4,455 research outputs found

    Secondary atmospheric tau neutrino production

    Full text link
    We evaluate the flux of tau neutrinos produced from the decay of pair produced taus from incident muons using a cascade equation analysis. To solve the cascade equations, our numerical result for the tau production ZZ moment is given. Our results for the flux of tau neutrinos produced from incident muons are compared to the flux of tau neutrinos produced via oscillations and the direct prompt atmospheric tau neutrino flux. Results are given for both downward and upward going neutrinos fluxes and higher zenith angles are discussed. We conclude that the direct prompt atmospheric tau neutrino flux dominates these other atmospheric sources of tau neutrinos for neutrino energies larger than a few TeV for upward fluxes, and over a wider range of energy for downward fluxes.Comment: 4 pages, 2 figure

    Prompt neutrinos and intrinsic charm at SHiP

    Full text link
    We present a new evaluation of the far-forward neutrino plus antineutrino flux and number of events from charm hadron decays in a 400 GeV proton beam dump experiment like the Search for Hidden Particles (SHiP). Using next-to-leading order perturbative QCD and a model for intrinsic charm, we include intrinsic transverse momentum effects and other kinematic angular corrections. We compare this flux to a far-forward flux evaluated with next-to-leading order perturbative QCD, without intrinsic transverse momentum, that used the angular distribution of charm quarks rather than the neutrinos from their decays. The tau neutrino plus antineutrino number of events in the perturbative QCD evaluation is reduced by a factor of about three when intrinsic transverse momentum and the full decay kinematics are included. We show that intrinsic charm contributions can significantly enhance the number of events from neutrinos from charm hadron decays. Measurements of the number of events from tau neutrino plus antineutrino interactions and of the muon charge asymmetry as a function of energy can be used to constrain intrinsic charm models.Comment: 39 pages, 18 figures; v2 with revisions of text for clarity, version to be published in JHE

    Residential Instability and the McKinney-Vento Homeless Children and Education Program: What We Know, Plus Gaps in Research

    Get PDF
    Reviews the literature on the effects of homelessness and residential instability on academic performance and describes the program designed to mitigate them. Calls for better data collection on the affected children's outcomes and the program's impact

    Reconciling neutrino flux from heavy dark matter decay and recent events at IceCube

    Full text link
    The IceCube detector has recently reported the observation of 28 events at previously unexplored energies. While the statistics of the observed events are still low, these events hint at the existence of a neutrino flux over and above the atmospheric neutrino background. We investigate the possibility that a significant component of the additional neutrino flux originates due to the decay of a very heavy dark matter (VHDM) particle via several possible channels into standard model particles. We show that a combination of a power law astrophysical neutrino spectrum and the neutrino flux from the decay of a DM species of mass in the range 150−400150-400 TeV improves the fit to the observed neutrino events than that obtained from a best-fit astrophysical flux alone. Assuming the existence of an astrophysical background described by the IC best-fit, we also show that, for the decay of even heavier DM particles (mDM∼1m_{\text{DM}} \sim 1 PeV), the same observations impose significant constraints on the decay lifetimes. Allowing the astrophysical flux normalization to vary leads to modifications of these limits, however, there is still a range of dark matter mass and lifetime that is excluded by the IC results.Comment: v1: 8 pages, 2 figures, 2 tables. v2: Minimization over three-parameters (DM mass, lifetime and astrophysical power-law flux normalization); better statistical quantification of fit-goodness; conclusions unchanged; 15 pg, 3 figs, 2 tables; version to appear in JHE

    Performance analysis of local area networks

    Get PDF
    A simulation of the TCP/IP protocol running on a CSMA/CD data link layer was described. The simulation was implemented using the simula language, and object oriented discrete event language. It allows the user to set the number of stations at run time, as well as some station parameters. Those parameters are the interrupt time and the dma transfer rate for each station. In addition, the user may configure the network at run time with stations of differing characteristics. Two types are available, and the parameters of both types are read from input files at run time. The parameters include the dma transfer rate, interrupt time, data rate, average message size, maximum frame size and the average interarrival time of messages per station. The information collected for the network is the throughput and the mean delay per packet. For each station, the number of messages attempted as well as the number of messages successfully transmitted is collected in addition to the throughput and mean packet delay per station

    Ultrahigh Energy Neutrinos

    Get PDF
    The ultrahigh energy neutrino cross section is well understood in the standard model for neutrino energies up to 1012^{12} GeV. Test of neutrino oscillations (νμ↔ντ\nu_\mu\leftrightarrow\nu_\tau) from extragalactic sources of neutrinos are possible with large underground detectors. Measurments of horizontal air shower event rates at neutrino energies above 1010^{10} GeV will be able to constrain nonstandard model contributions to the neutrino-nucleon cross section, e.g., from mini-black hole production.Comment: 7 pages, presented at Neutrinos and Implications for Physics Beyond the Standard Model, Stony Brook, NY, October 11-13, 200

    Promoting Awareness of Teen Pregnancy Through Multimedia Storytelling: The Case of Elizabeth House in Ecuador

    Get PDF
    Advocacy journalism takes the basic principles of journalism — factual integrity, clear concise writing, storytelling, and educating the public — and uses them to tell the story of a particular cause or organization. Advocacy journalism moves one step past the traditional confines of journalism to reach an audience with a particular message. As Reader (2011) said, Objectivity is about presenting what is, but advocacy is about changing what will be (p. 2). The goal of this project was to use advocacy journalism within a blog platform to raise awareness of the work for the not-for-profit organization, Casa Elizabeth, a home for pregnant teenagers in crisis situations in Quito, Ecuador. The project represents a creative project begun during the summer of 2014 (when the researcher served as an intern living in Casa Elizabeth for two months with five teen moms and their children) and continued through the 2014-2015 school year. The project was accomplished through a blog that told the stories of the home — the participants\u27, the workers\u27, and mine (as participant-observer journalist) — to gain support for Casa Elizabeth. The blog posts were both in Spanish and English, incorporating media such as photography, audio and info graphics. To measure effectiveness, a record was kept of followers, hits, shares, and the likes of particular posts. This record was used to create a best practices methodology. Conclusions show that consistent posting increases blog participation over time, builds a social media network surrounding the blog and creates a greater reader-investment in the cause
    • …
    corecore