119433922
New Precision Electroweak Tests in Supergravity Models
We update the analysis of the precision electroweak tests in terms of four epsilon parameters, e1,2,3,b, to obtain more accurate experimental values of them by taking into account the new LEP data released at the 28th ICHEP (Poland, 1996). We also compute e1 and eb in the context of the no-scale SU(5)×U(1) supergravity model to obtain the updated constraints by imposing the correlated constraints in terms of the experimental ellipses in the e1–eb plane and also by imposing the new conservative bound on the lightest chargino mass, . Upon imposing these new experimental results, we find that the situations in the no-scale model are much more favorable than those in the standard model, and if mt≳ 170 GeV, then the allowed regions at the 95% C.L. in the no-scale model are tan β≳ 4 and for μ>0 (μ< 0), which are in fact much more stringent than in our previous analysis. Therefore, assuming that mt≳ 170 GeV, if the lightest chargino mass bound were to be pushed up to 82 GeV, the sign on the Higgs mixing term μ in the no-scale model could well be determined from the e1–eb constraint to be positive at the 95% C.L. At any rate, better accuracy in the measured mt from the Tevatron in the near future combined with the LEP data is most likely to provide a decisive test of the no-scale SU(5)×U(1) supergravity model.
16963420
Evolution equation for the heavy quark distribution function in the parton model approach
We explore the perturbative QCD corrections to the inclusive semileptonic decays of $B$ mesons. In inclusive $B$ decay processes the parton picture works well and the scaling feature manifests because the mass of $b$ quark is larger than the QCD scale. Due to this property, the decay rate may be expressed by a single structure function describing the light-cone distribution of $b$ quark apart from the kinematic factor. We derive a $q^2$ evolution equation for the distribution function, which violates the scaling property through the Altarelli-Parisi type approach. The evolution equation is numerically solved and its phenomenological implications are also discussed.
14611917
Polarization effects on W boson pair productions with the extra neutral gauge boson at the e^+ e^- Linear Collider
We perform the comprehensive analysis of the polarization effects on the e^+e^- -> W^+W^- process in the presence of the extra neutral gauge boson at the LC energies. Consideration of the polarizations of the produced W bosons and the beam polarizations provides substantial enhancements of the sensitivity to the Z-Z' mixing angles in various models and the asymmetry variables also give the strict constraints on the mixing angles. We find that the \chi-model and the left-right model get the strict constraint from \sigma_{LL}^{unpol} while the \psi-model and the \eta-model from the beam polarization asymmetry.
16221979
POLARIZATION EFFECTS ON THE E+E- W+W- PROCESS WITH LARGE EXTRA DIMENSIONS
Abstract We study large extra dimension effects on the polarizations of the W pair and electron beam at the e + e − → W + W − process. It is shown that the measurements of the cross section for transversely polarized W pair with the right-handed electron beam remarkably enhance the possibilities to see the low scale quantum gravity effects. Higher Linear Collider bounds on the string scale in this model can be obtained by using the left-handed electron beam.
