Betty Abelev

Betty Abelev's picture
Process Improvement Data Analysis Lead
Invitae
Research Areas: 
Nuclear Physics
Research Type: 
Experimentalist
Education: 
Ph.D. 2007, Yale University
Advisor: 
John Harris
Dissertation Title: 
Multi-strange baryon correlations at RHIC
Dissertation Abstract: 

A hot and dense medium is produced in central Au197+Au 197 collisions at [special characters omitted]NN = 200 GeV at the Relativistic Heavy Ion Collider (RHIC) in Brookhaven National Laboratory. A particular puzzle has been the origin of hadrons produced in the inter-mediate transverse momentum (2 < pT < 6 GeV/c) region. Recombination and Coalescence models have been proposed to explain the mechanism of particle production in this energy range. Because the production of s-quarks via parton fragmentation is suppressed in the pT region of interest with respect to the lighter quarks, the fragmentation contribution of s-quarks to strange particles should also be suppressed. Therefore, particles made entirely of s and  quarks which originated from fragmentation are not expected to be detected. A statistical measurement of jets via azimuthal correlations using multi-strange (Ξ± and Ω±) baryons as trigger particles is performed in the most central Au+Au collisions. Contrary to predictions, a strong same-side peak (correlated with the jet direction) with non-zero yield has been observed in both cases. The correlation function for Ξ baryons is also studied as a function of pseudorapidity η and azimuthal angle &phis;. An elongation in Δη, commonly called the “ridge”, is observed under the trigger-particle (same-side) peak.

The Ξ± correlation function with charged particles has been obtained in p+p and d+Au minimum bias collisions for comparison with that in central Au+Au events. While there are insufficient statistics to calculate the same-side yields in the p+p data, the yield in the d+Au data is extracted. Correlation functions are also studied in events triggered on high-energy deposits in the electromagnetic calorimeter. These will be presented along with the possibility of using the STAR calorimeter as an anti-baryon trigger.