518 research outputs found

    Measurement of beta_s at CDF

    Full text link
    The latest results for the measurement of the CP violating phase beta_s in B0s -> J/psi phi decays, from 5.2 fb-1 integrated luminosity of CDF data are presented. For the first time, this measurement includes the contribution of B0s -> J/psi K+K- or B0s -> J/psi f0 events to the signal sample, where the f0 and non-resonant K+K- are S-wave states. Additional improvements to the analysis include more than doubling the signal sample, improved selection and particle ID, and fully calibrated flavour tagging for the full dataset. Additionally, the world's most precise single measurements of the B0s lifetime, tau_s, and width difference, DeltaGamma_s are given.Comment: Proceedings of FPCP 2010, 7 pages, 4 figure

    Light Neutralino Dark Matter in the NMSSM

    Full text link
    Neutralino dark matter is generally assumed to be relatively heavy, with a mass near the electroweak scale. This does not necessarily need to be the case, however. In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and other supersymmetric models with an extended Higgs sector, a very light CP-odd Higgs boson can naturally arise making it possible for a very light neutralino to annihilate efficiently enough to avoid being overproduced in the early Universe. In this article, we explore the characteristics of a supersymmetric model needed to include a very light neutralino, 100 MeV < \mcnone < 20 GeV, using the NMSSM as a prototype. We discuss the most important constraints from Upsilon decays, b→sÎłb \to s \gamma, Bs→Ό+Ό−B_s \to \mu^+ \mu^- and the magnetic moment of the muon, and find that a light bino or singlino neutralino is allowed, and can be generated with the appropriate relic density. It has previously been shown that the positive detection of dark matter claimed by the DAMA collaboration can be reconciled with other direct dark matter experiments such as CDMS II if the dark matter particle is rather light, between about 6 and 9 GeV. A singlino or bino-like neutralino could easily fall within this range of masses within the NMSSM. Additionally, models with sub-GeV neutralinos may be capable of generating the 511 keV gamma-ray emission observed from the galactic bulge by the INTEGRAL/SPI experiment. We also point out measurements which can be performed immediately at CLEO, BaBar and Belle using existing data to discover or significantly constrain this scenario.Comment: References updated, accepted for publication in PR

    The Atmospheric Muon Charge Ratio at the MINOS Near Detector

    Full text link
    The magnetized MINOS near detector can accurately determine the charge sign of atmospheric muons, this facilitates a measurement of the atmospheric muon charge ratio. To reduce the systematic error associated with geometric bias and acceptance we have combined equal periods of data obtained with opposite magnetic field polarities. We report a charge ratio of 1.2666±0.0015(stat.)−0.0088+0.0096(syst.)1.2666\pm0.0015(stat.)^{+0.0096}_{-0.0088}(syst.) at a mean EÎŒ,0cos(Ξ)_{\mu,0}cos(\theta)=\unit[63]{GeV}. This measurement is consistent with the world average\cite{Hebbeker}\cite{Haino}\cite{Achard} but significantly lower than the earlier observation at the MINOS far detector\cite{Adamson}. This increase is shown to be consistent with the hypothesis that a greater fraction of the observed muons arise from kaon decay within the cosmic ray shower.Comment: Proceedings for the 2009, 31st International Cosmic Ray Conference in Lodz Polan

    The VLBA Imaging and Polarimetry Survey at 5 GHz

    Get PDF
    We present the first results of the VLBA Imaging and Polarimetry Survey (VIPS), a 5 GHz VLBI survey of 1,127 sources with flat radio spectra. Through automated data reduction and imaging routines, we have produced publicly available I, Q, and U images and have detected polarized flux density from 37% of the sources. We have also developed an algorithm to use each source's I image to automatically classify it as a point-like source, a core-jet, a compact symmetric object (CSO) candidate, or a complex source. The mean ratio of the polarized to total 5 GHz flux density for VIPS sources with detected polarized flux density ranges from 1% to 20% with a median value of about 5%. We have also found significant evidence that the directions of the jets in core-jet systems tend to be perpendicular to the electric vector position angles (EVPAs). The data is consistent with a scenario in which ~24% of the polarized core-jets have EVPAs that are anti-aligned with the directions of their jet components and which have a substantial amount of Faraday rotation. In addition to these initial results, plans for future follow-up observations are discussed.Comment: 36 pages, 3 tables, 13 figures; accepted for publication in Ap

    Music for Thought: Examining Saudi Identities Expressed Through Music on Social Media

    Get PDF
    The aim of this chapter is to investigate how social media help create and diffuse popular music in Saudi Arabia and how such music questions the officially accepted identities and social practices. Social media are widely used as means of promotion among artists around the world; yet Saudi Arabia deserves special attention. This is because traditional media act much more strictly as gatekeepers in the kingdom; hence, social media offer greater possibility for circulation of popular entertainment, especially when it touches upon the questions related to the core values of the Saudi society. Such is the case of recordings by Hesham Fageeh “No woman, No drive” (2013) or the recently trending video clip “Hwages” that, both, received peak visibility online and sparked debates about women empowerment. Similarly, some videos trending online prompted a dance craze, for instance, “Barbs” showed a choreography that was subsequently copied by fans who uploaded their performances online. Dancing is a prohibition among the conservative segments of society; yet, the vastly young population of Saudi Arabia seeks entertainment.Social media in Saudi Arabia have become primordial means of communication in the kingdom with highest rates of social media participation in the Middle East and seventh rank in the world (2016). Consequently, this chapter employs a mixed-method approach in order to uncover how social media breaks the monopoly on entertainment by promoting different musical genres and encouraging social debate
    • 

    corecore