1,011 research outputs found

    Tracking of urban aerosols using combined LIDAR-based remote sensing and ground-based measurements

    Get PDF
    A measuring campaign was performed over the neighboring towns of Nova Gorica in Slovenia and Gorizia in Italy on 24 and 25 May 2010, to investigate the concentration and distribution of urban aerosols. Tracking of two-dimensional spatial and temporal aerosol distributions was performed using scanning elastic LIDAR, operating at 1064 nm. In addition, PM<sub>10</sub> concentrations of particles, NO<sub>x</sub> concentrations and meteorological data were continuously monitored within the LIDAR scanning region. Based on the data we collected, we investigated the flow dynamics and the aerosol concentrations within the lower troposphere and found an evidence for daily aerosol cycles. We observed a number of cases with spatially localized increased LIDAR returns, which are associated with the presence of point sources of particulate matter. Daily aerosol concentration cycles were also clearly visible with a peak in aerosol concentration during the morning rush hours and daily plateau at around 17:00 Central European Time. We also found that horizontal atmospheric extinction at the height of 200 m, averaged in limited region with a radius of 300 m directly above the ground-based measuring site, was linearly correlated to the PM<sub>10</sub> concentration with a correlation coefficient of 0.84. When considering the average of the horizontal atmospheric extinction over the entire scanning region, a strong dependence on traffic conditions (concentration of NO<sub>x</sub>) in the vicinity of the ground-based measuring site was observed

    Measurements of Branching Fractions and Polarization in B > K^* rho Decays

    Full text link
    We present results of a study of the charmless vector-vector decays B^0 -> K^{*0} rho^0 and B^+ ->K^{*0} rho^+. The results are based on a 140 fb^{-1} data sample collected by the Belle detector at the KEKB asymmetric e^+e^- collider. We obtain the branching fraction B(B^+ -> K^{*0} rho^+)=(6.6 +- 2.2(stat.) +- 0.8 (syst.)) x 10^{-6}, and set upper limits on the branching fractions B(B^0 -> K^{*0} rho^0) f_0(980) K^{*0})<5.2 x 10^{-6}. We also perform a helicity analysis of the rho and K^* vector mesons in the decay B^+ -> K^{*0} rho^+, and obtain the longitudinal polarization fraction R_0(B^+ -> K^{*0} rho^+)=0.50 +- 0.19(stat.)+0.05-0.07}(syst.).Comment: 11 pages, 4 figures, submitted to ICHEP04, Beijing, Chin

    Improved measurement of time-dependent CP violation in B0 -> J/Psi pi0 decays

    Full text link
    We report improved measurements of time-dependent CP violation parameters for B0(Bˉ0)J/ψπ0B^0(\bar{B}^0) \to J/\psi \pi^0 decay. This analysis is based on 535 million BBˉB\bar{B} pairs accumulated at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. From the distribution of proper time intervals between the two B decays, we obtain the following CP violation parameters SJ/ψπ0=0.65±0.21(stat)±0.05(syst)\mathcal{S}_{J/\psi \pi^0} = -0.65\pm0.21 (\rm{stat})\pm0.05 (\rm{syst}) and AJ/ψπ0=+0.08±0.16(stat)±0.05(syst)\mathcal{A}_{J/\psi \pi^0} = +0.08\pm0.16 (\rm{stat})\pm0.05 (\rm{syst}), which are consistent with Standard Model expectations.Comment: Resubmitted to PRD(RC), including 4 figures, 6pages Revision has been made according to communication with PRD referee

    Observation of B+->Lambda_c+Lambda_c-K+ and B0->Lambda_c+Lambda_c^-K0 decays

    Full text link
    We report first measurements of the doubly charmed baryonic B decays B->Lambda_c+Lambda_c-K. The B+->Lambda_c+Lambda_c-K+ decay is observed with a branching fraction of (6.5+1.0-0.9+-1.1+-3.4)x10^{-4} and a statistical significance of 15.4sigma. The B0->Lambda_c+Lambda_c-K0 decay is observed with a branching fraction of (7.9+2.9-2.3+-1.2+-4.2)x10^{-4} and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of Lambda_c+->pK-pi+ decay branching fraction. The analysis is based on 357fb-1 of data accumulated at the Y(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider.Comment: 10 pages, 3 figure

    Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle

    Full text link
    The cross section for e+e- to pi+ pi- psi(2S) between threshold and \sqrt{s}=5.5 GeV is measured using 673 fb^{-1} of data on and off the \Upsilon(4S) resonance collected with the Belle detector at KEKB. Two resonant structures are observed in the pi+ pi- psi(2S) invariant mass distribution, one at 4361\pm 9\pm 9 MeV/c2 with a width of 74\pm 15\pm 10 MeV/c2, and another at 4664\pm 11\pm 5 MeV/c2 with a width of 48\pm 15\pm 3 MeV/c2, if the mass spectrum is parameterized with the coherent sum of two Breit-Wigner functions. These values do not match those of any of the known charmonium states.Comment: 10 pages, 5 figures, 2 tables, version to appear in Phys. Rev. Let

    Study of CP Violating Effects in Time Dependent B0(B0ˉ)D()π±B^0(\bar{B^0}) \to D^{(*)\mp}\pi^{\pm} Decays

