117 research outputs found

    Preliminary test of functionalized ZnO2 against Bipolaris sorokiniana and other seed associated mycoflora for better wheat germination

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    Bipolaris sorokiniana that causes foliar blight of wheat is one of the most serious worries for growers in warmer and humid areas around the world. Use of ecologically sound molecules for management of plant diseases is considered as one of the best options to achieve sustainability of ecology, agriculture and human health. Attempts were made to synthesize PVP functionalized ZnO2 nanomaterials to explore antifungal ability and impact on plant growth. The growth and spore germination of B. sorokiniana was significantly reduced. The seed germination was improved with good development of plumule and radicles. Moreover, the proliferation of wheat seed associated pathogenic and saprophytic mycoflora was completely inhibited. These new informations suggest use of PVP functionalized ZnO2 nanoparticles as an alternative to harmful fungicides for seed treatment and lower agricultural cost and environmental risk

    Elliptic anisotropy measurement of the f0_0(980) hadron in proton-lead collisions and evidence for its quark-antiquark composition

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    International audienceDespite the f0_0(980) hadron having been discovered half a century ago, the question about its quark content has not been settled: it might be an ordinary quark-antiquark (qqˉ\mathrm{q\bar{q}}) meson, a tetraquark (qqˉqqˉ\mathrm{q\bar{q}q\bar{q}}) exotic state, a kaon-antikaon (KKˉ\mathrm{K\bar{K}}) molecule, or a quark-antiquark-gluon (qqˉg\mathrm{q\bar{q}g}) hybrid. This paper reports strong evidence that the f0_0(980) state is an ordinary qqˉ\mathrm{q\bar{q}} meson, inferred from the scaling of elliptic anisotropies (v2v_2) with the number of constituent quarks (nqn_\mathrm{q}), as empirically established using conventional hadrons in relativistic heavy ion collisions. The f0_0(980) state is reconstructed via its dominant decay channel f0_0(980) \toπ+π\pi^+\pi^-, in proton-lead collisions recorded by the CMS experiment at the LHC, and its v2v_2 is measured as a function of transverse momentum (pTp_\mathrm{T}). It is found that the nqn_q = 2 (qqˉ\mathrm{q\bar{q}} state) hypothesis is favored over nqn_q = 4 (qqˉqqˉ\mathrm{q\bar{q}q\bar{q}} or KKˉ\mathrm{K\bar{K}} states) by 7.7, 6.3, or 3.1 standard deviations in the pTp_\mathrm{T}<\lt 10, 8, or 6 GeV/cc ranges, respectively, and over nqn_\mathrm{q} = 3 (qqˉg\mathrm{q\bar{q}g} hybrid state) by 3.5 standard deviations in the pTp_\mathrm{T}<\lt 8 GeV/cc range. This result represents the first determination of the quark content of the f0_0(980) state, made possible by using a novel approach, and paves the way for similar studies of other exotic hadron candidates

    Extracting the speed of sound in the strongly interacting matter created in ultrarelativistic lead-lead collisions at the LHC

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    International audienceUltrarelativistic nuclear collisions create a strongly interacting state of hot and dense quark-gluon matter that exhibits a remarkable collective flow behavior with minimal viscous dissipation. To gain deeper insights into its intrinsic nature and fundamental degrees of freedom, we extracted the speed of sound in this medium created using lead-lead (PbPb) collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 0.607 nb1^{-1}. The measurement is performed by studying the multiplicity dependence of the average transverse momentum of charged particles emitted in head-on PbPb collisions. Our findings reveal that the speed of sound in this matter is nearly half the speed of light, with a squared value of 0.241 ±\pm 0.002 (stat) ±\pm 0.016 (syst) in natural units. The effective medium temperature, estimated using the mean transverse momentum, is 219 ±\pm 8 (syst) MeV. The measured squared speed of sound at this temperature aligns precisely with predictions from lattice quantum chromodynamic (QCD) calculations. This result provides a stringent constraint on the equation of state of the created medium and direct evidence for a deconfined QCD phase being attained in relativistic nuclear collisions

    Search for CPCP violation in D0^0\to KS0^0_\mathrm{S}KS0^0_\mathrm{S} decays in proton-proton collisions at s\sqrt{s} = 13 TeV

