Experimental constraints on coefficients of αS-expansion of Gottfried sum rule
نویسندگان
چکیده
The xand Q2-dependences of the Gottfried sum rule SG(x,Q 2) based on the experimental data on proton and deuteron structure functions are studied. The dependence of SG(x,Q 2) on Q2 for low x points to flavour asymmetry of sea quark distributions. For the first time, the coefficients c1, c2 of the expansion of SG(x,Q 2) in αS/π up to second order are evaluated through the phenomenological analysis of NMC and H1 data. It is found that c1 is negative while c2 is positive. The obtained result is in disagreement with QCD predictions for these coefficients. We suggest measuring the low x-dependence of the FD 2 deuteron structure function at HERA in order to study the Q2-dependence of the Gottfried sum rule.
منابع مشابه
The Pion-Nucleon Coupling Constant in QCD Sum Rules
The pion-nucleon coupling constant gπN is studied on the basis of the QCD sum rules. Both the Borel sum rules and the finite energy sum rules for gπN are used to examine the effects of higher dimensional operators (up to dim. 7) and αs corrections in the operator product expansion. Agreement with the experimental number is reached only when Sπ/SN is greater than one, where Sπ (SN ) is the conti...
متن کاملOn Reconciling Gottfried Sum Rule Violation with Cabibbo Theory†
We discuss the seemingly contradictory constraints of simultaneously preserving the SU(3)-symmetric Cabibbo description of the weak vector baryon matrix elements, accounting for SU(3) flavor symmetry breaking and describing the observed violation of the Gottfried Sum Rule. We try to construct a simple model that will satisfy these constraints and use it to explain the generic difficulties and t...
متن کاملThe Subleading Isgur-Wise Form Factor χ3(v ·v′) to Order αs in QCD Sum Rules
We calculate the contributions arising at order αs in the QCD sum rule for the spin-symmetry violating universal function χ3(v ·v′), which appears at order 1/mQ in the heavy quark expansion of meson form factors. In particular, we derive the twoloop perturbative contribution to the sum rule. Over the kinematic range accessible in B → D(∗)l ν decays, we find that χ3(v · v) does not exceed the le...
متن کاملStatistical Inspired Parton Distributions and the Violation of QPM Sum Rules
A quantum statistical parametrization of parton distributions has been considered. In this framework, the exclusion Pauli principle connects the violation of the Gottfried sum rule with the Ellis and Jaffe one, and implies a defect in the Bjorken sum rule. However, in terms of standard parametrizations of the polarized distributions a good description of the data is obtained once a large gluon ...
متن کاملPadé Approximants , Borel Transforms and Renormalons : the Bjorken Sum Rule as a Case Study
We prove that Padé approximants yield increasingly accurate predictions of higher-order coefficients in QCD perturbation series whose high-order behaviour is governed by a renormalon. We also prove that this convergence is accelerated if the perturbative series is Borel transformed. We apply Padé approximants and Borel transforms to the known perturbative coefficients for the Bjorken sum rule. ...
متن کامل