CT14 PDF update J. Huston* PDF4LHC meeting April 13, 2015 *for CTEQ-TEA group: S. Dulat, J. Gao, M. Guzzi, T.-J. Hou, J. Pumplin, C. Schmidt, D. Stump, C.-P. Yuan …and a thanks to Apfel for increasing my quota.

CT14 PDFs now final, will be uploaded to LHAPDF  PDFs at LO, NLO and NNLO  in this talk I will concentrate on NNLO  with comparisons to CT10 and to MMHT2014 and NNPDF3.0  paper mostly complete, but still being revised Main features of CT10 are still present in CT14; but  d/u and dbar/ubar change due to new LHC (and D0) data  strangeness smaller for x>0.01  gluon smaller at high x  some changes in PDF uncertainty bands as a result of including new data

Data sets for CT data points  2 /DOF~1.1 multiplicative systematic errors used where appropriate

CT14 and LHC data sets CT14 provides PDFs at LO, NLO and NNLO  fastNLO and applgrid interfaces used for quick evaluation of NLO matrix elements; supplemented by NNLO K-factors; NNLO K-factors from ResBox for W/Z/W asym LHC data sets chosen for measurements are those for which NNLO predictions are available and which are expected to provide additional constraints on PDFs in regions applicable for LHC physics analyses One exception is made for inclusive jet cross section measurements (given their importance), where the NNLO corrections are currently known only for the gg channel However, the NNLO corrections for this channel are small and flat as a function of p T, and there is reason to believe that the same is true for the other initial states NLO used for inclusive jet cross section predictions both at the Tevatron and at the LHC No restrictions on jet data used

Parametrization CT14 has a somewhat more flexible parametrization than CT10  and some restrictions on PDF combinations in CT10 were relaxed  PDFs expressed as a linear combination of Bernstein polynomials  z 4, 4z 3 (1-z), 6z 2 (1-z) 2, 4z(1-z) 3, (1-z) 4  each basis polynomial has a single peak, with peaks at different values of x; correlations among parameters are reduced  LM studies used to validate uncertainties in regions not constrained by data->fairly important aspect NLO and NNLO PDFs will have error sets with 27 eigenvectors  for example, by adding additional parameters for up, upbar, down and downbar PDFs, better agreement with BCDMS and NMC data at low Q  s (m Z )=0.118 for NLO and NNLO; PDFs at different values are also provided (variations of 0.001) at LO, as for CTEQ6, two versions provided; 1-loop  s (m Z )=0.130 and 2-loop  s (m Z )=0.118

NNLO

Some comparisons to data very constraining for u and d at high x and ubar and dbar at low x LHCb 7 TeV

LHC jet data

CMS W+c not included in the global fit (and available only at NLO)

W and Z correlations:CT10 and CT14 CT14 predictions slightly lower, error bands in good agreement

Higgs and tT correlations:CT10 and CT14 ggH and tT cross sections slightly higher; see later

tT and W + correlations: CT10 and CT14

good agreement of CT14, MMHT14 and NNPDF3.0 within uncertainty bands

some differences showing up with NNPDF3.0 at low x

d/u -> ~ at high x CT14 assumes that d val and u val both go as (1-x) a2, as x->1, where different normalizations are allowed consistent with spectator counting rules

some differences at low x

strange quark comparable to NNPDF3.0 at x~few X at low Q strange quark distribution for CT14 lower than CT10 central value for x>0.01 but consistent with CT10 within uncertainties

NNLO luminosities (68% CL uncertainties) ~1-1.5% higher at Higgs mass

very good agreement now; especially important now that ggF known to NNNLO

A comparison of ggF at NNLO CT14MMHT2014NNPDF3.0 8 TeV18.66 pb -2.2% +2.0% pb -1.9% +1.4% pb -1.8% +1.8% 13 TeV42.68 pb -2.4% +2.0% pb -1.8% +1.3% pb -1.9% +1.9%

a bit more of a spread for W/Z now

Summary and outlook PDFs will be uploaded to LHAPDF; paper forthcoming  photon PDF will also be released More details on CT14 in DIS2015 talk by Carl Schmidt Plans to add more LHC data including TeV ATLAS jet, dijet, trijet data with correlations 8 TeV ATLAS and CMS jet data Looking forward to complete inclusive jet NNLO calculation HERA2 combined data Differential tT data …and W+jet data now that NNLO calculation available( ) With data in TeV range, NLO EW corrections will be as important as NNLO QCD corrections