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Update on fs and fc

Update on fs and fc. Sensitivity of fc to Q 2 0 and mc. with ‘new inbetween, indeed find fc = 0.15, the input value with ‘ optimised ZEUS-JET’ get the dynamical value of fc :. Confirm that fc = 0.15 at Q 2 0 = 4 is too large, 0.09-0.10 more adequat. Sensitivity of fs to Q 2 0 and mc.

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Update on fs and fc

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  1. Update on fs and fc 20.06.2008 JF / HERA SF WG

  2. 20.06.2008 JF / HERA SF WG Sensitivity of fc to Q20 and mc with ‘new inbetween, indeed find fc = 0.15, the input value with ‘ optimised ZEUS-JET’ get the dynamical value of fc : Confirm that fc = 0.15 at Q20 = 4 is too large, 0.09-0.10 more adequat

  3. 20.06.2008 JF / HERA SF WG Sensitivity of fs to Q20 and mc Param : ‘ optimised ZEUS-JET’ fs is not dynamically generated but given at Q20 as strange = 0.25 (usea + dsea), (ZEUS style)‏ which is not equivalent to strange /Dbar = 0.33 when ubar and dbar are different (ZEUS param)‏ fs is not sensitive to mc (as it should not be)‏

  4. Sensitivity of fc and fs to HQ Scheme with ‘new inbetween’, indeed find fc = 0.15 and fs = 0.33, the input values with ‘ optimised ZEUS-JET’ get the dynamical value of fc : No significant difference between ZMVFN and ACOT !! 20.06.2008 JF / HERA SF WG

  5. 20.06.2008 JF / HERA SF WG Suggestion for fs and fc to be discussed • At Q20 = 4 , fs = 0.33, fc = 0.1 or 0.09 (was 0.15)‏ • At Q20 = 2 , fs = 0.31, fc = 0.0 (was 0.15 !!)‏ • At Q20 = 6, fs = 0.34, fc = 0.14 or 0.13 (was 0.15)‏ • Variation of fs : 0.25 to 0.4 (as before)‏ • Variation of fc : 0.06 to 0.12 (was 0.1 to 0.2) • prefer to keep a safe window because a large fraction of the integrals on x to determine fc comes from the x > 0.1 domain where the constraint comes from the parametrisation and not from the data : debatable. Any how a minute effect on PDFs except on cbar distribution.

  6. 20.06.2008 JF / HERA SF WG At Q2 = 10 GeV2 and x > 0.3, sea(x) > gluon (x)‏

  7. 20.06.2008 JF / HERA SF WG At Q2 = 10 GeV2 and x > 0.3, sea(x) > gluon (x)but it it is within the experimental errors of the sea

  8. 20.06.2008 JF / HERA SF WG At Q2 = 104 GeV2 and x > 0.2, sea(x) > gluon (x)‏

  9. 20.06.2008 JF / HERA SF WG At Q2 = 104 GeV2 and x > 0.2, sea(x) > gluon (x)but it it is within the experimental errors of the sea Not a strong worry !

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