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The CNO cycle is the main energy source in massive stars during their hydrogen burning phase, and, for our sun, it contributes at the ≈1% level. As the ¹⁴N(p,γ)¹⁵O reaction is the slowest in the cycle, it determines the CNO energy production rate and thus the CNO contribution to the solar neutrino flux. These CNO neutrinos are produced primarily from the β decay of ¹⁵O and, to a lesser extent, from the decay of ¹³N. Solar CNO neutrinos are challenging to detect, but they can provide independent new information on the metallicity of the solar core. Recently, CNO neutrinos from ¹⁵O have been identified for the first time with the Borexino neutrino detector at the INFN Gran Sasso underground laboratory. There are, however, still some considerable uncertainties in the ¹⁴N(p,γ)¹⁵O reaction rate under solar temperature conditions. The low energy reaction data presented here, measured at the CASPAR underground accelerator, aim at connecting existing measurements at higher energies and attempts to shed light on the discrepancies between the various data sets, while moving towards a better understanding of the ¹⁴N(p,γ)¹⁵O reaction cross section. The present measurements span proton energies between 0.27 and 1.07 MeV, closing a critical gap in the existing data. A multichannel R-matrix analysis was performed with the entire new and existing data sets and is used to extrapolate the astrophysical S factors of the ground state and the 6.79 MeV transition to low energies. The extrapolations are found to be in agreement with previous work, but find that the discrepancies between measured data and R-matrix fits, both past and present, still exist. We examine the possible reasons for these discrepancies and thereby provide recommendations for future studies.

Background: A multitude of broad interfering resonances characterize the ¹⁰B(p,α)⁷Be cross section at low energies. The complexity of the reaction mechanism, as well as conflicting experimental measurements, have so far prevented a reliable prediction of the cross section over the energy ranges pertinent for a boron-proton fusion reactor environment. Purpose: To improve the evaluated cross section of the ¹⁰B(p,α)⁷Be reaction, this study targets the proton energy region from 0.8 to 2.0 MeV, where kinematic overlap of the scattered protons and reaction α particles have made past measurements very challenging. Method: New detailed studies of the reaction have been performed at the Edwards Accelerator Laboratory at Ohio University and the Nuclear Science Laboratory at the University of Notre Dame using time-of-flight and degrader foil techniques, respectively. Results: Proton and α-particle signals were clearly resolved using both techniques, and 16 point differential cross sections were measured over an angular range of θlab=45° and 157.5°. A comprehensive R-matrix analysis of the experimental data, including data from previous low-energy studies of the ¹⁰B(p,α)⁷Be, ¹⁰B(p,p)¹⁰B, and ¹⁰B(p,γ)¹¹C reactions, was achieved over the region of measurement. Using a representative set of previous data, the fit was extended to very low energies. Conclusions: On the basis of this data and R-matrix analysis, a more reliable and consistent description of the ¹⁰B(p,α)⁷Be cross section has been established. The uncertainty over the energy range of this study has been reduced from ≈20% to ≈10%, and the level structure over this region has been clarified considerably.

This letter from Seymour Heyman, Deputy Chancellor of the City University of New York, answers on a point-by-point basis the criticism leveled against the open admissions policy of CUNY by Evans and Novak in an article in the Washington Post. The letter identifies "the utterly baffled freshman" as a newly arrived student from Greece with good academic credentials, and argues that: (1) of the 35,000 admitted students, half were found to need remedial education, but only 9,000 of these would not have been admitted under pre open admissions policy (OAP) criteria; (2) almost 80 percent of the entering freshmen had a B average or better in high school, better than the national average; (3) the decision to advance the OAP from 1975 to 1970 was not just the result of radical student pressure, but also at the urging of all non-radical groups on campus; (4) academic standards have not been lowered; (5) the cost relative to the potential benefit is low; (6) new constituencies can be reached without sacrificing instructional quality; (7) academic standards at CUNY mean the rate and effectiveness of knowledge transmission, and not the students' scholastic track record or the faculty's scholarly prestige; (8) the majority of freshmen are white; and (9) that the faculty continue to support open admissions. (AF)

Nuclear reactions play a key role in the framework of the Big Bang Nucleosynthesis. A network of 12 principal reactions has been identified as the main path that drove the elemental nucleosynthesis in the first 20 min of the history of the Universe. Among them an important role is played by neutron-induced reactions, which, from an experimental point of view, are usually a difficult task to be measured directly. Nevertheless big efforts in the last decades have led to a better understanding of their role in the primordial nucleosynthesis network. In this work we apply the Trojan Horse Method to extract the cross section at astrophysical energies for the 3He (n,p)3H reaction after a detailed study of the 2H (3He ,pt)H three-body process. Data extracted from the present measurement are compared with other published sets.