1,540 research outputs found

    Observation of χc1\chi_{c1} decays into vector meson pairs ϕϕ\phi\phi, ωω\omega\omega, and ωϕ\omega\phi

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    Decays of χc1\chi_{c1} to vector meson pairs ϕϕ\phi\phi, ωω\omega\omega and ωϕ\omega\phi are observed for the first time using (106±4)×106(106\pm4)\times 10^6 \psip events accumulated at the BESIII detector at the BEPCII e+ee^+e^- collider. The branching fractions are measured to be (4.4±0.3±0.5)×104(4.4\pm 0.3\pm 0.5)\times 10^{-4}, (6.0±0.3±0.7)×104(6.0\pm 0.3\pm 0.7)\times 10^{-4}, and (2.2±0.6±0.2)×105(2.2\pm 0.6\pm 0.2)\times 10^{-5}, for χc1ϕϕ\chi_{c1}\to \phi\phi, ωω\omega\omega, and ωϕ\omega\phi, respectively. The observation of χc1\chi_{c1} decays into a pair of vector mesons ϕϕ\phi\phi, ωω\omega\omega and ωϕ\omega\phi indicates that the hadron helicity selection rule is significantly violated in χcJ\chi_{cJ} decays. In addition, the measurement of χcJωϕ\chi_{cJ}\to \omega\phi gives the rate of doubly OZI-suppressed decay. Branching fractions for χc0\chi_{c0} and χc2\chi_{c2} decays into other vector meson pairs are also measured with improved precision.Comment: 4 pages, 2 figure

    Precision measurement of CPCP violation in Bs0J/ψK+KB_s^0 \to J/\psi K^+K^- decays

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    The time-dependent CPCP asymmetry in Bs0J/ψK+KB_s^0 \to J/\psi K^+K^- decays is measured using pppp collision data, corresponding to an integrated luminosity of 3.03.0fb1^{-1}, collected with the LHCb detector at centre-of-mass energies of 77 and 88TeV. In a sample of 96 000 Bs0J/ψK+KB_s^0 \to J/\psi K^+K^- decays, the CPCP-violating phase ϕs\phi_s is measured, as well as the decay widths ΓL\Gamma_{L} and ΓH\Gamma_{H} of the light and heavy mass eigenstates of the Bs0Bˉs0B_s^0-\bar{B}_s^0 system. The values obtained are ϕs=0.058±0.049±0.006\phi_s = -0.058 \pm 0.049 \pm 0.006 rad, Γs(ΓL+ΓH)/2=0.6603±0.0027±0.0015\Gamma_s \equiv (\Gamma_{L}+\Gamma_{H})/2 = 0.6603 \pm 0.0027 \pm 0.0015ps1^{-1}, andΔΓsΓLΓH=0.0805±0.0091±0.0032\Delta\Gamma_s \equiv \Gamma_{L} - \Gamma_{H} = 0.0805 \pm 0.0091 \pm 0.0032ps1^{-1}, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of those quantities to date. A combined analysis with Bs0J/ψπ+πB_s^{0} \to J/\psi \pi^+\pi^- decays gives ϕs=0.010±0.039\phi_s = -0.010 \pm 0.039 rad. All measurements are in agreement with the Standard Model predictions. For the first time the phase ϕs\phi_s is measured independently for each polarisation state of the K+KK^+K^- system and shows no evidence for polarisation dependence.Comment: 6 figure

    Study of J/ψ production and cold nuclear matter effects in pPb collisions at sNN \sqrt{{{s_{NN }}}} = 5 TeV

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    The production of J/psi mesons with rapidity 1.5 < y < 4.0 or 5.0 < y < 2.5 and transverse momentum PT < 14 GeV/e is studied with the LHCb detector in proton-lead collisions at a nucleon-nucleon centre-of-mass energy, root(NN)-N-S = 5 TeV. The J/psi mesons are reconstructed using the dimuon decay mode. The analysis is based on a data sample corresponding to an integrated luminosity of about 1.6 nb-1. For the first time the nuclear modification factor and forward-backward production ratio are determined separately for prompt J/psi mesons and J/psi from b-hadron decays. Clear suppression of prompt J/psi production with respect to proton-proton collisions at large rapidity is observed, while the production of J/psi from b-hadron decays is less suppressed. These results show good agreement with available theoretical predictions. The measurement shows that cold nuclear matter effects are important for interpretations of the related quark-gluon plasma signatures in heavy-ion collisions

    Doxorubicin-mediated radiosensitivity in multicellular spheroids from a lung cancer cell line is enhanced by composite micelle encapsulation

