1. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh). 1 Nuclear Force Spin dependent  difference in neutron scattering cross sections of ortho- and para-hydrogen. Compare n-p to n-n and p-p  Charge independence of nuclear force.

2. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh). 2 Nuclear Force Mirror Nuclei

3. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh). 3 If two charges, q and q' exchange photons, the Coulomb force occurs between them. If pions are exchanged between two nucleons, the strong nuclear force occurs. Remember the weak nuclear force… Just for comparison. What about forces between quarks? Color? Krane 4.5 Boson? Nuclear Force

4. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh). 4 Nuclear Force

5. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh). 5 Only Hadrons. Typical time: 10 -24 s. (c, 10 -15 m). Exchange of light  140 MeV pions.  t = ħ/  E = 4.7 x 10 -24 s. (Why  E?). Range   t c = ħ/mc = 1.4 x 10 -15 m. Range and time complicated by possibilities of heavier hadron exchange. Isospin. Conservation of Isospin. Only relevant to hadrons. Hadron multiplets: Doublet of nucleons and triplet of pions and … The members of a multiplet have the same strangeness, hypercharge, spin, etc …, but differ in charge and differ slightly in mass. Relationship between particle and nuclear physics. Accelerators and large accelerators.  Nuclear Force

6. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh). 6 Isospin Isospin Isospin Magnitude T 3 can take T, T-1, T-2, ….., -T. 1,2,3 not x,y,z (Isospin space). Singlets (T = 0), Doublets (T = ½), Triplet (T = 1), Quartet (??). -T 3 for antiparticles. Isospin addition: for a collection of hadrons (e.g. in interaction) Example:  + -p scattering, T max = 3 / 2, T 3 = 3 / 2  T can only be 3 / 2. Read Krane 11.3.

7. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh). 7 The Deuteron

8. Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 8 The Deuteron Deuterium (atom). The only bound state of two nucleons  simplest bound state. Neither di-proton nor di-neutron are stable. Why? Experimentally  2.224 MeV (Recoil..!). Also inverse ( ,n) reaction using Bremsstrahlung (Recoil…!). Mass spectroscopy  mass of D (or deuterium atom).  mc 2 = 2.224…??…MeV  Very weakly bound. Mass doublet method  all results are in agreement. Compare 2.224 MeV to 8 MeV (average B/A for nuclei). Only ground state. (There is an additional virtual state). HW 18 Problems 4.1 - 4.5 in Krane.

9. Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 9 The Deuteron V(r) = -V 0 r < R = 0r > R Oversimplified. HW 19 Assuming l = 0, show that V 0  35 MeV. (Follow Krane Ch.4 and Problem 4.6), or similarly any other reference. Really weakly bound. What if the force were a bit weaker…? Yukawa?

10. Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 10 The Deuteron

11. Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 11 The Deuteron Experiment  deuteron is in triplet state   = 1. Experiment  even parity.  = l + s n + s p parity = (-1) l Adding spins of proton and neutron gives: s = 0 (antiparallel) or s = 1 (parallel). For  = 1 parallels-stateeven parallelp-stateodd antiparallelp-stateodd paralleld-stateeven

12. Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 12 Experiment   = 0.8574376  N  spins are aligned…..But.? Direct addition  0.8798038  N. Direct addition of spin components assumes s-state (no orbital component). Discrepancy  d-state admixture.  = a 0  0 + a 2  2  = a 0 2  0 + a 2 2  2 HW 20 In solving HW 19 you assumed an s-state. How good was that assumption? The Deuteron

13. Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 13 The Deuteron S-state  No quadrupole moment. Experiment  +0.00288 b. HW 21 Discuss this discrepancy. From  and Q, is it really admixture? What about other effects? Important to know the d-state wavefunction.

14. Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 14 Nuclear Force Read Secs. 4.4 and 4.5 in Krane.