Scattering studies with low-energy kaon-proton femtoscopy in proton-proton collisions at the LHC

S. Acharya , Kamil Deja , Łukasz Graczykowski , Monika Jakubowska , Małgorzata Janik , Adam Kisiel , Julian Myrcha , Piotr Nowakowski , Janusz Oleniacz , Jan Pluta , Przemysław Rokita , Krystian Rosłon , M. O. Schmidt , Tomasz Trzciński , Hanna Zbroszczyk

Abstract

The study of the strength and behavior of the antikaon-nucleon ( ̄KN) interaction constitutes one of thekey focuses of the strangeness sector in low-energy quantum chromodynamics (QCD). In this Letter aunique high-precision measurement of the strong interaction between kaons and protons, close and abovethe kinematic threshold, is presented. The femtoscopic measurements of the correlation function at lowpair-frame relative momentum of (Kþp⊕K− ̄p) and (K−p⊕Kþ ̄p) pairs measured inppcollisions atffiffiffisp¼5, 7, and 13 TeVare reported. A structure observed around a relative momentum of58MeV=cin themeasured correlation function of (K−p⊕Kþ ̄p) with a significance of4.4σconstitutes the firstexperimental evidence for the opening of theð ̄K0n⊕K0 ̄nÞisospin breaking channel due to the massdifference between charged and neutral kaons. The measured correlation functions have been compared toJülich and Kyoto models in addition to the Coulomb potential. The high-precision data at low relativemomenta presented in this work prove femtoscopy to be a powerful complementary tool to scatteringexperiments and provide new constraints above the ̄KNthreshold for low-energy QCD chiral models