Al+Au Analysis Plan Why study asymmetric systems like Al+Au (or Cu+Au as was recently done at RHIC)? Collisions of symmetric heavy ions do not create a isotropic equilibrated static source. The interaction zone is characterized by gradients in pressure, chemical potential, temperature, and flow velocity. As varying thicknesses of nuclear matter from one participant overlap with varying opposing thicknesses. The 4-5 GeV energy range is a regime of partial stopping. In collisions of symmetric nuclei, this partial stopping is seen as a broadening of the proton rapidity distribution. In asymmetric collisions, both the shift and the broadening of the rapidity distribution provide clues to the stopping. In central Al+Au collisions, the ratio of participants from the gold to aluminium nucleus is about 2:1. Thus Al+Au is a laboratory to study the upper and lower regions of the interaction zone is semi-central Au+Au collisions. 1:2 1:1 2:1

Background – What has been done previously AGS 14.6 AGeV/c Silicon beams run in the December 1988 and June 1989 AGS 14.6 AGeV/c Silicon beams in 1991 and 1992 AGS 11.7 AGeV/c Gold beams in 1993 Experiments: E802/859/E866 (Spectrometer) E810 (MPS TPC) E814 (Forward Calorimeter)

Becattini PRC64(2001) Becattini has reviewed the measured particle yields and performed a statistical thermal model to extract the temperature, baryon chemical potential, and strangeness parameters.

He has compared these results to those from symmetric collisions. Becattini PRC64(2001)024901

E AGeV/c Si+Au, Si+Cu, and Si+Al Central and Peripheral E AGeV/c Si+Au, Si+Al Centrality determination. I am impressed by how many particles E802 is able to measure in their events. They get up to 250 charged particles. We are well below that total. E802 PRC50(1994)1024

These are the basic particles yields at various rapidity slices. E802 PRC50(1994)1024

dN/dy and T parameters E802 PRC50(1994)1024

The data from the tables on the previous page, now is graphic form. E802 PRC50(1994)1024

A comparison of E802’s results to those of E810 and E814 E802 PRC50(1994)1024

E802 PRC60(1999)044904

E814 The E810 and E814 data are shown in the E802 figures. There is little new in their figures

GEISS --- HSD transport Geiss NPA644(1998)107

Nix 1993

PBM

Wagner BUU This is the most useful of the model fits to the Si+Au data. Wagner explores the important of the q-qbar (or resonance) channel which is simulated by the strong model in meson nucleon collisions. He considers p+Au, Si+Au, and Au+Au. This really gets at the relative importance of resonance versus direct production for pions and kaons.

Preliminary STAR results --- Brooke Haag August 2013

Preliminary STAR results --- Chris Flores October 2013 These are the data that we are trying to complete. Unfortunately, they are at 4.5, not 4.9 GeV. Still, we can scale…

OK… What next… We really ought to be preparing the Analysis Note as we are going along. Please refer to the Fixed Target Coulomb Paper analysis note for reference: I will follow the layout of that analysis note and figure out where we are and what we need to be doing next. 1.Motivation: Refer back to the first slide of this.pptx.

2. Fixed Target Basics: OK… here we just want some pretty picture of fxt Al+Au events… we really want pix of both Au+Al and Al+Au. 4.5 GeV Au+Al GeV Al+Au 2015

3. Data Sets: 4.5 Au+Al GeV 19.6 Au+Au GeV /24 to 5/ M83M 4.9 GeV Al+Au FXT Test / TBDNA3.4 M

4. Event Selection: Trigger == no selection 210 < Vz < < Vx < 0 -2 < Vy < -1.6 TofMatch > GeV Al+Au Saturated DAQ Bandwidth with 2 bunches. 78% of trigger were Al+Au events

5. Centrality Determination: Ok… we need the Glauber fits to this plot and we need all the numbers…. See the FXT Vc AN

6. Track Selection: Refer to the FXT Vc AN and make some track QA plots… we need to decide on the track quality cuts…

7. Acceptance in FXT mode:

8. PID Plots: K -,  - p, d, t, K +,  +, p, d, t, K +,  +,

9. dE/dx Fits:

10. Efficiency Corrections:

11. Energy Loss Corrections

12. Background and Feed down Corrections

13. Invariant Transverse Mass Spectra

14. Rapidity Density Plots:

15. Slope Parameter Plots: