ATLAS_2019_I1762584
A dedicated sample of Large Hadron Collider proton-proton collision data at centre-of-mass energy $\sqrt{s} = 8$ TeV is used to study inclusive single diffractive dissociation, $pp \to X p$. The intact final-state proton is reconstructed in the ATLAS ALFA forward spectrometer, while charged particles from the dissociated system X are measured in the central detector components. The fiducial range of the measurement is $-4.0 < \log_{10} \xi < -1.6$ and $0.016 < |t| < 0.43$ GeV$^{2}$, where $\xi$ is the proton fractional energy loss and $t$ is the squared four-momentum transfer. The total cross section integrated across the fiducial range is $1.59 \pm 0.13$ mb. Cross sections are also measured differentially as functions of $\xi$, $t$, and $\Delta \eta$, a variable that characterises the rapidity gap separating the proton and the system X. The data are consistent with an exponential $t$ dependence, d$\sigma$/d$t \approx e^{Bt}$ with slope parameter $B = 7.65 \pm 0.34$ GeV$^{-2}$. Interpreted in the framework of triple Regge phenomenology, the $\xi$ dependence leads to a pomeron intercept of $\alpha(0) = 1.07 \pm 0.09$.
