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| CMS-PAS-FSQ-15-005 | ||
| Measurement of the inelastic proton-proton cross section at $\sqrt{s}=$ 13 TeV | ||
| CMS Collaboration | ||
| April 2016 | ||
| Abstract: A measurement of the inelastic cross section for proton-proton collisions at a centre-of-mass energy of $\sqrt{s} =$ 13 TeV is presented. The analysis is performed with the CMS detector based on information from forward calorimetry, at pseudorapidity 3.0 $< \eta <$ 5.2 and --6.6 $< \eta <$ --3.0, and thus covers particle production over more than 11 units of pseudorapidity and down to small transverse momenta. A visible cross section of 66.9 $\pm$ 0.4 (exp) $\pm$ 2.0 (lumi) mb is obtained for $M_\mathrm{X} >$ 4.1 GeV and $M_\mathrm{Y} > $ 13 GeV, where $M_\mathrm{X}$ and $M_\mathrm{Y}$ are the masses of the diffractive dissociation systems moving towards negative and positive pseudorapidity, respectively. The visible cross section is extrapolated to the full inelastic phase space domain, yielding 71.3 $\pm$ 0.5 (exp) $\pm$ 2.1 (lumi) $\pm$ 2.7 (ext) mb. The results are compared with those of other experiments, and with models used to describe high-energy hadronic interactions. | ||
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Links:
CDS record (PDF) ;
inSPIRE record ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, JHEP 07 (2018) 161. The superseded preliminary plots can be found here. |
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| Figures | |
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Figure 1-a:
Fully corrected cross section in various phase space regions, compared to different models (a) and the same cross sections scaled to the cross section obtained for $\xi > 10^{-6}$ (b). The data point for $\sigma _{\rm inel}$ is obtained from a model-dependent extrapolation of the cross section for $\xi _{\rm X} > 10^{-7}$ or $\xi _{\rm Y} > 10^{-6}$. |
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Figure 1-b:
Fully corrected cross section in various phase space regions, compared to different models (a) and the same cross sections scaled to the cross section obtained for $\xi > 10^{-6}$ (b). The data point for $\sigma _{\rm inel}$ is obtained from a model-dependent extrapolation of the cross section for $\xi _{\rm X} > 10^{-7}$ or $\xi _{\rm Y} > 10^{-6}$. |
| Tables | |
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Table 1:
Overview of purity ($N_{\rm cor}/(N_{\rm ZB} \times F_{\rm ZB})$), average pileup ($\lambda $), and fully corrected particle level cross section (with statistical uncertainty) for all runs used in this analysis. |
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Table 2:
Overview of systematic uncertainties from various sources. |
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Table 3:
Model extrapolation factors from $\xi _{\rm X} > 10^{-7}$ or $\xi _{\rm Y} > 10^{-6}$ to the total inelastic phase space. |
| Summary |
| A measurement of the inelastic cross section for proton-proton collisons at $\sqrt{s} =$ 13 TeV obtained with the CMS detector at the LHC has been presented. A visible cross section of 66.9 $\pm$ 0.4 (exp) $\pm$ 2.0 (lum) mb is obtained for $M_{\rm X} > $ 4.1 GeV and $M_{\rm Y} >$ 13 GeV, where $M_{\rm X}$ and $M_{\rm Y}$ are the masses of the diffractive dissociation systems moving towards negative and positive pseudorapidity, respectively. The visible cross section is extrapolated to the full inelastic phase space domain, yielding 71.3 $\pm$ 0.5 (exp) $\pm$ 2.1 (lum.) $\pm$ 2.7 (ext) mb. The measured cross section is significanlty lower than predicted by models for hadronic scattering. |
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Compact Muon Solenoid LHC, CERN |
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