Long-distance behavior of the quark-antiquark static potential. Application to light-quark mesons and heavy quarkonia

Screening effects from sea pairs on the quark-antiquark static potential are analyzed phenomenologically from the light-quark to the heavy-quark meson spectra. From the high excited light-quark meson spectrum a universal form for the screened static potential is proposed. This potential is then succesfully applied to heavy quarkonia. Our results suggest the assignment of X(4260) to the 4s state of charmonium and the possible existence of a 5s bottomonium resonance around 10748 MeV.Comment: Accepted in PR

Pionic effects in deep inelastic scattering off nuclei

The structure functions calculated in the Chiral bag model reproduce quite well, after appropriate perturbative evolution to large energy scales, the experimental data. We use these results to interpret the structure of the $EMC$ data as a quenching of the pion decay constant due to the in medium behavior of the nucleon. This explanation supports recent proposals of this phenomenon whose origin is the scale invariance of the $QCD$ lagrangian.Comment: 7 pages, figures not included, ftuv92-2

Dirac Quasinormal Modes of New Type Black Holes in New Massive Gravity

We study new type black holes in three-dimensional New Massive Gravity and we calculate analytically the quasinormal modes for fermionic perturbations for some special cases. Then, we show that for these cases the new type black holes are stable under fermionic field perturbations.Comment: improved version. arXiv admin note: text overlap with arXiv:1306.5974, arXiv:1404.317

Drugs and violence in Colombia: a VECM analysis

It has been widely argued that the production of illegal drugs, particularly cocaine, has financed guerrilla activity in Colombia. This paper uses quarterly time-series data for Colombia 1994-2005 to examine the interaction between legal agricultural production, illegal agricultural production of drugs and the number of guerrilla attacks. The time series analysis suggests that drug production acts as a weakly exogenous stochastic trend which has a negative effect on legal agricultural production and a positive effect on guerrilla attacks; with a long-run elasticity of attacks to drug production very close to unity

What is Driving Immigrants from El Salvador to Las Vegas? (2000-2010)

The purpose of this study is to examine if death rates due to crime or unemployment drove immigrants from El Salvador to migrate to Las Vegas between the years of 2000 to 2010. This study will be most directly based on the research conducted in the study Unauthorized Immigrant Population: National and State Trends, 2010, conducted by the Pew Research Center. Pew Research Center’s study focuses on finding an estimation on the number of undocumented immigrants that have entered the United States, the number of immigrants that are in the United States workforce, and the trends regarding what states and what cities immigrants are deciding to reside. The importance of my research proposal is that immigration as a topic tends to be biased based on the political climate. Research should be unbiased and should allow a platform where all of the facts surrounding a particular topic can be found. This will allow a deeper discussion surrounding the topic of Salvadoran immigrants in Las Vegas, Nevada, instead of discussing whether immigration is right or wrong based upon an individual’s moral reasoning. It is crucial that we focus on facts and that researchers are committed to unbiased research for the betterment of understanding the necessity of immigration policy reform. Through my research, I hypothesize that there will be a direct correlation to the number of immigrants in Las Vegas from El Salvador due to high unemployment and high homicide rates