    Full text link
    We report measurements of time dependent decay rates for B0(Bˉ0)D()π±B^0(\bar{B}^0) \to D^{(*)\mp}\pi^{\pm} decays and extraction of CP violation parameters containing ϕ3\phi_3. Using fully reconstructed D()πD^{(*)}\pi events from a 140fb1140 {\rm fb}^{-1} data sample collected at the Υ(4S)\Upsilon(4S) resonance, we obtain the CP violation parameters for DπD^* \pi and DπD \pi decays, 2RD()πsin(2ϕ1+ϕ3±δD()π)2R_{D^{(*)} \pi} \sin (2\phi_1 + \phi_3 \pm \delta_{D^{(*)} \pi}), where RD()πR_{D^{(*)} \pi} is the ratio of the magnitudes of the doubly-Cabibbo-suppressed and Cabibbo-favoured amplitudes, and δD()π\delta_{D^{(*)} \pi} is the strong phase difference between them. Under the assumption of δD()π\delta_{D^{(*)} \pi} being close to either 0 or 180180^{\circ}, we obtain 2RDπsin(2ϕ1+ϕ3)=0.060±0.040(stat)±0.019(sys)|2R_{D^* \pi} \sin (2\phi_1 + \phi_3)| = 0.060 \pm 0.040(\mathrm{stat}) \pm 0.019(\mathrm{sys}) and 2RDπsin(2ϕ1+ϕ3)=0.061±0.037(stat)±0.018(sys)|2R_{D \pi} \sin (2\phi_1 + \phi_3)| = 0.061 \pm 0.037(\mathrm{stat}) \pm 0.018(\mathrm{sys}).Comment: 9 pages, 3 figures, Submitted to Physical Review Letter

    Measurement of the decay B0π+νB^0\to\pi^-\ell^+\nu and determination of Vub|V_{ub}|

    Full text link
    We present a measurement of the charmless semileptonic decay B0π+νB^0\to\pi^-\ell^+\nu using a data sample containing 657×106\times 10^6 BBˉB\bar{B} events collected with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider operating near the Υ(4S)\Upsilon(4S) resonance. We determine the total branching fraction of the decay, B(B0π+ν)=(1.49±0.04(stat)±0.07(syst))×104\mathcal{B}(B^0\to\pi^-\ell^+\nu)=(1.49\pm 0.04{(\mathrm{stat})}\pm 0.07{(\mathrm{syst})})\times 10^{-4}. We also report a new precise measurement of the differential decay rate, and extract the Cabibbo-Kobayashi-Maskawa matrix element Vub|V_{ub}| using model-independent and -dependent approaches. From a simultaneous fit to the measured differential decay rate and lattice QCD results, we obtain Vub=(3.43±0.33)×103|V_{ub}|=(3.43\pm 0.33)\times 10^{-3}, where the error includes both statistical and systematic uncertainties.Comment: 8 pages, 3 figures, Submitted to PRD(RC

    Study of B -> D** l nu with full reconstruction tagging

    Full text link
    We report a study of semileptonic B decays to P-wave D** mesons. Semileptonic decay to D*_2 meson is observed for the first time and its product branching ratio is measured to be Br(B+ -> anti-D*0_2 l+nu) x Br(anti-D*0_2 -> D- pi+) = 0.22 +- 0.03(stat.) +- 0.04(syst.)%. The result is obtained using the fully reconstructed B tags from a data sample that contains 657 millions BB-bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.Comment: 12 pages, 4 figures, submitted to PRD(RC

    Search for CP violation in the decays D(s)+KS0π+D^+_{(s)} \to K_S^0\pi^+ and D(s)+KS0K+D^+_{(s)} \to K_S^0K^+

    Full text link
    We have searched for CP violation in the charmed meson decays D(s)+KS0π+D^{+}_{(s)}\to K^0_S\pi^+ and D(s)+KS0K+D^{+}_{(s)}\to K^0_S K^+ using 673 fb1^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. No evidence for CP violation is observed. We report the most sensitive CP asymmetry measurements to date for these decays: ACPD+KS0π+=(0.71±0.19±0.20)A_{CP}^{D^+\to K^0_S\pi^+}=(-0.71\pm0.19\pm0.20)%, ACPDs+KS0π+=(+5.45±2.50±0.33)A_{CP}^{D^+_s\to K^0_S\pi^+}=(+5.45\pm2.50\pm0.33)%, ACPD+KS0K+=(0.16±0.58±0.25)A_{CP}^{D^+\to K^0_S K^+}=(-0.16\pm0.58\pm0.25)%, and ACPDs+KS0K+=(+0.12±0.36±0.22)A_{CP}^{D^+_s\to K^0_S K^+}=(+0.12\pm0.36\pm0.22)%, where the first uncertainties are statistical and the second are systematic

    First study of \eta_c, \eta(1760) and X(1835) production via \eta'\pi^+\pi^- final states in two-photon collisions

    Full text link
    The invariant mass spectrum of the \eta' \pi^+ \pi^- final state produced in two-photon collisions is obtained using a 673 fb^{-1} data sample collected in the vicinity of the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We observe a clear signal of the \eta_c and measure its mass and width to be M(\eta_c)=(2982.7 +- 1.8(stat) +- 2.2(syst) +- 0.3(model)) MeV/c^2 and \Gamma(\eta_c) = (37.8^{+5.8}_{-5.3}(stat) +- 2.8(syst) +- 1.4(model)) MeV/c^2. The third error is an uncertainty due to possible interference between the \eta_c and a non-resonant component. We also report the first evidence for \eta(1760) decay to \eta' \pi^+ \pi^-; we find two solutions for its parameters, depending on the inclusion or not of the X(1835), whose existence is of marginal significance in our data. From a fit to the mass spectrum using coherent X(1835) and \eta(1760) resonant amplitudes, we set a 90% confidence level upper limit on the product \Gamma_{\gamma\gamma} \BR (\eta' \pi^+ \pi^-) for the X(1835).Comment: 13 pages, 7 figures, submitted to PR
    corecore