Results of measurements of the analyzing powers for polarized neutrons on C, CH <inf>2</inf> and Cu targets for momenta between 3 and 4.2 GeV/c

The analyzing powers for neutron charge exchange nA → pX reactions on nuclei have been measured on C, CH2 and Cu targets at incident neutron momenta 3.0 - 4.2 GeV/c by detecting one charged particle in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from breakup of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic 2H(e, e'n) reaction, which yields information on the charge and magnetic elastic form factors of the neutron

Spectroscopic evidence of topological phase transition in the three dimensional Dirac semimetal Cd 3 As1 xPx 2

We study the low-energy electronic structure of three-dimensional Dirac semimetal, Cd-3(As1-xPx)(2 )x = 0 and 0.34(3)], by employing angle-resolved photoemission spectroscopy (ARPES). We observe that the bulk Dirac states in Cd-3(As0.66P0.34)(2) are gapped out with an energy of 0.23 eV, contrary to the parent Cd3As2 in which the gapless Dirac states have been observed. Thus, our results confirm the earlier predicted topological phase transition in Cd3As2 with perturbation. We further notice that the critical P substitution concentration, at which the two Dirac points that are spread along the c-axis in Cd3As2 form a single Dirac point at Gamma, is much lower x(c)(P) < 0.34(3)] than the predicted value of x(c) (P) = 0.9. Therefore, our results suggest that the nontrivial band topology of Cd3As2 is remarkably sensitive to the P substitution and can only survive over a narrow substitution range, i.e., 0 <= x(P) < 0.34(3)

Measurement of neutron and proton analyzing powers on CC, CHCH, CH2CH_2 and CuCu targets in the momentum region 3-4.2 GeV/c

International audienceThe analyzing powers for proton elastic scattering (\varvec{p} A\rightarrow pX) and neutron charge exchange (\varvec{n} A\rightarrow p X) reactions on nuclei have been measured on C, CH, $CH_2$ and Cu targets at incident neutron momenta 3.0–4.2 GeV/c by detecting one charged particle in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from break-up of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic ^2H(\varvec{e},e'\varvec{n}) reaction, which yields information on the charge and magnetic elastic form factors of the neutron