1,328 research outputs found

    Strong Phases in the Decays B to pi pi

    Full text link
    Two sources of strong phases in the decays BB to ππ\pi\pi are identified: (1) "quasi-elastic scattering" corresponding to intermediate states like ππ\pi\pi and ρρ\rho\rho, (2) ``ccˉc\bar{c}'' corresponding to intermediate states like DDˉD\bar{D} and DDˉD^{*}\bar{D}^{*}. Possibilities of using data to identify these two sources are discussed and illustrated. Present data suggests both sources may be significant.Comment: 6 pages, 1 figure

    Neutrino Masses and Oscillations in Models with Large Extra Dimensions

    Get PDF
    We discuss the profile of neutrino masses and mixings in models with large extra dimensions when right handed neutrinos are present in the branes along with the usual standard model particles. In these models, string scale must be bigger than 10810^{8} GeV to have desired properties for the neutrinos at low energies. The lightest neutrino mass is zero and there is oscillations to sterile neutrinos that are different from other models with the bulk neutrino.Comment: Minor changes. 9 pages, latex file, uses epsf style, two figures included. To appear at Phys. Lett.

    Bounds on sterile neutrino mixing for cosmologically interesting mass range

    Get PDF
    This talk summarizes our recent work which studied the impact of resonant νeνs\nu_e \to\nu_s and νˉeνˉs\bar{\nu}_e\to\bar{\nu}_s (νs\nu_s is a sterile neutrino) conversions on supernova physics, under the assumption that the mass of the sterile state is in the few eV -cosmologically significant range.Comment: Latex file, 3 pages including 4 ps figures, Talk given by H. Nunokawa in TAUP97, Gran Sasso, Italy, 7-11 September, 199

    Non-leptonic B-decays, CP violation & the UT

    Full text link
    We study the implication of the time-dependent CP asymmetry in Bπ+πB\to\pi^+\pi^- decays on the extraction of weak phases taking into account the precise measurement of sin2β\sin 2\beta, obtained from the ``gold-plated''mode BJ/ψKSB\to J/\psi K_S. Predictions and uncertainties for the hadronic parameters are investigated in QCD factorization. Furthermore, independent theoretical and experimental tests of the factorization framework are briefly discussed. Finally, a model-independent bound on the unitarity triangle from CP violation in Bπ+πB\to\pi^+\pi^- and BJ/ψKSB\to J/\psi K_S is derived.Comment: 4 pages; 4 figures (requires epsfig, psfrag); To appear in the proceedings of the 11th International Conference on Quantum Chromodynamics (QCD 04), Montpellier, France, 5--10th July 200

    Comment on ``Neutrino masses and mixing angles in a predictive theory of fermion masses''

    Full text link
    In the extension of the Dimopoulos--Hall--Raby model of the fermion mass matrices to the neutrino sector, there is an entry in the up-quark and neutrino Dirac mass matrices which can be assumed to arise from the Yukawa coupling of a {\bf 120}, instead of a {\bf 10} or a {\bf 126}, of SO(10). Although this assumption leads to an extra undetermined complex parameter in the model, the resulting lepton mixing matrix exhibits the remarkable feature that the ντ \nu_{\tau} does not mix with the other two neutrinos. Making a reasonable assumption about the extra parameter, we are able to fit the large-mixing-angle MSW solution of the solar-neutrino problem, and we obtain mντ10 m_{\nu_{\tau}} \sim 10 eV, the right mass range to close the Universe. Other possibilities for explaining the solar-neutrino deficit are also discussed.Comment: standard LATEX, 6 pages, 2 figures available from the authors, report No. CMU-HEP93-20 and DOE-ER/40682-4

    Neutrinoless Double Beta Decay and CP Violation

    Full text link
    We study the relation between the Majorana neutrino mass matrices and the neutrinoless double beta decay when CP is not conserved. We give an explicit form of the decay rate in terms of a rephasing invariant quantity and demonstrate that in the presence of CP violation it is impossible to have vanishing neutrinoless double beta decay in the case of two neutrino generations (or when the third generation leptons do not mix with other leptons and hence decouple).Comment: 9 pages, UTPT-93-1

