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Full-Text Articles in Physics

Understanding Hard Interaction In Qcd And The Search For The Gluon Spin Contribution To The Spin Of The Proton, Amaresh Datta May 2012

Understanding Hard Interaction In Qcd And The Search For The Gluon Spin Contribution To The Spin Of The Proton, Amaresh Datta

Open Access Dissertations

In the following discourse unpolarized cross sections and double helicity asymmetries of single inclusive positive and negative charged hadrons at mid-rapidity from p + p collisions at p s = 62:4 GeV are presented. Measurements for the transverse momentum range 1:0 < pT < 4:5 GeV/c are done with PHENIX detector at Relativistic Heavy-Ion Collider (RHIC) and are consistent with calculations based on perturbative quantum chromodynamics (pQCD) at next-to-leading order (NLO) in the strong coupling constant, s. Resummed pQCD calculations including terms with next-to-leading log (NLL) accuracy, yielding reduced theoretical uncertainties, also agree with the data. The double helicity asymmetry, sensitive at leading order to the gluon polarization in a momentum fraction range of 0:05


Probing Novel Properties Of Nucleons And Nuclei Via Parity Violating Electron Scattering, Luis Rafael Mercado May 2012

Probing Novel Properties Of Nucleons And Nuclei Via Parity Violating Electron Scattering, Luis Rafael Mercado

Open Access Dissertations

This thesis reports on two experiments conducted by the HAPPEx (Hall A Proton Parity Experiment) collaboration at the Thomas Jefferson National Accelerator Facility. For both, the weak neutral current interaction (WNC, mediated by the Z0 boson) is used to probe novel properties of hadronic targets. The WNC interaction amplitude is extracted by measuring the parity-violating asymmetry in the elastic scattering of longitudinally polarized electrons off unpolarized target hadrons. HAPPEx-III, conducted in the Fall of 2009, used a liquid hydrogen target at a momentum transfer of Q2 = 0.62 GeV2. The measured asymmetry was used to set new …


Inclusive And Differential Measurements Of The Tt̅ Charge Asymmetry In Proton–Proton Collisions At √S= 7 Tev, Cms Collaboration, Ekaterina Avdeeva, Kenneth A. Bloom, S. Bose, J. Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, J. Keller, Ilya Kravchenko, J. Lazo-Flores, H. Malbouisson, Sudhir Malik, Gregory Snow Jan 2012

Inclusive And Differential Measurements Of The Tt̅ Charge Asymmetry In Proton–Proton Collisions At √S= 7 Tev, Cms Collaboration, Ekaterina Avdeeva, Kenneth A. Bloom, S. Bose, J. Butt, Daniel R. Claes, Aaron Dominguez, Michael Eads, J. Keller, Ilya Kravchenko, J. Lazo-Flores, H. Malbouisson, Sudhir Malik, Gregory Snow

Kenneth Bloom Publications

The tt̅ charge asymmetry is measured in events containing a charged lepton (electron or muon) and at least four jets, one of which is identified as originating from b-quark hadronization. The analyzed data set corresponds to an integrated luminosity of 5.0 fb−1 collected with the CMS detector at the LHC. An inclusive and three differential measurements of the tt̅ charge asymmetry as a function of rapidity, transverse momentum, and invariant mass of the tt̅ system are presented. The measured inclusive tt̅ charge asymmetry is AC = 0.004 ± 0.010 (stat.) ± 0.011 (syst.). This result and the three …