This page presents summary PDF files comparing the performance of VPDstart and Startless modes for the Run21 O+O 200 GeV FF and RFF datasets. The calibrations focus on both the BTOF and VPD systems.

Two key observations from the analysis are highlighted:

• Improved T0 Resolution: The STARTLESS mode shows a higher T0 resolution compared to the VPDSTART mode in both datasets.

• Proton Mass Splitting: A clear observation of proton mass splitting has been made. This splitting is more evident in the RFF dataset.

• zLocal Shifts Bands: zLocal bands appear outside the normal zLocal distribution in both FF and RFF (more clearly observed in FF dataset).

Please refer to the attached summary files for further details.

Reverse Full Field (RFF)

• STAR/system/files/userfiles/6735/Geom-align_xLocal_qa.pdf
• STAR/system/files/userfiles/6735/Geom-align_yLocal_qa.pdf
• STAR/system/files/userfiles/6735/tofCalibSummary_oo200Gev_FF_VPDSTART.pdf
• STAR/system/files/userfiles/6735/tofCalibSummary_oo200Gev_FF_VPDSTARTLess.pdf

Full Field (FF)

• STAR/system/files/userfiles/6735/Geom-align_xLocal_RFF_qa.pdf
• STAR/system/files/userfiles/6735/Geom-align_yLocal_RFF_qa.pdf
• STAR/system/files/userfiles/6735/tofCalibSummary_oo200Gev_RFF_VPDSTART.pdf
• STAR/system/files/userfiles/6735/tofCalibSummary_oo200Gev_RFF_VPDSTARTLess.pdf