17539215
Implications of the recent CERN LEP data on nonuniversal interactions with the precision electroweak tests
We explore the nonuniversal interaction effects in terms of the precision variables epsilons with the recent CERN LEP data reported by the Electroweak Working Group. The epsilon variables with the nonuniversal interactions are calculated and constrained by the experimental ellipses in the {epsilon}{sub 1}{endash}{epsilon}{sub b}, {epsilon}{sub 2}{endash}{epsilon}{sub b}, and {epsilon}{sub 3}{endash}{epsilon}{sub b} planes. We find that the new data enable us to make a stringent test on the correction to Z{r_arrow}b{bar b} vertex. The {epsilon}{sub b} variable is sensitive to the Zb{bar b} couplings and thus plays a major role to give constraints on the nonuniversal interaction effects. Upon imposing the new data on {epsilon}{sub b}, we have the allowed range of the model parameter {kappa}{sub L}=0.0063{plus_minus}0.0030 at 1-{sigma} level with m{sub t}=175 GeV. Along with the minimal contact term, we predict the new physics scale {Lambda}{approximately} 1.6 TeV. By combining the experimental results from all planes we obtain the allowed range of {kappa}{sub L}: 0.003{lt}{kappa}{sub L}{lt}0.010 at 95{percent} C.L. {copyright} {ital 1997} {ital The American Physical Society}
15426025
Large extra dimension effects on the spin configuration of the top quark pair at e + e − colliders
Large extra dimension effects on the spin configuration of the top quark pair at the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}t\overline{t}$ process are studied. It is shown that the TeV scale quantum gravity effects cause significant deviations from standard model (SM) predictions for the spin configuration in the off-diagonal basis: they lead to substantial cross sections of the like-spin states of the top quark pair, which vanish in the SM; they weaken the pure dominance of the processes, the up-down (down-up) spin states for the left-handed (right-handed) beam. In addition it is shown that the angular cut $\ensuremath{-}0.5l\mathrm{cos}\ensuremath{\theta}l0$ is very effective to determine the sign of the quantum gravity corrections.
14906179
Chern-Simons solitons, chiral model, and (affine) Toda model on noncommutative space
We consider the Dunne-Jackiw-Pi-Trugenberger model of a U(N) Chern-Simons gauge theory coupled to a nonrelativistic complex adjoint matter on noncommutative space. Soliton configurations of this model are related the solutions of the chiral model on noncommutative plane. A generalized Uhlenbeck's uniton method for the chiral model on noncommutative space provides explicit Chern-Simons solitons. Fundamental solitons in the U(1) gauge theory are shaped as rings of charge and spin − where the Chern-Simons level should be an integer upon quantization. Toda and Liouville models are generalized to noncommutative plane and the solutions are provided by the uniton method. We also define affine Toda and sine-Gordon models on noncommutative plane. Finally the first order moduli space dynamics of Chern-Simons solitons is shown to be trivial.
118918211
Tales of D0 on D6 branes: matrix mechanics of identical particles
Abstract We investigate a class of matrix model which describes the dynamics of identical particles in even-dimensional space. We show that the degrees of freedom after some constraints are implemented is proportional to particle number and consist of those for positions and internal degrees. The particle dynamics is given by the metric on the smooth moduli space. The moduli space metric for two particles is found. The size of tightly packed N particles grows like N . Our matrix model is related to the matrix model for fractional quantum Hall effect, the ADHM formalism of U (1) instantons on noncommutative space, and supersymmetric D0 branes on D6 branes with nonzero B-field in type IIA theory.
15490488
A Family of N=2 gauge theories with exact S duality
We study an infinite family of N = 2 Sp(2n) gauge theories that naturally arise from the D3-brane probe dynamics in F-theory. The matter sector consists of four fundamental and one antisymmetric tensor hypermultiplets. We propose that, in the limit of vanishing bare masses, the theory has exact SO(8) ⋉ SL(2, Z) duality. We examine the semiclassical BPS spectrum in the Coulomb phase by quantizing various monopole moduli space dynamics, and show that it is indeed consistent with the exact S-duality.
122069269
Ground state of high-density matter
Abstract It is shown that if an upper bound to the false vacuum energy of the electroweak Higgs potential is satisfied, the true ground state of high-density matter is not nuclear matter, or even strange-quark matter, but rather a non-topological soliton where the electroweak symmetry is exact and the fermions are massless. We examine this possibility in the standard SU(3) C ⊗ SU(2) L ⊗ U(1) Y model. The bound to the false vacuum energy is satisfied only for a narrow range of the Higgs boson masses in the minimal electroweak model (within a few eV of its minimum allowed value of 6.6 GeV), and a somewhat wider range for electroweak models with a non-minimal Higgs sector.
125445926
2nd Mini Workshop on Higgs Factory: Lattice and Detector