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Full-Text Articles in Physical Sciences and Mathematics
Beam Energy Dependence Of Moments Of The Net-Charge Multiplicity Distributions In Au + Au Collisions At Rhic, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, D. Plyku, Star Collaboration
Beam Energy Dependence Of Moments Of The Net-Charge Multiplicity Distributions In Au + Au Collisions At Rhic, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, D. Plyku, Star Collaboration
Physics Faculty Publications
We report the first measurements of the moments-mean (M), variance (σ2), skewness (S), and kurtosis (κ)-of the net-charge multiplicity distributions at midrapidity in Au + Au collisions at seven energies, ranging from √ˢᶰᶰ = 7.7 to 200 GeV, as a part of the Beam Energy Scan program at RHIC. The moments are related to the thermodynamic susceptibilities of net charge, and are sensitive to the location of the QCD critical point. We compare the products of the moments, σ2/M, Sσ, and κσ2, with the expectations from Poisson and negative binomial distributions (NBDs). The Sσ …
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √ S = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √ S = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration
Physics Faculty Publications
The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<η/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry ALL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured ALL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry AL is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in Feynman-x and PT. Such measurements may aid our understanding of the onset and kinematic dependence of the large asymmetries observed …
Virtuality Distributions In Application To Ɣɣ* → Π0 Transition Form Factor At Handbag Level, Anatoly V. Radyushkin
Virtuality Distributions In Application To Ɣɣ* → Π0 Transition Form Factor At Handbag Level, Anatoly V. Radyushkin
Physics Faculty Publications
We outline basics of a new approach to transverse momentum dependence in hard processes. As an illustration, we consider hard exclusive transition process ɣ*ɣ -> π0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O(0, z)) describing a hadron with momentum p. Treated as functions of (pz) and z2, they are parametrized through virtuality distribution amplitudes (VDA) Φ(x, σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z2. For intervals with z+ = 0, we introduce the transverse momentum distribution …
Beam-Energy Dependence Of The Directed Flow Of Protons, Antiprotons, And Pions In Au+Au Collisions, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, I. Koralt, Star Collaboration
Beam-Energy Dependence Of The Directed Flow Of Protons, Antiprotons, And Pions In Au+Au Collisions, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, I. Koralt, Star Collaboration
Physics Faculty Publications
Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y= 0) are reported in √ˢᴺᴺ = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeVAu+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter d v1/ d y│y=0 shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton d v1/ d y│y=0 changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions …