The Solar pp and hep Processes in Effective Field Theory

The strategy of modern effective field theory is exploited to pin down accurately the flux $S$ factors for the $pp$ and $hep$ processes in the Sun. The technique used is to combine the high accuracy established in few-nucleon systems of the "standard nuclear physics approach" (SNPA) and the systematic power counting of chiral perturbation theory (ChPT) into a consistent effective field theory framework. Using highly accurate wave functions obtained in the SNPA and working to \nlo3 in the chiral counting for the current, we make totally parameter-free and error-controlled predictions for the $pp$ and $hep$ processes in the Sun.Comment: 5 pages, aipproc macros are included. Talk given at International Nuclear Physics Conference 2001, Berkeley, California, July 30 - August 3, 200

Corrections to the Nuclear Axial Vector Coupling in a Nuclear Medium

We examine further corrections to the time component of the axial vector coupling constant in a nuclear medium. The dominant correction is that of exchange currents. The corrections we examine make the remaining discrepancy worse.Comment: 6 pages, 2 figure

Spin-dependent neutrino-induced nucleon knockout

We study neutrino-induced nucleon knockout off atomic nuclei and examine the polarization properties of the ejectile. A detailed study of the spin dependence of the outgoing nucleon is presented. The numerical results are derived within a non-relativistic plane-wave impulse-approximation approach. Our calculations reveal large polarization asymmetries, and clear dissimilarities between neutrino- and antineutrino-induced reactions. They reflect the fact that neutrino-induced nucleon knockout is dominated by the transverse axial current and gains its major contributions from forward nucleon emission and backward lepton scattering.Comment: 9 pages, 7 figures, accepted for publication in Phys. Rev.

Solar-neutrino reactions on deuteron in effective field theory

The cross sections for low-energy neutrino-deuteron reactions are calculated within heavy-baryon chiral perturbation theory employing cut-off regularization scheme. The transition operators are derived up to next-to-next-to-next-to-leading order in the Weinberg counting rules, while the nuclear matrix elements are evaluated using the wave functions generated by a high-quality phenomenological NN potential. With the adoption of the axial-current-four-nucleon coupling constant fixed from the tritium beta decay data, our calculation is free from unknown low-energy constants. Our results exhibit a high degree of stability against different choices of the cutoff parameter, a feature which indicates that, apart from radiative corrections, the uncertainties in the calculated cross sections are less than 1 %.Comment: 12 pages, 3 figures. Error estimation of higher order corrections detaile

Taxonomy and zoogeography of the family Onychoteuthidae

The Oegopsida family Onychoteuthidae contains five genera, namely, Onychoteuthis, Ancistroteuthis, Onykia, Moroteuthis. and Kondakovia. The genus Chaunotuethis is considered to represent spent individuals of the other genera of the family. The present study clarified that two well-known nominal species, Onychoteuthis banksii (Leach, 1817) and Ancistroteuthis lichtensteinii (Ferussac and Orbigny, 1839), both represent species complexes in their broad distributional ranges. The genus Onykia may represent immature stages of other onychoteuthids. Moroteuthis robsoni Adam, 1962, which has hitherto been considered to be a Southem Ocean species, appears to extend its distribution into the warm Atlantic region. Reliable taxonomic records as weil as knowledge of distributional differentiation by growth stagearestill too scarce to draw a zoogeographical picture of each species in this family

Neutrino reactions on the deuteron

The cross sections for the ν-d and ν̅ -d reactions are calculated for incident energy up to Eν=170 MeV with the use of a phenomenological Lagrangian approach. We assess and improve the reliability of the employed calculational method by examining the dependence of the results on various input and approximations that go into the calculation. The main points of improvement over the existing work are (1) use of the “modern” NN potentials, (2) use of the more accurate nucleon weak-interaction form factors, and (3) monitoring the strength of a vertex that governs the exchange-current contribution, with the use of data on the related process,n+p⃗d+γ. In addition to the total cross sections, we present various differential cross sections that are expected to be useful for the SNO and other experiments. In the low-energy regime relevant to the solar neutrinos, the newly calculated total cross sections essentially agree with the existing literature values. The origins of slight differences found for higher energies are discussed. The ratio between the neutral-current and charged-current reaction cross sections is found to be extremely stable against any variations in the input of our calculation

Neutrino-deuteron reactions at solar neutrino energies

In interpreting the SNO experiments, very accurate estimates of the \nu d reaction cross sections are of great importance. We improve the previous estimates of our group by updating some of its inputs and by taking into account the results of a recent effective-field-theoretical calculation. The new cross sections are slightly (\sim 1%) larger than the previously reported values. We present arguments that lead to the conclusion that it is reasonable to assign 1% uncertainty to the \nu d cross sections reported here.Comment: 13 pages, 1 figur