Phenomenological analysis of angular correlations in 7 TeV proton-proton collisions from the CMS experiment

A phenomenological analysis is presented of recent two-particle angular correlation data on relative pseudorapidity ($\eta$) and azimuth reported by the Compact Muon Solenoid (CMS) Collaboration for $\sqrt{s}$ = 7 TeV proton-proton collisions. The data are described with an empirical jet-like model developed for similar angular correlation measurements obtained from heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC). The same-side (small relative azimuth), $\eta$-extended correlation structure, referred to as the {\em ridge}, is compared with three phenomenological correlation structures suggested by theoretical analysis. These include additional angular correlations due to soft gluon radiation in $2 \rightarrow 3$ partonic processes, a one-dimensional same-side correlation ridge on azimuth motivated for example by color-glass condensate models, and an azimuth quadrupole similar to that required to describe heavy ion angular correlations. The quadrupole model provides the best overall description of the CMS data, including the ridge, based on $\chi^2$ minimization in agreement with previous studies. Implications of these results with respect to possible mechanisms for producing the CMS same-side correlation ridge are discussed.Comment: 11 pages, 2 figures, 1 tabl

Dissipation and fragmentation of low-Q^2 scattered partons in Au-Au collisions at RHIC

Two-particle correlations and event-wise fluctuations in transverse momentum p_t are reported for Au-Au collisions at sqrt{s_{NN}} = 62 and 200 GeV on pseudorapidity (eta) and azimuth (phi). Distributions of all pairs of particles (no leading trigger particle) reveal jet-like correlations, or peaks at pair-wise opening angles of order 1 radian or less. The width of this same-side correlation peak increases dramatically on pseudorapidity and decreases on azimuth for increasing collision centrality. Evolution of the same-side peak with centrality suggests dissipation of low-Q^2 partons via strong coupling to an expanding bulk medium. p_t correlations, which provide access to temperature and/or velocity distributions in the colliding system, are also presented.Comment: 4 pages, 2 figures, conference poster write-u

Real-time in-flight thrust calculation on a digital electronic engine control-equipped F100 engine in an F-15 airplane

Computer algorithms which calculate in-flight engine and aircraft performance real-time are discussed. The first step was completed with the implementation of a real-time thrust calculation program on a digital electronic engine control (DEEC) equiped F100 engine in an F-15 aircraft. The in-flight thrust modifications that allow calculations to be performed in real-time, to compare results to predictions, are presented

Test and evaluation of the HIDEC engine uptrim algorithm

The highly integrated digital electronic control (HIDEC) program will demonstrate and evaluate the improvements in performance and mission effectiveness that result from integrated engine-airframe control systems. Performance improvements will result from an adaptive engine stall margin mode, a highly integrated mode that uses the airplane flight conditions and the resulting inlet distortion to continuously compute engine stall margin. When there is excessive stall margin, the engine is uptrimmed for more thrust by increasing engine pressure ratio (EPR). The EPR uptrim logic has been evaluated and implemented into computer simulations. Thrust improvements over 10 percent are predicted for subsonic flight conditions. The EPR uptrim was successfully demonstrated during engine ground tests. Test results verify model predictions at the conditions tested