189 research outputs found

    A multidisciplinary study on the spatial variability of the local stratigraphic conditions in partially saturated slopes for flow-like landslide prediction

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    Flow-like landslides, which occur mainly in shallow granular deposits resting on steep bedrock, represent a major natural hazard worldwide. The pore water pressure distribution and the soil water content directly affect the soil shear strength, thus controlling the triggering of these landslides. Criticalgeomorphological and topographical settings, together with peculiar stratigraphic and hydrogeological features, are commonly recognized as predisposing factors for flow-like landslides occurrence. Hence, investigating the spatial and temporal variability of hydraulic slope conditions is a fundamental activity that consists of identifying local geological factors and seasonal monitoring of the subsurface water regime. The present work proposes an integrated geological, geophysical and geotechnical approach to identify the spatial variability of the local stratigraphic setting and hydrogeological conditions in a partially saturated slope, in order to set up a procedure able to provide a prediction of the flow-like landslides occurrence atslope scale. The multidisciplinary study has been applied to a test site on Mt. Faito, in the Lattari Mts. (Southern Italy), where extensive geophysical, geological and geotechnical soil characterization and in situmonitoring data collected over two years are available

    Observation of the J/ψJ/\psi and ψ(3686)\psi(3686) decays into ηΣ+Σˉ\eta\Sigma^{+}\bar{\Sigma}^{-}

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    The decays J/ψηΣ+ΣˉJ/\psi\to\eta\Sigma^{+}\bar{\Sigma}{}^- and ψ(3686)ηΣ+Σˉ\psi(3686)\to\eta\Sigma^{+}\bar{\Sigma}{}^- are observed for the first time, using (10087±44)×106(10087 \pm 44)\times 10^{6} J/ψJ/\psi and (448.1±2.9)×106(448.1 \pm 2.9)\times 10^{6} ψ(3686)\psi(3686) events collected with the BESIII detector at the BEPCII collider. We determine the branching fractions of these two decays to be B(J/ψηΣ+Σˉ)=(6.34±0.21±0.37)×105{\cal B}(J/\psi\to\eta\Sigma^{+}\bar{\Sigma}{}^-)=(6.34 \pm 0.21 \pm 0.37)\times 10^{-5} and B(ψ(3686)ηΣ+Σˉ)=(9.59±2.37±0.61)×106{\cal B}(\psi(3686)\to\eta\Sigma^{+}\bar{\Sigma}{}^-)=(9.59 \pm 2.37 \pm 0.61)\times 10^{-6}, where the first uncertainties are statistical and the second are systematic. The ratio of these two branching fractions is determined to be B(ψ(3686)ηΣ+Σˉ)B(J/ψηΣ+Σˉ)=(15.1±3.8)%\frac{{\cal B}(\psi(3686)\to\eta\Sigma^{+}\bar{\Sigma}{}^-)}{{\cal B}(J/\psi\to\eta\Sigma^{+}\bar{\Sigma}{}^-)}=(15.1 \pm 3.8)\%, which is in agreement with the "12\% rule."Comment: 9 pages and 10 figure

    Measurement of the absolute branching fraction of the inclusive decay Ds+π+π+πXD_s^+\to \pi^+\pi^+\pi^- X

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    Using an e+ee^+ e^- collision data sample with a total integrated luminosity of 3.193.19 fb1^{-1} collected with the BESIII detector at a center-of-mass energy of 4.178 GeV, the branching fraction of the inclusive decay of the Ds+D_s^+ meson to final states including at least three charged pions is measured for the first time to be B(Ds+π+π+πX)=(32.81±0.35stat±0.82syst)%{\cal B}(D_s^+\to\pi^+ \pi^+ \pi^- X) = (32.81 \pm 0.35_{\rm stat} \pm {0.82_{\rm syst}})\%. In this measurement the charged pions from KS0K_S^0 meson decays are excluded. The partial branching fractions of Ds+π+π+πXD_s^+\to\pi^+ \pi^+ \pi^- X are also measured as a function of the π+π+π\pi^+ \pi^+ \pi^- invariant mass.Comment: 13 pages, 4 figure

    Observation and branching fraction measurement of the decay J ⁣/ ⁣ψpˉΣ+KS0+c.c.J\!/\!\psi \rightarrow \bar{p} \Sigma^{+} K_{S}^{0} + c.c.

