Quark Distributions Nuclear Effect in the K-factor non-constancy

1. Quark Distributions Nuclear Effect in the K-factor non-constancy Zhao-yu Hou Shijiazhuang Railway College Gui Lin 2006. 10. 31

2. Abstract Considering K-factor non-constancy, we can establish mathematical plan to solve valence quark distributions and sea quark distributions nuclear effects functions and from experiments data of high energy h -A Drell-Yan process and the high energy l -A deep inelastic scattering process.

3. outline • Introduction • The Nucleon Structure Function Ratio in DIS • Drell-Yan Cross Section Ratio • Affection of QCD Non-Perturbation Effect to the Quark Discussion • Nuclear Binding Energy Effect to the Quark Discussion • Result and Discussion

4. 1. Introduction • In the wake of the development of quark-parton model study, Drell-Yan process, like DIS, has been profoundly used to investigate nucleon structure and certain important nuclear features such as quark distributions. • Especially our effort shonld be aimed at to extracting nuclear effect from available data of experimental information.

5. The first explained high energy h and nucleon A collision process within the framework of the quark-parton model

6. 2. The Nucleon Structure Function Ratio in DIS

7. In the above equation, the F is the deuteron structure function. Usually, the ratio

8. of the DIS data for C/D, Ca/D and Fe/D

9. 3. Drell-Yan Cross Section Ratio

11. After some parameterization disposal, the integral cross-section ratios of p -A and p -D in Drell-Yan collision process is defined as

12. of the Drell-Yan data for C/2H, Ca/2H and Fe/2H

15. Result

16. 4. Affection of QCD Non-Perturbation Effect to the Quark Discussion

18. 4.Affection of QCD Non-Perturbation Effect to the Quark Discussion

19. 5. Nuclear Binding Energy Effect to the Quark Discussion [1] P. Vogel, Nucl. Phys., 2000, A662: 148. [2] Hiroyuki Koura, Masahiro Uno, Takahiro Tachibana, Masami Yamada, Nucl. Phys., 2000, A674: 47.

20. Nuclear Binding Energy Effect to the ValenceQuark Discussion

22. Nuclear Binding Energy Effect to the Sea Quark Discussion

24. 6. Result and Discussion • Numerical results of Rv (x₂) have been obtained as shown in Fig. From Fig. it appears to show that the nuclear effect of value quark distribution and that of sea quark are quite different. In the whole calculation region, Rs(x₂) decreases as x₂ increases. At the position x₂=0.05 the value of Rv (x₂) is very large , that is, valence quark distribution in the bound nucleon of nucleus is much greater than that for the case of free nucleon. With the increase of x₂, and untill x₂=0.3, Rv (x₂) approaches to 1, namely, the valence quark distribution in the bound nucleon of nucleus changes into the same as in free nucleon.

25. As for Rs (x₂) it is always less than 1 when x₂≤0.3 and approaches to zero at the position x₂=0.05, that is, in the region x₂≤0.3, the sea quark distributions in bound nucleon of nucleus are always below the sea quark distribution in free nucleon. The variation of Rv (x₂) for the three nuclei is that Fe>Ca>C, which shows that quark distribution induced nuclear effect in C, Ca and Fe are slightly different.

26. About K-Factor’s Non-Constancy

27. About K-Factor’s Non-Constancy

28. About K-Factor’s Non-Constancy • [1] W. Zhu, L. Qian,J. G. Shen. Phys. Rev., 1991, D44: 2762. • [2] Liu Chun-Xiu, He Zhen-Min, Duan Chun-Gui and Peng HongAn, High Energy Physics and Nuclear Physics, 2000, 24: 131. • [3] Hou Zhao-Yu, Zheng Qiao, Duan Chun-Gui, Zhang Ben-Ai, Commun. Theor. Phys., 2000, 34: 377. • [4] Hou Zhao-Yu, Zheng Qiao, Zhang Ben-Ai, Chin. Phys. Lett.,2002, 19: 488. • [5] Hou Zhao-Yu, Zheng Qiao, Zhang Ben-Ai, High Energy Physics and Nuclear Physics, 2002, 26: 364. • [6] Hou Zhao-Yu, Zhi Hai-Su, Commun. Theor. Phys., 2006, 45: 517-520.

29. Thanks!