Antinucleus Production at RHIC

Light antinuclei may be formed in relativistic heavy ion collisions via final state coalescence of antinucleons. The yields of antinuclei are sensitive to primordial antinucleon production, the volume of the system at kinetic freeze-out, and space-momentum correlations among antinucleons at freeze-out. We report here preliminary STAR results on antideuteron and antihelion production in 130A GeV Au+Au collisions. These results are examined in a coalescence framework to elucidate the space-time structure of the antinucleon source.Comment: 4 pages, 3 figures, talk given at Quark Matter 200

Spin physics with STAR

The STAR collaboration aims to study polarized proton-proton collisions at RHIC. The emphasis of the spin run this year is on transverse single spin asymmetries. Beyond 2001, we aim to determine directly and precisely the gluon polarization, as well as the polarizations of the u, $\bar{u}$, d and $\bar{d}$ quarks in the proton by measuring in addition longitudinal and double spin asymmetries. Furthermore, we aim to measure for the first time the quark transversity distributions. These measurements will improve substantially the knowledge and understanding of the spin structure of the nucleon.Comment: 9 pages, 3 figures. Talk presented at The 3rd Circum-Pan-Pacific Symposium on "High Energy Spin Physics" October 8-13 2001, Beijing, Chin

Elliptic flow in Au+Au collisions at sNN\sqrt{s_{_{NN}}} = 130 GeV

We report the elliptic flow of charged and identified particles at mid-rapidity in Au+Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV using the STAR TPC at RHIC. The integrated elliptic flow signal, $v_2$, for charged particles reaches values of about 0.06, indicating a higher degree of thermalization than at lower energies. The differential elliptic flow signal, $v_2$($p_t$) up to 1.5 GeV/$c$, shows a behavior expected from hydrodynamic model calculations. Above 1.5 GeV/$c$, the data deviate from the hydro predictions; however the $v_2$($p_t$) is still large, suggesting finite asymmetry for the products of hard scattering. For the identified particles, elliptic flow as a function of $p_t$ and centrality differ significantly for particles of different masses. This dependence can be accounted for in hydrodynamic models, indicating that the system created shows a behavior consistent with collective hydrodynamical flow.Comment: 6 pages, 8 figures, Quark Matter 200

Resonance Studies at STAR

We report on the observed signals of ${K^{\star0}(892)}\to\pi K$ and $\phi(1020)\to K^{+}K^{-}$ using the mixed-event method with powerful statistics from the large acceptance and highly efficient STAR TPC. Preliminary results from the first observation of such states from the year-one STAR data in $\sqrt{s_{NN}}=130$ GeV Au-Au collisions are presented. The $K^{\star0}/h^{-}$ ratios with an assumed $K^{\star0}$ $p_{T}$ inverse slope of 300MeV are compatible with that from pp at ISR. For 14% central Au+Au collisions, we observe $K^{\star0}/h^{-}=0.060\pm0.007(stat)$ and $\bar{K^{\star0}}/h^{-}=0.058\pm0.007(stat)$. We show that $\bar{\Lambda}/\Lambda=0.77\pm0.07(stat)$ from this method is consistent with the measurement via decay topology.Comment: 4 pages, 4 figures, Quark Matter 2001, contributed talk; typos of K*/h- numbers in abstract fixe

Measurements of Photon and Neutral Pion Production in Heavy Ion Collisions at RHIC

Inclusive transverse momentum spectra of photons and neutral pions about mid-rapidity are presented for Au+Au collisions at sqrt(s_NN} = 130 GeV. Photon pair conversions have been reconstructed from charged tracks measured with the central Time Projection Chamber (TPC) of STAR. Contributions of the pi^0 -> \gamma\gamma decay in the inclusive photon spectra have been studied. It was found that this contribution begins to decrease at a transverse momentum of 1.65 GeV/c in the top 11% most central centrality class.Comment: 5 pages, 3 figures, contribution to the Proceedings of Quark Matter 2002, Nantes, France, July 18-24, 200

Resonance Production in STAR

The recent results from resonance production in central Au+Au and p+p collisions at $\sqrt{s_{\rm NN}} =$ 200 GeV from the STAR experiment at RHIC are presented and discussed.Comment: 7 pages, proceedings 19th Winter Workshop on Nuclear Dynamics, Breckenridge, Colorado, USA, February 8-15, 200

Correlations, Fluctuations, and Flow Measurements from the STAR Experiment

New measurements of short-range and long-range two-particle correlations, azimuthal anisotropy, and event-by-event fluctuations from the STAR experiment for sqrt{s_{NN}}= 130 and 200 GeV Au+Au collisions are summarized. Striking evidence is presented for large, non-statistical fluctuations in mean transverse momentum. Descriptions of the data in terms of phenomenological source function models are also presented.Comment: 10 pages, 10 figures, Conference proceedin

Cerebellar intracellular calcium signaling and proapoptotic/proinflammatory protein changes common to motor dysfunctions with divergent etiologies

Introduction Binge drinking among adolescents is an ongoing public health concern. Although binge drinking can also be harmful to adults, the adolescent population is more susceptible to aberrant neurological changes as their brains are still undergoing significant development. The waddles (wdl) mouse is characterized by a namesake waddling gait due to a homozygous mutation of the Car8 gene. Carbonic anhydrase type 8 (CAR8) controls the intracellular release of calcium (Ca²⁺) from internal stores. Both models display a similar cerebellar based ataxia which is why they were chosen for comparison. Methods Groups of pre-adolescent post-natal day (PND 26) and adolescent (PND 34) rats underwent a series of behavioral tests designed to assess memory, anxiety regulation, and motor function. Subjects were first exposed to either ethanol or plain air through a vapour chamber apparatus for five consecutive days (two hours per day). Rota-rod testing was conducted to characterize the wdl mutation and ethanol treatment effects on motor output. Acute cerebellar slices from wdl mice were subsequently utilized for fluorescent calcium imaging experiments. Western blotting was used for protein quantification in the homogenized cerebella of both models. Results Behavioral testing using the rota-rod, cage-hang, novel object recognition, light-dark box, and elevated plus maze apparatuses showed significantly decreased object memory and measures of anxiety-related behaviors in ethanol treated subjects. Western blotting indicated elevated levels of proinflammatory/proapoptotic proteins in the cerebella of ethanol treated and wdl animals. Younger homozygous wdl mice outperformed their older cohorts on the rota-rod. Heterozygotes, which were thought to be free of motor impairment, displayed motor learning deficiencies. Calcium imaging revealed significant attenuation of cerebellar granule cell somatic Ca²⁺ signaling in homozygous mice. Conclusion Differences on anxiety tests indicate a failure of behavioral inhibition in the ethanol treated group. There are also impairments to motor coordination and object memory, which involve the cerebellar and hippocampal brain regions, respectively. When taken together with work on the wdl mouse, these findings suggest disruptions in cerebellar circuitry hampering proper neuronal communication have drastic consequences for behavioral output of the cerebellum