On the EDM Cancellations in D-brane models

We analyze the possibility of simultaneous electron, neutron, and mercury electric dipole moment (EDM) cancellations in the mSUGRA and D--brane models. We find that the mercury EDM constraint practically rules out the cancellation scenario in D-brane models whereas in the context of mSUGRA it is still allowed with some fine-tuning.Comment: 10 pages, to appear in Phys. Rev. Let

Probing scalar-pseudoscalar mixing in the CP violating MSSM at high-energy e+e−e^+e^- colliders

We study the production processes $e^+e^-\to H^0_iZ$, $H^0_iH^0_j$ and $H^0_i\nu_e\overline \nu_e$ in the context of the CP violating MSSM. In a given channel we show that the cross-section for all i (=1,2,3) can be above 0.1 fb provided M_{H_{2,3}}\la 300 GeV. This should be detectable at a Next Linear Collider and would provide evidence for scalar-pseudoscalar mixing.Comment: 17 pages, RevTex, 4 ps figures, figure 4 changed, minor modifications to text, version to appear in PR

The Electric Dipole Moment and CP Violation in B→Xsl+l−B \to X_s l^+ l^- in SUGRA Models with Nonuniversal Gaugino Masses

The constraints of electric dipole moments (EDMs) of electron and neutron on the parameter space in supergravity (SUGRA) models with nonuniversal gaugino masses are analyzed. It is shown that with a light sparticle spectrum, the sufficient cancellations in the calculation of EDMs can happen for all phases being order of one in the small tan$\beta$ case and all phases but $\phi_{\mu}$ ($|\phi_{\mu}| <\sim \pi/6$) order of one in the large tan$\beta$ case. This is in contrast to the case of mSUGRA in which in the parameter space where cancellations among various SUSY contributions to EDMs happen $|\phi_{\mu}|$ must be less than $\pi/10$ for small $tan\beta$ and ${\cal{O}}(10^{-2})$ for large $tan\beta$. Direct CP asymmetries and the T-odd polarization of lepton in $B\to X_s l^+l^-$ are investigated in the models. In the large tan$\beta$ case, $A_{CP}^2$ and $P_N$ for l=$\mu$ ($\tau$) can be enhanced by about a factor of ten (ten) and ten (three) respectively compared to those of mSUGRA.Comment: 12 pages, latex, 4 figures, a few change

Mixing of the CP Even and the CP Odd Higgs Bosons and the EDM Constraints

The mixing among the CP even and the CP odd neutral Higgs bosons of MSSM by one loop induced effects in the presence of CP phases is investigated using three different mechanisms to satisfy the EDM constraints, i.e., a fine tuning of phases, a heavy sparticle spectrum, and the cancellation mechanism. It is shown that if a mixing effect among the CP even and the CP odd Higgs bosons is observed experimentally, then it is only the cancellation mechanism that can survive under the naturalness constraint.Comment: 14 pages, Latex and 4figures. A new paragraph is added and few more references. One figure is modified. To appear in Phys. Rev.

CP Violation and Dark Matter

A brief review is given of the effects of CP violation on the direct detection of neutralinos in dark matter detectors. We first summarize the current developments using the cancellation mechanism which allows for the existence of large CP violating phases consistent with experimental limits on the electron and on the neutron electric dipole moments in a broad class of SUSY, string and D brane models. We then discuss their effects on the scattering of neutralinos from quarks and on the event rates. It is found that while CP effects on the event rates can be enormous such effects are reduced significantly with the imposition of the EDM constraints. However, even with the inclusion of the EDM constraints the effects are still very significant and should be included in a precision prediction of event rates in any SUSY, string or D brane model.Comment: Based on an invited talk at the conference "Sources and Detection of Dark Matter in the Universe", at Marina del Rey, CA, Feb. 23-25, 2000; 12 pages, Latex including 2 figure

CP violating asymmetries in single top quark production at the Tevatron p pbar collider

Analytic expressions for the angular distributions of the $b$-quarks associated with single $t$-quark production in $p \bar p \to W^* \to t \bar b \to b \bar b W$ and of the leptons from the subsequent decay $W \to l\nu$ are obtained in the laboratory system. CP violation in the $t$-production vertex is assumed. Different angular and total cross section CP violating asymmetries are considered. Relations testing CP violation solely in the $t$-decay vertex are also obtained. A numerical analysis is performed in the MSSM with a CP violating phase of the trilinear coupling $A_{\tilde t}$. The asymmetries are typically of the order $10^{-3}$ - $10^{-4}$.Comment: The numerical results are corrected and some changes that meet the requirements of Phys. Rev. D are mad

CP-odd A^0 production at e^+e^- colliders in MSSM with CP violating phases

We study the production of a heavy CP-odd $A^0$ boson in association with a photon $e^+e^-\to A^0\gamma$ and a Z boson $e^+e^-\to A^0 Z$ as well as the single production of $A^0$ via $e^+e^- \to \nu_e\bar{\nu}_e A^0$ in the MSSM with CP violating phases. In the case of $e^+e^-\to A^0\gamma / A^0 Z$, we show that the squark contribution, which vanishes in the MSSM with real parameters, turns out to be sizeable in presence of CP violating phases in the soft SUSY parameters. For $e^+e^- \to \nu_e \bar{\nu}_e A^0$ in both the 2HDM and MSSM with real parameters, the cross section does not reach observable rates at a NLC. It is found that with a large CP violating phase for $A_t$, cross sections of the order 0.1 fb are attainable for all the processes $e^+e^-\to A^0\gamma$, $e^+e^-\to A^0 Z$ and $e^+e^- \to \nu_e \bar{\nu}_e A^0$.Comment: 12 pages, latex, 7 eps figures. One new figure, new discussion arroud it. Version to appear in Phys. Rev.

Dislocation Dynamics in an Anisotropic Stripe Pattern

The dynamics of dislocations confined to grain boundaries in a striped system are studied using electroconvection in the nematic liquid crystal N4. In electroconvection, a striped pattern of convection rolls forms for sufficiently high driving voltages. We consider the case of a rapid change in the voltage that takes the system from a uniform state to a state consisting of striped domains with two different wavevectors. The domains are separated by domain walls along one axis and a grain boundary of dislocations in the perpendicular direction. The pattern evolves through dislocation motion parallel to the domain walls. We report on features of the dislocation dynamics. The kinetics of the domain motion are quantified using three measures: dislocation density, average domain wall length, and the total domain wall length per area. All three quantities exhibit behavior consistent with power law evolution in time, with the defect density decaying as $t^{-1/3}$, the average domain wall length growing as $t^{1/3}$, and the total domain wall length decaying as $t^{-1/5}$. The two different exponents are indicative of the anisotropic growth of domains in the system.Comment: 8 figures: 7 jpeg and 1 pd

Loop-Induced CP Violation in the Gaugino and Higgsino Sectors of Supersymmetric Theories

We show that the gaugino and higgsino sectors of supersymmetric theories can naturally acquire observable CP violation through radiative effects which originate from large CP-violating trilinear couplings of the Higgs bosons to the third-generation scalar quarks. These CP-violating loop effects are not attainable by evolving the supersymmetric renormalization-group equations from a higher unification scale down to the electroweak one. We briefly discuss the phenomenological consequences of such a scenario, and as an example, calculate the two-loop contribution to the neutron electric dipole moment generated by the one-loop chromo-electric dipole moment of the gluino.Comment: 9 pages, as to appear in Physical Review