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    International audienceA search is reported for charge-parity D0^0\to KS0^0_\mathrm{S}KS0^0_\mathrm{S}CPCP violation in D0^0\to KS0^0_\mathrm{S}KS0^0_\mathrm{S} decays, using data collected in proton-proton collisions at s\sqrt{s} = 13 TeV recorded by the CMS experiment in 2018. The analysis uses a dedicated data set that corresponds to an integrated luminosity of 41.6 fb1^{-1}, which consists of about 10 billion events containing a pair of ẖadrons, nearly all of which decay to charm hadrons. The flavor of the neutral D meson is determined by the pion charge in the reconstructed decays D+^{*+}\to D0π+^0\pi^+ and D^{*-}\to D0π^0\pi^-. The D0^0\to KS0^0_\mathrm{S}KS0^0_\mathrm{S}CPCP asymmetry in D0^0\to KS0^0_\mathrm{S}KS0^0_\mathrm{S} is measured to be ACPA_{CP}( KS0^0_\mathrm{S}KS0^0_\mathrm{S}) = (6.2 ±\pm 3.0 ±\pm 0.2 ±\pm 0.8)%, where the three uncertainties represent the statistical uncertainty, the systematic uncertainty, and the uncertainty in the measurement of the D0^0 \to KS0^0_\mathrm{S}KS0^0_\mathrm{S} CPCP asymmetry in the D0^0 \to KS0π+π^0_\mathrm{S}\pi^+\pi^- decay. This is the first D0^0 \to KS0^0_\mathrm{S}KS0^0_\mathrm{S} CPCP asymmetry measurement by CMS in the charm sector as well as the first to utilize a fully hadronic final state

    Test of lepton flavor universality in B± ⁣ ⁣K±μ+μ {\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mu^{+}\mu^{-} and B± ⁣ ⁣K±e+e {\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mathrm{e}^+\mathrm{e}^- decays in proton-proton collisions at s= \sqrt{s} = 13 TeV

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    A test of lepton flavor universality in B± ⁣ ⁣K±μ+μ {\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mu^{+}\mu^{-} and B± ⁣ ⁣K±e+e {\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mathrm{e}^+\mathrm{e}^- decays, as well as a measurement of differential and integrated branching fractions of a nonresonant B± ⁣ ⁣K±μ+μ {\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mu^{+}\mu^{-} decay are presented. The analysis is made possible by a dedicated data set of proton-proton collisions at s= \sqrt{s} = 13 TeV recorded in 2018, by the CMS experiment at the LHC, using a special high-rate data stream designed for collecting about 10 billion unbiased b hadron decays. The ratio of the branching fractions B(B± ⁣ ⁣K±μ+μ) \mathcal{B}({\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mu^{+}\mu^{-}) to B(B± ⁣ ⁣K±e+e) \mathcal{B}({\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mathrm{e}^+\mathrm{e}^-) is determined from the measured double ratio R(K) R(\mathrm{K}) of these decays to the respective branching fractions of the B± ⁣ ⁣J/ψK± {\mathrm{B}^{\pm}} \!\to\! {\mathrm{J}/\psi} \mathrm{K^{\pm}} with J/ψ ⁣ ⁣μ+μ {\mathrm{J}/\psi} \!\to\!\mu^{+}\mu^{-} and e+e \mathrm{e}^+\mathrm{e}^- decays, which allow for significant cancellation of systematic uncertainties. The ratio R(K) R(\mathrm{K}) is measured in the range 1.1 <q2< < q^2 < 6.0 GeV2^2 , where q q is the invariant mass of the lepton pair, and is found to be R(K)= R(\mathrm{K})= 0.78 0.23+0.47 ^{+0.47}_{-0.23} , in agreement with the standard model expectation R(K) R(\mathrm{K}) \approx 1. This measurement is limited by the statistical precision of the electron channel. The integrated branching fraction in the same q2 q^2 range, B(B± ⁣ ⁣K±μ+μ)= \mathcal{B}({\mathrm{B}^{\pm}} \!\to\! \mathrm{K^{\pm}}\mu^{+}\mu^{-}) = (12.42 ± \pm 0.68) ×\times 108^{-8} , is consistent with the present world-average value and has a comparable precision.A test of lepton flavor universality in B±^{\pm}\to K±μ+μ^{\pm}\mu^+\mu^- and B±^{\pm}\to K±^{\pm}e+^+e^- decays, as well as a measurement of differential and integrated branching fractions of a nonresonant B±^{\pm}\to K±μ+μ^{\pm}\mu^+\mu^- decay are presented. The analysis is made possible by a dedicated data set of proton-proton collisions at s\sqrt{s} = 13 TeV recorded in 2018, by the CMS experiment at the LHC, using a special high-rate data stream designed for collecting about 10 billion unbiased b hadron decays. The ratio of the branching fractions B\mathcal{B}(B±^{\pm}\to K±μ+μ^{\pm}\mu^+\mu^-) to B\mathcal{B}(B±^{\pm}\to K±^{\pm}e+^+e^-) is determined from the measured double ratio RR(K) of these decays to the respective branching fractions of the B±^\pm\to J/ψ\psiK±^\pm with J/ψ\psi\toμ+μ\mu^+\mu^- and e+^+e^- decays, which allow for significant cancellation of systematic uncertainties. The ratio RR(K) is measured in the range 1.1 <q2<\lt q^2 \lt 6.0 GeV2^2, where qq is the invariant mass of the lepton pair, and is found to be RR(K) = 0.780.23+0.47^{+0.47}_{-0.23}, in agreement with the standard model expectation RR(K) \approx 1. This measurement is limited by the statistical precision of the electron channel. The integrated branching fraction in the same q2q^2 range, B\mathcal{B}(B±^{\pm}\to K±μ+μ^{\pm}\mu^+\mu^-) = (12.42 ±\pm 0.68) ×\times 108^{-8}, is consistent with the present world-average value and has a comparable precision

