Measurement of Lambda and Lambda(macro) particles in Au+Au collisions at the square root of S(NN) = 130 GeV

We present results on the measurement of Lambda and Lambda(macro) production in Au+Au collisions at square root of (S (NN) = 130 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The Lambda;/Lambda ratios are constant as a function of p(T) and the number of participants. The measured net Lambda density is significantly larger than predicted by models based on hadronic strings (e.g., HIJING) but in approximate agreement with models which include the gluon-junction mechanism.     

Flow measurements via two-particle azimuthal correlations in Au + Au collisions at sqrt [s(NN)]=130 GeV

Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p(T). A breakdown of this epsilon scaling is observed for charged hadrons with pT >1.0 GeV/c.     

Missing mass spectra in pp inelastic scattering at total energies of 23 GeV and 31 GeV

Results are reported of measurements of the momentum spectra of protons emitted at small angles in inelastic reactions at the CERN ISR. The data are for total energies $\text{s}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of 23 GeV and 31 GeV. The structure of the peak at low values of the missing mass M (of the system recoiling against the observed proton) is studied. The missing mass distributions have the form (M²)^?B(t) where t is the four-momentum transfer squared. B(t) drops from 0.98±0.06 at t=?0.15 GeV² to 0.20±0.15 at t=?1.65 GeV². The results are compared with a simple triple-Regge formula.     

Correlation between the pionization region and the fragmentation region in high energy proton-proton collisions

Measurements are reported of two-particle correlations in high energy proton-proton collisions with one particle in the pionization region and the other a proton in the fragmentation region. The correlation function is independent of x of the fragmentation proton for 0.55 ? x ? 0.9 and rises at small x. There is an indication that the correlation is an energy-independent function of x. The measurements for two values of the rapidity of the pionization particle give similar results.     

Determinants and current flows in electric networks

We consider electrical networks in which current enters at a single node and leaves at another. It has long been known that the currents and potential differences in such networks can be expressed in terms of determinants, or alternatively as counts of trees. Here we give alternative determinantal expressions.     

Molecular sieving platinum nanoparticle catalysts kinetically frozen in nanoporous carbon

Highly active shape selective catalysts with excellent thermal stability are synthesized by entrapping well dispersed platinum nanoparticles in a polyfurfuryl alcohol derived nanoporous carbon matrix; these nanocomposites are excellent candidates for new catalytic applications including fuel cells, pharmaceutical synthesis and biomass conversion.     

Double helicity asymmetry in inclusive midrapidity pi0 production for polarized p+p collisions at square root s = 200 GeV

We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at sqrt[s]=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.     

Nuclear modification factors for hadrons at forward and backward rapidities in deuteron-gold collisions at sqrt[s(NN)]=200 GeV

We report on charged hadron production in deuteron-gold reactions at sqrt[s(NN)]=200 GeV. Our measurements in the deuteron direction cover 1.4相似文献   

1.1 MW peak-power, 7 W average-power, high-spectral-brightness, diffraction-limited pulses from a photonic crystal fiber amplifier

We report a large-core, Yb-doped photonic crystal fiber amplifier generating diffraction-limited (M2 = 1.04), approximately 0.45 ns, approximately 8 GHz linewidth pulses with energies of 540 microJ, peak power in excess of 1.1 MW, and average power of approximately 7.2 W at a repetition rate of 13.4 kHz. The pulse peak spectral brightness exceeds 10 kW/(sr Hz cm2) and is the highest generated by a fiber source, to our knowledge.