Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta

We have measured the 4He(e,e'p)3H reaction at missing momenta of 130-300 MeV/c using the three-spectrometer facility at the Mainz microtron MAMI. Data were taken in perpendicular kinematics to allow us to determine the response function Rlt and the asymmetry term Atl. The data are compared to both relativistic and non-relativistic calculations.

We present updated calculations for observables in the processes $^3$He($e,e^\prime p$)$^2$H, $^4$He($e,e^\prime p$)$^3$H, and $^4$He($\vec{e},e^\prime \vec{p}\,$)$^3$H. This update entails the implementation of improved nucleon-nucleon ($NN$) amplitudes to describe final state interactions (FSI) within a Glauber approximation and includes full spin-isospin dependence in the profile operator. In addition, an optical potential, which has also been updated since previous work, ...

We have measured the 3He(e,e'pp)n reaction at 2.2 GeV over a wide kinematic range. The kinetic energy distribution for `fast' nucleons (p > 250 MeV/c) peaks where two nucleons each have 20% or less, and the third nucleon has most of the transferred energy. These fast pp and pn pairs are back-to-back with little momentum along the three-momentum transfer, indicating that they are spectators. Experimental and theoretical evidence indicates that we have measured distorted two-nu...

The d(e,e'p) cross section at a momentum transfer of 3.5 (GeV/c)^2 was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle theta_nq and to extract missing momentum distributions for fixed values of theta_nq up to 0.55 GeV/c. In the region of 35 (deg) <= theta_nq <= 45 (deg) recent calculations, which predict that final state interactions are small, agree reasonably well wit...

The differential and total cross sections for the d+p->3He+eta reaction have been measured in a high precision high statistics COSY-ANKE experiment near threshold using a continuous beam energy ramp up to an excess energy Q of 11.3 MeV with essentially 100% acceptance. The kinematics allowed the mean value of Q to be determined to about 9 keV. Evidence is found for the effects of higher partial waves for Q>4 MeV. The very rapid rise of the total cross section to its maximum v...

We report new measurements of the total cross section for the 3H(p,n)3He reaction from threshold (Ep=1.02 MeV) to Ep=4.5 MeV. The experiment utilized specially prepared Ti-3H targets, and neutrons were detected using a 4-pi detector. A weak resonant structure due to an excited state in 4He is observed which was not seen in previous cross section measurements. A new expression for the 3He(n,p)3H thermonuclear reaction rate for temperatures below 10 GK is presented which will a...

Measurements of the differential and total cross sections for the $p d \to ^3$He $\eta$ reaction at five energies were recently reported [Phys. Rev. C {\bf 75}, 014004 (2007)] and comparisons with theoretical models were made. We point out that these comparisons involved a model based on ad hoc assumptions and hence the conclusions regarding the reaction mechanism as well as the role of the higher partial waves drawn in the above work are misleading. Revised conclusions bas...

The differential and total cross-sections for the dp \to 3He \eta reaction have been measured in a high precision high statistics COSY-ANKE experiment near threshold using a continuous beam energy ramp up to an excess energy Q of 11.3 MeV with essentially 100% acceptance. The kinematics allowed the mean value of Q to be determined to about 9 keV. Evidence is found for the effects of higher partial waves for Q > 4 MeV. The very rapid rise of the total cross-section to its maxi...

We have measured the $^3$He(e,e$'$pp)n{} reaction in the Jefferson Lab CLAS with 2.2 and 4.4 GeV electrons. We looked at the energy distribution of events with all three nucleons at high momentum (p > 250 MeV/c). This distribution has peaks where two nucleons each have 20% or less of the energy transfer (ie: the third or `leading' nucleon carries most of the kinetic energy). The angular distribution of these two `fast' nucleons shows a very large back-to-back peak, indicating...

The cross-sections and analyzing powers for $(p,n)$ reactions on ${}^{3}{\rm He}$ and ${}^{4}{\rm He}$ have been measured at a bombarding energy of $T_p$ = 346 MeV and reaction angles of $\theta_{\rm lab}$ = $9.4^{\circ}$--$27^{\circ}$. The energy transfer spectra for ${}^{3}{\rm He}(p,n)$ at large $\theta_{\rm lab}$ ($\ge$ $16^{\circ}$) are dominated by quasielastic contributions, and can be reasonably reproduced by plane-wave impulse approximation (PWIA) calculations for ...