Preliminary Results - Longitudinal double-spin asymmetry for inclusive jet production at √s=200 GeV (2015 dataset)
Longitudinal double-spin asymmetries of inclusive jet production at 200 GeV from the 2015 dataset
The results were planned to be shown during the DIS2020 conference, March, 2020, NYC, USA as a part of the following oral presentation:
DIS2020 Abstract
The Solenoidal Tracker at the Relativistic Heavy Ion Collider (STAR) experiment probes the gluon helicity distribution ∆G(x) using collisions of longitudinally polarized protons at sqrt s = 200 GeV and sqrt s = 510 GeV. Access to ∆G(x) is possible through the double spin asymmetries A LL in gluon-dominated hard scattering processes of inclusive jet and di-jet production. Previously published results on inclusive jet processes at sqrt s = 200 GeV and |η jet | < 1 are based on data collected in 2009, which correspond to an integrated luminosity L of 20 pb −1 with an average beam polarization P of 57%. When included in perturbative QCD analysis of global data, they provide evidence for positive gluon polarization for a momentum fraction x > 0.05 at a hard perturbative scale Q2 = 10 GeV2 . Additional data were collected in 2015 with an approximately twice larger figure of merit LP4 . This contribution will cover the status of the analysis of 2015 inclusive jet and di-jet data, as well as, the jet measurements based on the most recent high-luminosity 510 GeV data collected in 2013, which will further constrain ∆G(x) at lower x.
Documentation
STAR Collaboration Meeting, 12th March, 2020
Update to PWG List, 18th March 2020
Spin PWG Meeting, 4th March, 2020
Blog posts
- Blog entries on embedding
- Blog entries on polarization calculation
- Blog entries on luminosity calculation
- Blog entries on QA and jet QA
Preliminary plots
The plots below show the longitudinal double-spin asymmetry for inclusive jet production for the 2015 data set for the jet eta region |eta| < 1.0. The results from the 2009 data set are shown with blue points. The ALL from NNPDF1.1 and DSSV'14 theoretical analysis are also presented. The plots have been prepared in 3 different versions: with 2019 data and theory curves, with 2009 data, and without any additional results.
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The plot below shows the longitudinal double-spin asymmetry for inclusive jet production for the 2015 data set for 2 different jet eta regions |eta| < 0.5 (top panel) and 0.5 < |eta| <1.0 (bottom panel). The results from the 2009 data set are shown with blue points.
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The plot below shows false asymmetries: blue beam single spin asymmetry, yellow beam single spin asymmetry, like-sign double spin asymmetry, and unlike-sign double spin asymmetry for the 2015 longitudinal data with constant function fit.
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Results for |eta| < 1.0
| Bin | xT | xT syst. | ALL | ALL syst. | ALL stat. |
| 1 | 6.43E-02 | 2.20E-03 | 1.56E-04 | 3.45E-04 | 9.63E-04 |
| 2 | 7.91E-02 | 2.57E-03 | 3.32E-03 | 1.33E-03 | 8.16E-04 |
| 3 | 9.38E-02 | 3.15E-03 | 2.63E-03 | 8.45E-04 | 7.45E-04 |
| 4 | 1.12E-01 | 3.30E-03 | 3.87E-03 | 9.77E-04 | 8.72E-04 |
| 5 | 1.33E-01 | 3.39E-03 | 5.48E-03 | 9.72E-04 | 1.11E-03 |
| 6 | 1.57E-01 | 3.51E-03 | 3.50E-03 | 7.41E-04 | 1.51E-03 |
| 7 | 1.84E-01 | 3.67E-03 | 1.53E-02 | 5.63E-04 | 2.22E-03 |
| 8 | 2.15E-01 | 4.13E-03 | 1.86E-02 | 1.22E-03 | 3.41E-03 |
| 9 | 2.50E-01 | 4.80E-03 | 2.06E-02 | 9.90E-04 | 5.72E-03 |
| 10 | 2.91E-01 | 5.47E-03 | 3.99E-02 | 1.25E-03 | 1.02E-02 |
| 11 | 3.35E-01 | 7.38E-03 | 4.11E-02 | 1.31E-03 | 1.94E-02 |
Results for |eta| < 0.5
| Bin | xT | xT syst. | ALL | ALL syst. | ALL stat. |
| 1 | 6.39E-02 | 2.25E-03 | 6.32E-04 | 4.36E-04 | 1.24E-03 |
| 2 | 7.85E-02 | 2.53E-03 | 2.29E-03 | 1.21E-03 | 1.05E-03 |
| 3 | 9.41E-02 | 3.30E-03 | 3.46E-03 | 8.34E-04 | 9.69E-04 |
| 4 | 1.12E-01 | 3.22E-03 | 4.11E-03 | 9.28E-04 | 1.12E-03 |
| 5 | 1.33E-01 | 3.46E-03 | 7.57E-03 | 9.72E-04 | 1.43E-03 |
| 6 | 1.59E-01 | 3.44E-03 | 4.81E-03 | 7.32E-04 | 1.92E-03 |
| 7 | 1.85E-01 | 3.74E-03 | 1.80E-02 | 5.62E-04 | 2.79E-03 |
| 8 | 2.16E-01 | 4.23E-03 | 2.22E-02 | 1.27E-03 | 4.25E-03 |
| 9 | 2.52E-01 | 4.96E-03 | 1.99E-02 | 1.03E-03 | 7.04E-03 |
| 10 | 2.93E-01 | 5.55E-03 | 3.44E-02 | 1.34E-03 | 1.23E-02 |
| 11 | 3.37E-01 | 8.44E-03 | 4.89E-02 | 1.55E-03 | 2.32E-02 |
Results for 0.5 < |eta| < 1.0
| Bin | xT | xT syst. | ALL | ALL syst. | ALL stat. |
| 1 | 6.50E-02 | 2.23E-03 | -5.89E-04 | 3.45E-04 | 1.53E-03 |
| 2 | 7.99E-02 | 2.81E-03 | 4.86E-03 | 1.77E-03 | 1.29E-03 |
| 3 | 9.34E-02 | 3.03E-03 | 1.43E-03 | 8.17E-04 | 1.17E-03 |
| 4 | 1.12E-01 | 3.51E-03 | 3.51E-03 | 1.09E-03 | 1.38E-03 |
| 5 | 1.32E-01 | 3.34E-03 | 2.28E-03 | 9.69E-04 | 1.78E-03 |
| 6 | 1.54E-01 | 3.84E-03 | 1.48E-03 | 7.60E-04 | 2.46E-03 |
| 7 | 1.82E-01 | 3.60E-03 | 1.08E-02 | 6.27E-04 | 3.67E-03 |
| 8 | 2.13E-01 | 4.01E-03 | 1.23E-02 | 1.18E-03 | 5.73E-03 |
| 9 | 2.46E-01 | 4.61E-03 | 2.24E-02 | 1.06E-03 | 9.80E-03 |
| 10 | 2.85E-01 | 5.41E-03 | 5.18E-02 | 1.32E-03 | 1.78E-02 |
| 11 | 3.31E-01 | 6.07E-03 | 2.31E-02 | 1.27E-03 | 3.55E-02 |
Code repository
Temporarly, the code to the analysis is stored locally at /star/u/zurek/ but will be uploaded to the official repository
- zurek's blog
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