Dark matter and neutrino masses in the R-parity violating NMSSM

The R-Parity symmetry Violating (RPV) version of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) is attractive simultaneously with regard to the so-called mu-problem and the accommodation of three-flavor neutrino data at tree level. In this context, we show here that if the Lightest Supersymmetric Particle (LSP) is the gravitino, it possesses a lifetime larger than the age of the universe since its RPV induced decay channels are suppressed by the weak gravitational strength. This conclusion holds if one considers gravitino masses ~ 10^2 GeV like in supergravity scenarios, and is robust if the lightest pseudoscalar Higgs field is as light as ~ 10 GeV [as may occur in the NMSSM]. For these models predicting in particular an RPV neutrino-photino mixing, the gravitino lifetime exceeds the age of the universe by two orders of magnitude. However, we find that the gravitino cannot constitute a viable dark matter candidate since its too large RPV decay widths would then conflict with the flux data of last indirect detection experiments. The cases of a sneutrino LSP or a neutralino LSP as well as the more promising gauge-mediated supersymmetry breaking scenario are also discussed. Both the one-flavor simplification hypothesis and the realistic scenario of three neutrino flavors are analyzed. We have modified the NMHDECAY program to extend the neutralino mass matrix to the present framework.Comment: Latex file, 23 pages, 7 figures. References added and discussion on the indirect detection modifie

Measuring cluster masses with CMB lensing: a statistical approach

We present a method for measuring the masses of galaxy clusters using the imprint of their gravitational lensing signal on the cosmic microwave background (CMB) temperature anisotropies. The method first reconstructs the projected gravitational potential with a quadratic estimator and then applies a matched filter to extract cluster mass. The approach is well-suited for statistical analyses that bin clusters according to other mass proxies. We find that current experiments, such as Planck, the South Pole Telescope and the Atacama Cosmology Telescope, can practically implement such a statistical methodology, and that future experiments will reach sensitivities sufficient for individual measurements of massive systems. As illustration, we use simulations of Planck observations to demonstrate that it is possible to constrain the mass scale of a set of 62 massive clusters with prior information from X-ray observations, similar to the published Planck ESZ-XMM sample. We examine the effect of the thermal (tSZ) and kinetic (kSZ) Sunyaev-Zeldovich (SZ) signals, finding that the impact of the kSZ remains small in this context. The stronger tSZ signal, however, must be actively removed from the CMB maps by component separation techniques prior to reconstruction of the gravitational potential. Our study of two such methods highlights the importance of broad frequency coverage for this purpose. A companion paper presents application to the Planck data on the ESZ-XMM sample.Comment: 9 pages, 5 figures, version accepted for publication in A&

Point Source Confusion in SZ Cluster Surveys

We examine the effect of point source confusion on cluster detection in Sunyaev-Zel'dovich (SZ) surveys. A filter matched to the spatial and spectral characteristics of the SZ signal optimally extracts clusters from the astrophysical backgrounds. We calculate the expected confusion (point source and primary cosmic microwave background [CMB]) noise through this filter and quantify its effect on the detection threshold for both single and multiple frequency surveys. Extrapolating current radio counts, we estimate that confusion from sources below 100 microJy limits single-frequency surveys to 1-sigma detection thresholds of Y 3.10^{-6} arcmin^2 at 30 GHz and Y 10^{-5} arcmin^2 at 15 GHz (for unresolved clusters in a 2 arcmin beam); these numbers are highly uncertain, and an extrapolation with flatter counts leads to much lower confusion limits. Bolometer surveys must contend with an important population of infrared point sources. We find that a three-band matched filter with 1 arcminute resolution (in each band) efficiently reduces confusion, but does not eliminate it: residual point source and CMB fluctuations contribute significantly the total filter noise. In this light, we find that a 3-band filter with a low-frequency channel (e.g, 90+150+220 GHz) extracts clusters more effectively than one with a high frequency channel (e.g, 150+220+300 GHz).Comment: Accepted for publication in Astronomy & Astrophysics; Updated grant information in acknowledgement

Weight Loss and Self-Monitoring among Young Men in a Technology-Driven Weight Loss Intervention

Background Young men with obesity have double the mortality risk compared to young men with a healthy weight, but are notoriously challenging to recruit for behavioral weight loss (BWL) programs. Emerging evidence suggests that young men might prefer self-guided or low touch interventions, but limited data are available as to their effectiveness. To inform future efforts, we conducted a secondary analysis of young men’s performance in a technology-driven BWL trial developed specifically for young adults. Objectives were to: 1) examine young men’s enrollment rates; and 2) compare young men and women’s weight loss outcomes and self-regulation behaviors. Methods Data were drawn from an ongoing randomized controlled trial targeting young adults (18-25 years, body mass index 25-45 kg/m2) for weight loss. Participants (N=184, 60% racial / ethnic minority, BMI=33.2) were recruited using a multi-method approach and randomized to one of three arms, all of which received a 6-month technology mediated intervention with content adapted specifically for young adults. For the purposes of the present analysis, outcomes of interest included weight change at 3 months (objectively assessed in-clinic) and engagement with self-regulation behaviors (captured via Bluetooth scales and self-monitoring app). Treatment arm was included as a covariate in all outcome analyses. Descriptive statistics were computed to capture enrollment rates. GLM was used to compare men and women on percent weight change at 3-months, days of self-weighing, and days of dietary self-monitoring. Results Young men represented 17% of enrolled participants. At 3-months, men manifested greater weight losses compared to women (-4.8±5.1% vs. -2.5±4.1%, p=.008). Over the course of the 3-months, engagement with self-regulation behaviors was similar for men and women; men had a similar number of days of self-weighing (46.77±24.6 vs. 47.42±24.0, p=.88) and a lower number of days for tracking diet (36.87±24.3 vs. 43.42±22.6, p=.15) relative to women. Conclusion While enrollment was low among young men in this technology-driven BWL program, those men who enrolled lost double the weight compared to women—even though engagement with self-monitoring behaviors was similar or lower. These results suggest that a low touch and primarily self-guided weight loss program may be sufficient to produce clinically meaningful weight loss among young men. Findings are discussed in terms of implications for future work.https://scholarscompass.vcu.edu/gradposters/1041/thumbnail.jp