663 research outputs found

    Unknowns after the SNO Charged-Current Measurement

    Get PDF
    We perform a model-independent analysis of solar neutrino flux rates including the recent charged-current measurement at the Sudbury Neutrino Observatory (SNO). We derive a universal sum rule involving SNO and SuperKamiokande rates, and show that the SNO neutral-current measurement can not fix the fraction of solar νe\nu_e oscillating to sterile neutrinos. The large uncertainty in the SSM 8^8B flux impedes a determination of the sterile neutrino fraction.Comment: Version to appear in PRL; includes analysis with anticipated SNO NC measuremen

    A p-Adic Model of DNA Sequence and Genetic Code

    Full text link
    Using basic properties of p-adic numbers, we consider a simple new approach to describe main aspects of DNA sequence and genetic code. Central role in our investigation plays an ultrametric p-adic information space which basic elements are nucleotides, codons and genes. We show that a 5-adic model is appropriate for DNA sequence. This 5-adic model, combined with 2-adic distance, is also suitable for genetic code and for a more advanced employment in genomics. We find that genetic code degeneracy is related to the p-adic distance between codons.Comment: 13 pages, 2 table

    Schizophrenic active neutrinos and exotic sterile neutrinos

    Get PDF
    We implement a schizophrenic scenario for the active neutrinos in a model in which there are also exotic right-handed neutrinos making a model with a local U(1)_(B-L) anomaly free. Two of right-handed neutrinos carry B-L=-4 while the third one carries B-L=5.Comment: I, A. C. B. Machado, apologize for having submitted the wrong file before. This is in fact the version to be published in Physics Letters B 698 (2011) pp. 128-13

    Bridging The Gaps: How Students Seek Disciplinary Coherence In Introductory Physics For Life Science

    Get PDF
    Students in one discipline often receive their scientific training from faculty in other disciplines. As a result of tacit disciplinary differences, especially as implemented in courses at the introductory college level, such students can have difficulty in understanding the nature of the knowledge they are learning in a discipline that they do not identify as their own. We developed a course in introductory physics for life science (IPLS) students that attempts to help them cross disciplinary boundaries. By analyzing student reasoning during recitation sections and interviews, we identified three broad ways in which students in our course meaningfully crossed boundaries: (i) by unpacking biochemical heuristics in terms of underlying physical interactions, (ii) by locating both biochemical and physical concepts within a mathematical bridging expression, and (iii) by coordinating functional and mechanistic explanations for the same biological phenomenon. Drawing on episodes from case-study interviews and in-class problem-solving sessions, we illustrate how each of these types of boundary crossing involves the coordination of students’ conceptual and epistemological resources from physics, chemistry, and biology in distinct but complementary ways. Together, these boundary crossing categories form a theoretical framework for classifying student coherence seeking. We explore how the IPLS course helps our life science students fill in the gaps that exist between traditional introductory courses, by finding and exploring questions that might otherwise fall through disciplinary cracks. By identifying these types of explanatory coherence, we hope to suggest ways of inviting life science students to participate in physics and see physics as a tool for making sense of the living world

    Search for a Lorentz invariance violation in atmospheric neutrino oscillations using MACRO data

    Get PDF
    The energy spectrum of neutrino-induced upward-going muons in MACRO was analysed in terms of special relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of nu_mu nu_tau transitions. The data disfavour these exotic possibilities even at a sub-dominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameters. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the Equivalence Principle.Comment: 8 pages, 5 EPS figures, uses article.sty. Invited talk at C2CR 2005, From Colliders to Cosmic Rays, Prague, Czech Republic, 7-13 September 200

    Symmetric Textures in SO(10) and LMA Solution for Solar Neutrinos

    Full text link
    We analyze a model based on SUSY SO(10) combined with SU(2) family symmetry and symmetric mass matrices constructed by the authors recently. Previously, only the parameter space for the LOW and vacuum oscillation (VO) solutions was investigated. We indicate in this note the parameter space which leads to large mixing angle (LMA) solution to the solar neutrino problem with a slightly modified effective neutrino mass matrix. The symmetric mass textures arising from the left-right symmetry breaking and the SU(2) symmetry breaking give rise to very good predictions for the quark and lepton masses and mixing angles. The prediction of our model for the |U_{e\nu_{3}}| element in the Maki-Nakagawa-Sakata (MNS) matrix is close to the sensitivity of current experiments; thus the validity of our model can be tested in the near future. We also investigate the correlation between the |U_{e\nu_{3}}| element and \tan^{2}\theta_{\odot} in a general two-zero neutrino mass texture.Comment: RevTeX4; 9 pages; 1 figur

    New interactions: past and future experiments

    Get PDF
    In this talk I will review the present status and future perspectives of some popular extensions of the conventional three-neutrino oscillation scenario, from a purely phenomenological point of view. For concreteness I will focus only on three specific scenarios: non-standard neutrino interactions with matters, models with extra sterile neutrinos, and neutrino decay and decoherence.Comment: LaTeX file using jpconf class, 8 pages, 2 tables. Proceedings of the "XXIII International Conference on Neutrino Physics and Astrophysics" (Neutrino 08), Christchurch, New Zealand, May 25-31, 200
    • …
    corecore