Update on BES light nucleiw.j. llope

I Analysis Mtg, 7/16/2013, Purdue

physics directions: http://wjllope.rice.edu/d/DNP2012_Llope.pdf

Tree, analysis, PID, spectra, and ratios codes all in place…Still improving corrections….

Since results shown at QM2012• Added 3He, anti-3He, and α • Five track cuts sets for systematics: none, loose, tight, cross-terms• Detailed event QA (a la bulkcorr)• Feeddown – added more events, centrality dependence• TOF match eff – improving systematic treatment• Extend/Simplify implementation of corrections in analysis code

Recent workFinalized absorption corrections, now includes nuclei tooAdded some new embedding sets to the tableSignificant improvement in TOF Match Eff approach

p pbar d dbar t tbar h hbar7.7 20123821

SL10h_emb191

20123822SL10h_emb192

2012402SL10k_emb183

2012402SL10k_emb183

2012401SL10k_emb182

2012401SL10k_emb182

20122402SL10k_emb185

20122402SL10k_emb185

11.5 20123815SL1hk_emb201

20123816SL10h_emb202

2012402SL10k_emb183

2012402SL10k_emb183

2012401SL10k_emb182

2012401SL10k_emb182

20122402SL10k_emb185

20122402SL10k_emb185

19.6 2012305SL11d_emb231

2012306SL11d_emb232

20122404SL11d_emb253

20122404SL11d_emb253

27 2012105SL11d_emb251

2012106SL11d_emb252

20122404SL11d_emb253

20122404SL11d_emb253

39 2012601SL10k_emb186(jetcorr)

2012601SL10k_emb187(jetcorr)

2012402SL10k_emb183

2012402SL10k_emb183

2012401SL10k_emb182

2012401SL10k_emb182

20122402SL10k_emb185

20122402SL10k_emb185

62.4 2011601SL10k_emb162(jetcorr)

2011601SL10k_emb166(jetcorr)

2012401SL10k_emb164

20101706SL10k_emb161

20101708SL10k_emb163

20101708SL10k_emb163

20122403SL10k_emb165

20122403SL10k_emb165

200(r10)

2011601SL10k_emb162(jetcorr)

2011601SL10k_emb166(jetcorr)

2012401SL10k_emb164

20101706SL10k_emb161

20101708SL10k_emb163

20101708SL10k_emb163

20122403SL10k_emb165

20122403SL10k_emb165

200(r11)

RM-matched RM-matched &/or Abs-scaled

scale by RM, Abs, and r11/r10…scale up by 4-9% depending on cuts

Reconstruction Eff from Embedding

He3 scaling not great even for |y|<0.1, and there’s a dip at pt~1.75Have been discussing with Gene recently...

https://www.star.bnl.gov/rt3/Ticket/Display.html?id=2561

pt<0.4 0.6<pt<0.8 1.0<pt<1.5 2.0<pt<3.0

40<RM<80 160<RM<200 360<RM<400 460<RM<500

RefMult

EffEff

pt

He3 “dip

He3 “hole” @pt~1.75 for |y|<0.1 & 0.1<|y|<0.3 – now fitting explicitly

RM<40

520<RM<560

Absorption ... Now with all brand new embedding for p and pbar at all root-s…

7.7 11.5 19.6 27.0

39.0 62.4 200

eff(

p)/e

ff(p

bar)

PT

Absorption is independentof root-s (as it must be).

0.61 factor is o.k., but0.45 is better

Absorptionhttp://wjllope.rice.edu/d/protected/LFSpectra_20130524.pdf

For the antinucleus half of my analyses, all I’d have to do is theusual xsec-scaling approach but use the factor of 0.45 instead of 0.61. But….

1. What am I supposed to do about the nucleus absorption?2. is this pbar to Abar xsec-scaling STAR uses for antinucleus absorption

consistent with more recently measured cross-sections?

These questions can be answered with GEANT4.

GEANT4 has extensively validated cross-sections for light (anti)nuclei basedon experimental data…

Google ‘geant4 validation’ etc… See also e.g. http://arxiv.org/abs/1208.3614v1 http://arxiv.org/abs/1209.4455v1

Do a GEANT3 simulation with a STAR mock-upDo a GEANT4 simulation with the same STAR mock-up. And then compare.

As I am only interested in the absorption itself, the STAR mock-up used in both only needs to be good, not perfect (STARSIM)... This can be tested (in two

ways)!

Embedding still handles all the real-life reconstruction aspects (resn, merging, cuts etc)

STAR Geometry from STARSIM, Y2010/11 “final”

STARSIM X0 values used to define theG3 & G4 geometries…

First test is to use the “material” functionsin G3 and G4 to show that the expected X0 values are reproduced.. ✔

pipe (Be)

C-fibersupportrods

IFC (Al/Cu)

P10

OFC (Al/Cu)

G4 code withvisualization

Throw 10 particles (p, pbar, d, dbar, t, tbar, h, hbar, a, abar)flat PT distribution |η|<0.5, or, as in my analysis, |y|<0.1, 0.1<|y|<0.3, 0.3<|y|<0.5

Wasted some time comparing different G4 physics lists. All but one were nonsensical.Then I learned FTFP_BERT is recommended. And this is the one that made sense!http://geant4.cern.ch/support/proc_mod_catalog/physics_lists/useCases.shtml

Let G3 and G4 swim these tracks, and deposit hits in a “TPC” and a “perfect TOF”If the particle exits the TPC (or makes hits the “TOF” layer) this track is “not absorbed”

Form the ratios of “not absorbed”/“generated” vs. PT for each particle thrown…This defines an “not absorbed efficiency” -- This is precisely what I need.Make ratios of these efficiencies to compare to the Struck approach…

G4 events were generated on the DAVINCI cluster at RICE. …several 10’s of millions of events were generated…

G3 events were generated on my laptop (10M events in ~5 hours)

Second key test… pbar absorption w.r.t. protons from G3 and G4

G3G4

Struck-style p/pbar parameterization using factor 0.45…

Struck abs(dbar)

G3 and G4 mock-up geometries reproduce the expected p/pbar absorption from embedding… Important.

PT

Struck abs(tbar,hbar)

Struck abs(abar)

Eff(A)/Eff(Abar)

G3 reproduces the expected values of Eff(p)/Eff(pbar), as expectedG3 gives Eff(A)/Eff(Abar) = 1 independent of PT, which is nonsense, as expectedG4 shows that Eff(Abar) < Eff(A), as expected

Eff(p)/Eff(pbar) d/dbar t/tbar h/hbar a/abar

PT

G3G4

Now forming the ratios that I need: Eff(p)/Eff(X)…

Green lines are a pol8 fit and define the absorption corrections I will use…

Improved TOF Match Efficiencies (this is an animation – full screen to view)

…Summary

Expanded table of embedding data with some new requestsAbsorption corrections for antinuclei and nuclei now finalized using Geant4 Significant improvements in TOF Match Efficiency calculations

…Time scale…

To be honest, this analysis isn’t my highest priority, but I am keeping codes running…

Two of the 5 cuts sets have been processed so farWill have some results to QA in a couple of weeks

…“new” physics directions…

- use of light nucleus ratios significantly reduce (mB,T) uncertainties in stat. model fits…http://arxiv.org/pdf/1010.2995v2.pdf

-d/p ratios possibly sensitive to spinodal decomposition near 1st order phase transitionhttp://meetings.aps.org/link/BAPS.2013.APR.D3.3