    Crowdsourcing Digital Public History

    Get PDF
    The generation of communal knowledge is not a new phenomenon. In the late nineteenth century, the Oxford English Dictionary solicited volunteers to submit words and their usage for inclusion in the dictionary ( 1 ). Carl Becker, writing in 1932 on what was already an old discussion in the historical profession, noted that if the essence of history is the memory of things said and done, then it is obvious that every normal person, Mr. Everyman, knows some history (2). The historian Jo Guldi\u27s work on participatory mapping shows that urban planners in the middle of the twentieth century attempted to learn from and listen to members of a community. There is plenty of precedent, then, for harnessing participatory knowledge. Today, the digital turn has offered new technologies to engage with communities and significantly widened the number of possible participants. The success of recent digital crowdsourcing projects, including Flickr Commons, the National Archive\u27s Citizen Archivist Dashboard, History Harvest, and Transcribe Bentham have demonstrated the degree of success that crowdsourcing offers to cultural heritage and public digital history. Like any research, a crowdsourcing project requires careful planning and an understanding of what is meant by crowdsourcing in a specific project. In this essay we discuss the importance of these definitions, describe a few successful and well-known crowdsourced projects, and discuss one of the projects we are working on here at Stanford\u27s Center for Spatial and Textual Analysis (CESTA)

    Desperately Seeking Non-Standard Phases via Direct CP Violation in bsgb\to sg^\ast Process

    Full text link
    Attributing the recent CLEO discovery of Bη+XsB \to \eta' + X_s to originate (primarily) from the fragmentation of an off-shell gluon (gg^*) via bs+gb \to s + g^*, gg+ηg^* \to g + \eta', we emphasize that many such states (XgX_g) should materialize. Indeed the hadronic fragments (XgX_g) of gg^* states are closely related to those seen in ψγ(ϕ,ω)+Xg\psi \to \gamma (\phi, \omega) + X_g. A particular final state of considerable interest is Xg=K+KX_g=K^+K^-. Signals from such states in BB decays can be combined to provide a very sensitive search for CP violating phase(s) from non-standard physics. The method should work even if the contribution of these source(s) to the rates is rather small (10\sim10%) to the point that a comparison between theory and experiment may find it extremely difficult to reveal the presence of such a new physics.Comment: 16 pages, 5 figure

    Electroweak Radiative Corrections to Muon Capture

    Full text link
    Electroweak radiative corrections to muon capture on nuclei are computed and found to be sizable. They enhance the capture rates for hydrogen and helium by 2.8% and 3.0% respectively. As a result, the value of the induced pseudoscalar coupling, g_P^exp, extracted from a recent hydrogen 1S singlet capture experiment is increased by about 21% to g_P^exp = 7.3 +/- 1.2 and brought into good agreement with the prediction of chiral perturbation theory, g_P^theory=8.2 +/- 0.2. Implications for helium capture rate predictions are also discussed.Comment: 6 page

    Probing neutrino oscillations jointly in long and very long baseline experiments

    Full text link
    We examine the prospects of making a joint analysis of neutrino oscillation at two baselines with neutrino superbeams. Assuming narrow band superbeams and a 100 kt water Cerenkov calorimeter, we calculate the event rates and sensitivities to the matter effect, the signs of the neutrino mass differences, the CP phase and the mixing angle \theta_{13}. Taking into account all possible experimental errors under general consideration, we explored the optimum cases of narrow band beam to measure the matter effect and the CP violation effect at all baselines up to 3000 km. We then focus on two specific baselines, a long baseline of 300 km and a very long baseline of 2100 km, and analyze their joint capabilities. We found that the joint analysis can offer extra leverage to resolve some of the ambiguities that are associated with the measurement at a single baseline.Comment: 23 pages, 11 figure
    corecore