[en] The magnitude of the EMC effect measured in electron deep inelastic scattering (DIS) is linearly related to the Short Range Correlation (SRC) scaling factor obtained from electron inclusive scattering. We speculate that the observed correlation is due to the fact that both the EMC effect and SRC are dominated by high momentum nucleons in the nucleus. The observed phenomenological relationship can be used to extract the ratio of the deuteron to the free pn-pair cross sections, the DIS cross section for a free neutron, View the MathML source, the ratio of the free neutron to free proton structure functions, and the u/d ratio in a free proton.

[en] The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars

[en] This Letter shows quantitatively that the magnitude of the EMC effect measured in electron deep inelastic scattering at intermediate x_B, 0.35≤x_B≤0.7, is linearly related to the short range correlation (SRC) scale factor obtained from electron inclusive scattering at x_B≥1. The observed phenomenological relationship is used to extract the ratio of the deuteron to the free pn pair cross sections and F₂ⁿ/F₂^p, the ratio of the free neutron to free proton structure functions. We speculate that the observed correlation is because both the EMC effect and SRC are dominated by the high virtuality (high momentum) nucleons in the nucleus.

[en] The magnitude of the EMC effect measured in electron deep inelastic scattering (DIS) is linearly related to the Short Range Correlation (SRC) scaling factor obtained from electron inclusive scattering. We speculate that the observed correlation is due to the fact that both the EMC effect and SRC are dominated by high momentum nucleons in the nucleus. The observed phenomenological relationship can be used to extract the ratio of the deuteron to the free pn-pair cross sections, the DIS cross section for a free neutron, F₂ⁿ/F₂^p, the ratio of the free neutron to free proton structure functions, and the u/d ratio in a free proton.

[en] High-precision measurements of the proton elastic form-factor ratio, μ_pG_E^p/G_M^p, have been made at four-momentum transfer, Q², values 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 G_E^p being smaller than expected

[en] We investigated simultaneously the ¹²C(e,e^'p) and ¹²C(e,e^'pp) reactions at Q²=2 (GeV/c)², x_B=1.2, and in an (e, e^'p) missing-momentum range from 300 to 600 MeV/c. At these kinematics, with a missing momentum greater than the Fermi momentum of nucleons in a nucleus and far from the delta excitation, short-range nucleon-nucleon correlations are predicted to dominate the reaction. For (9.5±2)% of the ¹²C(e,e^'p) events, a recoiling partner proton was observed back-to-back to the ¹²C(e,e^'p) missing-momentum vector, an experimental signature of correlations

[en] The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.

[en] The five-fold differential cross section for the ¹²C(e,e^′p)¹¹B reaction was determined over a missing momentum range of 200–400 MeV c⁻¹, in a kinematics regime with x_B>1 and Q²=2.0 (GeV c⁻¹)². A comparison of the results with previous lower missing momentum data and with theoretical models are presented. The extracted distorted momentum distribution is shown to be consistent with previous data and extends the range of available data up to 400 MeV c⁻¹. The theoretical calculations are from two very different approaches, one mean field and the other short range correlated; yet for this system the two approaches show striking agreement with the data and each other up to a missing momentum value of 325 MeV c⁻¹. For larger momenta, the calculations diverge which is likely due to the factorization approximation used in the short range approach. (paper)

[en] Nuclear transparency, T_p(A), is a measure of the average probability for a struck proton to escape the nucleus without significant re-interaction. Previously, nuclear transparencies were extracted for quasi-elastic A(e,e^′p) knockout of protons with momentum below the Fermi momentum, where the spectral functions are well known. In this Letter we extract a novel observable, the transparency ratio, T_p(A)/T_p(¹²C), for knockout of high-missing-momentum protons from the breakup of short-range correlated pairs (2N-SRC) in Al, Fe and Pb nuclei relative to C. The ratios were measured at momentum transfer Q²⩾1.5(GeV/c)² and x_B⩾1.2 where the reaction is expected to be dominated by electron scattering from 2N-SRC. The transparency ratios of the knocked-out protons coming from 2N-SRC breakup are 20–30% lower than those of previous results for low missing momentum. They agree with Glauber calculations and agree with renormalization of the previously published transparencies as proposed by recent theoretical investigations. The new transparencies scale as A^−1/3, which is consistent with dominance of scattering from nucleons at the nuclear surface