Inclusive and Exclusive Processes with a Leading Neutron in ep and pp collisions

Transcription

1 Inclusive and Exclusive Processes with a Leading Neutron in ep and pp collisions Victor P. Goncalves High and Medium Energy Group UFPel Brazil Based on PLB 572(2016) 76, PRD93 (2016) and PRD94 (2016) In collaboration with D. Spiering, B. Moreira, F. Navarra and F. Carvalho. Lund 01 Dec 2016

2 Motivation High precision data on leading neutrons produced in electron proton reaction at HERA at high energies became available.

3 Motivation High precision data on leading neutrons produced in electron proton reaction at HERA at high energies became available.

4 Motivation High precision data on leading neutrons produced in electron proton reaction at HERA at high energies became available. In spite of intense experimental and theoretical efforts (*), the Feynman momentum distribution of the leading neutrons remains without a satisfactory theoretical description. (*) D Alesio, Holtmann, Kaidalov, Khoze, Kopeliovich, Martin, Melnitchouk, Nikolaev, Pirner, Ryskin, Sczureck, Schäfer, Speth, Thomas,.

5 Motivation High precision data on leading neutrons produced in electron proton reaction at HERA at high energies became available. In spite of intense experimental and theoretical efforts, the Feynman momentum distribution of the leading neutrons remains without a satisfactory theoretical description. The interpretation of cosmic ray data depends on the accurate knowledge of the leading baryon momentum spectrum and its energy dependence.

6 Motivation

7 Motivation High precision data on leading neutrons produced in electron proton reaction at HERA at high energies became available. In spite of intense experimental and theoretical efforts, the Feynman momentum distribution of the leading neutrons remains without a satisfactory theoretical description. The interpretation of cosmic ray data depends on the accurate knowledge of the leading baryon momentum spectrum and its energy dependence. Leading neutron production at high energies probes the low x component of the target wave function, where nonlinear effects are expected to be present in the description of the QCD dynamics.

8 Motivation

9 Our goal Treat the inclusive and exclusive processes with a leading neutron in ep collision using the color dipole formalism (*). (*) Largely used to successfully describe the HERA data w/o a leading neutron.

10 Our goal Treat the inclusive and exclusive processes with a leading neutron in ep collision using the color dipole formalism. Describe the current high precision HERA data.

11 Our goal Treat the inclusive and exclusive processes with a leading neutron in ep collision using the color dipole formalism. Describe the current high precision HERA data. Estimate the impact of the nonlinear effects.

12 Our goal Treat the inclusive and exclusive processes with a leading neutron in ep collision using the color dipole formalism. Describe the current high precision HERA data. Estimate the impact of the nonlinear effects. Predict the magnitude of the cross sections for inclusive and exclusive processes with a leading neutron in future electron proton colliders and in exclusive processes at the LHC.

13 Leading Neutron Processes at HERA Inclusive process:

14 Leading Neutron Processes at HERA Inclusive process:

15 Leading Neutron Processes at HERA Inclusive process:

16 Leading Neutron Processes at HERA Inclusive process: Exclusive process:

17 Leading Neutron Processes at HERA Inclusive process: Exclusive process:

18 Leading Neutron Processes at HERA

19 Leading Neutron Processes at HERA Photon pion cross section at energy

20 Leading Neutron Processes at HERA Pion flux / Pion splitting function

21 Leading Neutron Processes at HERA Pion flux / Pion splitting function: Form factors: light cone reggeized pion monopole dipole

22 Leading Neutron Processes at HERA Theoretical and experimental analysis indicate that absorptive effects should be taken into account in order to describe the experimental data.

23 Leading Neutron Processes in the Color Dipole Formalism Inclusive processes:

24 Leading Neutron Processes in the Color Dipole Formalism Inclusive processes: Photon wave function: Dipole cross section:

25 Leading Neutron Processes in the Color Dipole Formalism Inclusive processes: Photon wave function: Dipole cross section:

26 Leading Neutron Processes in the Color Dipole Formalism Inclusive processes: Photon wave function: Dipole cross section:

27 Leading Neutron Processes in the Color Dipole Formalism Exclusive processes:

28 Leading Neutron Processes in the Color Dipole Formalism Exclusive processes: Scattering amplitude:

29 Leading Neutron Processes in the Color Dipole Formalism Exclusive processes: Scattering amplitude: Overlap functions for Vector Mesons:

30 Leading Neutron Processes in the Color Dipole Formalism Exclusive processes: Scattering amplitude: Overlap functions for Deeply Virtual Compton Scattering (DVCS):

31 Leading Neutron Processes in the Color Dipole Formalism Exclusive processes: Scattering amplitude: Overlap functions for Deeply Virtual Compton Scattering (DVCS):

32 Leading Neutron Processes in the Color Dipole Formalism Main assumption:

33 Leading Neutron Processes in the Color Dipole Formalism Main assumption: Constrained by HERA data for inclusive and exclusive processes (w/o a leading neutron)

34 Leading Neutron Processes in the Color Dipole Formalism Main assumption: With :

35 Leading Neutron Processes in the Color Dipole Formalism Main assumption: With : bcgc : Constrained by HERA data for inclusive and exclusive processes (w/o a leading neutron)

36 Leading Neutron Processes in the Color Dipole Formalism Main assumption: With : bcgc : Constrained by HERA data for inclusive and exclusive processes (w/o a leading neutron)

