Background: –CCFR-NuTeV measurements of dimuon production in scattering (on iron)(2001) –NuTeV measurement of the Weinberg angle, using the Paschos-Wolfenstein ratio – the Anomaly (2002) (What’s the fuss about) Strangeness Asymmetry of the Nucleon and the NuTeV Anomaly Prospect:Much Ado About Nothing?Much yet to be learned!  - Recent development: –“CTEQ” global analysis of the strangeness sector of nucleon structure, using the dimuon data; and its impact on the anomaly – reports to LP03 Symposium(July/Aug, 03) –NuTeV reaction; interaction CTEQ-NuTeV; follow up work, …

Special Acknowledgements Fred Olness (SMU) (with the help of T. Bolton and M. Goncherov of CCFR): preparation of the dimuon data for global QCD analysis. Jon Pumplin and Dan Stump (MSU): development of the global analysis tools, and participation in the analysis. Kevin McFarland (Rochester): stimulating discussions about the differences of the methods of global analysis and experimental analysis. Stefan Kretzer (BNL): development of the programs for NLO calculation of the cross sections for the P-W ratio calculation.  -

Use a quantity related to the Paschos-Wolfenstein Ratio: (isoscalar target) The NuTeV measurement: NuTeV LEP EWWG a 3.1  discrepancy Must be corrected for a target with a fractional neutron excess, and if Motivation: NuTeV Anomaly

Corrections to R - : neutron excess strange asymmetry NLO correction (NuTeV : LO) reduction These corrections have been under close scrutiny by many authors, in particular BPZ (Barone et.al) and Davidson et.al. Kulagin hep-ph/ : “Needs a comprehensive global QCD analysis to clarify many of the relevant issues … ”

Strangeness Structure of the Nucleon: Dimuon Production in Scattering Process that provides the most direct (LO) constraints on the strangeness sector of the parton structure of the nucleon.  - # of events: (d is Cabibbo suppressed) Modeling needed for com- paring theory with data.

CCFR-NuTeV Analysis of Strange Quarks and the Weinberg Angle Measurement Ingredients to the CCFR-NuTeV dimuon analysis: –Data on –Fragmentation functions heavy quark fragmentation: –Buras-Gaemer Para./CTEQ/GRV non-strange partons –Strange distributions given by  Gave parameters  and  ; but no actual plots of s(x,Q), …

Strangeness Asymmetry according to NuTeV For implication on NuTeV anomaly, the key is the Strangeness Asymmetry. Define: and the corresponding momentum fractions: In particular, it is [S - ] that enters the P-W ratio correction term. CCFR-NuTeV claimed [S - ]~ in the opposite direction of accounting for the anomaly.

“CTEQ” Global Analysis Same ingredients as “CTEQ6” analysis (almost) Add CCFR-NuTeV dimuon data (and a few more) Allow a non-symmetric strangeness sector: Parametrization of the Strangeness sector (at some Q=Q 0 ) Where x 0 is to be determined by the condition [s-] = 0.

Qualitative Expectations: (really by hindsight) positive [S - ] case Negative [S-] case: flipped.

What does this analysis say about the Strangeness Asymmetry?

Main Conclusions of the CTEQ LP03 Reports

Implication on the NuTeV anomaly

What about the CCFR-NuTeV claim (to the contrary)? A picture is better than a thousand words? The CCFR ansatz:

Results on the strange sea asymmetry from BPZ without CCFR, same asymmetry as in previous studies using all data sets, the asymmetry is strongly reduced momentum asymmetry is compatible with zero all data no CCFR

What happened after LP03? Well, it is now 1:50 pm, Sept. 2. The seminar starts in 10 minutes ….