1 / 9

A. Molochkov Far Eastern National University

Sea-quark flavor asymmetry in the nucleon from a relativistic analysis of the Drell-Yan scattering off nuclei. A. Molochkov Far Eastern National University. Drell-Yan scattering. pp and pn Drell-Yan lepton pair production is sensitive to the anti-quark distribution in the nucleon

bryony
Télécharger la présentation

A. Molochkov Far Eastern National University

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. Sea-quark flavor asymmetry in the nucleon from a relativistic analysis of the Drell-Yan scattering off nuclei A. Molochkov Far Eastern National University Chiral 07, Osaka, November 12-16, 2007

  2. Drell-Yan scattering • pp and pn Drell-Yan lepton pair production is sensitive to the anti-quark distribution in the nucleon • The only source of information about the neutron is a nucleus. • The deuteron is a simplest nucleus. Neglecting nuclear effects in the deuteron we get: Chiral 07, Osaka, November 12-16, 2007

  3. Ratio of the cross-sections provide direct information on the flavor asymmetry of the light quarks in the nucleon assuming The ratio equals 1 in case of flavor symmetry of the quark sea Chiral 07, Osaka, November 12-16, 2007

  4. Results for the ratio show flavor asymmetry FNAL E866 data 2001 Can binding effects change the conclusion? Chiral 07, Osaka, November 12-16, 2007

  5. : Integration with respect the 2. Second order pole puts the struck nucleon on-shell, but produces additional corrections that originate from the dependence of the cross-section Covariant view on the binding effect in the Drell-Yan pair production The cross section for the pD scattering within the BS formalism: 1. First order pole gives IA with off-shell nucleon. Simple, but we have to account off-mass-shell nucleon structure change. Chiral 07, Osaka, November 12-16, 2007

  6. Result of the integration where the impulse approximation and the correction The variables are defined as The derivative comes form the energy dependence of the cross-section: It can produce deviations in the ratio Chiral 07, Osaka, November 12-16, 2007

  7. Result of the numerical calculations FNAL E866 data 2001 Input DY nucleon cross-sections are constructed from fGRV98 parameterization with The relativistic kinematics can reproduce the deviation without the flavor asymmetry of the nucleon sea Chiral 07, Osaka, November 12-16, 2007

  8. A-dependence of the ratio The A-dependence of the deviations is defined by the coefficient in front of the cross-section derivative • Same dependence as in case of nuclear DIS: • Three A-independent points where R=1 • The ratio scales as number of nucleons inside the nucleus NR interpretation: contribution of the surface nucleons to the second term is small A-dependence can clarify nature of the effect Chiral 07, Osaka, November 12-16, 2007

  9. Conclusions • Observed flavor asymmetry results from the relativistic kinematics of bound nucleons • The bound nucleons structure change have the same nature in the DIS and DY processes • A-dependence data is required • High x data is required Chiral 07, Osaka, November 12-16, 2007

More Related