Solar Neutrinos: Radiative Corrections in Neutrino-Electron Scattering Experiments

Radiative corrections to the electron recoil-energy spectra and to total cross sections are computed for neutrino-electron scattering by solar neutrinos. Radiative corrections change monotonically the electron recoil spectrum for incident \b8 neutrinos, with the relative probability of observing recoil electrons being reduced by about 4 \% at the highest electron energies. For $p-p$ and \be7 neutrinos, the recoil spectra are not affected significantly. Total cross sections for solar neutrino-electron scattering are reduced by about 2 \% compared to previously computed values. We also calculate the recoil spectra from $^{13}$N and $^{15}$O neutrinos including radiative corrections.Comment: 40 pages, uuencoded, Z-compress file

On the observability of the neutrino charge radius

It is shown that the probe-independent charge radius of the neutrino is a physical observable; as such, it may be extracted from experiment, at least in principle. This is accomplished by expressing a set of experimental neutrino-electron cross-sections in terms of the finite charge radius and two additional gauge- and renormalization-group-invariant quantities, corresponding to the electroweak effective charge and mixing angle.Comment: 10 pages, 1 figure; a typo in Eq.1 corrected, some comments adde

Electroweak radiative corrections to deep-inelastic neutrino scattering - implications for NuTeV ?

We calculate the O(alpha) electroweak corrections to charged- and neutral-current deep-inelastic neutrino scattering off an isoscalar target. The full one-loop-corrected cross sections, including hard photonic corrections, are evaluated and compared to an earlier result which was used in the NuTeV analysis. In particular, we compare results that differ in input-parameter scheme, treatment of real photon radiation and factorization scheme. The associated shifts in the theoretical prediction for the ratio of neutral- and charged-current cross sections can be larger than the experimental accuracy of the NuTeV result.Comment: 19 pages late

On a Neutrino Electroweak Radius

We study a combination of amplitudes for neutrino scattering that can isolate a (gauge-invariant) difference of chirality-preserving neutrino electroweak radii for $\nu_\mu$ and $\nu_\tau$. This involves both photon and $Z_\mu$ exchange contributions. It is shown that the construction singles out the contributions of the hypercharge gauge field $B_{\mu}$ in the standard model. We comment on how gauge-dependent terms from the charge radii cancel with other terms in the relative electroweak radii defined.Comment: 16 pages, revtex with embedded figure

Standard Model Contributions to the Neutrino Index of Refraction in the Early Universe

With the standard electroweak interactions, the lowest-order coherent forward scattering amplitudes of neutrinos in a CP symmetric medium (such as the early universe) are zero, and the index of refraction of a propagating neutrino can only arise from the expansion of gauge boson propagators, from radiative corrections, and from new physics interactions. Motivated by nucleosynthesis constraints on a possible sterile neutrino (suggested by the solar neutrino deficit and a possible $17\ keV$ neutrino), we calculate the standard model contributions to the neutrino index of refraction in the early universe, focusing on the period when the temperature was of the order of a few $MeV$. We find sizable radiative corrections to the tree level result obtained by the expansion of the gauge boson propagator. For $\nu_e+e(\bar{e})\to \nu_e+e(\bar{e})$ the leading log correction is about $+10\%$, while for $\nu_e+\nu_e(\bar{\nu}_e)\to \nu_e+\nu_e(\bar{\nu}_e)$ the correction is about $+20\%$. Depending on the family mixing (if any), effects from different family scattering can be dominated by radiative corrections. The result for $\nu+\gamma\to\nu+\gamma$ is zero at one-loop level, even if neutrinos are massive. The cancellation of infrared divergence in a coherent process is also discussed.Comment: 46pp, 13 figures (not included), UPR-0495

Designing Research

The aim of this chapter is to set out a process that researchers can follow to design a robust quantitative research study of occupant behavior in buildings. Central to this approach is an emphasis on intellectual clarity around what is being measured and why. To help achieve this clarity, researchers are encouraged to literally draw these relationships out in the form of a concept map capturing the theoretical model of the cause and effect between occupant motivations and energy use. Having captured diagrammatically how the system is thought to work, the next step is to formulate research questions or hypotheses capturing the relationship between variables in the theoretical model, and to start to augment the diagram with the measurands (things that can actually be measured) that are good proxies for each concept. Once these are identified, the diagram can be further augmented with one or more methods of measuring each measurand. The chapter argues that it is necessary to carefully define concepts and their presumed relationships, and to clearly state research questions and identify what the researcher intends to measure before starting data collection. The chapter also explains the ideas of reliability, validity, and uncertainty, and why knowledge about them is essential for any researcher

