Extracting the kaon Collins function from ${e}^{+}{e}^{\ensuremath{-}}$ hadron pair production data

Extracting the kaon Collins function from $e^{+} e^{-}$ hadron pair production data

M. Anselmino, M. Boglione, U. D’Alesio, J. O. Gonzalez Hernandez, S. Melis, F. Murgia, and A. Prokudin

Phys. Rev. D 93, 034025 – Published 16 February 2016

Abstract

The latest data released by the BABAR Collaboration on azimuthal correlations measured for pion-kaon and kaon-kaon pairs produced in $e^{+} e^{-}$ annihilations allow, for the first time, a direct extraction of the kaon Collins functions. These functions are then used to compute the kaon Collins asymmetries in semi-inclusive deep inelastic scattering processes, which result in good agreement with the measurements performed by the HERMES and COMPASS collaborations.

Received 10 December 2015

DOI:https://doi.org/10.1103/PhysRevD.93.034025

Physics Subject Headings (PhySH)

Electron & positron scattering

Kaons Pions

Particles & Fields

Authors & Affiliations

M. Anselmino^1,2, M. Boglione^1,2, U. D’Alesio^3,4, J. O. Gonzalez Hernandez^1,2, S. Melis¹, F. Murgia⁴, and A. Prokudin⁵

¹Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, I-10125 Torino, Italy
²INFN, Sezione di Torino, Via P. Giuria 1, I-10125 Torino, Italy
³Dipartimento di Fisica, Università di Cagliari, I-09042 Monserrato, Cagliari, Italy
⁴INFN, Sezione di Cagliari, C.P. 170, I-09042 Monserrato, Cagliari, Italy
⁵Division of Science, Penn State Berks, Reading, Pennsylvania 19610, USA

Collins functions for pions from SIDIS and new $e^{+} e^{-}$ data: A first glance at their transverse momentum dependence

M. Anselmino, M. Boglione, U. D’Alesio, J. O. Gonzalez Hernandez, S. Melis, F. Murgia, and A. Prokudin

Phys. Rev. D 92, 114023 (2015)

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 93, Iss. 3 — 1 February 2016

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
The experimental data on the azimuthal correlations $A_{0}^{U C}$ and $A_{0}^{U L}$ as functions of $z_{1}$ and $z_{2}$ in unpolarized $e^{+} e^{-} \to π K X$ processes, as measured by the BABAR Collaboration, are compared to the curves obtained from our reference fit, given by the parameters shown in Eq. (26). The shaded area corresponds to the statistical uncertainty on these parameters.
Reuse & Permissions
Figure 2
The experimental data on the azimuthal correlations $A_{0}^{U C}$ and $A_{0}^{U L}$ as functions of $z_{1}$ and $z_{2}$ in unpolarized $e^{+} e^{-} \to K^{+} K^{-} X$ processes, as measured by the BABAR Collaboration, are compared to the curves obtained from our reference fit, given by the parameters shown in Eq. (26). The shaded area corresponds to the statistical uncertainty on these parameters.
Reuse & Permissions
Figure 3
The experimental data on the SIDIS azimuthal moment $A_{U T}^{\sin (ϕ_{h} + ϕ_{S})}$ as measured by the HERMES Collaboration [5] are compared with our computation of the same quantity. The solid (red) lines correspond to our reference fit, with the parameters given in Eq. (26). The shaded area corresponds to the statistical uncertainty on these parameters. For the transversity distributions we used the fixed parameters reported in Table 1.
Reuse & Permissions
Figure 4
The experimental data on the SIDIS Collins single spin asymmetry (SSA) $A_{U T}^{\sin (ϕ_{h} + ϕ_{S})}$ as measured by the COMPASS Collaboration on proton (upper panel) [8] and deuteron (lower panel) targets [7] are compared with our computation of the same quantity. The solid (red) lines correspond to our reference fit, with the parameters given in Eq. (26). The shaded area corresponds to the statistical uncertainty on these parameters. For the transversity distributions we used the fixed parameters reported in Table 1.
Reuse & Permissions
Figure 5
Correlation between the parameters: $N_{fav}^{light}$ and $N_{dis}$ (left panel) and $N_{fav}^{heavy}$ and $N_{dis}$ (right panel). Red points represent solutions with positive $N_{fav}^{heavy}$ , while blue points represent solutions with negative $N_{fav}^{heavy}$ . All points in the figure correspond to a total $χ^{2}$ included between $χ_{\min}^{2}$ and $χ_{\min}^{2} + Δ χ^{2}$ ; the spread of the points indicates the statistical error which affects the two parameters. Lighter (darker) shades of color represent higher (lower) values of $χ^{2}$ . The points in which $χ^{2} \equiv χ_{\min}^{2}$ are shown as green squares.
Reuse & Permissions
Figure 6
Plot of $z$ times the lowest $p_{⊥}$ -moment, Eqs. (27) and (28), of the $u^{↑} \to K^{+} X$ Collins function, as extracted in our reference fit [with the parameters of Eq. (26)]. The analogous plots for heavy-flavor favored and (all flavor) disfavored Collins functions are not shown; in fact, it is not possible to reliably distinguish between these two contributions to the available BABAR data. Furthermore, not even the sign of the heavy-flavor favored Collins function can be determined.
Reuse & Permissions

Physical Review D

covering particles, fields, gravitation, and cosmology

Extracting the kaon Collins function from $e^{+} e^{-}$ hadron pair production data

M. Anselmino, M. Boglione, U. D’Alesio, J. O. Gonzalez Hernandez, S. Melis, F. Murgia, and A. Prokudin

Phys. Rev. D 93, 034025 – Published 16 February 2016

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

See Also

Collins functions for pions from SIDIS and new $e^{+} e^{-}$ data: A first glance at their transverse momentum dependence

M. Anselmino, M. Boglione, U. D’Alesio, J. O. Gonzalez Hernandez, S. Melis, F. Murgia, and A. Prokudin

Phys. Rev. D 92, 114023 (2015)

Article Text (Subscription Required)

References (Subscription Required)

Issue

Access Options

Physical Review D

covering particles, fields, gravitation, and cosmology

Extracting the kaon Collins function from e+e− hadron pair production data

M. Anselmino, M. Boglione, U. D’Alesio, J. O. Gonzalez Hernandez, S. Melis, F. Murgia, and A. Prokudin

Phys. Rev. D 93, 034025 – Published 16 February 2016

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

See Also

Collins functions for pions from SIDIS and new e+e− data: A first glance at their transverse momentum dependence

M. Anselmino, M. Boglione, U. D’Alesio, J. O. Gonzalez Hernandez, S. Melis, F. Murgia, and A. Prokudin

Phys. Rev. D 92, 114023 (2015)

Article Text (Subscription Required)

References (Subscription Required)

Issue

Access Options

Authorization Required

Other Options

Download & Share

Images

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Log In

Search

Article Lookup

Paste a citation or DOI

Enter a citation

Extracting the kaon Collins function from $e^{+} e^{-}$ hadron pair production data

Collins functions for pions from SIDIS and new $e^{+} e^{-}$ data: A first glance at their transverse momentum dependence