\bar{K}^0+c.c.$, and $Υ(2S)$ → $K^0_sK^+\pi^- + c.c.$ Branching fractions are measured for all the processes, while 90% confidence level upper limits on the branching fractions are also set for the modes with a statistical significance of less than $3σ$. The ratios of the branching fractions of $Υ(2S)$ and $Υ(1S)$ decays into the same final state are used to test a perturbative QCD prediction for OZI-suppressed bottomonium decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