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Articles 1 - 2 of 2
Full-Text Articles in Physics
Measurement Of Bottom Versus Charm As A Function Of Transverse Momentum With Electron-Hadron Correlations In P Þ P Collisions At Square Root Of S = 200 Gev, Andrew Marshall Adare, Sergey V. Afanasiev, Christine A. Aidala, N. N. Ajitanand, Yasuyuki Akiba, Gyöngyi Baksay, László A. Baksay, Marcus Hohlmann, S. Rembeczki, Klaus Dehmelt
Measurement Of Bottom Versus Charm As A Function Of Transverse Momentum With Electron-Hadron Correlations In P Þ P Collisions At Square Root Of S = 200 Gev, Andrew Marshall Adare, Sergey V. Afanasiev, Christine A. Aidala, N. N. Ajitanand, Yasuyuki Akiba, Gyöngyi Baksay, László A. Baksay, Marcus Hohlmann, S. Rembeczki, Klaus Dehmelt
Aerospace, Physics, and Space Science Faculty Publications
The momentum distribution of electrons from semileptonic decays of charm and bottom quarks for midrapidity jyj < 0:35 in p þ p collisions at ffiffi s p ¼ 200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider over the transverse momentum range 2 < pT < 7 GeV=c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D=D ! e KX (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV=c in pT. A fixed-order-plus-next-to-leading-log perturbative quantum chromodynamics calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is bb ¼ 3:2þ1:2 1:1ðstatÞ þ1:4 1:3ðsystÞb.
Gluon-Spin Contribution To The Proton Spin From The Double-Helicity Asymmetry In Inclusive Π0 Production In Polarized P+P Collisions At Square Root Of S = 200 Gev, Andrew Marshall Adare, Sergey V. Afanasiev, Christine A. Aidala, N. N. Ajitanand, Yasuyuki Akiba, H. Al-Bataineh, Gyöngyi Baksay, László A. Baksay, Marcus Hohlmann, S. Rembeczki
Gluon-Spin Contribution To The Proton Spin From The Double-Helicity Asymmetry In Inclusive Π0 Production In Polarized P+P Collisions At Square Root Of S = 200 Gev, Andrew Marshall Adare, Sergey V. Afanasiev, Christine A. Aidala, N. N. Ajitanand, Yasuyuki Akiba, H. Al-Bataineh, Gyöngyi Baksay, László A. Baksay, Marcus Hohlmann, S. Rembeczki
Aerospace, Physics, and Space Science Faculty Publications
The double helicity asymmetry in neutral pion production for pT ¼ 1 to 12 GeV=c was measured with the PHENIX experiment to access the gluon-spin contribution, G, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of 2 ¼ 4 GeV2 a next to leading order QCD analysis gives G½0:02;0:3 ¼ 0:2, with a constraint of 0:7 < G½0:02;0:3 < 0:5 at 2 ¼ 9 (3) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generated from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the G constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.