7,693 research outputs found
Drell-Yan process in TMD factorization
This article presents the review of the current understanding on the
pion-nucleon Drell-Yan process from the point of view of the TMD factorization.
Using the evolution formalism for the unpolarized and polarized TMD
distributions developed recently, we provide the theoretical expression of the
relevant physical observables, namely, the unpolarized cross section, the
Sivers asymmetry, and the asymmetry contributed by the double
Boer-Mulders effects. The corresponding phenomenology, particularly at the
kinematical configuration of the COMPASS Drell-Yan facility, is
displayed numerically.Comment: Version published in Advances in High Energy Physic
Stochastic Trust Region Methods with Trust Region Radius Depending on Probabilistic Models
We present a stochastic trust-region model-based framework in which its
radius is related to the probabilistic models. Especially, we propose a
specific algorithm, termed STRME, in which the trust-region radius depends
linearly on the latest model gradient. The complexity of STRME method in
non-convex, convex and strongly convex settings has all been analyzed, which
matches the existing algorithms based on probabilistic properties. In addition,
several numerical experiments are carried out to reveal the benefits of the
proposed methods compared to the existing stochastic trust-region methods and
other relevant stochastic gradient methods
Transverse momentum spectrum of dilepton pair in the unpolarized Drell-Yan process within TMD factorization
We study the transverse momentum spectrum of dilepton produced in the
unpolarized Drell-Yan process, using transverse momentum dependent
factorization up to next-to-logarithmic order of QCD. We extract the
nonperturbative Sudakov form factor for the pion in the evolution formalism of
the unpolarized TMD distribution function, by fitting the experimental data
collected by the E615 Collaboration at Fermilab. With the extracted Sudakov
factor, we calculate the normalized differential cross section with respect to
transverse momentum of the dimuon and compare it with the recent measurement by
the COMPASS Collaboration.Comment: 17 pages, 3 figure
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