23 research outputs found
Fermionic decays of sfermions: a complete discussion at one-loop order
We present a definition of an on-shell renormalization scheme for the
sfermion and chargino-neutralino sector of the Minimal Supersymmetric Standard
Model (MSSM). Then, apply this renormalization framework to the interaction
between charginos/neutralinos and sfermions. A kind of universal corrections is
identified, which allow to define effective chargino/neutralino coupling
matrices. In turn, these interactions generate (universal) non-decoupling terms
that grow as the logarithm of the heavy mass. Therefore the full MSSM spectrum
must be taken into account in the computation of radiative corrections to
observables involving these interactions. As an application we analyze the full
one-loop electroweak radiative corrections to the partial decay widths
\Gamma(\tilde{f} -> f\neut) and \Gamma(\tilde{f} -> f'\cplus) for all sfermion
flavours and generations. These are combined with the QCD corrections to
compute the corrected branching ratios of sfermions. It turns out that the
electroweak corrections can have an important impact on the partial decay
widths, as well as the branching ratios, in wide regions of the parameter
space. The precise value of the corrections is strongly dependent on the
correlation between the different particle masses.Comment: LaTeX 53 pages, 22 figures, 3 tables. Typos correcte
Higgs Boson Flavor-Changing Neutral Decays into Bottom Quarks in Supersymmetry
We analyze the maximum branching ratios for the Flavor Changing Neutral
Current (FCNC) decays of the neutral Higgs bosons of the Minimal Supersymmetric
Standard Model (MSSM) into bottom quarks, h -> b\bar{s} (h=h^0,H^0,A^0). We
consistently correlate these decays with the radiative B-meson decays (b->
s\gamma). A full-fledged combined numerical analysis is performed of these
high-energy and low-energy FCNC decay modes in the MSSM parameter space. Our
calculation shows that the available data on B(b->s \gamma) severely restricts
the allowed values of B(h->b\bar{s}). While the latter could reach a few
percent level in fine-tuned scenarios, the requirement of naturalness reduces
these FCNC rates into the modest range B(h->b\bar{s}) ~ 10^{-4}-10^{-3}. We
find that the bulk of the MSSM contribution to B(h->b\bar{s}) could originate
from the strong supersymmetric sector. The maximum value of the FCNC rates
obtained in this paper disagree significantly with recent (over-)estimates
existing in the literature. Our results are still encouraging because they show
that the FCNC modes h->b\bar{s} can be competitive with other Higgs boson
signatures and could play a helpful complementary role to identify the
supersymmetric Higgs bosons, particularly the lightest CP-even state in the
critical LHC mass region m_{h^0} ~= 90-130 GeV.Comment: LaTeX, 19 pages, 4 tables, 7 figures. Clarifications and discussions
added, references added. Slight changes in Figs2b,6b and 7b. Version accepted
in JHE
Prospects for heavy supersymmetric charged Higgs boson searches at hadron colliders
We investigate the production of a heavy charged Higgs boson at hadron
colliders within the context of the MSSM. A detailed study is performed for all
important production modes and basic background processes for the
t\bar{t}b\bar{b} signature. In our analysis we include effects of initial and
final state showering, hadronization, and principal detector effects. For the
signal production rate we include the leading SUSY quantum effects at high
\tan\beta>~ mt/mb. Based on the obtained efficiencies for the signal and
background we estimate the discovery and exclusion mass limits of the charged
Higgs boson at high values of \tan\beta. At the upgraded Tevatron the discovery
of a heavy charged Higgs boson (MH^+ >~ 200 GeV) is impossible for the
tree-level cross-section values. However, if QCD and SUSY effects happen to
reinforce mutually, there are indeed regions of the MSSM parameter space which
could provide 3\sigma evidence and, at best, 5\sigma charged Higgs boson
discovery at the Tevatron for masses M_H^+<~ 300 GeV and M_H^+<~ 250 GeV,
respectively, even assuming squark and gluino masses in the (500-1000) GeV
range. On the other hand, at the LHC one can discover a H^+ as heavy as 1 TeV
at the canonical confidence level of 5\sigma; or else exclude its existence at
95% C.L. up to masses ~ 1.5 TeV. Again the presence of SUSY quantum effects can
be very important here as they may shift the LHC limits by a few hundred GeV.Comment: Latex2e, 44 pages, 15 figures, 6 tables, uses JHEP3.sty, axodraw.sty.
