Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 1

Resonance Spin Structure

Frank R. Wesselmann

Overview

Developments

Outlook

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.1

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 2

E-01-006: RSSNucleon Spin Structure in the Resonance Region

Inclusive Scattering, Polarized Beam & TargetUVa Target, HMS

Proton & Deuteron,

� & � �� � & � �� � � & � �consistent setup, minimal model input

ran January – March 2002

Dependence

Polarized Local Duality

GDH Sum Rule

Higher Twist Effects

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.2

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 3

RSS CollaborationAram Aghalaryan, Abdellah Ahmidouch, Razmik Asaturyan, Hu Bitao, Frederic Bloch,

Werner Boeglin, Peter Bosted, Roger Carlini, Jinseok Cha, Jian-Ping Chen, Eric Christy,Leon Cole, Luminita Coman, Marius Coman, Donald Crabb, Sam Danagoulian, Donal Day,

Jim Dunne, Mostafa Elaasar, Rolf Ent, Howard Fenker, Emil Frlez, Lipin Gan, Javier Gomez,Mark Jones, Chris Keith, Cynthia Keppel, Mahbub Khandaker, Andi Klein, Yongguang Liang,

Jechiel Lichtenstadt, Richard Lindgren, Dave Mack, Paul McKee, Dustin McNulty,Hamlet Mkrtchyan, Rakhsha Nasseripour, Maria-Ioana Niculescu, Kristoff Normand,

Blaine Norum, Dinko Pocanic, Yelena Prok, Brian Raue, Joerg Reinhold, Julie Roche,Daniela Rohe, Oscar Rondon, Nikolai Savvinov, Brad Sawatzky, Ingo Sick, Cole Smith,Greg Smith, Sam Stepanyan, Liguang Tang, Giuseppe Testa, Bill Vulcan, Kebin Wang,Glen Warren, Frank R. Wesselmann, Steve Wood, Chen Yan, Lulin Yuan, Junho Yun,

Marko Zeier-Koch, Hongguo Zhu

Florida International University, Hampton University, Mississippi State University,Norfolk State University, North Carolina A&T University, Old Dominion University,

Southern University at New Orleans, Tel Aviv University,Thomas Jefferson National Accelerator Facility, Universität Basel, University of Maryland,

University of Massachusetts, University of North Carolina at Wilmington, University of Virginia,Virginia Polytechnic Institute & State University, Yerevan Physics Institute

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.3

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 4

World Kinematics

� �

vs. �

� � � � � � � �� �

� �� � �

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.4

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 5

RSS Kinematics

Beam Energy

� � ��� � � �

HMS Settings:� � � �� � � � �

� � ���

,

�

� � ��

��

� � � � �� �

� � � � � � � ��

� �

vs.

��� � � �� � � � � �� � ��� � � � � � � � ��

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.5

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 6

Measured Asymmetries

x

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

RSS

A||

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

deuterons

protons

PRELIMINARY (Uncorrected)

PRELIMINARY (Uncorrected)

x

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

RSS

A_|

_

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

deuterons

protons

Preliminary Results

Approximate DilutionFactor

No Other Corrections

���

�� � � ���� ��

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.6

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 7

Physics from Data

�� � ��� � ��

� � � � or

��� � ���

��� ���

charge, deadtime normalized:

� � �

�

�� �

�

�� ���� � � � � �� � � �

� �

������ � Beam Polarization���� !� � Target Polarization"Dilution Factor#%$ & , "$ & Radiative Corrections')( , ')* Nitrogen Corrections

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.7

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 8

Beam Polarization

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.8

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 9

Target Polarization

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.9

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 10

Monte Carlo Simulation

0

5

10

15

Yie

ld

Data at pcent

= 4.7 GeV/c

Monte CarloData at p

cent = 4.0 GeV/c

1 1.5 2

W (GeV)0.8

0.9

1

1.1

Rat

io D

ata/

MC

Parallel field

0

5

10

Yie

ld

Data at pcent

= 4.7 GeV/c

Monte CarloData at p

cent = 4.0 GeV/c

1 1.5 2

W (GeV)0.8

0.9

1

1.1R

atio

Dat

a/M

C

Perpendicular field

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.10

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 11

Dilution Factor

Packing Fraction, ���

�–

��

�

, from Ratio of

��� to � Rates

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.11

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 12

Beam Raster

Distribution ofEvents,

� vs.

��� � � �

Data (top) cfg.MC (bottom)

Initial (left) andImproved (right)

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.12

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 13

Target Field

Strong Target Fieldaffects particletrajectoriescomplex

Perpendicularunique to RSSfield more significant:

� � � � � �� � � � � � � � � � � �Actual Field not Identical toField Map

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.13

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 14

Target Field

Large Effects inShort Path Lengths

� � � path length error

� � � of

� �� � ��� � � �

MC now Reproduces DataFeatures

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.14

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 15

RSS – Results

based on Hall C fits for

�

and

� �

Not Fully Corrected

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.15

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 16

RSS – Results

ξ0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

g 1p

-0.10

0.00

0.10

0.20

0.30

g1 BBS

RSS preliminary

(BBS: Bourrely, Bucella & Soffer)OARA 8/04

prel

imin

ary

Not Fully Corrected

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.16

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 slide 17

Status & OutlookIndividual Cell Packing Fractions,Dilution Factors

��

��ongoing

Count Asymmetries, Pass 2�

�

��final preparations

Final Off-Line Target Polarizations

��

��ongoing

Nitrogen and Radiative Corrections

��

��preliminary

By End of 2004:

Spin Asymmetries

��� & � �

Neutron SSF’s

Systematic Errors

Polarized Local Duality

p Elastic Asymmetry

Frank R. Wesselmann, Resonance Spin Structure, Hall C Summer Workshop 2004 – p.17

E-01-006: RSSRSS CollaborationWorld KinematicsRSS KinematicsMeasured AsymmetriesPhysics from DataBeam PolarizationTarget PolarizationMonte Carlo SimulationDilution FactorBeam RasterTarget FieldTarget FieldRSS -- ResultsRSS -- ResultsStatus & Outlook