Experimental Proton-Deuteron and Antiproton-Antideuteron correlation function measured in high-multiplicity pp collisions at √s = 13 TeV as a function of the reduced relative pair momentum (k*). The data points are not plotted in the center of the bins, but at the center of gravity according to the underlying same-event distribution. The error bars represent the statistical uncertainties. The orange boxes show the systematic uncertainties due to cut variations, whereas the blue box at 1 indicates the relative systematic uncertainty due to the variation of the normalization range.
The data points are compared to theory curves using only the Coulomb interaction. The source radius is varied from r = 1 fm to r = 20 fm. The chi2/ndf is calculated for the first three bins, i.e. k* < 120 MeV/c.
The following AOD data samples were analysed (all available pp datasets with √s = 13 TeV):
META_LHC16_AOD234
META_LHC17_pass1_AOD234
META_LHC18_pass1_AOD234
The standard Run2 event selection criteria were applied including |Vertex_z| < 10 cm and pileup rejection cuts. Only high-multiplicity events triggered with the kHighMultV0 trigger were used.
The most important single particle cuts used for the deuteron and anti-deuteron selection are listed below:
FilterBit 256
0.5 GeV/c < pT < 1.4 GeV/c
-0.8 < η < +0.8
-3.0 < nσTPC < +3.0
-2.0 < nσITS < +∞
The most important single particle cuts used for the proton and anti-proton selection are listed below:
FilterBit 128
0.5 GeV/c < pT < 4.0 GeV/c
-0.8 < η < +0.8
-3.0 < nσTPC < +3.0 (for p < 0.75 GeV/c)
-3.0 < nσCom < +3.0 (for p > 0.75 GeV/c) → nσCom = √ (nσTPC)2 + (nσTOF)2