© 2014

Longitudinal Double-Spin Asymmetry of Electrons from Heavy Flavor Decays in Polarized p + p Collisions at √s = 200 GeV


Part of the Springer Theses book series (Springer Theses)

Table of contents

  1. Front Matter
    Pages i-xvi
  2. Katsuro Nakamura
    Pages 1-44
  3. Katsuro Nakamura
    Pages 45-71
  4. Katsuro Nakamura
    Pages 73-99
  5. Katsuro Nakamura
    Pages 101-120
  6. Katsuro Nakamura
    Pages 121-127
  7. Katsuro Nakamura
    Pages 129-129
  8. Back Matter
    Pages 131-141

About this book


In this thesis, the measurement of double-spin asymmetry for electron production from heavy flavor decays was performed in a Relativistic Heavy Ion Collider (RHIC) in the PHENIX experiment at Brookhaven National Laboratory to measure the polarized parton distribution function of gluon in the small Bjorken x region (x~0.01).


For this experiment, for the first time a Hadron Blind Detector (HBD), which is a position-sensitive gas Cherenkov counter with Gas Electron Multiplier whose surface is evaporated by CsI, was employed. This HBD contributes to reducing the background from electron pairs produced by real and virtual photon conversion. Furthermore, the author develops a new analysis method for the background reduction, and the signal-to-background ratio is improved by a factor of roughly 2.0. Using the combination of the HBD and a new analysis method, the double-spin asymmetry of the electron production with transverse momentum ranging 0.5 < pT < 3.0 GeV/c is measured and confirmed to be zero-consistent within the limit of the statistical uncertainty of about 1%. This result identifies the constraint of the gluon polarization in the small Bjorken x region, a worldwide first.


Gluon Polarization Hadron Blind Detector Heavy Quark Decay Measurement of Electrons from Heavy Flavor Decays Nucleon Spin Structure Polarized Hadron Collider Proton-Proton Collisions QCD Dynamics RHIC The Small Bjorken X Region

Authors and affiliations

  1. 1.TsukubaJapan

About the authors

Dr. Katsuro Nakamura Kyoto University

Bibliographic information