2,107 research outputs found
Assisted freeze-out
We explore a class of dark matter models with two dark matter candidates,
only one interacts with the standard model sector. One of the dark matter is
thermalized with the assistance of the other stable particle. While both stable
particles contribute to the total relic density only one can elastically
scatter with nuclei, thus effectively reducing the direct detection rate.Comment: 16 pages, 13 figures, minor corrections, the final version published
in JCA
Comparison of SUSY spectrum calculations and impact on the relic density constraints from WMAP
We compare results of four public supersymmetric (SUSY) spectrum codes,
Isajet, Softsusy, Spheno and Suspect to estimate the present-day uncertainty in
the calculation of the relic density of dark matter in mSUGRA models. We find
that even for mass differences of about 1% the spread in the obtained relic
densities can be 10%. In difficult regions of the parameter space, such as
large tan(beta) or large m_0, discrepancies in the relic density are much
larger. We also find important differences in the stau co-annihilation region.
We show the impact of these uncertainties on the bounds from WMAP for several
scenarios, concentrating on the regions of parameter space most relevant for
collider phenomenology. We also discuss the case of non-zero A_0 and the stop
co-annihilation region. Moreover, we present a web application for the online
comparison of the spectrum codes.Comment: 26 pages, 6 figures, 10 tables; version to appear in PR
Indirect search for dark matter with micrOMEGAs2.4
We present a new module of micrOMEGAs devoted to the computation of indirect
signals from dark matter annihilation in any new model with a stable weakly
interacting particle. The code provides the mass spectrum, cross-sections,
relic density and exotic fluxes of gamma rays, positrons and antiprotons. The
propagation of charged particles in the Galactic halo is handled with a new
module that allows to easily modify the propagation parameters.Comment: 24 pages, 6 figures, typos corrected, acknowledgements modifie
GRACE/SUSY Automatic Generation of Tree Amplitudes in the Minimal Supersymmetric Standard Model
GRACE/SUSY is a program package for generating the tree-level amplitude and
evaluating the corresponding cross section of processes of the minimal
supersymmetric extension of the standard model (MSSM). The Higgs potential
adopted in the system, however, is assumed to have a more general form
indicated by the two-Higgs-doublet model. This system is an extension of GRACE
for the standard model(SM) of the electroweak and strong interactions. For a
given MSSM process the Feynman graphs and amplitudes at tree-level are
automatically created. The Monte-Carlo phase space integration by means of
BASES gives the total and differential cross sections. When combined with
SPRING, an event generator, the program package provides us with the simulation
of the SUSY particle productions.Comment: 39 page, 1 figur
Feebly-interacting dark matter
We briefly review scenarios with feebly interacting particles (FIMPs) as dark
matter candidates. The discussion covers issues with dark matter production in
the early universe as well as signatures of FIMPs at the high energy and high
intensity frontier as well as in astroparticle and cosmology.Comment: 6 pages, 2 captioned figures. Review article for EPJ ST Special
Issue: Frontier 23: Elementary particle physics, dark matter and
astroparticle physic
Spousal support and relationship happiness in adults with type 2 diabetes and their spouses
Objectives
The purpose of this study was to examine the association between the perceptions of spousal support self-efficacy in terms of dietary self-care and relationship happiness.
Methods
Forty-six couples, in which only one spouse has type 2 diabetes, completed questionnaires on perceptions of spousal support self-efficacy and relationship happiness.
Results
Using an actor-partner interdependence model, we found that when persons with type 2 diabetes were more confident in their spouse’s ability to provide them with support regarding their dietary self-care, they reported more relationship happiness. We also found that when their spouse without diabetes was more confident in their own abilities to provide such support to their partner, they reported more relationship happiness. However, the person with diabetes’ confidence in their spouse’s support abilities and the spouse’s confidence in their own support abilities were not associated with the other partner’s relationship happiness.
