330 research outputs found

    Handedness of direct photons

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    The azimuthal asymmetry of direct photons originating from primary hard scatterings between partons is calculated. This can be accounted for by the inclusion of the color dipole orientation, which is sensitive to the rapid variation of the nuclear profile. To this end we introduce the dipole orientation within the saturation model of Golec-Biernat and W\"usthoff, while preserving all its features at the cross-section level. We show that the direct photon elliptic anisotropy v2 coming from this mechanism changes sign and becomes negative for peripheral collisions, albeit it is quite small for nuclear collisions at the RHIC energy.Comment: 6 pages, 6 figures, Based on talk given by A.H.R. at II LAWHEP, Sao Miguel das Missoes, Brazil, December 3-7, 200

    Applied QCD

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    These lectures stress the theoretical elements that underlie a wide range of phenomenological studies of high-energy QCD, which include both soft and hard processes. After a brief introduction to the basics of QCD, various aspects of QCD-based phenomenology are covered: colour transparency, hadronization of colour charges, Regge phenomenology, parton model, Bjorken scaling and its violation, DGLAP evolution equation, BFKL formalism, GLRMQ evolution equation and saturation. In the last part of the lecture, we employ the lightcone dipole formalism to describe deep inelastic lepton scattering, DrellYan processes, direct photon production, diffraction, quark and gluon shadowing in nuclei, the Cronin effect and nuclear broadening

    Hadron multiplicity in pp and AA collisions at LHC from the Color Glass Condensate

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    We provide quantitative predictions for the rapidity, centrality and energy dependencies of inclusive charged-hadron productions for the forthcoming LHC measurements in nucleus-nucleus collisions based on the idea of gluon saturation in the color-glass condensate framework. Our formulation gives very good descriptions of the first data from the LHC for the inclusive charged-hadron production in proton-proton collisions, the deep inelastic scattering at HERA at small Bjorken-x, and the hadron multiplicities in nucleus-nucleus collisions at RHIC.Comment: 7 pages, 8 figures; v3: minor changes, one reference added, results unchanged, the version to appear in Phys. Rev.

    Comparing AdS/CFT Calculations to HERA F_2 Data

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    We show that HERA data for the inclusive structure function F_2(x,Q^2) at small Bjorken-x and Q^2 can be reasonably well described by a color-dipole model with an AdS/CFT-inspired dipole-proton cross section. The model contains only three free parameters fitted to data. In our AdS/CFT-based parameterization the saturation scale varies in the range of 1-3 GeV becoming independent of energy/Bjorken-x at very small x. This leads to the prediction of x-independence of the F_2 and F_L structure functions at very small x. We provide predictions for F_2 and F_L in the kinematic regions of future experiments. We discuss the limitations of our approach and its applicability region, and argue that our AdS/CFT-based model of non-perturbative physics could be viewed as complimentary to the perturbative description of data based on saturation/Color Glass Condensate physics.Comment: 23 pages, 10 figures; v3: new plots added showing our model predictions for charm and longitudinal structure functions and photoproduction cross-section, discussion extended. The version to appear in PR

    Plasma Brain Natriuretic Peptide (BNP) as an Indicator of Left Ventricular Function, Early Outcome and Mechanical Complications after Acute Myocardial Infarction

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    Aims This study investigated the prognostic value of B type natriuretic peptide (BNP) in acute myocardial infarction (AMI) patients and its relation with left ventricular function and post-myocardial infarction complications. Methods In this cross-sectional study, plasma BNP level was measured for 42 consecutive patients (mean ± SD: 61.6 ± 10.85 years old) with acute ST elevation myocardial infarction (MI) and 42 healthy, age and gender matched subjects. Result BNP level in AMI patients were significantly higher than control group (@ P < 0.001). Regarding to infarct location, the highest BNP level measured in inferoposterior MI (BNP = 4436.63 ± 6188.159 pg/ml) and the lowest one indicated in standalone inferior MI (BNP = 598.83 ± 309.867 pg/ml ( P = 0.071). There was significant reverse relation between BNP and EF ( P = 0.006, OR = −0.47) and a significant relationship between BNP and killip classification ( P = 0.036). There was no significant relation between diastolic and right-ventricular function and BNP level ( P = 0.61, P = 0.21). The highest BNP level was detected in LV septal rupture and false aneurysm ( P = 0.02) and in ventricular tachycardia, but without significant relationship ( P = 0.25). Conclusion After the onset of AMI, BNP blood level can be used as an important predictor for left ventricular dysfunction, killip classification, early mechanical complications and cardiac death
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