Speaker
Description
We discuss central exclusive diffractive dihadron production in the reactions $pp \to pp \,\pi^{+} \pi^{-}$, $pp \to pp \,K^{+} K^{-}$ and $pp \to pp \,p \bar{p}$. The calculation is based on a tensor pomeron model and the amplitudes for the processes are formulated in an effective field-theoretic approach [1]. We include a purely diffractive dipion continuum, and the scalar and tensor resonances [2, 3] as well as the photoproduction contributions [4]. The theoretical results are compared with existing STAR, CDF, and CMS experimental data.Predictions for planned or being carried out experiments (ALICE, ATLAS) are presented. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions for outgoing particles.
We discuss the Drell-Hiida-Deck type mechanism with centrally produced $\rho^{0}$ meson associated with a very forward/backward $\pi N$ system [5]. The $pp \to pp \rho^{0} \pi^{0}$ and $pp \to pn \rho^{0} \pi^{+}$ processes constitute an inelastic (non-exclusive) background to the $p p \to p p \rho^0$ reaction in the case when only the centrally produced $\rho^{0}$ meson decaying into $\pi^{+} \pi^{-}$ is measured, the final state protons are not observed, and only rapidity-gap conditions are checked experimentally.
We discuss also the $pp \to pp \pi^{+} \pi^{-} \pi^{+} \pi^{-}$ reaction. Here the $\sigma \sigma$ and $\rho \rho$ contributions [6] as well as the triple Regge exchange mechanism [7] are considered focussing on their specificities. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions. We discuss whether the triple Regge exchange processes could be identified with the existing LHC detectors.
References:
[1] C. Ewerz, M. Maniatis, O. Nachtmann, Annals Phys. 342 (2014) 31;
[2] P. Lebiedowicz, O. Nachtmann, A. Szczurek, Annals Phys. 344 (2014) 301;
[3] P. Lebiedowicz, O. Nachtmann, A. Szczurek, Phys.Rev.D93 (2016) 5, 054015;
[4] P. Lebiedowicz, O. Nachtmann, A. Szczurek, Phys.Rev.D91 (2015) 074023;
[5] P. Lebiedowicz, O. Nachtmann, A. Szczurek, Phys.Rev.D95 (2017) 034036;
[6] P. Lebiedowicz, O. Nachtmann, A. Szczurek, Phys.Rev.D94 (2016) 034017;
[7] R. Kycia, P. Lebiedowicz, A. Szczurek, J. Turnau, arXiv:1702.07572.