Phenomenological study of the atypical heavy flavor production observed at the Fermilab Tevatron

We address known discrepancies between the heavy flavor properties of jets produced at the Tevatron collider and the prediction of conventional-QCD simulations. In this study, we entertain the possibility that these effects are real and due to new physics. We show that all anomalies can be simultaneously fitted by postulating the additional pair production of light bottom squarks with a 100% semileptonic branching fraction.Comment: 30 pages, 13 figures, 3 tables. Submitted to Phys. Rev.

Comment on "Evolution of a Quasi-Stationary State"

Approximately forty years ago it was realized that the time development of decaying systems might not be precisely exponential. Rolf Winter (Phys. Rev. {\bf 123}, 1503 (1961)) analyzed the simplest nontrivial system - a particle tunneling out of a well formed by a wall and a delta-function. He calculated the probability current just outside the well and found irregular oscillations on a short time scale followed by an exponential decrease followed by more oscillations and finally by a decrease as a power of the time. We have reanalyzed this system, concentrating on the survival probability of the particle in the well rather than the probability current, and find a different short time behavior.Comment: 8 pages, 6 figures, RevTex

Properties of ρ\rho and ω\omega Mesons at Finite Temperature and Density as Inferred from Experiment

The mass shift, width broadening, and spectral density for the $\rho$ and $\omega$ mesons in a heat bath of nucleons and pions are calculated using a general formula which relates the self-energy to the real and imaginary parts of the forward scattering amplitude. We use experimental data to saturate the scattering amplitude at low energies with resonances and include a background Pomeron term, while at high energies a Regge parameterization is used. The real part obtained directly is compared with the result of a dispersion integral over the imaginary part. The peaks of the spectral densities are little shifted from their vacuum positions, but the widths are considerably increased due to collisional broadening. Where possible we compare with the UrQMD model and find quite good agreement. At normal nuclear matter density and a temperature of 150 MeV the spectral density of the $\rho$ meson has a width of 345 MeV, while that for the $\omega$ is in the range 90--150 MeV.Comment: 21 pages revtex + 9 postscript figure

Optimization of R(e+e-) and "Freezing" of the QCD Couplant at Low Energies

The new result for the third-order QCD corrections to R_{e^+e^-}, unlike the old, incorrect result, is nicely compatible with the principle-of-minimal-sensitivity optimization method. Moreover, it leads to infrared fixed-point behaviour: the optimized couplant, alpha_s/pi, for R(e+e-) does not diverge at low energies, but "freezes" to a value 0.26 below about 300 MeV. This provides some direct theoretical evidence, purely from perturbation theory, for the "freezing" of the couplant -- an idea that has long been a popular and successful phenomenological hypothesis. We use the "smearing" method of Poggio, Quinn, and Weinberg to compare the resulting theoretical prediction for R(e+e-) with experimental data down to the lowest energies, and find excellent agreement.Comment: 27 pages, LaTeX, 8 uuencoded figures, DE-FG05-92ER40717-

Down Low Under the Big Sky

Often synonymous with the rural environment is a sense of a heteronormativity and pervasive homophobia. Despite stories of gay men fleeing rural, conservative areas for larger, more accepting cities, not all men have chosen to leave. Some have chosen to quietly maintain their identity, modifying their sexual schemata in response to the desire to stay within the rural cultural environment. It is known that homophobia and stigmatization of same-sex sexual acts regulate a person\u27s ability to be open about their sexual encounters, but exactly how they influence the daily lives of down low men who have sex with men (MSM) remains unknown. Influenced by schema theory and informed by queer theory, the current study investigated the role of the rural environment in shaping men\u27s decisions to remain on the down low about their same-sex sexual activity and the impact of that decision on daily life. It sought to understand the influence of the rural environment on men\u27s decisions to not be out about their same-sex sexual identity and in turn how that decision influenced sexual risk behavior and HIV prevention. The data gathered during semi-structured qualitative interviews with forty-five self-identified closeted men living in Montana was analyzed using a modified grounded theory approach. Several reasons for remaining closeted emerged and the level that each man was affected by his decision to remain closeted differed. Overarching themes of isolation and depression emerged from men feeling as if they had no choice, but to remain closeted while living in a rural environment. For many, homosexuality is still viewed in direct contrast to these traditional ideals, leaving many men questioning how to maintain their place within the rural social environment. As Gerard Wright states, being gay in `cowboy country\u27 similarly involves tactics of sexual camouflage: To be gay in western states such as Colorado, Wyoming, Nebraska, and Montana is to know when and how to `butch up\u27 or `cowboy up. One means of maintaining this sense of camouflage adopted by rural men is to remain on the down low about their same-sex sexual activity. A desire for increased social support and a more accepting social environment emerged from this research. This dissertation provides a voice for men previously excluded from the literature on rural sexual minorities. It provides insight into men\u27s everyday life experiences stemming from feelings of having to remain closeted about a part of their personal identity. This dissertation seeks to contribute to the literature on rural gay lives

Christian School Relationships with Homeschool Families

This mixed-methods study began with a survey sent to all CSI superintendents followed up by interviews with a purposeful sample of six school leaders to discover perceived relationship models that exist between Christian schools and homeschool families. Analysis of the qualitative and quantitative data was done with the intention of gaining a deeper understanding of the current relationship models that exist between Christian schools and homeschool families and to understand the benefits and barriers of the given relationship models. The results of the study suggest that nearly 60% of Christian schools surveyed are choosing some form of relationship with homeschool families, and for many of those schools, the benefits that come with the relationship outweigh the barriers. While the study does not give enough evidence to prove that having an inclusive relationship between Christian schools and home school families is a best practice, it does offer many recommendations for schools who would like to explore the possibility of an inclusive or partially inclusive relationship

Improved Limits on B0B^{0} decays to invisible (+γ)(+\gamma) final states

We establish improved upper limits on branching fractions for B0 decays to final States 10 where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a photon. Within the Standard Model, these decays have branching fractions that are below the current experimental sensitivity, but various models of physics beyond the Standard Model predict significant contributions for these channels. Using 471 million BB pairs collected at the Y(4S) resonance by the BABAR experiment at the PEP-II e+e- storage ring at the SLAC National Accelerator Laboratory, we establish upper limits at the 90% confidence level of 2.4x10^-5 for the branching fraction of B0-->Invisible and 1.7x10^-5 for the branching fraction of B0-->Invisible+gammaComment: 8 pages, 3 postscript figures, submitted to Phys. Rev. D (Rapid Communications

Precise Measurement of the e+ e- --> pi+ pi- (gamma) Cross Section with the Initial-State Radiation Method at BABAR

A precise measurement of the cross section of the process $e^+e^-\to\pi^+\pi^-(\gamma)$ from threshold to an energy of 3GeV is obtained with the initial-state radiation (ISR) method using 232fb$^{-1}$ of data collected with the BaBar detector at $e^+e^-$ center-of-mass energies near 10.6GeV. The ISR luminosity is determined from a study of the leptonic process $e^+e^-\to\mu^+\mu^-(\gamma)\gamma_{\rm ISR}$, which is found to agree with the next-to-leading-order QED prediction to within 1.1%. The cross section for the process $e^+e^-\to\pi^+\pi^-(\gamma)$ is obtained with a systematic uncertainty of 0.5% in the dominant $\rho$ resonance region. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the measured $\pi\pi$ cross section from threshold to 1.8GeV is $(514.1 \pm 2.2({\rm stat}) \pm 3.1({\rm syst}))\times 10^{-10}$.Comment: 58 pages, 56 figures, to be submitted to Phys. Rev.