SANE Asymmetries Hovhannes Baghdasaryan

Measurement We are measuring Assumption is that background asymmetry is small Then Measured asymmetry is the physics asymmetry Needs to be corrected for Radiative effects (Elastic tail and internal radiation)

Background dilution Source of dilution is neutral pion Generated using Wiser code Agreement for the RCS part of BigCAL Dilution is small for low energies (is the problem as the background asymmetry is not necessarily 0 )

Background Signal Generation RCS part of BIGCAL described by Positron Simulation with 4.6% rad length Protvino part of BigCal is inefficient. Energy dependent inefficiency observed.

Background dilution Cluster Energy 5.9 GeV 4.7 GeV 4.7GeV has less contribution Used 4.6% rad length

Elastic Tail Corrections Used Mascarad CODE Calculated for region E(0.8:3)GeV and theta(25-60)degree for 4.7 and 5.9 beam energies para and perp cases Black f rc Red A rc E-1.3GeV Parallel case

Radiative corrections Using ACC model Data fits with assumptions Scaling G1 scaling G2-has linear term Asymptotic behavior

Radiative Corrections Assumption fits Correction Convergence Main correction is obtained from ACC model Assumptions are used for systematics calculation

Results Raw Asymmetry is stable Parallel Asymmetry is large 80 degree asymmetry is small Asymmetry extraction Fixed bin method Measure A180 and A80 for fixed Q2 and X bins Apply Radiative corrections (for central bin) on obtained results Event by event basis Extract A180 and A90 with event by event basis Radiative corrections

Event by Event Asymmetry Extraction + Hence where

Extraction Extracted A 90 Asymmetry Red points are using phi angle cut (- 20:20) degree Blue points using full specter of azimuthal angle (-20:60) (Positron contribution, Elastic tail radiative corrections dilution factor) Procedure works E=5.9 GeV E’(1.3:1.6)GeV

Analysis Current analysis Data divided to theta and Energy bins Energy bins ( ) ( ) ( ) Angle bins are chosen to keep almost same Q 2 All corrections bins are 50 MeV wide Analysis done by James and Jonathan Data divided by Q2 and W or X bins Corrections are done for that bin

Raw results without corrections Raw results (no radiative or positron corrections) Extraction using fixed bin method by James Maxwell

Results All points are independent from each other Points can be combined Some agreement with models

Same results vs W

Extracted g 1 and g 2