منابع مشابه
Quark and Gluon Sivers Functions *
The physics of hadron single transverse spin asymmetries is discussed. Possible measurements of both the quark and gluon Sivers functions are proposed.
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We establish a connection between the distribution functions of quarks in spin-one hadrons and the helicity matrix for forward scattering of antiquarks off spin-one hadrons. From positivity of this matrix we obtain inequality relations among the distribution functions. Analogous relations hold also for fragmentation functions. The bounds we obtained can be used to constrain estimates of unknown...
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We consider the Cauchy problem on the positive half-line for the differential-delay equation ü(t) + 2c0(t)u̇(t) + c1(t)u̇(t − h) + d0(t)u(t) + d1(t)u(t − h) + d2(t)u(t − 2h) = 0 where ck(t), dj(t) (t ≥ 0; k = 0, 1; j = 0, 1, 2) are continuous functions. Conditions providing the positivity of the Green function and a lower bound for that function are derived. Our results are new even in the case o...
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We describe algebraic certificates of positivity for functions belonging to a finitely generated algebra of Borel measurable functions, with particular emphasis to algebras generated by semi-algebraic functions. In which case the standard global optimization problem with constraints given by elements of the same algebra is reduced via a natural change of variables to the better understood case ...
متن کاملPositivity Questions for Cylindric Skew Schur Functions
Recent work of A. Postnikov shows that cylindric skew Schur functions, which are a generalisation of skew Schur functions, have a strong connection with a problem of considerable current interest: that of finding a combinatorial proof of the non-negativity of the 3-point Gromov-Witten invariants. After explaining this motivation, we study cylindric skew Schur functions from the point of view of...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 2011
ISSN: 0370-2693
DOI: 10.1016/j.physletb.2010.11.045