Thu·Mar 24, 2016Thursday·March 24, 2016

1. 01*

   Reanalysis of Rosenbluth measurements of the proton form factors

   A. V. Gramolin🇷🇺 · D. M. Nikolenko🇷🇺

   We present a reanalysis of the data from Stanford Linear Accelerator Center (SLAC) experiments E140 [R. C. Walker et al., Phys. Rev. D 49, 5671 (1994)] and NE11 [L. Andivahis et al., Phys. Rev. D 50, 5491 (1994)] on elastic electron-proton scattering. This work is motivated by recent progress in calculating the corresponding radiative corrections and by the apparent discrepancy between the Rosenbluth and polarization transfer measurements of the proton electromagnetic form factors. New, corrected values for the scattering cross sections are presented, as well as a new form factor fit in the $Q^2$ range from 1 to 8.83 ${\text{GeV}}^2$. We also provide a complete set of revised formulas to account for radiative corrections in single-arm measurements of unpolarized elastic electron-proton scattering.

   nucl-exhep-exhep-phPRC(2016)·35 citations
2. 02*

   Meaning of the nuclear wave function

   John D. Terry🇺🇸 · Gerald A. Miller🇺🇸

   Background The intense current experimental interest in studying the structure of the deuteron and using it to enable accurate studies of neutron structure motivate us to examine the four-dimensional space-time nature of the nuclear wave function, and the various approximations used to reduce it to an object that depends only on three spatial variables. Purpose: The aim is to determine if the ability to understand and analyze measured experimental cross sections is compromised by making the reduction from four to three dimensions. Method: Simple, exactly-calculable, covariant models of a bound-state wave state wave function (a scalar boson made of two constituent-scalar bosons) with parameters chosen to represent a deuteron are used to investigate the accuracy of using different approximations to the nuclear wave function to compute the quasi-elastic scattering cross section. Four different versions of the wave function are defined (light-front spectator, light-front, light-front with scaling and non-relativistic) and used to compute the cross sections as a function of how far off the mass-shell (how virtual) is the struck constituent. Results: We show that making an exact calculation of the quasi-elastic scattering cross section involves using the light-front spectator wave function. All of the other approaches fail to reproduce the model exact calculation if the value of Bjorken $x$ differs from unity. The model is extended to consider an essential effect of spin to show that constituent nucleons cannot be treated as being on their mass shell even when taking the matrix element of a `good' current. Conclusions: It is necessary to develop realistic light-front spectator wave functions to meet the needs of current and planned experiments.

   ↳ nucl-thhep-phnucl-exPRC(2016)·1 citation
3. 03*

   Correlations of $\mathbf{\pi N}$ Partial Waves for Multi-Reaction Analyses

   M. Döring🇺🇸 · J. Revier🇺🇸 · D. Rönchen🇩🇪 · R. Workman🇺🇸

   In the search for missing baryonic resonances, many analyses include data from a variety of pion- and photon-induced reactions. For elastic $\pi N$ scattering, however, usually the partial waves of the SAID or other groups are fitted, instead of data. We provide the partial-wave covariance matrices needed to perform correlated ${\chi }^2$ fits, in which the obtained ${\chi }^2$ equals the actual ${\chi }^2$ up non-linear and normalization corrections. For any analysis relying on partial waves extracted from elastic pion scattering, this is a prerequisite to assess the significance of resonance signals and to assign any uncertainty on results. The influence of systematic errors is also considered.

   ↳ nucl-thnucl-exPRC(2016)·18 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.