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    BACKGROUND: The purpose of this study is to evaluate the efficacy of composite doxorubicinloaded micelles for enhancing doxorubicin radiosensitivity in multicellular spheroids from a non-small cell lung cancer cell line. METHODS: A novel composite doxorubicin-loaded micelle consisting of polyethylene glycolpolycaprolactone/Pluronic P105 was developed, and carrier-mediated doxorubicin accumulation and release from multicellular spheroids was evaluated. We used confocal laser scanning microscopy and flow cytometry to study the accumulation and efflux of doxorubicin from A549 multicellular spheroids. Doxorubicin radiosensitization and the combined effects of irradiation and doxorubicin on cell migration and proliferation were compared for the different doxorubicin delivery systems. RESULTS: Confocal laser scanning microscopy and quantitative flow cytometry studies both verified that, for equivalent doxorubicin concentrations, composite doxorubicin-loaded micelles significantly enhanced cellular doxorubicin accumulation and inhibited doxorubicin release. Colony-forming assays demonstrated that composite doxorubicin-loaded micelles are radiosensitive, as shown by significantly reduced survival of cells treated by radiation + composite micelles compared with those treated with radiation + free doxorubicin or radiation alone. The multicellular spheroid migration area and growth ability verified higher radiosensitivity for the composite micelles loaded with doxorubicin than for free doxorubicin. CONCLUSION: Our composite doxorubicin-loaded micelle was demonstrated to have radiosensitization. Doxorubicin loading in the composite micelles significantly increased its cellular uptake, improved drug retention, and enhanced its antitumor effect relative to free doxorubicin, thereby providing a novel approach for treatment of cancer

    Childhood gene-environment interactions and age-dependent effects of genetic variants associated with refractive error and myopia : The CREAM Consortium

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    Myopia, currently at epidemic levels in East Asia, is a leading cause of untreatable visual impairment. Genome-wide association studies (GWAS) in adults have identified 39 loci associated with refractive error and myopia. Here, the age-of-onset of association between genetic variants at these 39 loci and refractive error was investigated in 5200 children assessed longitudinally across ages 7-15 years, along with gene-environment interactions involving the major environmental risk-factors, nearwork and time outdoors. Specific variants could be categorized as showing evidence of: (a) early-onset effects remaining stable through childhood, (b) early-onset effects that progressed further with increasing age, or (c) onset later in childhood (N = 10, 5 and 11 variants, respectively). A genetic risk score (GRS) for all 39 variants explained 0.6% (P = 6.6E-08) and 2.3% (P = 6.9E-21) of the variance in refractive error at ages 7 and 15, respectively, supporting increased effects from these genetic variants at older ages. Replication in multi-ancestry samples (combined N = 5599) yielded evidence of childhood onset for 6 of 12 variants present in both Asians and Europeans. There was no indication that variant or GRS effects altered depending on time outdoors, however 5 variants showed nominal evidence of interactions with nearwork (top variant, rs7829127 in ZMAT4; P = 6.3E-04).Peer reviewe

    Observation of D+KS0a0(980)+D^{+}\to K_{S}^{0}a_{0}(980)^{+} in the amplitude analysis of D+KS0π+ηD^{+} \to K_{S}^{0}\pi^+\eta

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    We perform for the first time an amplitude analysis of the decay D+KS0π+ηD^{+}\to K_{S}^{0}\pi^+\eta and report the observation of the decay D+KS0a0(980)+D^{+}\to K_{S}^{0}a_{0}(980)^{+} using 2.93 fb1^{-1} of e+ee^+e^- collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector. As the only W-annihilation free decay among DD to a0(980)a_{0}(980)-pseudoscalar, D+KS0a0(980)+D^{+}\to K_{S}^{0}a_{0}(980)^{+} is the ideal decay to extract the contributions of the external and internal WW-emission amplitudes involving a0(980)a_{0}(980) and study the final-state interactions. The absolute branching fraction of D+KS0π+ηD^{+}\to K_{S}^{0}\pi^+\eta is measured to be (1.27±0.04stat.±0.03syst.)%(1.27\pm0.04_{\rm stat.}\pm0.03_{\rm syst.})\%. The product branching fractions of D+KS0a0(980)+D^{+}\to K_{S}^{0}a_{0}(980)^{+} with a0(980)+π+ηa_{0}(980)^{+}\to \pi^+\eta and D+π+K0(1430)0D^{+}\to \pi^+ K_0^*(1430)^0 with K0(1430)0KS0ηK_0^*(1430)^0\to K_{S}^{0}\eta are measured to be (1.33±0.05stat.±0.04syst.)%(1.33\pm0.05_{\rm stat.}\pm0.04_{\rm syst.})\% and (0.14±0.03stat.±0.01syst.)%(0.14\pm0.03_{\rm stat.}\pm0.01_{\rm syst.})\%, respectively

