97 research outputs found

    Muon fluxes derived from the directly measured primary cosmic-ray elemental spectra using hadron-proton machine interaction results

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    The directly measured elemental spectra of primary cosmic rays obtained from JACEE, MSU, SOKOL and CRN data on p, He, CNO, Ne-S and Fe fluxes have been considered for the calculation of elemental nucleon spectra at the top of the atmosphere. Treating these spectra as parents of the secondary mesons, the sea-level muon fluxes at zenith angles 0 7 and 897 from each species have been derived using Z-factors based on the FNAL cross-section data for meson production and duly corrected for A-A collisions. The conventional muon spectra at 07 and 897 estimated from the individual elemental spectra and the prompt muon contribution arising from the charmed meson decays have been found comparable with the directly measured muon fluxes determined by Thompson et al., Allkofer et al., Matsuno et al., Khalchukov et al., Ivanova et al., Afanesieva et al., Bakatanov et al., Gettert et al. and Zatsepin et al. The muon spectra derived from the primary nucleon spectrum with a constant spectral index of value 22.73 are found in approximate agreement with the present results

    Effective R-parity violation from supersymmetry breaking

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    We present a scenario in which Yukawa-like R-parity violating (RPV) couplings are naturally suppressed. In our framework, RPV is assumed to originate from the SUSY breaking mechanism and then transmitted into the SUSY Lagrangian only through soft SUSY breaking operators in the scalar potential. The RPV Yukawa-like operators of the superpotential, conventionally parametrized by the couplings \lambda, \lambda' and \lambda'', are then generated through loops containing the SUSY scalars, the gauginos and the soft RPV interactions and are, therefore, manifest as effective operators with a typical strength of order 10^{-3}.Comment: 4 pages, 2 figures, Revtex4. Main changes with respect to Version 1 are: improved discussions on RGE effects, discussion added on neutrino masses, a toy model added for the proposed scenario. Conclusions remain unchanged. As will appear in Phys. Rev.

    Flavor changing Z-decays from scalar interactions at a Giga-Z Linear Collider

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    The flavor changing decay Z -> d_I \bar{d}_J is investigated with special emphasis on the b \bar{s} final state. Various models for flavor violation are considered: two Higgs doublet models (2HDM's), supersymmetry (SUSY) with flavor violation in the up and down-type squark mass matrices and SUSY with flavor violation mediated by R-parity-violating interaction. We find that, within the SUSY scenarios for flavor violation, the branching ratio for the decay Z -> b \bar{s} can reach 10^{-6} for large \tan\beta values, while the typical size for this branching ratio in the 2HDM's considered is about two orders of magnitudes smaller at best. Thus, flavor changing SUSY signatures in radiative Z decays such as Z -> b \bar{s} may be accessible to future ``Z factories'' such as a Giga-Z version of the TESLA design.Comment: 27 pages, 15 figures, REVTeX4. A new section added and a few minor corrections were made in the tex

    Implication of Super-Kamiokande Data on R-parity Violation

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    R-parity violating bilinear (soft) terms in the supersymmetric standard model would be the leading source for nonzero neutrino masses and mixing. We point out that the mixing between neutralinos (charginos) and neutrinos (charged leptons) driven by the bilinear terms take factorized forms, which may enable us to probe the neutrino mixing parameters in a collider. It is then shown that the Super-Kamiokande data on atmospheric neutrinos require all the baryon number violating couplings to be substantially suppressed: λany′′<10−9\lambda''_{\rm any} <10^{-9}.Comment: 11 pages, LaTeX, to appear in Phys. Rev.

    Search for R-parity Violating Decays of Supersymmetric Particles in e+e- Collisions at LEP

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    A search, in e^+e^- collisions, for chargino, neutralino, scalar lepton and scalar quark pair-production is performed, without assuming R-parity conservation in decays, in the case that only one of the coupling constants lambda_ijk or lambda''_ijk is non-negligible. No signal is found in data up to a centre-of-mass energy of 208GeV. Limits on the production cross sections and on the masses of supersymmetric particles are derived

    Phylogenomic analysis of a 55.1 kb 19-gene dataset resolves a monophyletic Fusarium that includes the Fusarium solani Species Complex

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    Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-userÂżs needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option availabl

    Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

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    Anemia is a globally widespread condition in women and is associated with reduced economic productivity and increased mortality worldwide. Here we map annual 2000–2018 geospatial estimates of anemia prevalence in women of reproductive age (15–49 years) across 82 low- and middle-income countries (LMICs), stratify anemia by severity and aggregate results to policy-relevant administrative and national levels. Additionally, we provide subnational disparity analyses to provide a comprehensive overview of anemia prevalence inequalities within these countries and predict progress toward the World Health Organization’s Global Nutrition Target (WHO GNT) to reduce anemia by half by 2030. Our results demonstrate widespread moderate improvements in overall anemia prevalence but identify only three LMICs with a high probability of achieving the WHO GNT by 2030 at a national scale, and no LMIC is expected to achieve the target in all their subnational administrative units. Our maps show where large within-country disparities occur, as well as areas likely to fall short of the WHO GNT, offering precision public health tools so that adequate resource allocation and subsequent interventions can be targeted to the most vulnerable populations.Peer reviewe

    Observation of a new Xi(b) baryon

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    The first observation of a new b baryon via its strong decay into Xi(b)^- pi^+ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 inverse femtobarns. The known Xi(b)^- baryon is reconstructed via the decay chain Xi(b)^- to J/psi Xi^- to mu^+ mu^- Lambda^0 pi^-, with Lambda^0 to p pi^-. A peak is observed in the distribution of the difference between the mass of the Xi(b)^- pi^+ system and the sum of the masses of the Xi(b)^- and pi^+, with a significance exceeding five standard deviations. The mass difference of the peak is 14.84 +/- 0.74 (stat.) +/- 0.28 (syst.) MeV. The new state most likely corresponds to the J^P=3/2^+ companion of the Xi(b).Comment: Submitted to Physical Review Letter

    Measurement of the charge ratio of atmospheric muons with the CMS detector

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    This is the pre-print version of this Article. The official published version can be accessed from the link below - Copyright @ 2010 ElsevierWe present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/c to 1 TeV/c. The surface flux ratio is measured to be 1.2766 \pm 0.0032(stat.) \pm 0.0032 (syst.), independent of the muon momentum, below 100 GeV/c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments

    Measurements of inclusive W and Z cross sections in pp collisions at root s=7 TeV

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    This is the pre-print version of the Published Article, which can be accessed from the link below - Copyright @ 2011 Springer VerlagMeasurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported
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