CMS-PAS-FSQ-12-004

CMS-PAS-FSQ-12-004
Measurement of exclusive $\pi^{+} \pi^{-}$ production in proton-proton collisions at $\sqrt{s} =$ 7 TeV
CMS Collaboration
December 2015

Abstract: We report a measurement of exclusive pion pair production in proton-proton collisions, dominated by $\mathrm{p} + \mathrm{p} \rightarrow \mathrm{p}^{()} + \pi^{+} \pi^{-} + \mathrm{p}^{()}$ , where the $\pi^{+} \pi^{-}$ pair is produced at central rapidities $y$ and the incident protons stay intact or dissociate without being detected. The measurement is performed with the CMS detector at the LHC, using an integrated luminosity of 450 $\mu \mathrm{b}^{-1}$ collected at a center-of-mass energy of $\sqrt{s} =$ 7 TeV in 2010. The cross section measured in the phase space defined by $p_{T}(\pi) >$ 0.2 GeV/ $c$ and $\|y(\pi)\| <$ 2 is 20.5 $\pm$ 0.3 (stat) $\pm$ 3.1 (syst) $\pm$ 0.8 (lumi) $\mu \mathrm{b}$ . The differential $\pi^{+}\pi^{-}$ cross sections as a function of invariant mass, $p_{\mathrm{T}}$ , and $y$ , and the single $\pi$ cross section as a function of $p_{\mathrm{T}}$ , are also shown and compared to model predictions.
Links: CDS record (PDF) ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; These preliminary results are superseded in this paper, Superseded by FSQ-16-006. The superseded preliminary plots can be found here.

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