37 Leading Neutron Processes in the Color Dipole Formalism Dipole proton scattering amplitude: Golec- Biernat Wusthoff (GBW) : Iancu Itakura Munier Soyez (IIMS): Running coupling Balitsky- Kovchegov equation (rcbk)

38 Leading Neutron Processes in the Color Dipole Formalism Absorption effects:

39 Leading Neutron Processes in the Color Dipole Formalism Absorption effects:

40 Leading Neutron Processes in the Color Dipole Formalism Absorption effects:

41 Leading Neutron Processes in the Color Dipole Formalism Absorption effects: Open questions:

42 Leading Neutron Processes in the Color Dipole Formalism Absorption effects: Open questions:

43 Leading Neutron Processes in the Color Dipole Formalism Absorption effects: Open questions:

44 Leading Neutron Processes in the Color Dipole Formalism Absorption effects: Open questions:

45 Leading Neutron Processes in the Color Dipole Formalism Absorption effects: Open questions: Our assumption:

46 Leading Neutron Processes in the Color Dipole Formalism Absorption effects: Consequently :

47 Results for Inclusive Processes ;K=1

48 Results for Inclusive Processes n ;K=1

49 Results for Inclusive Processes Rq. K = 0.5

50 Results for Inclusive Processes Rq = 2/3; K = 1 Rq. K = 0.5 Rq = 1/3; K = 0.5

51 Results for Exclusive Processes Initially, we will assume that:

52 Results for Exclusive Processes Initially, we will assume that: Our strategy to constrain the K-factor: For a given model of the pion flux, Rq and dipole scattering amplitude, we estimate the total cross section. The value of K will be the value necessary to make our predictions consistent with the HERA data.

53 Results for Exclusive Processes Initially, we will assume that: Our strategy to constrain the K-factor: For a given model of the pion flux, Rq and dipole scattering amplitude, we estimate the total cross section. The value of K will be the value necessary to make our predictions consistent with the HERA data. Important to remember that:

54 Results for Exclusive Processes Dependence on the pion flux:

55 Results for Exclusive Processes Dependence on the dipole target amplitude: 55

56 Results for Exclusive Processes bcgc bcgc

57 Predictions for Exclusive Processes with a leading neutron at HERA

58 Future ep colliders Typical values of Bjorken-x probed in future ep colliders:

59 Future ep colliders Feynman scaling in inclusive processes: Linear X Nonlinear

60 Future ep colliders Dependence on the energy for exclusive processes:

61 Photon induced interactions at the LHC

62 Photon induced interactions at the LHC

63 Photon Induced Interactions: Motivation Photon induced interactions Centerat of the mass energies LHC

64 Photon induced interactions at the LHC

65 Diffractive vector meson photoproduction in UPHIC Probing the nuclear gluon distribution

66 Predictions for the LHC Vector Meson photoproduction with a leading neutron in UPHIC

67 Predictions for the LHC Vector Meson photoproduction with a leading neutron in UPHIC

68 Predictions for the LHC Vector Meson photoproduction with a leading neutron in UPHIC

69 Summary The color dipole formalism can be used to describe the inclusive and exclusive processes with a leading neutron at HERA. The nonlinear effects in the QCD dynamics implies Feynman scaling at large energies. Large cross sections for inclusive and exclusive processes with a leading neutron in future ep colliders. Next steps: D-meson production, dijet production, exclusive processes with a leading neutron in UPHIC,.

70 Summary The color dipole formalism can be used to describe the inclusive and exclusive processes with a leading neutron at HERA. The nonlinear effects in the QCD dynamics imply Feynman scaling at large energies. Large cross sections for inclusive and exclusive processes with a leading neutron in future ep colliders. Next steps: D-meson production, dijet production, exclusive processes with a leading neutron in UPHIC,.

71 Summary The color dipole formalism can be used to describe the inclusive and exclusive processes with a leading neutron at HERA. The nonlinear effects in the QCD dynamics imply Feynman scaling at large energies. Large cross sections for inclusive and exclusive processes with a leading neutron in future ep colliders and at the LHC. Next steps: D-meson production, dijet production, exclusive processes with a leading neutron in UPHIC,.

72 Summary The color dipole formalism can be used to describe the inclusive and exclusive processes with a leading neutron at HERA. The nonlinear effects in the QCD dynamics imply Feynman scaling at large energies. Large cross sections for inclusive and exclusive processes with a leading neutron in future ep colliders and at the LHC. Next steps: D-meson production, dijet production,.

73 Summary The color dipole formalism can be used to describe the inclusive and exclusive processes with a leading neutron at HERA. The nonlinear effects in the QCD dynamics imply Feynman scaling at large energies. Large cross sections for inclusive and exclusive processes with a leading neutron in future ep colliders and at the LHC. Next steps: D-meson production, dijet production,. Thank you for your attention!

74 Extras 74

75 Chiral perturbation theory Salamu, Ji, Melnitchouk, Wang, PRL (2015) Burkardt et al., PRD (2013)

76 Leading Neutron Processes at HERA Pion flux / Pion splitting function: 76

77 Dependence on the vector meson wave function 77

78 Parameter free prediction 78

79 Future ep colliders ependence on the photon virtuality for exclusive processes: 79