# Publications

### Publications:

2006 FPD inclusive neutral pion AN link

2006 inclusive jet paper (ALL, AN, ATT, and AΣ). link

Charged pion cross section and ALL  link

2005 Lamda spin transfer paper link

2005 BEMC inclusive neutral pion paper (ALL, z frag.) link

2009 W and Z cross section link

2006 FPD neutral pion and η cross section and AN link

2006 EEMC inclusive neutral pion cross section, ALL, and AN link

# Paper Proposal

## Cross section and longitudinal double-spin asymmetry for inclusive charged pion production in polarized proton collisions at sqrt(s) = 200 GeV

Phys. Rev. Lett.

### Principal Authors

A. Kocoloski, L. Ruan, B. Surrow, Y. Xu, Z. Xu

### Abstract

We report an extension in transverse momentum to 15 GeV/c for the differential cross section and a first measurement of the longitudinal double-spin asymmetry A_{LL} for inclusive midrapidity charged pion production in polarized proton collisions at sqrt(s) = 200 GeV. The pi-/pi+ ratio shows significant p_{T} dependence from unity at low p_{T} to 0.83±0.01(stat)±0.04(syst) at high p_{T}, an experimental signature of significant valence quark contribution. The next-to-leading order perturbative QCD models incorporating flavor dependence in the fragmentation functions can describe the cross sections and the isospin asymmetry. The charged pion A_{LL} data covering 2 < pT < 13 GeV/c disfavor a large polarized gluon distribution in the proton and provide the first glimpse of a direction of future measurements. The predicted A_{LL} difference in the positively and negatively charged pions can be tested in future RHIC data.

### Summary

In summary, we report the differential cross section and longitudinal double-spin asymmetry A_{LL} for inclusive charged pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The pion cross sections were determined up to p_{T} = 15 GeV/c and are described by NLO pQCD evaluations over 7 orders of magnitude. The asymmetries A_{LL} cover 2 < p_{T} < 13 GeV/c. They are consistent with NLO pQCD calculations utilizing polarized quark and gluon distributions from inclusive DIS analyses and disfavor large positive values of gluon polarization in the polarized nucleon.

### Proposed Figures

Figure 1: “Technical” or “instrumental” figure on the use of a jet patch trigger for this analysis. Final graphics are still to be determined. The left panel shows the minimum-bias and triggered distributions obtained from PYTHIA simulations and used to correct the measured pion spectra. The right panel plots the mean fraction of the jet momentum carried by associated (R=0.4) charged pions in the case of jets that fired the trigger (black filled squares) and jets opposite trigger jets (red open squares). The inset shows the ($\eta$, $\phi$) distribution of charged pions relative to the trigger jet in the data.

Figure 2: Transverse momentum spectra for charged pions at midrapidity ($\left|{y}\right| < 0.5$) (a) and comparison of data to DSS prediction versus $p_{T}$ (b). (c) shows ratio of π-/π+ data compared to DSS and AKK predictions.

Figure 3: The longitudinal double-spin asymmetry $A_{LL}$ in $\vec{p} + \vec{p} \rightarrow \pi^{+/-} + X$ at $\sqrt{s}=200 GeV$ versus pion $p_{T}$. The uncertainties on the data points are statistical. The gray bars indicate the total point-to-point systematic uncertainty, and the curves show predictions based on parameterizations of gluon polarization from global analyses.

# 2005 Dijet

Supporting documentation on the 2005 Dijet Paper, targetted for PRDRC

Title: Dijet production in proton-proton collisions at sqrt(s) = 200 GeV

PAs: Matthew Walker, Joseph Seele, Bernd Surrow

Analysis Note

Preliminary Presentation

Paper Draft

Abstract:

# BEMC Calibration

This page is intended to provide documentation of how I arrived at the numbers and figures relevant to the BEMC calibration quoted in the paper.  Data and macros can be found at

http://deltag5.lns.mit.edu/~kocolosk/protected/long_jet_paper/

If you want to reproduce these plots, you're probably best off just downloading the whole directory.  Here's a tarball:

http://deltag5.lns.mit.edu/~kocolosk/protected/long_jet_paper/bemcCalibration.tar

## 2003

Nothing to see here just yet.  I asked Alex about the availability of the data and was told that they used the last dAu combined production.

## 2004

Run 4 BTOW Calibration

Nevents = 20-57 M.  Run 4 is funny because we've reproduced P05ia since I did my analysis, so the old query I used isn't really valid anymore.  I took these numbers from Jamie's page at

http://www.star.bnl.gov/protected/common/common2004/trigger2004/200gev/sums_emc.txt

The 20M number is the total number of trigId==15007 events.  These are what we used for the MIP calibration, but we also applied centrality and vertex cuts that aren't reflected in that number.  The number is also complicated by the warning not to use minbias triggers from productionLow || Mid || High before 5042040, which I did not heed (not sure if we knew about the problem at the time).  For the electrons we required trigId!=15203, which if I take all-bTid15203 from that link gives me 57.2M events.

No attempt has been made to figure out exactly what fraction of these data was actually analyzed in my jobs.  In Run 5 that number was 94%, here I've just taken it to be 100%.

Nmips = 1.4 x 10^{6}.  This is the number of entries in the "mH0" histogram in 2004_mips.root

Nelectrons = 1.5 x 10^{6}  makeElectronCounts.C The reason we have Nmips ~= Nelectrons is that the electron sample dropped the refMult and vertex cuts and took some triggered data as well.  Specifically, we used trigId==15007 for the MIPs and trigId!=15203 for the electrons.

Figure 2a:  makeMipFigures.C

Figure 4a:  makeElectronFigure2.C

Figure 5:  makeGainsFigure.C

Note that in each case you'll have to download the ROOT files required by the macro and put them in the same directory.

## 2005

Run 5 BTOW Calibration

Nevents = 57M.  This one is a bit tricky, as I never saved a tree with all the events I looked at.  Here's how I arrived at the number.  I used a catalog query

get_file_list.pl -cond 'production=P05if,filetype=daq_reco_mudst,storage=HPSS,filename~physics,sanity=1,tpc=1,emc=1' -keys 'sum(sanity),sum(events),sum(size),grp(trgsetupname)'

to get number of files and events for each trgsetupname I used in the calibration (ppProduction || ppProductionMinBias || ppTransProduction).  The query returned a total of 73716 files in HPSS.  I did save my original filelists, and when I cat them together I find that I analyzed about 94% of available files (69297 to be exact).  The event sample from catalog was 60.8 M events, and I just multiplied that number by the percentage of analyzed files.  This doesn't reflect the |vz|<30 cut that was applied to the MIP study.

Nmips = 4.3 x 10^{6}  This is the number of entries in "h" in 2005_mips.root.  All the cuts from Run 5 BTOW Calibration had already been applied.  You might have noticed that this number is much larger than the number of MIPs in Run 4.  The reason for this is that in Run 4 we used only minbias (trigId == 15007) and we also applied a centrality cut of 60-100% (refMult<57).  In addition, it's quite a lot harder to find an isolated track in a AuAu event versus a pp event, and Run 5 had a 3/4 barrel instead of just 1/2.

Nelectrons = 0.4 x 10^{6}  makeElectronCounts.C applies all the cuts and spits out the final counts for 2004 and 2005.

Figure 2b:  makeMipFigures.C

Figure 4b:  makeElectronFigure2.C

Figure 5:  makeGainsFigure.C

Figure 8:  makeElectronFigure3.C