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Paper Proposal: run 15 FMS diffractive EM-jet A_N

Updated on Thu, 2024-12-12 17:02. 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. Cases where either the unpolarized proton stays intact (single diffractive process) or the polarized proton stays intact (semi-exclusive process) are explored. A_N for the single diffractive process is consistent with A_N for inclusive EM-jet production. Furthermore, the cross section in single diffractive process compared to the inclusive process is small. The A_N in the semi-exclusive process has the opposite sign to the inclusive EM-jet A_N . These results show diffractive processes can not make a significant contribution to the large A_N found for inclusive EM-jet production at forward rapidity.



 - 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  PWGC review

 - Analysis note:

    12/12/2024: First draft for PWGC review

 - Paper draft: preparing

 - Figures:

    Figure 1: Describing four processes

    

    Fig. 1: Four processes mentioned in this paper: (from top to bottom) inclusive process, rapidity gap event, single diffractive process, semi-exclusive process.

     Figure 2: A_N for Rapidity Gap events

    

  Fig. 2: 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). 

    Figure 3: A_N for single diffractive process


 Fig. 3: 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). 

  Figure 4: Cross section fraction (\sigma_SD / \sigma_inc)


  Fig. 4: Cross section fraction of the single diffractive process (\sigma_SD) to the inclusive process (\sigma_inc) as a function of x_F.

  

  Figure 5: Comparison plot of A_N for inclusive, single diffractive, and rapidity gap events

  Fig.5 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), the rapidity gap events (magenta), and single diffractive process (blue)

  Figure 6: A_N for semi-exclusive process

  Fig. 6: A_N as a function of x_F for the semi-exclusive process with 1 or 2 photon multiplicity EM-jets.

 - 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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