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Baryon to Meson Ratios in Jets from p+p and Au+Au Collisions at 200 GeV

Updated on Wed, 2024-09-25 00:50. Originally created by gdalegau on 2024-03-27 16:04.
  • PA list: Gabriel Dale-Gau
  • target journal: PLB
  • paper title:  Baryon to Meson ratios in Jets from Au+Au and p+p Collisions at \sqrt{s_NN} = 200 GeV
  • abstract: 
    •Measurements at RHIC and the LHC show strongly enhanced baryon-to-meson yield ratios at intermediate transverse momenta (p_T) in high-energy nuclear collisions compared to p+p baseline. This enhancement is attributed to the following QGP effects: strong hydrodynamic flow and parton recombination. Jet probes have been used extensively to gain insights into QGP properties, with substantial modifications to jet yields and internal structures seen across multiple measurements. Despite apparent medium-induced changes to jet fragmentation patterns, the LHC results indicate that in-jet baryon-to-meson ratios remain similar to that of p+p measurements and are significantly different from that of the QGP bulk. To explore this behavior at RHIC, we employ particle identification through time-of-flight and TPC dE/dx information alongside jet-track correlations to measure in-jet particle ratios for p_T < 5.0 GeV/c. We present the first in-cone baryon-to-meson yield ratios associated with fully reconstructed jets from Au+Au and p+p collisions at = 200 GeV using the STAR detector at RHIC. 

  • figures with major if not all systematic uncertainties and captions: Attached
  • conclusions including physics messages: 
    •First in-jet Baryon-to-Meson ratio measurement from STAR

    •Strong preference for pion over proton production in jets

    •Similar in-jet proton to pion ratio between Au+Au and p+p, despite enhancement in mid p_T inclusive measurement from central Au+Au

    •Result might be influenced by bias towards jets with less interaction with QGP

    Minutes from first GPC meeting, September 17th, 2024:

    ====================
    Participants:
    PAs:  Gabriel Dale-Gau, Olga Evdokimov
    GPC:  Jana Bielcikova, Ondrej Lomicky, Isaac Mooney, Richard Witt, Zebo Tang

    Gabe presented an overview of his analysis and results and in discussion we clarified several things including choice of the jet pT constituent cut selection, background subtraction, fit of PID nsigma distributions and identified several key points that should be looked at by PAs in the coming weeks listed below. Ondrej and Gabe also started their work on code Q/A and will report on the progress in the coming weeks after Hard Probes.

    1. Please check whether in the pseudo-embedding the vertex is aligned to that of the data

    2. It would be good to see and have it included in the analysis note as well, how well your corrected inclusive baryon-to-meson ratio agree with that in the published STAR data in PRL 637 (2006) 161 that is used in the paper.

    3. Can we also have a figure with R or delta(R) dependence in the paper?

    4. Figure 3: it would be good to include some model comparisons (PYTHIA, HERWIG, AMPT ...) as well as e+/e- data and perhaps also consider plotting explictily p/pi inclusive data points istead of the curve (but we should definitely avoid to have a crowded figure, so it will depend what else will be added to the figure in terms of models).

    5. Rewrite the analysis part in the ligth of recent development of background subtraction reported at the meeting (slide 16 and following of Gabe's presentation)

     

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