247 research outputs found
Gluon TMDs in quarkonium production
I report on our investigations into the impact of (un)polarized transverse
momentum dependent parton distribution functions (TMD PDFs or TMDs) for gluons
at hadron colliders, especially at A Fixed Target Experiment at the LHC
(AFTER@LHC). In the context of high energy proton-proton collisions, we look at
final states with low mass (e.g. ) in order to investigate the
nonperturbative part of TMD PDFs. We study the factorization theorem for the
spectrum of produced in proton-proton collisions relying on the
effective field theory approach, defining the tools to perform phenomenological
investigations at next-to-next-to-leading log (NNLL) and next-to-leading order
(NLO) accuracy in the perturbation theory. We provide predictions for the
unpolarized cross section and comment on the possibility of extracting
nonperturbative information about the gluon content of the proton once data at
low transverse momentum are available.Comment: Proceedings of the Light Cone Conference 201
Optimal distributed control of an extended model of tumor growth with logarithmic potential
This paper is intended to tackle the control problem associated with an
extended phase field system of Cahn-Hilliard type that is related to a tumor
growth model. This system has been investigated in previous contributions from
the viewpoint of well-posedness and asymptotic analyses. Here, we aim to extend
the mathematical studies around this system by introducing a control variable
and handling the corresponding control problem. We try to keep the potential as
general as possible, focusing our investigation towards singular potentials,
such as the logarithmic one. We establish the existence of optimal control, the
Lipschitz continuity of the control-to-state mapping and even its Fr\'echet
differentiability in suitable Banach spaces. Moreover, we derive the
first-order necessary conditions that an optimal control has to satisfy
Flavor dependence of unpolarized TMDs from semi-inclusive pion production
Recent data from semi-inclusive deep inelastic scattering collected by the
HERMES collaboration allow for the first time to discuss how the
transverse-momentum dependence of unpolarized distribution and fragmentation
functions is affected by the flavor of the involved partons. A model built with
flavor-dependent Gaussian transverse-momentum distributions fits data better
than the same flavor-independent model. The current analysis is performed for
totally unpolarized scattering of leptons off protons and deuterons, with
detected pions in the final state. There are convincing indications of flavor
dependence in the fragmentation functions, while for parton distribution
functions the evidence is weaker.Comment: To appear in the proceedings of the QCD Evolution Workshop 2013 (May
6-10, JLAB
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