eic tf meeting, feb 16 th , 2012

1

EIC TF meeting, Feb 16th, 2012

Another Update: eRHIC Impact on Helicity PDFs

progress on plots for white paper

Marco Stratmannmarco@bnl.gov

work based on Elke’s DIS/SIDIS pseudo-data; in collaboration with Rodolfo

2

recall: new pseudo-data

• use relative uncertainty of each point to produce mock data (based on DSSV)• “randomize” data within 1-sigma• for SIDIS: incl. 5% (10%) uncertainty from pion (kaon) frag. fcts.• map out χ2 profiles with Lagrange multiplier method (Hessian is work in progress)

5x100 and 5x250data for DIS & SIDIS (π± and K±)

10 fb-1 each, 70% beam pol.

cuts:• W2 > 10 GeV2 • depol. factor > 0.1• 0.01 < y < 0.95• pelec > 0.5 GeV• 1o < θ < 179o

• phadr > 1 GeV

global analysis:

Elke

3

recall: first profiles for sea quarks

• very encouraging results• as expected, DIS has no impact • need to translate into error on x-shape

read off PDF parameters

for a given Δχ2

4

first results on x-dep bands for quark

sea

5

first results on sea quark asymmetry

to propagate uncertainties properly this is based on its own L.M. analysis

6

new plot showing kinematic coverage &

current data

stage-1 5x100

20x250

plan: produce similar plots for GPDs, TMDs, and nuclear PDFs✔ Salvatore

7

impact of 20x250 data on helicity PDFs ?

• range 0.001-1 covered best by 5 x 100 data

• 5x250 add more Q2 bins to play with Q2

min cut

8

hot off the press: Δg profile at small x

20x250 mattersa lot here !

9

best probe for small x gluonspQCD scaling violations

pos

itive

Dg

fixed targetdata

white paper: g1 scaling violation plot ?

x

10

the “scaling violation plot”

try to put in othertheoretical curves

for different Δg

5x250 datastart t0

contribute

5x100 datastart t0

contribute

11

last minute result: alternative Δg’s

DSSV+

more negative Δg

positive Δg

12

underlying g1 “data” vs DSSV+

to do list: PDF correlations a la CTEQ

need to produce Hessian sets first – goal: ΔΣ – Δg correlation