    Study of the doubly Cabibbo-suppressed decays Ds+K+K+πD^+_s\to K^+K^+\pi^- and Ds+K+K+ππ0D^+_s\to K^+K^+\pi^-\pi^0

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    Based on 7.33 fb1^{-1} of e+ee^+e^- collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, the experimental studies of the doubly Cabibbo-suppressed decays Ds+K+K+πD^+_s\to K^+K^+\pi^- and Ds+K+K+ππ0D^+_s\to K^+K^+\pi^-\pi^0 are reported. We determine the absolute branching fraction of Ds+K+K+πD^+_s\to K^+K^+\pi^- to be (1.230.25+0.28(stat)±0.06(syst){1.23^{+0.28}_{-0.25}}({\rm stat})\pm0.06({\rm syst})) ×104\times 10^{-4}. No significant signal of Ds+K+K+ππ0D^+_s\to K^+K^+\pi^-\pi^0 is observed and the upper limit on its decay branching fraction at 90\% confidence level is set to be 1.7×1041.7\times10^{-4}.Comment: 10 pages, 4 figures, 4 table

    Amplitude analysis and branching fraction measurement of the decay Ds+π+π0π0D_{s}^{+} \to \pi^{+}\pi^{0}\pi^{0}

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    Using a data set corresponding to an integrated luminosity of 6.32~fb1\rm fb^{-1} recorded by the BESIII detector at center-of-mass energies between 4.178 and 4.226~GeV, an amplitude analysis of the decay Ds+π+π0π0D_{s}^{+} \to \pi^{+}\pi^{0}\pi^{0} is performed, and the relative fractions and phases of different intermediate processes are determined. The absolute branching fraction of the decay Ds+π+π0π0D_{s}^{+} \to \pi^{+}\pi^{0}\pi^{0} is measured to be (0.50±0.04stat±0.02syst)%(0.50\pm 0.04_{\text{stat}}\pm 0.02_{\text{syst}})\%. The absolute branching fraction of the intermediate process Ds+f0(980)π+,f0(980)π0π0D_{s}^{+} \to f_0(980)\pi^{+}, f_0(980)\to\pi^{0}\pi^{0} is determined to be (0.21±0.03stat±0.03syst)%(0.21\pm 0.03_{\text{stat}}\pm 0.03_{\text{syst}})\%

    Precision measurements of branching fractions for ψπ0Jψ \psi'\to\pi^0 J\psi and ηJψ\eta J\psi

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    We present a precision study of the \psip\to\pi^0 J/\psi and ηJ/ψ\eta J/\psi decay modes. The measurements are obtained using 106×106106\times10^6 ψ\psi' events accumulated with the BESIII detector at the BEPCII \ee collider operating at a center-of-mass energy corresponding to the \psip mass. We obtain \mathcal{B}(\psip\to\pi^0 J/\psi)=(1.26\pm0.02{\rm (stat.)}\pm0.03{\rm (syst.)})\times 10^{-3} and \mathcal{B}(\psip\to\eta J/\psi)=(33.75\pm0.17{\rm (stat.)}\pm0.86{\rm (syst.)})\times 10^{-3}. The branching fraction ratio R=\frac{\mathcal{B}(\psip\to\pi^0 J/\psi)}{\mathcal{B}(\psip\to\eta J/\psi)} is determined to be (3.74±0.06(stat.)±0.04(syst.))×102(3.74\pm0.06 {\rm(stat.)}\pm0.04 {\rm(syst.)})\times 10^{-2}. The precision of these measurements of \mathcal{B}(\psip\to\pi^{0} J/\psi) and RR represent a significant improvement over previously published values.Comment: four figures, 12 page

    Precise Measurement of the e^{+}e^{-}→D_{s}^{*+}D_{s}^{*-} Cross Sections at Center-of-Mass Energies from Threshold to 4.95 GeV

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    The process e^{+}e^{-}→D_{s}^{*+}D_{s}^{*-} is studied with a semi-inclusive method using data samples at center-of-mass energies from threshold to 4.95&nbsp;GeV collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross sections of the process are measured for the first time with high precision in this energy region. Two resonance structures are observed in the energy-dependent cross sections around 4.2 and 4.4&nbsp;GeV. By fitting the cross sections with a coherent sum of three Breit-Wigner amplitudes and one phase-space amplitude, the two significant structures are assigned masses of (4186.8±8.7±30) and (4414.6±3.4±6.1)  MeV/c^{2}, widths of (55±15±53) and (122.5±7.5±8.1)  MeV, where the first errors are statistical and the second ones are systematic. The inclusion of a third Breit-Wigner amplitude is necessary to describe a structure around 4.79&nbsp;GeV
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