- Slides: 12
Application of Straw Tube Detectors to Hyperon Studies Sedigheh Jowzaee Symposium on Applied Nuclear Physics and Innovative Technologies 24 -27 Sep. 2014, Krakow, Poland
“To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge” Nicolaus Copernicus
Structure of Matter Three generation of matter (fermions) I • Current knowledge based on Standard Model of particle physics Ø Matter • Quarks • Leptons Ø Fundamental forces • Gauge bosons mass charge Spin name Stable matter II III
Hyperons • All observed color neutral hadrons ( (baryons), • Baryons lightest three quark flavors (u, d, s) Decuplet baryons • Hyperons: baryons contain s-quarks (mesons)) Octet baryons
Straw Tube Tracker (STT) • The straw tube is a proportional counter, gas-filled cylindrical tube as a cathode and a thin wire as an anode stretched along the tube axis as an anode reconstruction of particle trajectory measure: t. Drift r. Dis
STT in COSY-TOF Detector • Hyperon study in pp • • • p. K+Λ reaction Strange quark does not exist in nucleon as a constituent How they create and how they interact COSY-TOF detector is Excellent for strangeness study p • Upgraded with STT • High statistics measurement • • • Beam momentum= 2. 95 Ge. V/c Polarization (87. 5 ± 2. 0)% Reconstruction of events with STT • • 140 μm spatial resolution 130000 reconstructed events 20 % reconstruction efficiency with MC Invariant mass resolution 1 Me. V/c 2 p Λ πK+
COSY-TOF STT Calibration • Reconstruction of p. K+Λ events with STT • Calibration steps precise calibration • TDC correction • Multiple hits removal , Signal width cut, Electronics offset correction • Estimation of correlation between drift time and radius • Straw double layers geometrical position correction • Spatial resolution determination Published: S. Jowzaee, Acta physica polonica B, Vol. 6, (2013).
p. K+Λ Dalitz Plot and Projections • The experiment covers the complete kinematic phase space • Interference between physical effects in KΛ and pΛ subsystems • Nucleon excited states (N*-resonances) • NΛ interaction (pΛ-FSI ) • NΣ-pΛ coupled channel effect (NΣ cusp) Prepare publication
STT in PANDA Detector • PANDA and Charmonium study • Charm quark is heavier than strange quark • higher beam momentum, pp reaction • STT is a main tracker in the PANDA detector • STT performance simulation for PID with TOT and charge methods Published: S. Jowzaee, et al. , Nuclear Instruments and methods in physics research A 718, (2013).
Summary • Modular straw tube trackers are good tools for tracking and particles identification in large scale experiments like the COSY-TOF and the PANDA • COSY-TOF upgraded with STT is an ideal detector to study Λ-hyperon in the pp p. K+Λ reaction • An improved invariant mass distribution and reconstruction efficiency were obtained due to the straw tube tracker performance
INTERNATIONAL PHD PROJECTS IN APPLIED NUCLEAR PHYSICS AND INNOVATIVE TECHNOLOGIES This project is supported by the Foundation for Polish Science – MPD program, co-financed by the European Union within the European Regional Development Fund Thank you
p. K+Λ Dalitz Plot Analysis • Dividing the Dalitz plot into three equal phase space volume sections by helicity angle cosθp. K in pΛ rest frame • Cusp effect is stronger at lower parts of the Dalitz plot • FSI effect seems to be same in three parts in the low enough range of the mpΛ Prepare publication