[en] High precision measurements of the proton elastic form factor ratio have been made at four-momentum transfers, Q², between 0.2 and 0.5 GeV². The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q² range the deviation from unity is primarily due to GEp being smaller than the dipole parameterization

[en] Measurements of particle emission, linear momentum transfer and angular momentum transfer have been used to explore reaction mechanisms in the intermediate energy range where qualitatively different nuclear processes may be observable. The current status of our understanding of heavy ion reaction mechanisms with projectiles having velocities comparable to the velocity of sound and the Fermi velocity is summarized. (orig.)

[en] The anomaly in the dynamics of the orbital vector l in superfluid ³He-A, which corresponds to the chiral anomaly and zero-charge effect in 3 + 1 quantum field theory (QFT) with chiral fermions, is considered in the presence of superflow. The hydrodynamic action which describes the dynamics of both the l vector and the superfluid velocity V_s field, is derived at T=0 in the collisionless limit using the fact that in the vicinity of the gap nodes the Bogoliubov quasiparticles behave as chiral relativistic fermions. While the quantity B=k_Fl plays the part of the vector potential of the effective electromagnetic field acting on the chiral fermions, the combination B₄=k_F(v_sl) corresponds to the scalar component of th electromagnetic field. As a result the v_s field contributes to the Wess-Zumino term in the action which is responsible for the chiral anomaly. In the collisionless limit the hydrodynamic momentum is conserved but is not well-defined because of the chiral anomaly: due to the flow of the quasiparticle energy levels through the gap nodes during the dynamics of l, the linear momentum of the liquid depends on the prehistory of the l field and therefore cannot be expressed in terms of the instantaneous values of l and v_s. In the opposite limit the quasiparticle scattering on the container wall becomes important. As a result the quasiparticles which fill the energy levels crossing the gap nodes are removed from the coherent motion of liquid and their linear momentum transfer to the walls at a rate dictated by the level flow process. In this limit the linear momentum is well defined in terms of l and v_s but is not conserved. This nonconservation of the hydrodynamic linear momentum is analogous to the nonconservation of the chiral charge in QFT with chiral anomaly. It leads to an additional force acting on the moving quantized vortices, which resembled the Iordanskii force. 10 refs

[en] The theory of acoustic excitation scattering in the surface of Brilloiun of opaque materials, is related to the question of momentum transfexed from radiation fields to the material when the incident eight is scattered in a measurable spectrum. (A.C.A.S.)

[en] The evolving way in which high-energy, small-momentum-transfer processes have been described over the past 30 years is briefly reviewed. (physics of our days)

[en] This conference report summarizes the contributions to, and discussions at, the 1st Asia-Pacific Transport Working Group Meeting held in Toki, Japan, on 14–17 June 2011. The topics of the meeting were organized under four main headings: momentum transport, non-locality in transport, edge turbulence and L–H transition and 3D effects on transport physics. The events which initiated this meeting are also described in this report. (conference report)

[en] Scattering probe particles from a quantum system can provide experimental access to information about the system’s state. However, measurement backaction and momentum transfer during scattering changes the state of the system, potentially destroying the state we wish to probe. Here we investigate how to probe the system’s initial state even in the presence of backaction and momentum transfer. We show that summing the scattering distributions of an ensemble of measurements reveals the initial state scattering pattern even when each of the individual measurements completely destroys the initial state. This procedure is effective provided the scattering takes place on a timescale that is short compared with the free evolution of the system. (paper)

[en] We have studied the pion form factor F_π(Q²) at large momentum transfers within the framework of the statistical model. Using the wave-function ψ(p) suggested from the model as an input, our computed results of F_π(Q²) foretell an exact zero at Q² = 3.3 GeV². Further, unlike other theoretical estimates, our computed results for the hard part of F_π(Q²) not only agree reasonably well with the corresponding experimental findings for large Q², i.e., for 4 ≤ Q² ≤ 20 in GeV² but its asymptotic fall with Q² compares favourably with the corresponding falling off of F_π exp (Q²). (orig.)

[en] Possible definitions for the relative momentum of identical particles are considered. (fast track communication)

[en] Using a simple model for nuclear GPDs, we study the role of the neutron contribution to nuclear DVCS observables. As an example, we use the beam-spin asymmetry A_LU^A measured in coherent and incoherent DVCS on a wide range of nuclear targets in the HERMES and JLab kinematics. We find that at small values of the momentum transfer t, A_LU^A is dominated by the coherent-enriched contribution, which enhances A_LU^A compared to the free proton asymmetry A_LU^p, A_LU^A(φ)/A_LU^p(φ)=1.8-2.2. At large values of t, the nuclear asymmetry is dominated by the incoherent contribution and A_LU^A/(φ)A_LU^p(φ)=0.66-0.74. The deviation of A_LU^A(φ)/A_LU^p(φ) from unity at large t is a result of the neutron contribution, which gives a possibility to constrain neutron GPDs in incoherent nuclear DVCS. A similar trend is expected for other DVCS asymmetries