The baryogenesis window in the MSSM

Thermal two-loop QCD corrections associated with light stops have a dramatic effect on the strength of the MSSM electroweak phase transition, making it more strongly first order as required for the viability of electroweak baryogenesis. We perform a perturbative analysis of the transition strength in this model, including these important contributions, extending previous work to arbitrary values of the pseudoscalar Higgs boson mass, m_A. We find a strong enough transition in a region with 2 120 GeV, a light Higgs boson with nearly standard couplings, and mass below 85 GeV within the reach of LEP II, and one stop not much heavier than the top quark. In addition, we give a qualitative discussion of the parameter space dependence of the transition strength and comment on the possibility that the transition turns to a crossover for sufficiently large Higgs masses.Comment: 33 pages, latex2e, 5 figures, epsfig.sty. Final version to appear in Nuclear Physics

Cold Dark Matter Candidate in a Class of Supersymmetric Models with an Extra U(1)

In supersymmetric models whose gauge group includes an additional U(1) factor at the TeV scale, broken by the VEV of an standard model singlet S, the parameter space can accommodate a very light neutralino not ruled out experimentally. This higgsino-like fermion, stable if R-parity is conserved, can make a good cold dark matter candidate. We examine the thermal relic density of this particle and discuss the prospects for its direct detection if it forms part of our galactic halo.Comment: 13 pages, LaTex, uses psfig.sty with 3 figure

Discovery of molecular subtypes in leiomyosarcoma through integrative molecular profiling.

Leiomyosarcoma (LMS) is a soft tissue tumor with a significant degree of morphologic and molecular heterogeneity. We used integrative molecular profiling to discover and characterize molecular subtypes of LMS. Gene expression profiling was performed on 51 LMS samples. Unsupervised clustering showed three reproducible LMS clusters. Array comparative genomic hybridization (aCGH) was performed on 20 LMS samples and showed that the molecular subtypes defined by gene expression showed distinct genomic changes. Tumors from the muscle-enriched cluster showed significantly increased copy number changes (P=0.04). A majority of the muscle-enriched cases showed loss at 16q24, which contains Fanconi anemia, complementation group A, known to have an important role in DNA repair, and loss at 1p36, which contains PRDM16, of which loss promotes muscle differentiation. Immunohistochemistry (IHC) was performed on LMS tissue microarrays (n=377) for five markers with high levels of messenger RNA in the muscle-enriched cluster (ACTG2, CASQ2, SLMAP, CFL2 and MYLK) and showed significantly correlated expression of the five proteins (all pairwise P<0.005). Expression of the five markers was associated with improved disease-specific survival in a multivariate Cox regression analysis (P<0.04). In this analysis that combined gene expression profiling, aCGH and IHC, we characterized distinct molecular LMS subtypes, provided insight into their pathogenesis, and identified prognostic biomarkers

The Light Stop Scenario from Gauge Mediation

In this paper we embed the light stop scenario, a MSSM framework which explains the baryon asymmetry of the universe through a strong first order electroweak phase transition, in a top-down approach. The required low energy spectrum consists in the light SM-like Higgs, the right-handed stop, the gauginos and the Higgsinos while the remaining scalars are heavy. This spectrum is naturally driven by renormalization group evolution starting from a heavy scalar spectrum at high energies. The latter is obtained through a supersymmetry-breaking mix of gauge mediation, which provides the scalars masses by new gauge interactions, and gravity mediation, which generates gaugino and Higgsino masses. This supersymmetry breaking also explains the \mu\ and B_\mu\ parameters necessary for electroweak breaking and predicts small tri-linear mixing terms A_t in agreement with electroweak baryogenesis requirements. The minimal embedding predicts a Higgs mass around its experimental lower bound and by a small extension higher masses m_H\lesssim 127 GeV can be accommodated.Comment: 20 pages, 3 figures; v2: changes in the conventions; v3: more details on the Higgs mass prediction, version published in JHE

Relationship between weight and linear dimensions of Bluefin tuna (Thunnus thynnus) following fattening on western Mediterranean farms

This study presents various models based on formulae relating weight and dimensions (length, height and width) of Bluefin tuna, Thunnus thynnus (L.), fattened in captivity. The main aim of establishing these expressions is to design tools for indirectly predicting the weight of a Bluefin tuna from measurements of one or more dimensions obtained using non- invasive methods such as stereoscopic cameras. Measurements of maximum length, height and width following slaughter were taken of fish fattened in captivity (n = 2078). Different relationships drawn from the dimensions of the tuna against their weight are fitted with part of the data collection and later checked against a reserved sample set. The resulting formu- lae are compared with the formulae most commonly used in the case of wild tuna. The results of this study confirm that, for tuna fattened in cages, the availability of more than one dimension to estimate weight improves the predictive power of the model and reduces error in the estimate.En prensa4,41

Emanation Study of Gas Radon on the Ancient Cuexcomate Geyser in Puebla City, Mexico

Radon measurements were collected over a period of nine months in the area of the ancient Cuexcomate geyser, in Puebla City. For measuring radon, the passive method of nuclear tracks in solids was used, using polycarbonate CR-39 as radiation sensitive material. Radon concentrations varied in strong anti-correlation with the rainfall intensity. And are lower compared to other locations, in concordance with the stratigraphic composition, as travertine and deposits of volcanic origin, corresponding to the geyser chemical composition and the active environment in the north part of the Trans-Mexican Volcanic Belt with an andesitic and basalt composition

Suppression of Ferromagnetic Double Exchange by Vibronic Phase Segregation

From Raman spectroscopy, magnetization, and thermal-expansion on the system La2/3(Ca1-xSrx)1/3MnO3, we have been able to provide a quantitative basis for the heterogeneous electronic model for manganites exhibiting colossal magnetoresistance (CMR). We construct a mean-field model that accounts quantitatively for the measured deviation of TC(x) from the TC predicted by de Gennes double exchange in the adiabatic approximation, and predicts the occurrence of a first order transition for a strong coupling regime, in accordance with the experiments. The existence of a temperature interval TC<T<T* where CMR may be found is discussed, in connection with the occurrence of an idealized Griffiths phase.Comment: Replaced with the final version accepted in Physical Review Letter

Higgs After the Discovery: A Status Report

Recently, the ATLAS and CMS collaborations have announced the discovery of a 125 GeV particle, commensurable with the Higgs boson. We analyze the 2011 and 2012 LHC and Tevatron Higgs data in the context of simplified new physics models, paying close attention to models which can enhance the diphoton rate and allow for a natural weak-scale theory. Combining the available LHC and Tevatron data in the ZZ* 4-lepton, WW* 2-lepton, diphoton, and b-bbar channels, we derive constraints on the effective low-energy theory of the Higgs boson. We map several simplified scenarios to the effective theory, capturing numerous new physics models such as supersymmetry, composite Higgs, dilaton. We further study models with extended Higgs sectors which can naturally enhance the diphoton rate. We find that the current Higgs data are consistent with the Standard Model Higgs boson and, consequently, the parameter space in all models which go beyond the Standard Model is highly constrained.Comment: 37 pages; v2: ATLAS dijet-tag diphoton channel added, dilaton and doublet-singlet bugs corrected, references added; v3: ATLAS WW channel included, comments and references adde