Measurement of diffractive dissociation cross sections in pp collisions at s =7TeV
Baarmand, Marc M.
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Measurements of diffractive dissociation cross sections in pp collisions at √s = 7 TeV are presented in kinematic regions defined by the masses M[subscript X] and M[subscript Y] of the two final-state hadronic systems separated by the largest rapidity gap in the event. Differential cross sections are measured as a function of ξ[subscript X] = M[2 over X]/s in the region −5.5 < log[subscript 10]ξ[subscript X] < −2.5, for log[subscript 10]M[subscript Y] < 0.5, dominated by single dissociation (SD), and 0.5 < log[subscript 10]M[subscript Y] < 1.1, dominated by double dissociation (DD), where M[subscript X] and M[subscript Y] are given in GeV. The inclusive pp cross section is also measured as a function of the width of the central pseudorapidity gap Δη for Δ[subscript η] > 3, log[subscript 10]M[subscript X] > 1.1, and log[subscript 10]M[subscript Y] > 1.1, a region dominated by DD. The cross sections integrated over these regions are found to be, respectively, 2.99 ± 0.02(stat)[+0.32 over −0.29](syst) mb, 1.18 ± 0.02(stat) ± 0.13(syst) mb, and 0.58 ± 0.01(stat)[+0.13 over −0.11](syst) mb, and are used to extract extrapolated total SD and DD cross sections. In addition, the inclusive differential cross section, dσ/dΔη[superscript F], for events with a pseudorapidity gap adjacent to the edge of the detector, is measured over Δη[superscript F] = 8.4 units of pseudorapidity. The results are compared to those of other experiments and to theoretical predictions and found compatible with slowly rising diffractive cross sections as a function of center-of-mass energy.