Search

Total and differential cross sections for {nu}{sub {mu}}{ital e}{r arrow}{nu}{sub {mu}}{ital e} and {bar {nu}}{sub {mu}}{ital e}{r arrow}{bar {nu}}{sub {mu}}{ital e} are measured. Values for the model-independent neutral-current couplings of the electron are found to be {ital g}{sub {ital V}}={minus}0.107{plus minus}0.035(stat){plus minus}0.028(syst) and {ital g}{sub {ital A}}={minus}0.514{plus minus}0.023(stat){plus minus}0.028(syst). The electroweak mixing parameter sin{sup 2}{theta}{sub {ital W}} is determined to be 0.195{plus minus}0.018(stat){plus minus}0.013(syst). Limits are set for the charge radius and magnetic moment of the neutrino as ({l angle}{ital r}{sup 2}{r angle}){lt}0.24{times}10{sup {minus}32} cm{sup 2} and {ital f}{sub {mu}}{lt}0.85{times}10{sup {minus}9} Bohr magnetons, respectively.

This paper describes the design criteria, construction, and performance of a detector to study neutral and charged current elastic neutrino interactions induced by neutrinos of average energy approximately 1 GeV from the Brookhaven National Laboratory Alternating Gradient Synchrotron.

We present data on the production by neutrinos of a prompt ..mu../sup -/..mu../sup -/ signal with a rate relative to the ..mu../sup -/..mu../sup +/ rate (single charm production) of 0.07 +- 0.04, 0.12 +- 0.03, and 0.12 +- 0.03 for p/sub ..mu../>5, >10, and >15 GeV/c, respectively. The energy dependence of the ratio N/sup pr/ (..mu../sup -/..mu../sup -/)/N(..mu../sup -/) is also presented. Like-sign dimuon data from various experiments are summarized and discussed. Our observed ..mu../sup -/..mu../sup -/ rate is roughly two orders of magnitude larger than that expected from leading-order quantum-chromodynamic calculations of associated charm production.

Measurements of the semileptonic weak neutral-current reactions ..nu../sub ..mu../p..--> nu../sub ..mu../p and nu-bar/sub ..mu../p..-->..nu-bar/sub ..mu../p which yield the absolute differential cross sections dsigma(..nu../sub ..mu../p)/dQ/sup 2/ and dsigma(nu-bar/sub ..mu../p)/dQ/sup 2/ described. The weak-neutral-current parameter, sin/sup 2/theta/sub W/, is determined to be sin/sup 2/theta/sub W/ = 0.220 +- 0.016 (stat)/sub -0.031//sup +0.023/(syst).

A search has been made for the decays of heavy (≈200–500 MeV/ c 2 ) neutrinos, ν H → νμ e, in a 23 m long detector, in the wide-band neutrino beam at the Brookhaven AGS. No significant excess of such events was found and limits are set on the neutrino mixing matrix elements, | U eH | 2 and | U μH | 2 . Results of a more general search for anomalous μe events are also reported.

The antineutrino quasielastic reaction ν μm p →μ + n has been studied in the Q 2 range up to 1.0 (GeV/ c ) 2 at the Brookhaven AGS. The value of the axial vector mass M A in the dipole parametrization of the from factor was determined from the shape of the Q 2 distribution to be 1.09±0.03±0.02 GeV/ c 2 . A search for second-class currents was also conducted. No significant effect was found.

This paper presents the final results on charged-current neutrino and antineutrino interactions with nuclei from experiment E-310 at Fermi National Accelerator Laboratory. The data sample, consisting of 21 578 neutrino-induced and 7358 antineutrino-induced events within the fiducial region in the energy range 20

A hierarchical, distributed intelligence data acquisition system which has been used for the past two years in neutrino experiments at Brookhaven National Laboratory is described. Performance characteristics and the nature of problems encountered in bringing the system to maturity are discussed and some generalizations of the experience are suggested.

Measured energy-dependent rates of opposite-sign dimuons produced by neutrinos and antineutrinos are presented and used to determine the fraction of strange quarks. Experimental distributions are compared with those expected from charm production and decay.

The result of a measurement of sigma(..nu../sub ..mu../+e/sup -/..--> nu../sub ..mu../+e/sup -/) is presented. With use of neutrinos of mean energy 1.5 GeV from the Brookhaven National Laboratory alternating gradient synchrotron and a massive, active, high-resolution detector, a signal of 51 +- 9 events with a average signal-to-background ratio greater than 2:1 is observed. sigma(..nu../sub ..mu../e/sup -/..--> nu../sub ..mu../+e/sup -/) = (1.60 +- 0.29(stat) +- 0.26(sys)) E/sub ..nu../ (GeV) x 10/sup -42/ cm/sup 2/ is obtained.

Analysis of 5180 $\overline{\ensuremath{\nu}}$ interactions shows a variation with energy of the inelasticity ($y$) distributions over the range 10 to 220 GeV and a dependence on the scaling variable $x$. From these data are obtained the approximate $x$ dependence of the sea quarks and a limit on the strength of right-handed coupling between the $u$ quark and a massive $b$ quark.

