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Paper Proposal: run 15 FMS diffractive EM-jet A_N

Updated on Fri, 2024-11-15 20:07. Originally created by liangxl on 2022-11-08 11:16.

 - Title: Transverse Single-Spin Asymmetry for Diffractive Electromagnetic Jets with p^{\uparrow} + p collision at \sqrt{s}=200 GeV

 - PAs: Kenneth Barish, Christopher Dilks, Carl Gagliardi, Latif Kabir, David Kapukchyan, Xilin Liang*, Mriganka Mondal

 - PA representative email address: xilin.liang@email.ucr.edu

 - Target journal: PLB

 - Abstract: The STAR Collaboration reports the transverse single-spin asymmetry, A_{N}, for the electromagnetic jets (EM-jets) at forward rapidity (2.8 < \eta < 3.8) in diffractive processes as the function of EM-jet Feynman-x (x_{F}) and photon multiplicity in transversely polarized pp collisions at \sqrt{s}= 200 GeV. The A_{N} in the processes with the situations that either the polarized proton stay intact (semi-exclusive process) or unpolarized proton stay intact (single diffractive process) are explored. A_{N} is found to be non-zero value for low photon multiplicity EM-jets in the single diffractive process but is consistent with A_{N} in the inclusive process within uncertainty. Furthermore, the cross section in single diffractive process compared to the inclusive process is small. The A_{N} in the semi-exclusive processes is non-zero with negative value. These results show the diffractive process can not provide evidence to have large contribution to the large A_{N} in the inclusive process.

 - Conclusion:

    

  • The non-zero A_N for single diffractive process and the semi-exclusive process are observed for the EM-jets with 1 or 2 photon multiplicity
  •  
  • The A_N values for the single diffractive process with the unpolarized proton intact are consistent with A_N for inclusive process within uncertainty, showing that the single diffractive process can not provide evidence to have great contribution to the large A_N in the inclusive process
  •  
  • The cross section fraction for single diffractive process to the inclusive process in the forward region is very small, so single diffractive process can not have major contribution to to the large A_N in the inclusive process
  •  
  • The A_N value for semi-exclusive process with polarized proton intact is negative, which also can not have great contribution to the large A_N in the inclusive process


 
 - Paper proposal slide: cold QCD PWG  

 - Analysis note: preparing

 - Paper draft: preparing

 - Figures:

    Figure 1: A_N for single diffractive process


 Fig. 1: A_N for single diffractive events as a function of x_F for 3 different photon multiplicity cases: all photon multiplicity (top), 1 or 2 photon multiplicity (middle), and 3 or more photon multiplicity (bottom). The A_N for x_F<0 (red points) shifts -0.013 along the x-axis. 

  Figure 2: Cross section fraction (\sigma_SD / \sigma_inc)


  Fig. 2: Cross section fraction of the single diffractive process (\sigma_SD) to the inclusive process (\sigma_inc) as a function of x_F.

  Figure 3: A_N for Rapidity Gap events

  Fig. 3: A_N for rapidity gap events as a function of x_F for 3 different photon multiplicity cases: all photon multiplicity (top), 1 or 2 photon multiplicity (middle), and 3 or more photon multiplicity (bottom). The A_N for x_F<0 (red points) shifts -0.013 along the x-axis. 

  Figure 4: Comparison plot of A_N for inclusive, single diffractive, and rapidity gap events

  Fig.4 A_N as a function of x_F for 3 processes for the case of photon multiplicity 1 or 2 (top panel) and photon multiplicity 3 or more (bottom panel) : inclusive process (red), single diffractive process (blue), and the rapidity gap events (magenta)

  Figure 5: A_N for semi-exclusive process

  Fig. 5: A_N as a function of x_F for the semi-exclusive process with 1 or 2 photon multiplicity EM-jets. The blue points are for x_F>0, while the red points are for x_F<0. 

 - Additional information:
 

    List of presentation for diffractive analysis:

  1.   FMS QA in spin PWG 
  2.   FMS and RP simulation in spin PWG
  3.   Preliminary request: page
  4.   DIS 2022 presentation and proceeding (focus on semi-exclusive process)
  5.   DIS 2024 presentation and proceeding (focus on single diffractive process and rapidity gap)
  6.   Updated semi-exclusive process presentation in spin PWG
  7.   Diffraction and low-x 2024 presentation and proceeding (include single diffractive and semi-exclusive preliminary results)
  8.   Cross section fraction presentation in spin PWG


 
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