Update to Proposal E12-06-105 Inclusive Scattering from Nuclei at x > 1 in the quasielastic and deeply inelastic regimes

E12-06-105 was approved to make measurements of inclusive scattering from nuclei at x > 1. There are two separate motivations for these measurements, corresponding to two different kinematic regions. Data at moderate Q but very large x (x > 1.3 -1.5) are dominated by quasielastic scattering from extremely high momentum nucleons, and is sensitive to the high-momentum tail of the nucleon distribution in nuclei. The distribution of high momentum nucleons is related to the short range structure and nucleon–nucleon correlations in nuclei. Data at much larger Q for 1 < ∼ x < ∼ 1.5 are dominated by DIS scattering from the x > ∼ 1 part of the nuclear parton distributions, and can be used to probe the distribution of these exceptionally high momentum quarks. The distribution of these “super-fast quarks” in nuclei is sensitive to short range structure in nuclei, including the possible contribution of non-hadronic components, such as six-quark bags. This document provides a brief update to and a summary of the original proposal for E12-06105 [1]. The scientific case for E12-06-105 has been strengthened by our ongoing analysis of E02-019. There we clearly see the indications of a transition from kinematics that dominated by quasielastic scattering to those dominated by deep inelastic scattering, strongly supporting the idea that the 11 GeV measurement will be able to provide a clean extraction of the nuclear pdfs at x > 1. In addition, the results from E03-013, which suggest that the size of the EMC effect is strongly correlated with the local nuclear density, led us to include additional light targets (Li, B) to the runplan for the study of short-range correlations, which are a direct measure of the amount of short distance, twonucleon interaction. Finally, the results of E02-019 demonstrated that short cryotargets complicate the subtraction of the end-cap contributions, and so we will use 8 cm cells rather than the 4 cm cells from the original proposal and take additional time for the x ≈ 3(4) settings for He and He. This additional running time, along with the time required for the additional light nuclei, is very close to the time saved by using the longer He cells for the remaining kinematics, and thus does not impact our beam time request.