Sevil.salur@yale.edu 1 Baryonic Resonance Why resonances and why  * ? How do we search for them ? What did we learn so far? What else can we do in the.

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  • Slide 1
  • sevil.salur@yale.edu 1 Baryonic Resonance Why resonances and why * ? How do we search for them ? What did we learn so far? What else can we do in the near future? Sevil Salur Yale University STAR Collaboration p p Studies with
  • Slide 2
  • sevil.salur@yale.edu 2 Chemical freeze-out Thermal freeze-out ** * measured * lost * measured time Why do we study resonances in heavy-ion collisions? Due to the very short lifetime ( < t ) of resonances: Large fraction of the decays occur inside the reaction zone Possible change in the physical properties: width broadening mass shift change in p T spectra Determination of the hadronic expansion time between chemical and thermal freeze-out Information about strangeness production due the strange quark content and high mass of * (1385) tt MeV/c 2 :35 MeV/c 2 I(J P ) =1(3/2 + )
  • Slide 3
  • sevil.salur@yale.edu 3 Particle Identification M inv GeV/c 2 * (1385) N ENTRIES s NN =200 GeV p+p - and N ENTRIES A candidate is combined with a to get a *(1385). The background is formed by mixing mesons from one event with candidates from another event.
  • Slide 4
  • sevil.salur@yale.edu 4 * Invariant Mass Spectra ** The masses and widths of are in agreement with the PDG and the results with other topological reconstruction techniques. M = 1387 MeV, 39 MeV ) ( M = 1383 MeV, 36 MeV ** s NN =200 GeV @ d+Au s NN =200 GeV @ p+p s NN =200 GeV @ Au+Au 0-5% N ENTRIES
  • Slide 5
  • sevil.salur@yale.edu 5 * Corrected p T Spectra Exponential Fit Function : |y|