    The CMS Statistical Analysis and Combination Tool: COMBINE

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    International audienceThis paper describes the COMBINE software package used for statistical analyses by the CMS Collaboration. The package, originally designed to perform searches for a Higgs boson and the combined analysis of those searches, has evolved to become the statistical analysis tool presently used in the majority of measurements and searches performed by the CMS Collaboration. It is not specific to the CMS experiment, and this paper is intended to serve as a reference for users outside of the CMS Collaboration, providing an outline of the most salient features and capabilities. Readers are provided with the possibility to run COMBINE and reproduce examples provided in this paper using a publicly available container image. Since the package is constantly evolving to meet the demands of ever-increasing data sets and analysis sophistication, this paper cannot cover all details of COMBINE. However, the online documentation referenced within this paper provides an up-to-date and complete user guide

    Dark sector searches with the CMS experiment

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    Astrophysical observations provide compelling evidence for gravitationally interacting dark matter in the universe that cannot be explained by the standard model of particle physics. The extraordinary amount of data from the CERN LHC presents a unique opportunity to shed light on the nature of dark matter at unprecedented collision energies. This Report comprehensively reviews the most recent searches with the CMS experiment for particles and interactions belonging to a dark sector and for dark-sector mediators. Models with invisible massive particles are probed by searches for signatures of missing transverse momentum recoiling against visible standard model particles. Searches for mediators are also conducted via fully visible final states. The results of these searches are compared with those obtained from direct-detection experiments. Searches for alternative scenarios predicting more complex dark sectors with multiple new particles and new forces are also presented. Many of these models include long-lived particles, which could manifest themselves with striking unconventional signatures with relatively small amounts of background. Searches for such particles are discussed and their impact on dark-sector scenarios is evaluated. Many results and interpretations have been newly obtained for this Report.Astrophysical observations provide compelling evidence for gravitationally interacting dark matter in the universe that cannot be explained by the standard model of particle physics. The extraordinary amount of data from the CERN LHC presents a unique opportunity to shed light on the nature of dark matter at unprecedented collision energies. This Report comprehensively reviews the most recent searches with the CMS experiment for particles and interactions belonging to a dark sector and for dark-sector mediators. Models with invisible massive particles are probed by searches for signatures of missing transverse momentum recoiling against visible standard model particles. Searches for mediators are also conducted via fully visible final states. The results of these searches are compared with those obtained from direct-detection experiments. Searches for alternative scenarios predicting more complex dark sectors with multiple new particles and new forces are also presented. Many of these models include long-lived particles, which could manifest themselves with striking unconventional signatures with relatively small amounts of background. Searches for such particles are discussed and their impact on dark-sector scenarios is evaluated. Many results and interpretations have been newly obtained for this Report

    Search for baryon number violation in top quark production and decay using proton-proton collisions at s= \sqrt{s} = 13 TeV

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    A search is presented for baryon number violating interactions in top quark production and decay. The analysis uses data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC with an integrated luminosity of 138 fb1 ^{-1} . Candidate events are selected by requiring two oppositely-charged leptons (electrons or muons) and exactly one jet identified as originating from a bottom quark. Multivariate discriminants are used to separate the signal from the background. No significant deviation from the standard model prediction is observed. Upper limits are placed on the strength of baryon number violating couplings. For the first time the production of single top quarks via baryon number violating interactions is studied. This allows the search to set the most stringent constraints to date on the branching fraction of the top quark decay to a lepton, an up-type quark (u or c), and a down-type quark (d, s, or b). The results improve the previous bounds by three to six orders of magnitude based on the fermion flavor combination of the baryon number violating interactions.A search is presented for baryon number violating interactions in top quark production and decay. The analysis uses data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC with an integrated luminosity of 138 fb1^{-1}. Candidate events are selected by requiring two oppositely-charged leptons (electrons or muons) and exactly one jet identified as originating from a bottom quark. Multivariate discriminants are used to separate the signal from the background. No significant deviation from the standard model prediction is observed. Upper limits are placed on the strength of baryon number violating couplings. For the first time the production of single top quarks via baryon number violating interactions is studied. This allows the search to set the most stringent constraints to date on the branching fraction of the top quark decay to a lepton, an up-type quark (u or c), and a down-type quark (d, s, or b). The results improve the previous bounds by three to six orders of magnitude based on the fermion flavor combination of the baryon number violating interactions
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