Comments added. Discussion on QCD factors clarified. Added discussion on
uncertainties. Change of presentation of Tables 4 and 5 and Fig.6. Results
and conclusions unchanged. Version accepted in JHE
Molecular Characterization of a Type I Quantitative Factor V Deficiency in a Thrombosis Patient that Is “Pseudo Homozygous” for Activated Protein C Resistance
A Nucleophilic Strategy for Enantioselective Intermolecular α‑Amination: Access to Enantioenriched α‑Arylamino Ketones
The
enantioselective addition of anilines to azoalkenes was accomplished
through the use of a chiral phosphoric acid catalyst. The resulting
α-arylamino hydrazones were obtained in good yields and excellent
enantioselectivities and provide access to enantioenriched α-arylamino
ketones. A serendipitous kinetic resolution of racemic α-arylamino
hydrazones is also described
Detailed architecture of a DNA translocating machine: The high-resolution structure of the bacteriophage φ29 connector particle
The three-dimensional crystal structure of the bacteriophage φ29 connector has been solved and refined to 2.1 Å resolution. This 422 kDa oligomeric protein connects the head of the phage to its tail and translocates the DNA into the prohead during packaging. Each monomer has an elongated shape and is composed of a central, mainly α-helical domain that includes a three-helix bundle, a distal α/β domain and a proximal six-stranded SH3-like domain. The protomers assemble into a 12-mer, propeller-like, super-structure with a 35 Å wide central channel. The surface of the channel is mainly electronegative, but it includes two lysine rings 20 Å apart. On the external surface of the particle a hydrophobic belt extends to the concave area below the SH3-like domain, which forms a crown that retains the particle in the head. The lipophilic belt contacts the non-matching symmetry vertex of the capsid and forms a bearing for the connector rotation. The structure suggests a translocation mechanism in which the longitudinal displacement of the DNA along its axis is coupled to connector spinning. © 2002 Academic Press.This study was supported by grants from the Ministerio de Educación y Cultura of Spain (PB98-1631 and 2FD97-0518 to M.C., PB97-1225-C02 to J.M.V., and PB96-0818 to J.L.C.) and the Generalitat de Catalunya (1999SGR-188 and Centre de Referència en Biotecnologia) to M.C. Synchrotron data collection was supported by the EU grants ERBFMGECT980134 and HPRI-CT-1999-00017 to the EMBL-DESY and by the ESRF. J.P. acknowledges a fellowship from the Ministerio de Educación y CulturaPeer Reviewe
RP11-362K2.2 : RP11-767I20.1 Genetic Variation Is Associated with Post-Reperfusion Therapy Parenchymal Hematoma. A GWAS Meta-Analysis
Stroke is one of the most common causes of death and disability. Reperfusion therapies are the only treatment available during the acute phase of stroke. Due to recent clinical trials, these therapies may increase their frequency of use by extending the time-window administration, which may lead to an increase in complications such as hemorrhagic transformation, with parenchymal hematoma (PH) being the more severe subtype, associated with higher mortality and disability rates. Our aim was to find genetic risk factors associated with PH, as that could provide molecular targets/pathways for their prevention/treatment and study its genetic correlations to find traits sharing genetic background. We performed a GWAS and meta-analysis, following standard quality controls and association analysis (fastGWAS), adjusting age, NIHSS, and principal components. FUMA was used to annotate, prioritize, visualize, and interpret the meta-analysis results. The total number of patients in the meta-analysis was 2034 (216 cases and 1818 controls). We found rs79770152 having a genome-wide significant association (beta 0.09, p-value 3.90 x 10(-8)) located in the RP11-362K2.2:RP11-767I20.1 gene and a suggestive variant (rs13297983: beta 0.07, p-value 6.10 x 10(-8)) located in PCSK5 associated with PH occurrence. The genetic correlation showed a shared genetic background of PH with Alzheimer's disease and white matter hyperintensities. In addition, genes containing the ten most significant associations have been related to aggregated amyloid-beta, tau protein, white matter microstructure, inflammation, and matrix metalloproteinases.Peer reviewe
Les Roques del Sarró (Lleida, Segrià): Evolució de l'assentament entre el 3600 cal. a.n.e i el i el 175 a.n.e
Prospects for supersymmetric charged Higgs boson discovery at the Fermilab Tevatron and the CERN Large Hadron Collider
We investigate the prospects for heavy charged Higgs boson production through the mechanisms pp? (pp)?H±tb+X at the upgraded Fermilab Tevatron and at the upcoming LHC at CERN, respectively. We focus on the minimal supersymmetric standard model case and include the leading quantum corrections at high tan?. A detailed study is performed for all important production modes and basic background processes for the tt? bb? signature. At the upgraded Tevatron a charged Higgs signal is potentially viable in the 220–250?GeV range or excluded at 95% C.L. up to 300?GeV. At the LHC, a H± of mass up to 800?GeV can be discovered at 5? or else be excluded up to a mass of ?1.5?TeV. The presence of SUSY quantum effects may highly influence the discovery potential in both machines and can typically shift these limits by 200?GeV at the LH