684 research outputs found
Electric dipole moment enhancement factor of thallium
The goal of this work is to resolve the present controversy in the value of
the EDM enhancement factor of Tl. We have carried out several calculations by
different high-precision methods, studied previously omitted corrections, as
well as tested our methodology on other parity conserving quantities. We find
the EDM enhancement factor of Tl to be equal to -573(20). This value is 20%
larger than the recently published result of Nataraj et al. [Phys. Rev. Lett.
106, 200403 (2011)], but agrees very well with several earlier results.Comment: 5 pages; v2: link to supplemental material adde
The Constraints on CP Violating Phases in models with a dynamical gluino phase
We have analyzed the electric dipole moment and the Higgs mass constraints on
the supersymmetric model which offers dynamical solutions to the \mu and strong
CP problems. The trilinear coupling phases, and \tan\beta-|\mu| are strongly
correlated, particularly in the low-\tan\beta regime. Certain values of the
phases of the trilinear couplings are forbidden, whereas the CP violating phase
from the chargino sector is imprisoned to lie near a CP conserving point, by
the Higgs mass and electric dipole moment constraints.Comment: 19 pages, 11 eps fig
CP violation versus flavour in supersymmetric theories
We show that the quark flavour structure and CP violating phenomena are
strongly correlated in supersymmetric theories. For a generic pattern of
supersymmetry breaking the two broad categories of Yukawa couplings, democratic
and hierarchical textures, have entirely different phenomenological
implications. With hierarchical Yukawas, the rephasing invariant phase,
arg(V_us V_cb V_cb^* V_cs^*), in the CKM mixing matrix has to be of order
unity, while the SUSY CP violating phases are severely constrained by electric
dipole moments, giving rise to the so-called SUSY CP problem. With democratic
Yukawas, all experimental CP results can be accommodated with small values for
the CKM and SUSY CP violating phases (i.e., CP can be considered as an
approximate symmetry at the high energy scale). We also show that within this
scenario, an entirely real CKM matrix in supersymmetric models is still allowed
by the present experimental results.Comment: 16 pages, 6 eps figure
Endotoxin-free purification for the isolation of Bovine Viral Diarrhoea Virus E2 protein from insoluble inclusion body aggregates
Background: Protein expression in Escherichia coli may result in the recombinant protein being expressed as insoluble inclusion bodies. In addition, proteins purified from E. coli contain endotoxins which need to be removed for in vivo applications. The structural protein, E2, from Bovine Viral Diarrhoea Virus (BVDV) is a major immunogenic determinant, and is an ideal candidate as a subunit vaccine. The E2 protein contains 17 cysteine residues creating difficulties in E. coli expression. In this report we outline a procedure for successfully producing soluble and endotoxin-free BVDV E2 protein from inclusion bodies (IB).Results: The expression of a truncated form of BVDV-E2 protein (E2-T1) in E. coli resulted in predominantly aggregated insoluble IB. Solubilisation of E2-T1 with high purity and stability from IB aggregates was achieved using a strong reducing buffer containing 100 mM Dithiothreitol. Refolding by dialysis into 50 mM Tris (pH 7.0) containing 0.2% Igepal CA630 resulted in a soluble but aggregated protein solution. The novel application of a two-phase extraction of inclusion body preparations with Triton X-114 reduced endotoxin in solubilised E2-T1 to levels suitable for in vivo use without affecting protein yields. Dynamic light scattering analyses showed 37.5% of the protein was monomeric, the remaining comprised of soluble aggregates. Mice immunised with E2-T1 developed a high titre antibody response by ELISA. Western hybridisation analysis showed E2-T1 was recognised by sera from immunised mice and also by several BVDV-E2 polyclonal and monoclonal antibodies.Conclusion: We have developed a procedure using E. coli to produce soluble E2-T1 protein from IB, and due to their insoluble nature we utilised a novel approach using Triton X-114 to efficiently remove endotoxin. The resultant protein is immunogenic and detectable by BVDV-E2 specific antibodies indicating its usefulness for diagnostic applications and as a subunit vaccine. The optimised E. coli expression system for E2-T1 combined with methodologies for solubilisation, refolding and integrated endotoxin removal presented in this study should prove useful for other vaccine applications
Nucleon matrix elements and baryon masses in the Dirac orbital model
Using the expansion of the baryon wave function in a series of products of
single quark bispinors (Dirac orbitals), the nonsinglet axial and tensor
charges of a nucleon are calculated. The leading term yields in
good agreement with experiment. Calculation is essentially parameter-free and
depends only on the strong coupling constant value . The importance
of lower Dirac bispinor component, yielding 18% to the wave function
normalization is stressed. As a check, the baryon decuplet masses in the
formalism of this model are also computed using standard values of the string
tension and the strange quark mass ; the results being in a good
agreement with experiment.Comment: 8 pages, 2 tables; LaTeX2
Electric Dipole moments of charged leptons and lepton flavor violating interactions in the general two Higgs Doublet model
We calculate the electric dipole moment of electron using the experimental
result of muon electric dipole moment and upper limit of the BR(\mu -->
e\gamma) in the framework of the general two Higgs doublet model. Our
prediction is 10^{-32} e-cm, which lies in the experimental current limits.
Further, we obtain constraints for the Yukawa couplings \bar{\xi}^{D}_{N,\tau
e} and \bar{\xi}^{D}_{N,\tau\mu}. Finally we present an expression which
connects the BR(\tau\to \mu\gamma) and the electric dipole moment of
\tau-lepton and study the relation between these physical quantities.Comment: 8 pages, 4 Figures (required epsf sty
Constraints on Phases of Supersymmetric Flavour Conserving Couplings
In the unconstrained MSSM, we reanalyze the constraints on the phases of
supersymmetric flavour conserving couplings that follow from the electron and
neutron electric dipole moments (EDM). We find that the constraints become weak
if at least one exchanged superpartner mass is >O(1 TeV) or if we accept large
cancellations among different contributions. However, such cancellations have
no evident underlying symmetry principle. For light superpartners, models with
small phases look like the easiest solution to the experimental EDM
constraints. This conclusion becomes stronger the larger is the value of
. We discuss also the dependence of , and
decay on those phases.Comment: 38 pages, 22 figures, uses epsfig.sty, axodraw.sty (not included);
error in sign of gluino contribution to EDM of u and d quarks and few figures
corrected, important conclusions unchange
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