1,801 research outputs found

    Electroweak Radiative Corrections To Polarized M{\o}ller Scattering Asymmetries

    Get PDF
    One loop electroweak radiative corrections to left-right parity violating M{\o}ller scattering (eeeee^-e^-\to e^-e^-) asymmetries are presented. They reduce the standard model (tree level) prediction by 40±3\pm 3 \% where the main shift and uncertainty stem from hadronic vacuum polarization loops. A similar reduction also occurs for the electron-electron atomic parity violating interaction. That effect can be attributed to an increase of sin2θW(q2)\sin^2\theta_W(q^2) by 3%3\% in running from q2=mZ2q^2=m_Z^2 to 0. The sensitivity of the asymmetry to ``new physics'' is also discussed.Comment: 14 pages, Revtex, postscript file including figures is available at ftp://ttpux2.physik.uni-karlsruhe.de/ttp95-14/ttp95-14.ps or via WWW at http://ttpux2.physik.uni-karlsruhe.de/cgi-bin/preprints/ (129.13.102.139

    Opening Eyes by Opening Classroom Doors: Multicultural Musings of Study Abroad in Italy

    Get PDF
    Abstract Opening Eyes by Opening Classroom Doors: Multicultural Musings of Study Abroad in Italy This narrative inquiry examines multicultural site-based experiences of five pre-service teachers (early childhood and special education) during a four-week university sponsored study abroad program. Experiential learning (Kolb, 1984) opportunities were created for observations and teaching mini-lessons in Italian classrooms and immersion into Italian culture. The researcher’s study emanates from the pre-service teachers’ daily journal entries, informal conversations, and personal observations of reflections of their developing multicultural understandings, scaffolding upon their rural American backgrounds. To facilitate processing their lived experiences, it was necessary to work from an operational definition of culture (Nieto & Bode, 2012), collecting and interpreting data, and making their unique stories personally meaningful (Connelly and Clandinin, 2006). Conclusions indicate program goals of opening eyes through opening classroom doors were met, stimulating a wider global lens and a more critical, deeper understanding of others, moving beyond generalizations and stereotypes. Keywords: Pre-service teachers, study abroad, multiculturalism, narrative inquir

    Radiative Tail in πe2\pi_{e2} Decay and Some Comments on μe\mu-e Universality

    Full text link
    The result of lowest-order perturbation theory calculations of the photon and positron spectra in radiative pion(e2) decay are generalized to all orders of perturbation theory using the structure-function method. An additional source of radiative corrections to the ratio of the positron and muon channels of pion decay, due to emission of virtual and real photons and pairs, is considered. It depends on details of the detection of the final particles and is large enough to be taken into account in theoretical estimates with a level of accuracy of 0.1%.Comment: 5 pages, LaTeX, some misprints are corrected, submitted to Pisma Zh. Eksp. Teor. Fi

    A new method for extracting the bottom quark Yukawa coupling at the CERN Large Hadron Collider

    Get PDF
    We propose a new method for measuring the H -> bb rate at the CERN LHC in a manner which would allow extraction of the b quark Yukawa coupling. Higgs boson production in purely electroweak WHjj events is calculated. The Standard Model signal rate including decays W -> l nu and H -> bb is 11 fb for M_H = 120 GeV. It is possible to suppress the principal backgrounds, Wbbjj and ttjj, to approximately the level of the signal. As the top quark Yukawa coupling does not appear in this process, it promises a reliable extraction of g_Hbb in the context of the Standard Model or some extensions, such as the MSSM.Comment: added background, updated/added references, additional comment

    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

    SM Kaluza-Klein Excitations and Electroweak Precision Tests

    Get PDF
    We consider a minimal extension to higher dimensions of the Standard Model, having one compactified dimension, and we study its experimental tests in terms of electroweak data. We discuss tests from high-energy data at the ZZ-pole, and low-energy tests, notably from atomic parity violation data. This measurement combined with neutrino scattering data strongly restricts the allowed region of the model parameters. Furthermore this region is incompatible at 95% CL with the restrictions from high-energy experiments. Of course a global fit to all data is possible but the χmin2\chi^2_{\rm min} for degree of freedom is unpleasantly large.Comment: LaTex, 14 pages, 2 figures. More refs. and one comment about the validity of our results for any number of extra dimensions adde

    Rare kaon decays in SUSY with non-universal A terms

    Full text link
    We study the rare kaon decays in the framework of general SUSY models. Unlike the results in the literature, we find the contributions from the gluino exchange to the branching ratio of K+π+ννˉK^+\to \pi^+ \nu \bar{\nu} can reach the central value (1.5×1010\sim 1.5 \times 10^{-10}) of the new E787 data while the predicted value of standard model is less than 101010^{-10}. We also find that the same effects also enhance the decays of KLπ0ννˉK_{L}\to \pi^0 \nu \bar{\nu}, KLπ0e+eK_L\to\pi^0e^{+} e^{-} and KLμ+μK_L\to\mu^+ \mu^-.Comment: 9 pages, references added, revised version to appear in J. Phys.

    The Height of a Giraffe

    Full text link
    A minor modification of the arguments of Press and Lightman leads to an estimate of the height of the tallest running, breathing organism on a habitable planet as the Bohr radius multiplied by the three-tenths power of the ratio of the electrical to gravitational forces between two protons (rather than the one-quarter power that Press got for the largest animal that would not break in falling over, after making an assumption of unreasonable brittleness). My new estimate gives a height of about 3.6 meters rather than Press's original estimate of about 2.6 cm. It also implies that the number of atoms in the tallest runner is very roughly of the order of the nine-tenths power of the ratio of the electrical to gravitational forces between two protons, which is about 3 x 10^32.Comment: 12 pages, LaTe
    corecore