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    The first observation of the decays J ⁣/ ⁣ψpˉΣ+KS0J\!/\!\psi \rightarrow \bar{p} \Sigma^{+} K_{S}^{0} and J ⁣/ ⁣ψpΣˉKS0J\!/\!\psi \rightarrow p \bar{\Sigma}^{-} K_{S}^{0} is reported using (10087±44)×106(10087\pm44)\times10^{6} J ⁣/ ⁣ψJ\!/\!\psi events recorded by the BESIII detector at the BEPCII storage ring. The branching fractions of each channel are determined to be B(J ⁣/ ⁣ψpˉΣ+KS0)=(1.361±0.006±0.025)×104\mathcal{B}(J\!/\!\psi \rightarrow \bar{p} \Sigma^{+} K_{S}^{0})=(1.361 \pm 0.006 \pm 0.025) \times 10^{-4} and B(J ⁣/ ⁣ψpΣˉKS0)=(1.352±0.006±0.025)×104\mathcal{B}(J\!/\!\psi \rightarrow p \bar{\Sigma}^{-} K_{S}^{0})=(1.352 \pm 0.006 \pm 0.025) \times 10^{-4}. The combined result is B(J ⁣/ ⁣ψpˉΣ+KS0+c.c.)=(2.725±0.009±0.050)×104\mathcal{B}(J\!/\!\psi \rightarrow \bar{p} \Sigma^{+} K_{S}^{0} +c.c.)=(2.725 \pm 0.009 \pm 0.050) \times 10^{-4}, where the first uncertainty is statistical and the second systematic. The results presented are in good agreement with the branching fractions of the isospin partner decay J ⁣/ ⁣ψpKΣˉ0+c.c.J\!/\!\psi \rightarrow p K^- \bar\Sigma^0 + c.c.

    A coupled-channel analysis of the X(3872)X(3872) lineshape with BESIII data

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    We perform a study of the X(3872)X(3872) lineshape using the data samples of e+eγX(3872)e^+e^-\to\gamma X(3872), X(3872)D0Dˉ0π0X(3872)\to D^0\bar{D}^0 \pi^0 and π+πJ/ψ\pi^+\pi^- J/\psi collected with the BESIII detector. The effects of the coupled-channels and the off-shell D0D^{*0} are included in the parameterization of the lineshape. The lineshape mass parameter is obtained to be MX=(3871.63±0.130.05+0.06)M_{X}=(3871.63\pm 0.13^{+0.06}_{-0.05}) MeV. Two poles are found on the first and second Riemann sheets corresponding to the D0Dˉ0D^{*0}\bar{D}^0 branch cut. The pole location on the first sheet is much closer to the D0Dˉ0D^{*0}\bar{D}^0 threshold than the other, and is determined to be 7.04±0.150.08+0.077.04\pm0.15^{+0.07}_{-0.08} MeV above the D0Dˉ0π0D^0\bar{D}^0\pi^0 threshold with an imaginary part 0.19±0.080.19+0.14-0.19\pm0.08^{+0.14}_{-0.19} MeV

    Search for an invisible muon philic scalar X0X_{0} or vector X1X_{1} via J/ψμ+μ+invisibleJ/\psi\to\mu^+\mu^-+\rm{invisible} decay at BESIII

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    A light scalar X0X_{0} or vector X1X_{1} particles have been introduced as a possible explanation for the (g2)μ(g-2)_{\mu} anomaly and dark matter phenomena. Using (8.998±0.039)×109(8.998\pm 0.039)\times10^9 \jpsi events collected by the BESIII detector, we search for a light muon philic scalar X0X_{0} or vector X1X_{1} in the processes J/ψμ+μX0,1J/\psi\to\mu^+\mu^- X_{0,1} with X0,1X_{0,1} invisible decays. No obvious signal is found, and the upper limits on the coupling g0,1g_{0,1}' between the muon and the X0,1X_{0,1} particles are set to be between 1.1×1031.1\times10^{-3} and 1.0×1021.0\times10^{-2} for the X0,1X_{0,1} mass in the range of 1<M(X0,1)<10001<M(X_{0,1})<1000~MeV/c2/c^2 at 90%\% confidence level.Comment: 9 pages 7 figure

    First Observation of a Three-Resonance Structure in e+ee^+e^-\rightarrow{non-open} Charm Hadrons