Capturing the essence of grounded theory: the importance of understanding commonalities and variants

This paper aims to capture the essence of grounded theory (GT) by setting out its commonalities and variants and, importantly, the implications of the latter for the implementation of the former, and for the truth claims and the contributions to knowledge that a GT study might make. Firstly, three ontological and epistemological variants of GT are outlined. Secondly, the commonalities of GT are set out as eight core elements of GT methodology that are individually necessary, but only sufficient collectively, to define a GT study. These elements are: an iterative process; theoretical sampling; theoretical sensitivity; codes, memos and concepts; constant comparison; theoretical saturation; fit, work, relevance and modifiability; and substantive theory. Thirdly, the implications of the ontological and epistemological variants of GT for, firstly, the implementation of the core common elements of the methodology and, secondly, the truth claims and contributions to knowledge that might be made, are discussed. Finally, the paper concludes by arguing that published GT studies in sport, exercise and health research have not always explicitly demonstrated a full understand of the commonalities and variants of GT, and that researchers publishing GT studies must take responsibility for doing this

Incorporation of QCD Effects in Basic Corrections of the Electroweak Theory

We study the incorporation of QCD effects in the basic electroweak corrections \drcar, \drcarw, and \dr. They include perturbative \Ord{\alpha\alpha_s} contributions and $t\bar{t}$ threshold effects. The latter are studied in the resonance and Green-function approaches, in the framework of dispersion relations that automatically satisfy relevant Ward identities. Refinements in the treatment of the electroweak corrections, in both the \ms\ and the on-shell schemes of renormalization, are introduced, including the decoupling of the top quark in certain amplitudes, its effect on \hat{e}^2(\mz) and \sincarmz, the incorporation of recent results on the leading irreducible \Ord{\alpha^2} corrections, and simple expressions for the residual, i.e.\ ``non-electromagnetic'', parts of \drcar, \drcarw, and \dr. The results are used to obtain accurate values for \mw\ and \sincarmz, as functions of \mt\ and \mh. The higher-order effects induce shifts in these parameters comparable to the expected experimental accuracy, and they increase the prediction for \mt\ derived from current measurements. The \ms\ and the on-shell calculations of \dr, in a recently proposed formulation, are compared and found to be in excellent agreement over the wide ranges 60\GeV \leq \mh \leq 1 \TeV, \mz \leq \mt \leq 250 \GeV.Comment: 51 pages (needs doublespace, equations, and cite styles

Precision Electroweak Tests of the Minimal and Flipped SU(5) Supergravity Models

We explore the one-loop electroweak radiative corrections in the minimal $SU(5)$ and the no-scale flipped $SU(5)$ supergravity models via explicit calculation of vacuum polarization contributions to the $\epsilon_{1,2,3}$ parameters. Experimentally, $\epsilon_{1,2,3}$ are obtained from a global fit to the LEP observables, and $M_W/M_Z$ measurements. We include $q^2$-dependent effects which have been neglected in most previous ``model-independent" analyses of this type. These effects induce a large systematic negative shift on $\epsilon_{1,2,3}$ for light chargino masses (m_{\chi^\pm_1}\lsim70\GeV). In agreement with previous general arguments, we find that for increasingly large sparticle masses, the heavy sector of both models rapidly decouples, \ie, the values for $\epsilon_{1,2,3}$ quickly asymptote to the Standard Model values with a {\it light} Higgs (m_{H_{SM}}\sim100\GeV). Specifically, at present the $90\%$ CL upper limit on the top-quark mass is m_t\lsim175\GeV in the no-scale flipped $SU(5)$ supergravity model. These bounds can be strengthened for increasing chargino masses in the 50-100\GeV interval. In particular, for m_t\gsim160\GeV, the Tevatron may be able to probe through gluino($\tilde g$) and squark($\tilde q$) production up to m_{\tilde g}\approx m_{\tilde q}\approx250\GeV, exploring at least half of the parameter space in this model.Comment: 15 pages,(6 ps figures available upon request), TeX(harvmac), CTP-TAMU-19/93, ACT-07/9