Study of Deuteron-Deuteron Scattering at 65 MeV/nucleon Ahmad Ramazani-Moghaddam-Arani (KVI-Cracow-Katowice-IUCF) 19th International IUPAP Conference on Few-Body Problems in Physics University of Bonn / Germany University of Kashan Iran

Outline  Three-nucleon force  Why dd scattering  Experimental setup  Analysis of the break-up channel  Results  Summary

Motivation How big is the 3NF? Effective field theory, based on  PT (low- energy expansion in QCD): perturbative calculationsperturbative calculations of the interactions between nucleons with pions as exchange particles. 3N forces smaller than 2NF 4N forces even smaller than 3NF!! Prediction of 3NF: H. Primakoff et al., Phys. Rev. 55, 1218 (1939)  Sensetive observaables  High presition measurements

Motivation 3NF effect is not negligible, and is not completely understood yet! p + d p +d use the 4-nucleon system to study 3NF ! Large sensitivity to 3NP effects exists in the minimum of the differential cross section H. Witala et al., Phys. Rev. Lett. 81, 1183 (1998). S. Nemoto et al., Phys. Rev. C 58, 2599 (1998)

4N Calculation Status Phys. Rev. C 76, (R) (2007) Deuteron Energy : 3MeV Below Break-up Threshold

dd Elastic Scattering at 65 MeV/nucleon Calculation: Deltuva, Fonseca, et al. Note: lowest-order terms in Born series expansion of the AGS equations High energies Low momentum transfer

Experiment and reaction channels Big Instrument for Nuclear-polarization Analysis Beam: Polarized deuteron Target: Liquid deuterium for dd Target: solid CH 2 for dp Beam Energy: 65 MeV/nucleon

Event Selection

Spin Observables Pure Vector-polarization Pure tensor-polarization

Three-body Breakup Result Cross section = (Invariant matrix) 2 * (Phase space factor) 42 configurations 500 data points

Quasi-free dp elastic scattering in the three-body break-up reaction d + d  d + p + n d + p  d + p

Quasi-free dp elastic result Data from literature NN NN + TM’

Quasi-free dp elastic result dp elastic from literature NN NN + TM’ dp elastic, this work

Quasi-free dp elastic result dp elastic from literature NN NN + TM’ dp elastic, this work Quasi-free dp elastic, this work

Summary and Outlook A few final states of the dd scattering at 65 MeV/nucleon have been identified. Differential cross sections, vector and tensor analyzing powers for the elastic d+d channel have been measured. The three-body break-up in dd scattering has been measured in and almost background free experiment. The quasi-free part of the three-body break-up data in dd scattering can be directly compared with the results of the dp elastic scattering. Surprisingly, the T20 results of the quasi-free dp show a big discrepancy from the dp elastic scattering. KVI experiments will provide an extensive database in four-nucleon scattering at intermediate energies. Theoretical calculations for dd scattering at intermediate energies are called for.

Our Collaborators A. Ramazani-Moghaddam-Arani, H. R. Amir-Ahmadi, A. D. Bacher,Ramazani-Moghaddam-AraniH. R. Amir-AhmadiA. D. Bacher C. D. Bailey, A. Biegun, M. Eslami-Kalantari, I. Gašparić,C. D. BaileyA. BiegunM. Eslami-KalantariI. Gašparić L. Joulaeizadeh, N. Kalantar-Nayestanaki, St. Kistryn, A. Kozela,L. JoulaeizadehN. Kalantar-NayestanakiSt. KistrynA. Kozela H. Mardanpour, J. G. Messchendorp, A. M. Micherdzinska,H. MardanpourJ. G. MesschendorpA. M. Micherdzinska H. Moeini,V. Shende, E. Stephan, E. J. Stephenson, and R. SworstH. MoeiniV. ShendeE. StephanE. J. StephensonR. Sworst Thanks for your attention

dp Elastic Scattering Observables A. Ramazani-Moghaddam-Arani et al., Phys. Rev. C 78, (2008) H. Mardanpour et al., Eur. Phys. J. A 31, 383 (2007). E. J. Stephenson et al., Phys. Rev. C 60, (1999). H. Shimizu et al., Nucl. Phys. A 382, 242 (1982).

dd Elastic Scattering Observables Calculation: Deltuva, Fonseca, et al. Note: lowest- order terms in Born series expansion of the AGS equations

Three-body Breakup Result Cross section = (Invariant matrix) 2 * (Phase space factor)

Available data and theories Theoretical attempts  To solve the four-body system: 1) A. Deltuva et al., Phys. Rev. C 69, (2004). 2) M. Viviani et al., Phys. Rev. Lett. 86, 3739 (2001). 3) F. Ciesielski, J. Carbonell, and C. Gignoux, Phys. Lett. B447, 199 (1999).  Calculation of the cross section and spin observables for elastic dd scattering : 4) A.C. Fonseca, Nucl. Phys. A737, S103, (2004).

Summary and outlook Differential cross section, vector and tensor analyzing powers for elastic channel at forward scattering angles are measured. Reliability of the obtained data is based on the dp elastic scattering results and comparison of the BINA and BBS results. Three-body breakup channel in the dd scattering at 65 MeV/nucleon has been identified. The differential cross section for few configurations are measured for the first time at KVI and compared with the phase space result. Outlook Measurement of the cross section and analyzing powers for more configurations. KVI experiments will providing a systematic database, which will be used to test the present and upcoming theoretical calculations. Theoretical calculations for dd scattering is called for!

Available data and theories A. M. Micherdzinske et al, Phys. Rev. C 75, (2007) Deviation of the data from theory calls for a systematic measurement of the cross sections and analyzing powers

Motivation π0π0 The observation demonstrates that CS is broken is odd under CS ? d d 4 He Observation provides access to the quark-mass difference m u -m d The results rely on a precise knowledge of the four-nucleon dynamics, in particular the initial-state interaction. (E. Stephenson et al. Phys. Rev. Lett. 91 (2003) )

Event Selection d + d d + p + n D

Three-body Break-up Channel d + d d + p + n E- DeltaE TOF

Elastic Channel Identification

Three-body Breakup Result

Motivation Effectieve Field Theorie, based on  PT (low-energy expansion in QCD): perturbative calculationsperturbative calculations of the interactions between nucleons with pions as exchange particles. 4N forces even smaller than 3NF!! … use the 4-nucleon system to study 3NF ! Unexplored territory at intermediate energies !!!

Nucleon-Nucleon Interaction The traditional goal of nuclear physics : Understanding the properties of atomic nuclei in terms of the 'bare' interaction between pairs of nucleons, or nucleon-nucleon forces. How to study the NN forces: 1- Attributing a potential to the nucleons and solving the Schrödinger equation. 2- Performing scattering experiments. 3-Determination of the potential parameters by fitting to the experimental data. Ultimate goal of the nuclear physics: describing all nuclear interactions from the basic interactions between nucleons. This is called the microscopic or ab initio approach of nuclear physics. The modern NNPs reproduce the world data base with a reduced chi-square close to one and have, therefore, been accepted as high-quality benchmark potentials.

Three-body Breakup Result dp elastic from literature NN NN + TM’ dp elastic, this work Quasi-free dp elastic, this work