Measurements have been made of the reactions ${\ensuremath{\nu}}_{e}$n\ensuremath{\rightarrow}${e}^{\mathrm{\ensuremath{-}}}$p and ${\ensuremath{\nu}}_{\ensuremath{\mu}}$n\ensuremath{\rightarrow}${\ensuremath{\mu}}^{\mathrm{\ensuremath{-}}}$p in a detector located an effective distance of 96 m from a neutrino source. These measurements yield directly the energy-dependent ratio of the neutrino fluxes [\ensuremath{\Phi}(E(${\ensuremath{\nu}}_{e}$))/\ensuremath{\Phi}(E(${\ensuremath{\nu}}_{\ensuremath{\mu}}$${))\phantom{\rule{0ex}{0ex}}]}_{\mathrm{obs}}$ incident on the detector. When combined with an estimate of the flux ratio emanating from the source [\ensuremath{\Phi}(E(${\ensuremath{\nu}}_{e}$))/\ensuremath{\Phi}(E(${\ensuremath{\nu}}_{\ensuremath{\mu}}$${))\phantom{\rule{0ex}{0ex}}]}_{\mathrm{calc}}$, the measured ratio provides an upper limit on the strength of mixing between ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ and ${\ensuremath{\nu}}_{e}$. We obtain ${\mathrm{sin}}^{2}$2\ensuremath{\alpha}3.4\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$ (90% C.L.) in the limit of large mass difference \ensuremath{\Delta}${m}^{2}$ (\ensuremath{\equiv}\ensuremath{\Vert}${m}_{1}$${}^{2}$-${m}_{2}$${}^{2}$\ensuremath{\Vert}) between neutrino mass eigenstates, ${m}_{1}$ and ${m}_{2}$; and an upper limit on the product \ensuremath{\Delta}${m}^{2}$ sin2\ensuremath{\alpha}0.43 ${\mathrm{eV}}^{2}$ in the limit of small mass difference.

Motivated by the apparent advantages of a narrow-band neutrino beam for neutrino-oscillation experiments, a search for ..nu../sub ..mu../..--> nu../sub e/ was made with a magnetic horn-focused 3-GeV narrow-band neutrino beam. The detector and its distance from the neutrino source were the same as in a previous search for ..nu../sub ..mu../..--> nu../sub e/ with a horn-focused wide-band neutrino beam of mean energy 1.2 GeV. A direct comparison of the results of the two searches is made, and a brief survey of events induced by a 1.3-GeV narrow-band neutrino beam is noted.

The neutrino fluxes phi(E-italic(..nu../sub ..mu../)), phi(E-italic(nu-bar/sub ..mu../)), and phi(E-italic(..nu../sub e-italic/)) in the Brookhaven Alternating Gradient Synchrotron wide-band beams have been determined by measurements of quasielastic interactions observed in a massive, high-resolution detector. These fluxes are accurately reproduced by Monte Carlo calculations.

The weak coupling constants of the electron, ${g}_{V}^{e}$ and ${g}_{A}^{e}$, are determined from measurements of the total and differential cross sections for the reaction ${\ensuremath{\nu}}_{\ensuremath{\mu}}$e\ensuremath{\rightarrow}${\ensuremath{\nu}}_{\ensuremath{\mu}}$e. The data also place limits of interest on the magnitudes of a neutrino charge radius and a possible neutrino magnetic dipole moment.

Measurements of the ratio R of the purely leptonic weak neutral-current cross sections sigma(..nu../sub ..mu../e..--> nu../sub ..mu../e)/sigma(nu-bar/sub ..mu../e..-->..nu-bar /sub ..mu../e) and of the absolute value of sigma(nu-bar/sub ..mu../e..-->..nu-bar/sub ..mu../e) are reported. These yield R = 1.38/sub -0.31//sup +0.40/(stat) +- 0.17(syst) and sigma(nu-bar/sub ..mu../e..-->..nu-bar/sub ..mu../e)/E..mu.. = (1.16 +- 0.20(stat) +- 0.14(syst)) x 10/sup -42/ cm/sup 2//GeV. This value of R determines the fundamental weak neutral-current parameter to be sin/sup 2/theta/sub W/ = 0.209 +- 0.029(stat) +- 0.013(syst).

This paper describes measurements of the semileptonic weak-neutral-current reactions $\ensuremath{\nu}_{\ensuremath{\mu}}p\ensuremath{\rightarrow}\ensuremath{\nu}_{\ensuremath{\mu}}p$ and $\overline{\ensuremath{\nu}}_{\ensuremath{\mu}}p\ensuremath{\rightarrow}\overline{\ensuremath{\nu}}_{\ensuremath{\mu}}p$ which yield the absolute differential cross sections $\frac{d\ensuremath{\sigma}(\ensuremath{\nu}_{\ensuremath{\mu}}p)}{d{Q}^{2}}$ and $\frac{d\ensuremath{\sigma}(\overline{\ensuremath{\nu}}_{\ensuremath{\mu}}p)}{d{Q}^{2}}$. The weak-neutral-current parameter, ${{sin}^{2}\ensuremath{\theta}}_{\mathrm{W}}$, is determined to be ${{sin}^{2}\ensuremath{\theta}}_{\mathrm{W}}=0.220\ifmmode\pm\else\textpm\fi{}0.016(\mathrm{stat}.)_{\ensuremath{-}0.031}^{+0.023}(\mathrm{syst}.)$.