14237353
epsilon b constraints on the minimal SU(5) and SU(5) x U(1) supergravity models.
We have performed a systematic analysis to compute the one-loop electroweak corrections to the [ital Z][r arrow][ital b[bar b]] vertex in terms of [epsilon][sub [ital b]] and [ital R][sub [ital b]] in the context of the minimal SU(5) and no-scale SU(5)[times]U(1) supergravity models. With the measured top mass, [ital m][sub [ital t]]=174[plus minus]10[sub [minus]12][sup +13] GeV, recently announced by CDF, we use the latest CERN LEP data on [epsilon][sub [ital b]] and [ital R][sub [ital b]] [[equivalent to][Gamma]([ital Z][r arrow][ital b[bar b]])/[Gamma]([ital Z][r arrow]hadrons)] in order to constrain further the two models. We find that the present LEP data on [epsilon][sub [ital b]] and [ital R][sub [ital b]] constrain the two models rather severely. Especially the low-tan[beta] region is constrained more severely. tan[beta][approx lt]2.5 (4.0) is excluded by [epsilon][sub [ital b]] at 90% C.L. for [ital m][sub [ital t]][approx gt]170 [180] GeV in the minimal SU(5) [no-scale SU(5)[times]U(1)] supergravity. An even more stringent constraint comes from [ital R][sub [ital b]]. It excludes tan[beta][approx lt]4.0 at 90% C.L. for [ital m][sub [ital t]][approx gt]160 [170] GeV in the minimal SU(5) [no-scale SU(5)[times]U(1)] supergravity. We also find that the sign on [mu] in the two models can be determined from [epsilon][sub [italmore » b]] and [ital R][sub [ital b]] at 90% C.L.« less
119883211
Conflicts between B-violating phenomena in supergravity models
Abstract We show that there is an incompatibility between matter stability and cosmological baryon production in standard N = 1 supergravity models. This discrepancy emerges from the bound on the reheating temperature T rh ⩽ 10 10 GeV which comes from the restriction on the gravitino decay after inflation. Some weird possibilities to bypass the controversy are also analyzed.
15739165
SO(10)-like Superstring Standard Model with R-parity from the Heterotic String
We construct a supersymmetric standard model in the context of the Z_{12-I} orbifold compactification of the E_8 x E_8' heterotic string theory. The gauge group is SU(3)_c x SU(2)_L x U(1)_Y x U(1)^4 x [SO(10) x U(1)^3]' with sin^2\theta_W = 3/8. We obtain three families of SO(10) spinor-like chiral matter states, and Higgs doublets. All other extra states are exactly vector-like under the standard model gauge symmetry. There are numerous standard model singlets, many of which get VEVs such that only the standard model gauge symmetry survives and desired Yukawa couplings can be generated at lower energies. In particular, all vector-like exotic states achieve superheavy masses and the R-parity can be preserved.
18138135
Neutrino masses from discrete gauge symmetries
Abstract We investigate a model with an extra Z 2 gauge symmetry in the Standard Model. The symmetry gives a structure to the mass matrix for the neutrinos. With two extra Higgs singlets and two extra singlet right-handed neutrinos we can build a model that fits the requirements of the MSW solution of the Solar neutrino problem. With a third singlet right-handed neutrino it is also possible to have a 10 eV neutrino.
14574575
Effective Gauss-Bonnet interaction in Randall-Sundrum compactification
The effective gravitational interaction below the Planck scale in the Randall-Sundrum world is shown to be the Gauss-Bonnet term. In this theory we find that there exists another static solution with a positive bulk cosmological constant. Also, there exist solutions for a positive visible sector cosmological constant, which is needed for a later Friedmann-Robertson-Walker universe.
119316975
GMSB at a stable vacuum and MSSM without exotics from heterotic string
Abstract We show that it is possible to introduce the confining hidden sector gauge group SU ( 5 ) ′ with the chiral matter 10 0 ′ plus 5 ¯ 0 ′ , which are neutral under the standard model gauge group, toward a gauge mediated supersymmetry breaking (GMSB) in a Z 12 − I orbifold compactification of E 8 × E 8 ′ heterotic string. Three families of MSSM result without exotics. We also find a desirable matter parity P (or R-parity) assignment. We note that this model contains the spectrum of the Lee–Weinberg model which has a nice solution of the μ problem.
46735209
Linear canonical transformations of coherent and squeezed states in the Wigner phase space. II. Quantitative analysis.
Il est possible de calculer les valeurs d'expectation et les probabilites de transition a partir de la fonction de distribution phase-espace de Wigner. Sur la base des proprietes de transformation canonique de la fonction de Wigner, n developpe un algorithme pour calculer ces quantites en optique quantique, pour des etats coherents et compresses
8529859
Measurement of parity violation in the elastic scattering of polarized electrons from 12C.
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from $^{12}\mathrm{C}$ nuclei. Our result is ${\mathit{A}}_{\mathrm{expt}}$=0.60\ifmmode\pm\else\textpm\fi{}0.14\ifmmode\pm\else\textpm\fi{}0.02 ppm, where the first error is statistical and the second is systematic. With a beam polarization of 0.37, we compute the isoscalar vector hadronic coupling constant \ensuremath{\gamma}\ifmmode \tilde{}\else \~{}\fi{} to be 0.136\ifmmode\pm\else\textpm\fi{}0.032\ifmmode\pm\else\textpm\fi{}0.009. The standard model predicts \ensuremath{\gamma}\ifmmode \tilde{}\else \~{}\fi{}=0.155 at the tree level, in agreement with our data.
35864870
Special relativity and interferometers.
14542071
Study of exclusive radiative B meson decays
We have studied exclusive, radiative B meson decays to charmless mesons in 9.7x10(6) B&Bmacr; decays accumulated with the CLEO detector. We measure B(B0-->K(*0)(892)gamma) = (4.55(+0.72)(-0. 68)+/-0.34)x10(-5) and B(B+-->K(*+)(892)gamma) = (3.76(+0.89)(-0. 83)+/-0.28)x10(-5). We have searched for CP asymmetry in B-->K(*)(892)gamma decays and measure A(CP) = +0.08+/-0.13+/-0.03. We report the first observation of B-->K(*)(2)(1430)gamma decays with a branching fraction of (1.66(+0.59)(-0.53)+/-0.13)x10(-5). No evidence for the decays B-->rhogamma and B0-->omegagamma is found and we limit B(B-->(rho/omega)gamma)/B(B-->K(*)(892)gamma)<0.32 at 90% C.L.
29225985
Fission of heavy nuclei induced by stopped antiprotons. I. Inclusive characteristics of fission fragments.
Antiproton-induced fission has been investigated with a novel double-arm fission fragment spectrometer. Inclusive distributions of total mass, individual mass, and total kinetic energy of the fragments, and of the momentum of the fissioning nucleus, were measured. A dynamical model which takes into account all stages of [ital [bar p]]-induced fission (atomic cascade, intranuclear cascade, evaporation cascade, fission of compound nucleus, evaporation from fission fragments) was formulated for the first time. In particular, the dynamics of the descent of fissioning nuclei from saddle point to scission point are described by the diffusion model. The data on [ital [bar p]]-induced fission were analyzed in the framework of this model and good agreement between experiment and theory was obtained.