442228
CP violation in associated charged Higgs boson production with a single top at the LHC
We explore the CP violation in the charged Higgs production associated with a top quark at the LHC within the context of the MSSM. The supersymmetric loop corrections to the tbH vertex lead to the CP violating asymmetry of the cross section in the pp → gb → tH process. We find that a large CP violation is possible if the charged Higgs boson is heavy enough and the CP asymmetry could be detected at the LHC. PACS numbers: Typeset using REVTEX
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.
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.
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}
6140839
QCD vacuum structure in strong magnetic fields
We study the response of the QCD vacuum to strong magnetic fields, using a potential model for the quark-antiquark interaction. We find that production of spin-polarized $u\ifmmode \bar{u}\else \={u}\fi{}$ pairs is energetically favorable for fields $Bg{B}_{\mathrm{crit}}\ensuremath{\sim}10 {\mathrm{GeV}}^{2}.$ We contrast the resulting $u\ifmmode \bar{u}\else \={u}\fi{}$ condensate with the quark condensate which is present at zero magnetic field, and we estimate the corresponding magnetization as a function of B.
15751584
BPS objects in N=2 supersymmetric gauge theories
We explore BPS soliton configurations in N=2 supersymmetric Yang-Mills theory with matter fields arising from parallel D3 branes on D7 branes. Especially we focus on a two parameter family of 1/8 BPS equations, dyonic objects, and 1/8 BPS objects and raise a possibility of the absence of BPS vortices when the number of D3 branes is larger than that of D7 branes.
11647076
MASSLESS MONOPOLES AND MULTI-PRONGED STRINGS
We investigate the role of massless magnetic monopoles in the N=4 supersymmetric Yang-Mills Higgs theories. They can appear naturally in the 1/4-BPS dyonic configurations associated with multi-pronged string configurations. Massless magnetic monopoles can carry nonabelian electric charge when their associated gauge symmetry is unbroken. Surprisingly, massless monopoles can also appear even when the gauge symmetry is broken to abelian subgroups.
117272166
Analysis of Hadronic Properties at SPS energies from a Statistical Model
Using a statistical model of multiparticle production by Chou, Yang and Yen, which looks similar to the thermal model and is known to account for the single particle distributions in e$^+$ e$^-$ collisions, we fit the rapidity and transverse mass spectra of pions and kaons measured in Pb+Pb collisions by NA49 collaboration. This model nicely fits both the rapidity and the transverse mass spectra of each particle species with a few parameters. However, fitting all the particles with a single value of $T_p$ is not possible. This analysis shows that the success of the thermal models does not necessarily mean the thermalization of the system in collision.
119336241
The Chern-Simons coefficient in the Higgs phase
Abstract We study one-loop corrections to the Chern-Simons coefficient ϰ in abelian self-dual Chern-Simons Higgs systems and their N =2 and N =3 supersymmetric generalizations in both symmetric and asymmetric phases. One-loop corrections to the Chern-Simons coefficient of these systems turn out to be integer multiples of 1 4 π in both phases. Especially in the maximally supersymmetric N =3 case, the correction in the symmetric phase vanishes and that in the asymmetric phase is ϰ /(2 π | ϰ |). Our results suggest that nonabelian self-dual system might enjoy similar features. We also discuss various issues arising from our results.