1 / 19

Double spin azimuthal asymmetries A LT and A LL in semi-inclusive DIS

Double spin azimuthal asymmetries A LT and A LL in semi-inclusive DIS. Introduction Positivity bounds for TMD DFs Status of Lorentz Invariance relations Predictions for azimuthal and p hT - dependence of A LT Predictions for azimuthal and p hT - dependence of A LL Conclusions.

nay
Download Presentation

Double spin azimuthal asymmetries A LT and A LL in semi-inclusive DIS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Double spin azimuthal asymmetries ALT and ALL in semi-inclusive DIS • Introduction • Positivity bounds for TMD DFs • Status of Lorentz Invariance relations • Predictions for azimuthal and phT- dependence of ALT • Predictions for azimuthal and phT- dependence of ALL • Conclusions Aram Kotzinian YerPhI, Armeniaand JINR, Russia and INFN, Torino In collaboration with B. Parsamyan, & A. Prokudin, hep-ph/0603194; Phys.Rev. D73 (2006) M. Anselmino, A. Efremov & B. Parsamyan, hep-ph/0608048, submitted to PRD AramKotzinian

  2. TMD quark DFs of Nucleon Twist-two: 6 T-even & 2 T-odd At twist-three: 8 T-even & 8 T-odd AramKotzinian

  3. Generalized positivity bounds Sivers function Naïve bound was used during fitting of Sivers DF: For d-quark this bound is reached at for the best fit parameters. But error bars of extracted parameters are large enough and allow to fulfill the general positivity bound. AramKotzinian

  4. 2001: explicit model calculations of DFs by Kundu & Metzshow that these relations are violated 2003: Goeke, Metz, Pobylitsa & Polyakov demonstrated that the same Wilson link in the definition of DFs which makes possible the existence of nonzero Sivers effect leads to violation of LI relations among DFs. Without Wilson link Sivers effect = 0. If observed by HERMES asymmetry is due to Sivers effect then LI relations can be strongly violated is g1T smaller or larger than proposed by LI relation? Status of Lorentz invariance (LI) relations Relations between kT-integrated twist-3 and twist-2 PDFs AramKotzinian

  5. SIDIS and TMD DF AramKotzinian

  6. Double Spin Asymmetry First estimations by A.K. & P.Mulders, PRD 54, 1229 (1996) Weighted asymmetry is related to the first kT-momentum of g1T: There exists a relation between first momentum of g1T and g2 (follows from Lorentz invariance, Tangerman & Mulders) : All ingredients (DFs & FFs) are known! AramKotzinian

  7. CUTS High x, y, z & pT Low x, y, z & pT + ATMD= Low x, y, z & pT High x, y, z & pT + AramKotzinian

  8. PT-weighted asymmetries AramKotzinian

  9. Factorized Gaussian parameterization From analysis of unpolarized PhT dependence andCahn effect Allμ are constant independent of flavor, x and z AramKotzinian

  10. Transverse momentum dependence (Proton) Deuteron Proton AramKotzinian

  11. Orbital momentum and g1L Model by Brodsky, Hwang, Ma & Schmidt, NPB 593 (2001) 311 AramKotzinian

  12. PT-dependence of ALL With factorized Gaussianparameterization of DFs and FFs we have simple expressions AramKotzinian

  13. Predicted PT-dependence of ALL Deuteron Proton AramKotzinian

  14. x l’ l S ST γ* z Azimuthal dependence of ALL In O(1/Q) approximation we have kinematical (Cahn) corrections and contribution from transverse component of target polarization AramKotzinian

  15. Cahn effect in ALL 1/Q kinematical correction:azimuthal modulation of lepton-quark non-coplanar hard scattering cross-section in presence of nonzero transverse momentum of quark in nucleon AramKotzinian

  16. cosφh-weighted ALL AramKotzinian

  17. Results PT-dependence Deuteron Influence of ΔσLT is negligible Proton AramKotzinian

  18. Results x,y,z-dependence at COMPASS AramKotzinian

  19. Conclusions • To check the self-consistency of LO QCD picture of polarized SIDIS with TMD DFs & FFs it is important • to measure at different energies the azimuthal and PhT dependence of • unpolarized SIDIS • ALL & ALT • These and also Sivers asymmetry measurements will allow • to check the Lorentz invariance relations • to perform a “global” analysis and extract the parameters describing g1T, g1L and Sivers function taking into account the positivity bounds for TMF DFs. • Data are already available at COMPASS, HERMES & JLab ! AramKotzinian

More Related