[Clascomment] OPT-IN: Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with Longitudinally Polarized Target

[Keith Griffioen]

Nice paper!  Please find below some suggested editorial changes that might improve the readability of the paper.  Thanks.

abstract, L7: \"over a wide kinematic range\"
p1c1p1l1:       \"A measurement of the transverse momenta...\"
p1c1p2l3:       \"to the transverse...\"
p1c2p1l1:       \"For a longitudinally polarized target, first discussed...
                the only SSA in leading order that depends on the
                azimuthal angle phi between the lepton...planes is the
                sin2phi moment.\"
line 4:         \"This moment is a convolution of the Ralston...
                into unpolarized hadrons, in which $x$ is the
                Bjorken scaling variable and $z$ is the fraction of the
                virtual photon energy carried by the final-state hadron.\"

line 15:        \"of the hadron in leading order is...\"
line 16:        [There\'s a problem here with P_T and p_T.  Unless you
                really mean something different, use on or the other
                consistently.]
p1c2p2l5:       \"performed in the perturbative limit for h_1L...performed
                on the lattice.\"
line 10:        \"accessible in double-polarized Drell-Yan production,
                where it gives rise...\"
p1c2p3l1:       \"The sin\\phi moment...target is dominated by higher-twist
                contributions which are suppressed by 1/Q at large
                momentum transfer.  This moment has been measured...\"
line 8:         \"understanding long-range quark-gluon...\"
line 8:         \"in terms of an average transverse force...\"
p1c2p4l1:       \"Although both sin\\phi...\"
p2c1p1l3:       \"provides a cleaner measurement of Collins fragmentation
                because it doesn not have a...\"
p2c1p2l10:      \"using an incident beam of 5 nA with... and an average beam
                polarization...\"
line12:         \"detector package [33] provided a clean identification...\"
line24:         \"and on the pion fractional energy (z<0.7)...\" [you\'ve
                defined z earlier]
line29:         pions coming from $\\rho^0$...\"
p2c1p3l4:       \"and N+_ are luminosity-weighted counts...\"
FIG1:           \"to the HERMES measurement...\"
p2c2p2l4:       \"with the HERMES semi-inclusive...\"
line 7:         \"The measured asymmetries...leading-order...and a
                simple parametrization...\"
p2c2p4l1:       \"A_1 is shown in Fig. 2 as a function of p_T, integrated
                over all x (0.12-0.48) for Q^2...\"
line 4:         \"Although these plots are...\"
p3c1p1l1:       \"group, which uses different values of the ratio of k_T
                widths for g_1 and f_1, assuming Gaussian k_T distributions
                with no flavor dependence.\"
FIG 2.          \"as a function of transverse momentum p_T, averaged over
                0.4<z<0.7.  The open band...
p3c1p2l4:       \"for an unpolarized beam...\"
line 5:         \"unpolarized beam (U),
                        [...Eq. (3) here]
                is measured from data by counting in...\"
p3c1p3l2:       \"involves sorting A_UL in bins of \\phi...\"
line 8:         [I\'m confused.  The unpolarized cross section can
                have a cos\\phi dependence, even if CLAS had perfect
                acceptance, right?]
Fig 3:          \"of the target single spin asymmetry A_UL for pions
                integraded over the full kinematics.
                \"lines for \\pi^+ show separately the contributions from
                sin\\phi...moments, whereas the solid line shows the sum.

p3c2p1l1:       \"The dependence of the target single spin asymmetry on
                \\phi...\"
line 3:         \"We observe a relatively small sin2\\phi term for \\pi^0...\"
p3c2p2l2:       \"Calculations [24,29] using...
                soliton model [44], the Collins function...
                Belle [43[ data are plotted...\"
p4c1p2l6:       \"indicate the possibility of different average transverse
                momenta...\"