Gluino production in ultrarelativistic heavy ion collisions and nuclear shadowing

In this article we investigate the influence of nuclear effects in the production of gluinos in nuclear collisions at the LHC, and estimate the transverse momentum dependence of the nuclear ratios $R_{pA} = {\frac{d\sigma (pA)}{dy d^2 p_T}} / A {\frac{d\sigma (pp)}{dy d^2 p_T}}$ and $R_{AA} = {\frac{d\sigma (AA)}{dy d^2 p_T}} / A^2 {\frac{d\sigma (pp)}{dy d^2 p_T}}$. We demonstrate that depending on the magnitude of the nuclear effects, the production of gluinos could be enhanced, compared to proton-proton collisions. The study of these observables can be useful to determine the magnitude of the shadowing and antishadowing effects in the nuclear gluon distribution. Moreover, we test different SPS scenarios, corresponding to different soft SUSY breaking mechanisms, and find that the nuclear ratios are strongly dependent on that choice.Comment: 7 pages, 5 figures; results and discussions changed/added. Accepted for publication in Physical Review

Soft and hard QCD dynamics in hadroproduction of charmonium

Both hard and soft QCD dynamics are important in charmonium production, as presented here through a next-to-leading order QCD matrix element calculation combined with the colour evaporation model. Observed $x_F$ and $p_\perp$ distributions of $J/\psi$ in hadroproduction at fixed target and $p\bar{p}$ collider energies are reproduced. Quite similar results can also be obtained in a more phenomenologically useful Monte Carlo event generator where the perturbative production of \ccbar pairs is instead obtained through leading order matrix elements and the parton shower approximation of the higher order processes. The soft dynamics may alternatively be described by the soft colour interaction model, originally introduced in connection with rapidity gaps. We also discuss the relative rates of different charmonium states and introduce an improved model for mapping the continuous \ccbar mass spectrum on the physical charmonium resonances.Comment: 21 pages, 13 eps figure

Soft and hard QCD in charmonium production

Hard and soft QCD dynamics are both important in charmonium hadroproduction, as presented here through a next-to-leading order QCD matrix element calculation combined with the colour evaporation model. Observed $x_F$ and $p_\perp$ distributions of $J/\psi$ in hadroproduction are reproduced. Quite similar results can also be obtained with a Monte Carlo event generator where \ccbar pairs are instead produced through leading order matrix elements and the parton shower approximation of higher order processes. The soft dynamics may alternatively be described by the soft colour interaction model. We also discuss the relative rates of different charmonium states and introduce an improved model for mapping the continuous ccbar mass spectrum on the physical charmonium resonances.Comment: Presented at Pan American Advanced Studies Institute (PASI 2002), Campos do Jord\~ao, Brazil, January 7-18, 200

College Readiness Initiative: AVID and Navigation 101

The purpose of this report is to provide summative feedback to personnel at the Office of Superintendent of Public Instruction (OSPI) and at the College Spark Washington regarding evidence of implementation and impact of the Advancement via Individual Determination (AVID) and Navigation 101 programs in schools funded by the College Readiness Initiative (CRI) in Washington State. The report, while addressing the effects of both programs, is also designed to provide formative feedback to assist in ongoing program development

Shock waves in ultracold Fermi (Tonks) gases

It is shown that a broad density perturbation in a Fermi (Tonks) cloud takes a shock wave form in the course of time evolution. A very accurate analytical description of shock formation is provided. A simple experimental setup for the observation of shocks is discussed.Comment: approx. 4 pages&figures, minor corrections^2, to be published as a Letter in Journal of Physics