Conclusions
This study offers a unique dyadic perspective on the determinants of happiness for couples in which one spouse has type 2 diabetes. The perceived quality of spousal support appears to be associated with relationship happiness in committed couples managing diabetes, regardless of the actual support received or provided
Gauge boson couplings at LEP
A review is given of the measurements of triple and quartic couplings among
the electroweak gauge bosons performed at LEP by the four experiments ALEPH,
DELPHI, L3 and OPAL. Emphasis is placed on recently published results and on
combinations of results performed by the LEP electroweak gauge-couplings group.
All measurements presented are consistent with the Standard Model expectations.Comment: 6 pages, 7 figures. To be published in the proceedings of the BEACH04
conference, Chicago, June 27-July 3 200
Relic density of neutralino dark matter in the MSSM with CP violation
We calculate the relic density of dark matter in the MSSM with CP violation.
We analyse various scenarios of neutralino annihilation: the cases of a bino,
bino-wino and bino-Higgsino LSP, annihilation through Higgs, as well as
sfermion coannihilation scenarios. Large phase effects are found, on the one
hand due to shifts in the masses, on the other hand due to modifications of the
couplings. Taking special care to disentangle the effects in masses and
couplings, we demonstrate that the presence of CP phases can have a significant
influence on the neutralino relic abundance. Typical variations in \Omega h^2
solely from modifications in the couplings are O(10%-100%), but can reach an
order of magnitude in some cases.Comment: 36 pages, 21 figures (low resolution). A version with high-resolution
figures can be downloaded from http://cern.ch/kraml/papers/omc
Full one-loop electroweak radiative corrections to single photon production in e+e-
Large scale calculation for the radiative corrections required for the
current and future collider experiments can be done automatically using the
GRACE-LOOP system. Here several results for e+e- --> 3-body processes are
presented including e+e- --> e+e-H and e+e- --> nu nubar gamma.Comment: 5 pages, contribution to ACAT03(Dec. 2003
Recommended from our members
Echocardiographic evaluation of velocity ratio, velocity time integral ratio, and pulmonary valve area in dogs with pulmonary valve stenosis.
BackgroundVelocity ratio, velocity time integral (VTI) ratio, and pulmonary valve area indexed to body surface area (iPVA) are methods of assessment of pulmonary valve stenosis (PS) severity that are less dependent on blood flow. Studies evaluating these methods are limited.ObjectivesTo determine the effects of butorphanol, atenolol, and balloon valvuloplasty (BV) on velocity ratio, VTI ratio, iPVA, mean PG, and max PG.AnimalsTwenty-seven dogs with PS (max PG >50 mm Hg).MethodsProspective study. All dogs underwent an echocardiogram at baseline, 5-minutes after administration of butorphanol (0.2-0.25 mg/kg IV), and 2-to-4 weeks after atenolol (1-1.5 mg/kg q12h). Twenty-one of these were evaluated 24-hours after BV.ResultsThere were no significant differences (P > .05) amongst any of the methods of assessment of PS severity after butorphanol. After atenolol, mean (SD) of mean (57.0 [21.0] mm Hg) and max PG (93.1 [33.8] mm Hg) were significantly decreased (P ≤ .047) compared with baseline (65.2 [26.2] mm Hg and 108 [44.4] mm Hg, respectively). After atenolol, there were no significant (P ≥ .12) differences in velocity ratio (0.29 [0.09]), VTI ratio (0.18 [0.05]), or iPVA (0.43 [0.16] cm2 /m2 ) compared with baseline (0.30 [0.09], 0.19 [0.09], 0.44 [0.17] cm2 /m2 , respectively).Conclusions and clinical importanceAtenolol might reduce mean and max PG but does not alter less flow-dependent methods of assessment of PS severity (velocity ratio, VTI ratio, and iPVA) in dogs with PS. Results support an integrative approach to assessment of PS severity that includes less flow-dependent methods, particularly in states of altered flow or right ventricular function
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