Search for disoriented chiral condensate at 11.6 AGeV Au + Pb

Author(s)

Patrícia Fachini

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 1998-11-03

Examining board members

Alejandro Szanto de Toledo; Márcia Begalli; Takeshi Kodama; Fernando Silveira Navarra; Emi Marcia Takagui

• Advisor: Alejandro Szanto de Toledo

Abstract

The search for the production of disoriented chiral condensates (DCC) in central relativistic Au + Pb collisions at 11.6 GeV /c per nucleon at the Alternating Gradient Synchrotron {AGS) is presented in this work. The search is conducted with the open geometry experiment E864. The signatures of events where a DCC was possibly formed are searched from the number of charged pions and gammas (from the decay of the °\'s) produced in each interaction, and using the robust observable formalism introduced by the MiniMax collaboration [37]. In this work, the DCC search is performed using two different approaches. In the first, the number of gammas produced in each interaction from the decay of the 7 °\'S is obtained from a lead glass Cherenkov detector placed dose to the target and covering back angles. The number of charged pions is obtained from the multiplicity counter of the experiment. No clear evidence for DCC production can be distinguished in a sample of 4.810.923 events. In the second approach, the full E864 spectrometer is used. The number of charged pions is provided by three planes of scintillator hodoscopes and two arrays of straw tubes. The number of gammas is obtained from the lead-scintillating fiber calorimeter located at the end of the spectrometer. No clear evidence for DCC production can be distinguished in a sample of 1.944.401 events. Using a simple DCC model, the 90% C.L. sensitivity of the DCC search is obtained for both approaches. (AU)