Comparative study of the specific charge hadron in electron SIDIS off proton and deuteron

1. Comparative study of the specific charge hadron in electron SIDIS off proton and deuteron Ben-Hao Sa China Institute of Atomic Energy Central China normal University

2. It was done in collaboration with CCNU: Dai-Mei Zhou Yun Cheng Xu Cai CIAE: Yu-Ling Yan Xing-Long Li Xiao-Mei Li Bao-Guo Dong benefit

3. Contents • Introduction • Brief description for PACIAE • Results • Conclusion

4. Introduction

5. Sketch oflowest order(Born approximation) e-p deep inelastic scattering (DIS) q2 = -Q2 q2 = -Q2 h h NC CC

6. IDIS (inclusive deep inelastic scattering) in which all accessible states X & h, all possible outgoing momenta, are included. Remainder is only the scattered electron SIDIS (semi-inclusive deep inelastic scattering) is the same as DIS but includes a specific type of hadron in addition

7. IDIS: an impotent & hot frontier in between particle & nuclear physics since eightieth of last century. It plays a crucial role in the field of • Confinement of quark and gluon in hadron, such as PDF, FF, & extractions, as well as searching for Higgs boson, SUSY, etc. • Hadronization processes space & time evolutions, energy loss, etc. • eRHIC (e-p,CM energy 45 – 175 GeV), LHeC (e-p, CM energy more than 1 TeV), and EIC We, extend PACIAE for l-p and l-A, Confront nDIS era

8. Second order e-p DIS Feynman diagram

9. Complete e-pNC differentia cross sectionmay be factorizedas : QED radiative correction : weak radiative correction (similar for CC)

10. Two independent variables: in the past: (E', ) presently: (xB ,Q2); or (xB ,W2); or (xB ,y)

11. HERMES e- SIDIS off p & D experiments HERRMES -> specific charged hadron yield of pi+,pi-,K+,K- in DISis crucial for reliable extraction of FF withdistinguished from HERMES corrects measured yield of type h hadrons for: limitation in geometric acceptance radiative effect detector resolution Born-level yield is then resulted. Normalizing it by DIS yield (yield of scattered e-) they obtain

12. Polar angle for the normalized hadron yield as a function of z

13. Brief description for PACIAE

14. 1) Initiation • Nucleons in colliding nucleus, distributed according to Woods-Saxon distribution • Paticipant nucleons, to be inside OZ • Spectator nucleons, to be outside OZ but inside nucleus system • Projectile nucleons (in Lab. frame): px=py=0, pz=pbeam • Target nucleons (in Lab, frame) px=py=pz=0 • Decompose nucleus-nucleus colli. -> NN collisions according to straight-line trajectories & NN total x-section PYTHIA 6.4 vs. PACIAE2.0

15. Describe each NN collision by PYTHIA with string fragmentation switched-off & qq ( ) broken into q pair ( pair) • A partonic initial state is obtained after all NN collisions are exhausted

16. 2) Parton rescattering (PRS) • PRS is performed by MC method • 2->2 LO perturbative QCD x-section is used

17. 3) Hadronization Two options are provied for hadronization • Lund string fragmentation • Phenomenological coalescence model

18. 4) Hadron rescattering (HRS) • Usual two body collision model is used • Only some hadrons are considered & their anti-particles

19. Some specials • For p+p & p+A (A+p), OZ is not introduced • l+p & l+A are dealt like p+p & p+A,respectively • As l+p x-section is a few order of magnitude lower than p+p, incident lepton is probably only one colliding with nucleon when it passes through the target • Strike nucleon is the one with lowest approaching distance from incident lepton

21. Results

22. 1. Comparison with data and other theories

23. HLMC: composed of Lepto e-p event generator <-JETSET 7.4 & PYTHIA 5.7 Program for detector simulation Event reconstruction where thirteen parameters were tuned to the yield as function of z, pT, & \eta • LOQCD: in factorization theorem framework: PDF, hard scattering x-section, & FF

24. in quark parton model: hadron yield is a convolution of PDF & FF

26. 2. Effect of α and β

32. 3. Effect of PRS & HRS

34. 4. Effect of SQSF

37. Conclusions

38. Default PACIAE reproduced HERMES data nearly as well as HLMC where thirteen paramters were tuned • Normalized yield increases (decreases) with increasing α and β • Effect of PRS & HPS is visual, former>later, due to interacting volume & # of particles • Effect of SQSF is obvious. It is possible to improve the agreement between HERMES & PACIAE by adjusting SQSF • Effects are expected to be increased with increasing target size

39. Thank you very much

40. hadron,(Eh,pl,pt) selected in order of Eqs. 2,1,3,4,5,6,7,& 8 direction of virtual photon

41. III) HERMES results: 27.6 GeV e- beam on A z > 0.1 >4 GeV taken from Nucl. Phys. B780(2007)1

42. Theoretical models 1)Phenomenological models: Formation time/legth Absorption cross section NP, B291(1987)793; NP, B346(1990)1; Z. Phys. C56(1992)493; Eur. Phys. J. C44 (2005)219; hep-ph/0205123 arXiV:1310.5285

43. 2) QCD-inspired models: Partonic rescattering (energy loss) NP, B483(1997)291; NP, B484(1997)265; PRL 85(2000)3591; PRL 89(2002)162301; JHEP 0211(2002)44; NP, A720(2003)131; Eur. Phys. J. C30(2003)213; arXiV:09073534; NP, A761(2005)67; PR, C81(2010)024902 3) PYTHIA + BUU simulation Formation time/length Hadronic rescattering PR, C70(2004)054609; NP, A801(2008)68

44. 4) PACIAE Partonic initiation for eA collisions Praton rescattering hadronization hadron rescatering As both partonic and hadronic rescatterings are considered in PACIAE, experimental results may be better studied by PACIAE

45. Plan for studying A dependence of ratio • Comparing withHERMES data • Predecte for LHeC (60 or 140 e- beam energy) • Utilize <z>, <Q2>, … (cf. NP,B780(2007)1) & same experimental constraints (Lorentz invarience)

46. Sketch ofep deep inelastic scattering black box,hints for QCD processes: vacume excitation,parton shower, resattering,etc. h first (born) second X e(K’,E’ ) h (q, ) … X q=-Q2 + + e(K,E) p(p) ;… *

47. Exchange Z,W+,and W-,bosons either A sketch for an exposing ofblack box struck quark fragments