CP--odd Correlation in the Decay of Neutral Higgs Boson into ZZZZ, W+W−W^+W^-, or ttˉt{\bar t}

We investigate the possibility of detecting CP--odd angular correlations in the various decay modes of the neutral Higgs boson including the modes of a $ZZ$ pair, a $W^+W^-$ pair, or a heavy quark pair. It is a natural way to probe the CP character of the Higgs boson once it is identified. Final state interactions (i.e. the absorptive decay amplitude) is not required in such correlations. As an illustrative example we take the fundamental source of the CP nonconservation to be in the Yukawa couplings of the Higgs boson to the heavy fermions. A similar correlation in the process $e^+e^- \to l^+ l^- H$ is also proposed. Our analysis of these correlations will be useful for experiments in future colliders such as LEP II, SSC, LHC or NLC.Comment: 16 pages, plus 8 postscript graphs not posted befor

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

Proton Decay and Cosmology Strongly Constrain the Minimal SU(5) Supergravity Model

We present the results of an extensive exploration of the five-dimensional parameter space of the minimal $SU(5)$ supergravity model, including the constraints of a long enough proton lifetime (\tau_p>1\times10^{32}\y) and a small enough neutralino cosmological relic density ($\Omega_\chi h^2_0\le1$). We find that the combined effect of these two constraints is quite severe, although still leaving a small region of parameter space with m_{\tilde g,\tilde q}<1\TeV. The allowed values of the proton lifetime extend up to \tau_p\approx1\times10^{33}\y and should be fully explored by the SuperKamiokande experiment. The proton lifetime cut also entails the following mass correlations and bounds: m_h\lsim100\GeV, m_\chi\approx{1\over2}m_{\chi^0_2}\approx0.15\gluino, $m_{\chi^0_2}\approx m_{\chi^+_1}$, and m_\chi<85\,(115)\GeV, m_{\chi^0_2,\chi^+_1}<165\,(225)\GeV for $\alpha_3=0.113\,(0.120)$. Finally, the {\it combined} proton decay and cosmology constraints predict that if m_h\gsim75\,(80)\GeV then m_{\chi^+_1}\lsim90\,(110)\GeV for $\alpha_3=0.113\,(0.120)$. Thus, if this model is correct, at least one of these particles will likely be observed at LEPII.Comment: 11 pages plus 5 figures (not included). CERN-TH.6628/92, CTP-TAMU-61/92. A condensed version of this paper will appear in the Proceedings of the XXVI International Conference on High Energy Physics, Dallas--Texas, August 5--12, 199

Higgs-Boson Decay to Four Fermions Including a Single Top Quark Below ttˉt \bar t Threshold

The rare decay modes Higgs $\rightarrow$ four light fermions, and Higgs $\rightarrow$ single top-quark + three light fermions for $m_t<M_H<2m_t$, are presented, and phenomenologically interpreted. The angular correlation between fermion planes is presented as a test of the spin and intrinsic parity of the Higgs particle. In Higgs decay to single top, two tree-level graphs contribute in the standard model (SM); one couples the Higgs to $W^+W^-(\sim gM_W)$, and one to t\bar t(\sim g_{top\;yukawa}=m_t/246\GeV). The large Yukawa coupling for m_t>100\GeV makes the second amplitude competitive or dominant for most $M_H,m_t$ values. Thus the Higgs decay rate to single top directly probes the SM universal mechanism generating both gauge boson and fermion masses, and offers a means to infer the Higgs-$t \bar t$ Yukawa coupling when $H\rightarrow t \bar t$ is kinematically disallowed. We find that the modes $pp\rightarrow Xt\bar t(H\rightarrow t\bar b W^{(*)})$ at the SSC, and $e^+ e^-\rightarrow Z\,or\,\nu\bar{\nu} + (H\rightarrow t\bar b W^{(*)})$ at future high energy, high luminosity colliders, may be measureable if $2m_t$ is not too far above $M_H$. We classify non-standard Higgses as gaugeo-phobic, fermio-phobic or fermio-philic, and discuss the Higgs$\rightarrow$ single top rates for these classes.Comment: 30 pages, 6 figures (figures available upon request); VAND-TH-93/

New Constraints on Neutralino Dark Matter in the Supersymmetric Standard Model

We investigate the prospects for neutralino dark matter within the Supersymmetric Standard Model (SSM) including the constraints from universal soft supersymmetry breaking and radiative breaking of the electroweak symmetry. The latter is enforced by using the one-loop Higgs effective potential which automatically gives the one-loop corrected Higgs boson masses. We perform an exhaustive search of the allowed five-dimensional parameter space and find that the neutralino relic abundance $\Omega_\chi h^2_0$ depends most strongly on the ratio $\xi_0\equiv m_0/m_{1/2}$. For $\xi_0\gg1$ the relic abundance is almost always much too large, whereas for $\xi_0\ll1$ the opposite occurs. For $\xi_0\sim1$ there are wide ranges of the remaining parameters for which $\Omega_\chi\sim1$. We also determine that m_{\tilde q}\gsim250\GeV and m_{\tilde l}\gsim100\GeV are necessary in order to possibly achieve $\Omega_\chi\sim1$. These lower bounds are much weaker than the corresponding ones derived previously when radiative breaking was {\it not} enforced.Comment: 12 pages plus 6 figures (not included), CERN-TH.6584/92, CTP-TAMU-56/92, UAHEP921

Tevatron and LEP-II Probes of Minimal and String-Motivated Supergravity Models

We explore the ability of the Tevatron to probe Minimal Supersymmetry with high energy scale boundary conditions motivated by supersymmetry breaking in the context of supergravity/superstring theory. A number of boundary condition possibilities are considered: dilaton-like string boundary conditions applied at the standard GUT unification scale or alternatively at the string scale; and extreme (``no-scale'') minimal supergravity boundary conditions imposed at the GUT scale or string scale. For numerous specific cases within each scenario the sparticle spectra are computed and then fed into ISAJET 7.07 so that explicit signatures can be examined in detail. We find that, for some of the boundary condition choices, large regions of parameter space can be explored via same-sign dilepton and isolated trilepton signals. For other choices, the mass reach of Tevatron collider experiments is much more limited. We also compare mass reach of Tevatron experiments with the corresponding reach at LEP 200.Comment: 44 pages, requires phyzzx.tex, tables.tex, full postscript file including embedded figures available via anonymous ftp at ucdhep.ucdavis.edu as [anonymous.gunion]bgkp.ps, preprint UCD-94-1

Christianity, Englishness and the southern English countryside: a study of the work of H.J. Massingham

This paper explores the relationships between Christianity, Englishness, and ideas about the southern English landscape in the writings of the 1930s and 1940s rural commentator, H.J. Massingham. The paper begins by looking in general terms at the conjunction of religious and national identities in the context of national landscapes before moving on to consider in more detail one particular instance of this in the writing of H.J. Massingham. Massingham's understanding of a divine natural order, his construction of a kind of 'divine Englishness' and the way in which he relates this to particular English landscapes is explored. In particular, the paper investigates the natural, social and political power relationships which are embedded in Massingham's work, and suggests that his writing provides an interesting example of one way in which theological reasoning can reflect and reinforce concepts of a naturally ordered national identity