92 research outputs found
The Sivers asymmetry in Drell–Yan production at the J /Ψ peak at COMPASS
The abundant production of lepton pairs via J/Ψ creation at COMPASS, π±p↑→J/ΨX→ℓ+ℓ−X, allows a measurement of the transverse single spin asymmetry, ANJ/Ψ, generated by the Sivers effect. The crucial issue of the sign change of the Sivers function in Drell–Yan lepton pair production, with respect to Semi Inclusive Deep Inelastic Scattering processes, can be addressed in a different context. Assuming that the Sivers asymmetry is related to a universal and intrinsic property of the proton, predictions for the expected magnitude of ANJ/Ψ, which turns out to be large, are given. A comparison with the suggested measurement of this single spin asymmetry – an important quantity by itself – should give valuable information
Challenges in the extraction of TMDs from SIDIS data: Perturbative vs non-perturbative aspects
Simultaneous extraction of transversity and Collins functions from new semi-inclusive deep inelastic scattering and e+e- data
Identifying the quark content of the isoscalar scalar mesons f_0(980), f_0(1370), and f_0(1500) from weak and electromagnetic processes
The assignments of the isoscalar scalar mesons f0(980), f0(1370), and
f0(1500) in terms of their qqbar substructure is still a matter of heated
dispute. Here we employ the weak and electromagnetic decays D(s)(+) to f0+pi(+)
and f0 two-photon decays, respectively, to identify the f0(980) and f0(1500) as
mostly ssbar, and the f0(1370) as dominantly nonstrange, in agreement with
previous work. The two-photon decays can be satisfactorily described with quark
as well as with meson loops, though the latter ones provide a less
model-dependent and more quantitative description.Comment: v1, 15 pages, plain LaTeX, 1 eps figure. v2, 18 pages, plain LaTeX
(figure included). More discussion, especially on the f0(1370) and its
empirical two-photon widt
Reassessment of the Collins mechanism for single-spin asymmetries and the behavior of Delta(d)(x) at large x
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