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    We report the measurement of the cross sections for e+ee^+e^-\rightarrow{nOCH} (nOCH stands for non-open charm hadrons) with improved precision at center-of-mass energies from 3.645 to 3.871 GeV. We observe for the first time a three-resonance structure in the energy-dependent lineshape of the cross sections, which are R(3760)\mathcal R(3760), R(3780)\mathcal R(3780) and R(3810)\mathcal R(3810) with significances of 9.4σ9.4\sigma, 15.7σ15.7\sigma, and 9.8σ9.8\sigma, respectively. The R(3810)\mathcal R(3810) is observed for the first time. We found two solutions in analysis of the cross sections. For solution I [solution II], we measure the mass, the total width and the product of electronic width and nOCH decay branching fraction to be (3805.8±1.1±2.7)(3805.8 \pm 1.1 \pm 2.7) [(3805.8±1.1±2.7)(3805.8 \pm 1.1 \pm 2.7)] MeV/c2c^2, (11.6±2.6±1.9)(11.6 \pm 2.6 \pm 1.9) [(11.5±2.5±1.8)(11.5 \pm 2.5 \pm 1.8)] MeV, and (10.8±3.2±2.3)(10.8\pm 3.2\pm 2.3) [(11.0±2.9±2.4)(11.0\pm 2.9\pm 2.4)] eV for the R(3810)\mathcal R(3810), respectively. In addition, we measure the branching fractions B(R(3760){\mathcal B}({\mathcal R}(3760)\rightarrow{nOCH})=(24.5±13.4±27.4)%[(6.8±5.4±7.6)%])=(24.5 \pm 13.4 \pm 27.4)\% [(6.8 \pm 5.4 \pm 7.6)\%] for the first time, and B(R(3780){\mathcal B}(\mathcal R(3780)\rightarrow{nOCH})=(11.6±5.8±7.8)%[(10.3±4.5±6.9)%])=(11.6 \pm 5.8 \pm 7.8)\% [(10.3 \pm 4.5 \pm 6.9)\%]. Moreover, we determine the open-charm (OC) branching fraction B(R{\mathcal B}({\mathcal R}(3760)(3760)\rightarrow{OC})=(75.5±13.4±27.4)%[(93.2±5.4±7.6)%])=(75.5 \pm 13.4 \pm 27.4)\% [(93.2 \pm 5.4 \pm 7.6)\%], which supports the interpretation of R(3760)\mathcal R(3760) as an OC pair molecular state, but contained a simple four-quark state component. The first uncertainties are from fits to the cross sections, and the second are systematic

    Amplitude analysis and branching fraction measurement of the decay D+KS0π+π0π0D^{+} \to K_S^0\pi^+\pi^0\pi^0

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    Using 2.93 fb1\rm{fb}^{-1} of e+ee^+e^- collision data collected with the BESIII detector at the center-of-mass energy 3.773\,GeV, we perform the first amplitude analysis of the decay D+KS0π+π0π0D^+\to K_S^0\pi^+\pi^0\pi^0 and determine the relative magnitudes and phases of different intermediate processes. The absolute branching fraction of D+KS0π+π0π0D^+\to K_S^0\pi^+\pi^0\pi^0 is measured to be (2.888±0.058stat.±0.069syst.)%(2.888\pm0.058_{\rm stat.}\pm0.069_{\rm syst.})\%. The dominant intermediate processes are D+KS0a1(1260)+(ρ+π0)D^+\to K_S^0a_1(1260)^+(\to \rho^+\pi^0) and D+Kˉ0ρ+D^+\to \bar{K}^{*0}\rho^+, with branching fractions of (8.66±1.04stat.±1.39syst.) ⁣× ⁣103(8.66\pm1.04_{\rm stat.}\pm1.39_{\rm syst.})\!\times \!10^{-3} and (9.70±0.81stat.±0.53syst.) ⁣× ⁣103(9.70\pm0.81_{\rm stat.}\pm0.53_{\rm syst.})\!\times \!10^{-3}, 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

    Measurement of the cross section of e+eΞΞˉ+e^+e^-\rightarrow\Xi^{-}\bar\Xi^{+} at center-of-mass energies between 3.510 and 4.843 GeV

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    Using e+ee^+e^- collision data corresponding to a total integrated luminosity of 12.9 fb1fb^{-1} collected with the BESIII detector at the BEPCII collider, the exclusive Born cross sections and the effective form factors of the reaction e+eΞΞˉ+e^+e^-\rightarrow\Xi^{-}\bar\Xi^{+} are measured via the single baryon-tag method at 23 center-of-mass energies between 3.510 and 4.843 GeV. Evidence for the decay ψ(3770)ΞΞˉ+\psi(3770)\rightarrow\Xi^{-}\bar\Xi^{+} is observed with a significance of 4.5σ\sigma by analyzing the measured cross sections together with earlier BESIII results. For the other charmonium(-like) states ψ(4040)\psi(4040), ψ(4160)\psi(4160), Y(4230)Y(4230), Y(4360)Y(4360), ψ(4415)\psi(4415), and Y(4660)Y(4660), no significant signal of their decay to ΞΞˉ+\Xi^-\bar \Xi^+ is found. For these states, upper limits of the products of the branching fraction and the electronic partial width at the 90% confidence level are provided.Comment: 18 pages, 10 pages, 4 table
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