arXiv subjects
Publications and source records attributed to N. Ya. Ivanov.
We review the properties of the single spin asymmetry (SSA) in heavy quark production by linearly polarized photons and analyze the possibility to measure this SSA in the planned E160/E161 experiments at SLAC.
We present the threshold resummation for the single spin asymmetry in heavy flavor production by linearly polarized photons. We analyze the soft-gluon contributions to the asymmetry at fixed order in $α_s$ to the next-to-leading logarithmic accuracy. Our analysis shows that, contrary to the production cross section, the azimuthal asymmetry is practically insensitive to soft radiation. Our calculations of the asymmetry up to the 6th order in $α_s$ lead only to small corrections (of order of few percent) to the Born predictions at energies of the fixed target experiments. Fast convergence of the perturbative series for the azimuthal asymmetry is due to the factorization properties of the photon-hadron cross section. We conclude that measurements of the single spin asymmetry would provide an excellent test of pQCD applicability to heavy flavor production.
We analyze in the framework of pQCD the properties of the single spin asymmetry in heavy flavor production by linearly polarized photons. At leading order, the parallel- perpendicular asymmetry in azimuthal distributions of both charm and bottom quark is predicted to be about 20% in a wide region of initial energy. Using the soft gluon resummation formalism, we have calculated the next-to-leading order corrections to the asymmetry to next-to-leading logarithmic accuracy. It is shown that radiative corrections practically do not affect the Born predictions for the azimuthal asymmetry at energies of the fixed target experiments. Both leading and next-to-leading order predictions for the asymmetry are insensitive to within few percent to theoretical uncertainties in the QCD input parameters: $m_{Q}$, $μ_{R}$, $μ_{F}$, $Λ_{QCD}$ and in the gluon distribution function. Our analysis shows that nonperturbative corrections to a $B$-meson azimuthal asymmetry due to the gluon transverse motion in the target are negligible. We conclude that measurements of the single spin asymmetry would provide a good test of pQCD applicability to heavy flavor production at fixed target energies.
We analyze in the framework of pQCD the properties of the single spin asymmetry in heavy flavor production by linearly polarized photons. At leading order, the parallel- perpendicular asymmetry in azimuthal distributions of both charm and bottom quark is predicted to be about 20% in a wide region of initial energy. Our analysis shows that the next-to-leading order corrections practically do not affect the Born predictions for the azimuthal asymmetry at energies of the fixed target experiments. Both leading and next-to-leading order predictions for the asymmetry are insensitive to within few percent to theoretical uncertainties in the QCD input parameters: $m_{Q}$, $μ_{R}$, $μ_{F}$, $Λ_{QCD}$ and in the gluon distribution function. We estimate also nonperturbative contributions to azimuthal distributions due to the gluon transverse motion in the target and the final quark fragmentation. Our calculations show that nonperturbative corrections to a $B$-meson azimuthal asymmetry are negligible. We conclude that measurements of the single spin asymmetry would provide a good test of pQCD applicability to heavy flavor production at fixed target energies.