310 research outputs found
Triple product correlations in top squark decays
We propose several T-odd asymmetries in the decay chains of the top squarks
and and , for . We
calculate the asymmetries within the Minimal Supersymmetric Standard Model with
complex parameters , and . We give the analytic formulae for
the decay distributions. We present numerical results for the asymmetries and
estimate the event rates necessary to observe them. The largest T-odd asymmetry
can be as large as 40%.Comment: 26 pages, 5 figures; misprints corrected; reference adde
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 in the MSSM. The supersymmetric phases of gaugino masses
and trilinear terms lead to a CP violating asymmetry of the cross section
in the process through loop corrections to the
vertex. We find that a CP violation more than 10 % is possible if the
charged Higgs boson is heavy enough.Comment: 8 pages including 5 eps figures, JHEP, corrections mad
CP violating asymmetry in decays
The CP violating asymmetry from the decay rates of
charged Higgs bosons into the lightest neutral Higgs boson and a boson
is calculated and discussed in the complex MSSM. The contributions from all
complex phases are considered, especially from the top-squark trilinear
coupling, which induces a large contribution to the CP asymmetry.Comment: 19 pages, 10 figures, version published in JHE
Conformational flexibility influences structure–function relationships in tyrosyl protein sulfotransferase-2
Tyrosine sulfation is a very important posttranslational modification of proteins. It is catalyzed by tyrosylprotein sulfotransferase and recently became increasingly important for biomedicine and pharmacy. An important insight about structure–activity relationships of human tyrosylprotein sulfotransferase has been received by elucidating the crystal structure, but there is still no understanding about how conformational flexibility and dynamics which are fundamental protein properties influence structure–function relationships of the enzyme. In order to provide this missing but crucially important knowledge we performed a comprehensive atomistic molecular dynamics study which revealed that (i) the conformational flexibility influences sensitively key structural determinants and interactions between the enzyme, the substrate and the cofactor; (ii) a more open conformation adopted by the substrate for binding in TPST 2; (iii) the mutations of key residues related with catalysis and binding change alter the enzyme structure and influence important interactions between the enzyme, the cofactor and the substrate
CP Nonconservation in at the Tevatron
The reaction is found to be rather rich in exhibiting
several different types of CP asymmetries. The spin of the top quark plays an
important role. Asymmetries are related to form factors arising from radiative
corrections of the production vertex due to non-standard physics. As
illustrations, effects are studied in two Higgs Doublet Models and in
Supersymmetric Models; asymmetries up to a few percent may be possible.Comment: 14 pages, 3 figures. Note: replaced due to minor problems that
appeared on some postscript previewers. No change in conten
Refining the predictions of supersymmetric CP-violating models: A top-down approach
We explore in detail the consequences of the CP-violating phases residing in
the supersymmetric and soft SUSY breaking parameters in the approximation that
family flavour mixings are ignored. We allow for non-universal boundary
conditions and in such a consideration the model is described by twelve
independent CP-violating phases and one angle which misaligns the vacuum
expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization
group equations (RGEs), for all parameters involved, including phases, and we
properly treat the minimization conditions using the one-loop effective
potential with CP-violating phases included. We show that the two-loop running
of phases may induce sizable effects for the electric dipole moments (EDMs)
that are absent in the one-loop RGE analysis. Also important corrections to the
EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the
large tanb region. Scanning the available parameter space we seek regions
compatible with accelerator and cosmological data with emphasis on rapid
neutralino annihilations through a Higgs resonance. It is shown that large
CP-violating phases, as required in Baryogenesis scenarios, can be tuned to
obtain agreement with WMAP3 cold dark matter constraints, EDMs and all
available accelerator data, in extended regions of the parameter space which
may be accessible to LHC.Comment: 41 pages, 22 eps figures. A reference added and a typo corrected;
version to appear in JHE
Conformational effects on the Circular Dichroism of Human Carbonic Anhydrase II: a multilevel computational study
Circular Dichroism (CD) spectroscopy is a powerful method for investigating conformational changes in proteins and therefore has numerous applications in structural and molecular biology. Here a computational investigation of the CD spectrum of the Human Carbonic Anhydrase II (HCAII), with main focus on the near-UV CD spectra of the wild-type enzyme and it seven tryptophan mutant forms, is presented and compared to experimental studies. Multilevel computational methods (Molecular Dynamics, Semiempirical Quantum Mechanics, Time-Dependent Density Functional Theory) were applied in order to gain insight into the mechanisms of interaction between the aromatic chromophores within the protein environment and understand how the conformational flexibility of the protein influences these mechanisms. The analysis suggests that combining CD semi empirical calculations, crystal structures and molecular dynamics (MD) could help in achieving a better agreement between the computed and experimental protein spectra and provide some unique insight into the dynamic nature of the mechanisms of chromophore interactions
- …