Strangeness production in pion induced reactions at HADES

Strangeness production in pion induced reactions at HADES A. Scordo, LNF-INFN ISU 2015, 27/11/2015 Frascati (LNF)

Contents The HADES detector and its principal motivations In-medium effects for Kaons Pion induced reactions → Effects in Cold Nuclear Matter Pion induced reactions @ HADES Kaon production results Conclusions 2

The HADES detector 3

Principal motivations Subthreshold kaons for imcompressibility measurements 4

In-medium effects for Kaons Consequently, the K− feel a strong attractive potential, whereas the K+ feel a weakly repulsive one. Due to the effect of the potential, the K− effective mass drops by roughly 25% at r ∼ r 0 and the K+ effective mass increases by about 10% at r ∼ r 0. 5

In-medium effects for Kaons 6

Pion induced reactions Several models: BUU (Boltzmann–Uehling–Uhlenbeck) QMD ( Quantum Molecular Dynamics) HSD ( Hadron String Dynamics) Others 7

In-medium effects at CNM 8

In-medium effects at CNM 9

p induced reactions @ HADES 10

p induced reactions @ HADES 11

p induced reactions @ HADES 12

PID for charged particles 13

PT Y phase space RPC TOF This is the rapidity of the boost along the beam axis which takes an observer from the lab frame to a frame in which the particle moves only perpendicular to the beam RPC TOF is the transverse momentum (i. e. the component of the three-momentum perpendicular to the beam axis). 14

K+ mass spectra Example: K+ in Carbon RPC 15

K- mass spectra Example: K- in Carbon RPC Less ‘’ good ‘’ bins, more background Very difficult analysis 16

K-/K+ K- suppression is observed! (Very preliminary → No eff. & acc. correction) 17

Conclusions The HADES detector is a very nice tool to test In-medium effects for Kaons Effects in Cold Nuclear Matter can be studied with pion induced reactions @ HADES Very preliminary results on Kaon production and absorption have been presented Efficiency correction is needed to provide cross sections 18