N. Poljak, FPD++ N. Poljak, U. of Zagreb

N. Poljak, TPC: -1.0 <  < 1.0 FTPC: 2.8 <  < 3.8 BBC : 2.2 <  < 5.0 EEMC:1 <  < 2 BEMC:-1 <  < 1 FPD: |  | ~ 4.0 & ~3.7 Layout

N. Poljak, pQCD Physics results Unlike at lower energies, the inclusive differential cross section for pion production at 200 GeV is consistent with NLO pQCD calculations at 3.3<η <4.0 As η increases, systematics regarding the comparison with NLO pQCD calculations begin to emerge. The data at low p T are more consistent with the Kretzer set of fragmentation functions.

N. Poljak, A N results J. Adams et al. (STAR), Phys. Rev. Lett. 92 (2004) A N grows with increasing x F for values larger then 0.35 Results from run2 don’t yet discriminate between different dynamics First result for the A N (p T ) was obtained using combined statistics from run3 and run5. There is evidence that the   analyzing power at x F >0.4 decreases with increasing p T

N. Poljak, Run 2 Published Result. Run 3 Preliminary Result. -More Forward angles. -More Forward angles. -FPD Detectors. -FPD Detectors. Run 3 Preliminary Backward Angle Data. Backward Angle Data. -No significant Asymmetry -No significant Asymmetry seen. seen. ( Presented at Spin 2004: hep-ex/ ) Run 3 + Run 5 Preliminary =3.7,4.0 (Presented SPIN 2005 Dubna Sept 27-Oct 1, Absolute polarization still preliminary) ~ 6  from 0 for x F >0.4

N. Poljak, Run-6 FPD++ FPD++ Physics for Run6 Run-5 FPD

N. Poljak, Basic physics Goals Ideas to be tested using FPD++ in Run6 Prototype for FMS (RUN7) Discriminate dynamical origin of the forward A N –Measurement of jetlike events and A N for those Similar to FPD (left, right) but with larger active area Measure shape of forward jet –Measure direct photons cross section, possibly A N --- separation of   and direct gamma Continue the study of   asymmetry in pp other

N. Poljak, Jet spin asymmetry Is the single spin asymmetry observed for   also present for the jet the   comes from? Answer discriminates between Sivers and Collins contributions Trigger on energy in small cells, reconstruct   and measure the energy in the entire FPD++ Average over the Collins angle and define a new x F for the event, then see if analyzing power increases with x F Expect that jet-like events are ~15% of   events

N. Poljak, Where do decay partners go? Gain sensitivity to direct photons by making sure we have high probability to catch decay partners This means we need dynamic range, because photon energies get low (~0.25 GeV), and sufficient area (typical opening angles few degrees at our  ranges). di-photon parameters z  = |E 1 -E 2 |/(E 1 +E 2 )   = opening angle M m = GeV/c 2 (   ) M m =0.548 GeV/c 2 (  )

N. Poljak, Sample decays on FPD++ The FPD++ is much closer to FPD then FMS will be. We can mimic the FPD trigger and search for the second   around the first With FPD++ module size and electronic dynamic range, the yellow area marks where we have 95% probability of detecting second photon from   decay

N. Poljak, Status report Calorimeter cells for free thanks to FNAL / U.Col. and Protvino Cells were refurbished and tested in physics South enclosure in place on STAR west platform, readout in place cell by cell IN SITU tests and cables connected

N. Poljak, To do list Put the north module in place Conect the readout electronics and test all readout Finalize the readout and trigger details Perform measurements with 15/pb delivered integrated luminosity (for 4-5  measurement of A N in jet like events) RUN 6 RUN 7

N. Poljak, BACKUP SLIDES

N. Poljak, Planned FMS Wall FMS …. To be installed for RUN7 Expanding the eta coverage -1<  <4 Measurement of the same side correlations Opposite side correlated pions (dijets) – Sivers effect –d-Au (Gluon saturation in Nuclei) Other future objectives –Forward Lepton pairs –Charm –Drell Yan

N. Poljak, Reconstruction FPD (Forward Pion Detector) proved we can reconstruct forward   in all (pp, dAu, CuCu) environments

N. Poljak, Separated x F and p T dependence Similar to ISR analysis J. Singh, et al Nucl. Phys. B140 (1978) 189. Shows the data consistency

N. Poljak, A N (p T ) in run3+run5 at √s=200 GeV Combined statistics from run3 and run5 allowed to distinguish nonzero effect in A N (p T ) plotCombined statistics from run3 and run5 allowed to distinguish nonzero effect in A N (p T ) plot There is an evidence that analyzing power at x F >0.4 decreases with increasing p TThere is an evidence that analyzing power at x F >0.4 decreases with increasing p T Theoretical prediction’s needed (for constraint on Sivers function).Theoretical prediction’s needed (for constraint on Sivers function). Online calibration of CNI polarimeter

N. Poljak, How to detect direct photons? We have good sensitivity to both photons in decay of known particles, so that unpaired photons become candidates for being “direct”. π 0  M=0.135 GeV BR=98.8% K 0  π 0 π 0   %   %  π 0    %  ’   % Other decay modes yield more photons with less Q Background simulations underway

N. Poljak, Proposed readout