5,255 research outputs found
Comment on Leptophobic Bosons and Neutral Current Scattering Data
The relevance of existing deep inelastic scattering data to models
containing a leptophobic neutral vector boson is discussed. It is shown that
this neutral current data is in good agreement with the Standard Model and
disfavors such a leptophobic boson.Comment: LaTeX, 3 pages, 1 embedded PS figure, available at
http://cordelia.fnal.gov/~ksmcf/publications/moriond_comment.ps.gz .
Presented at the XXXIieme Rencontres de Moriond, Electroweak Interactions and
Unified Theorie
A Precision Measurement of Electroweak Parameters in Neutrino-Nucleon Scattering
The CCFR collaboration reports a precise measurement of electroweak
parameters derived from the ratio of neutral-current to charged-current
cross-sections in neutrino-nucleon scattering at the Fermilab Tevatron. This
ratio of cross-sections measures the neutral current couplings to quarks, which
implies a determination of sin^2 theta_W (on-shell) = 0.2236 +/- 0.0028(expt.)
+/- 0.0030(model) for m_top=175 GeV, m_Higgs=150 GeV. This is equivalent to
M_W=80.35+/-0.21 GeV. The good agreement of this measurement with Standard
Model expectations implies the exclusion of additional
neutrino-neutrino-quark-quark contact interactions at 95% confidence at a mass
scale of 1-8 TeV, depending on the form of the contact interaction.Comment: formatted in revtex, 5 pages, 3 eps figures included via psfig,
submitted to Physical Review Letter
Neutrino Scattering in a Magnetic Field
Motivated by the evidence for a finite neutrino mass we examine anew the
interaction of neutrinos in a magnetic field. We present the rate for radiative
scattering for both massless and massive neutrinos in the standard model and
give the corresponding numerical estimates. We also consider the effects
arising from a possible neutrino magnetic moment.Comment: 10 pages, 3 figures; Acknowledgements added 05.07.200
Data Preservation at MINERvA
Over the past ten years, MINERvA has collected an accelerator neutrino
interaction dataset that is uniquely relevant to the energy range of DUNE.
These are the only currently available data at intermediate and high momentum
transfers for multiple nuclear targets in the same beam. MINERvA is undertaking
a campaign to preserve these data and make them publicly available so that they
may be analyzed beyond the end of the MINERvA collaboration. We encourage the
community to consider the development of centralized resources to enable
long-term access to these data and analysis tools for the entire HEP community.Comment: Snowmass 2021 Letter of Interes
Influence of Phase Matching on the Cooper Minimum in Ar High Harmonic Spectra
We study the influence of phase matching on interference minima in high
harmonic spectra. We concentrate on structures in atoms due to interference of
different angular momentum channels during recombination. We use the Cooper
minimum (CM) in argon at 47 eV as a marker in the harmonic spectrum. We measure
2d harmonic spectra in argon as a function of wavelength and angular
divergence. While we identify a clear CM in the spectrum when the target gas
jet is placed after the laser focus, we find that the appearance of the CM
varies with angular divergence and can even be completely washed out when the
gas jet is placed closer to the focus. We also show that the argon CM appears
at different wavelengths in harmonic and photo-absorption spectra measured
under conditions independent of any wavelength calibration. We model the
experiment with a simulation based on coupled solutions of the time-dependent
Schr\"odinger equation and the Maxwell wave equation, including both the single
atom response and macroscopic effects of propagation. The single atom
calculations confirm that the ground state of argon can be represented by its
field free symmetry, despite the strong laser field used in high harmonic
generation. Because of this, the CM structure in the harmonic spectrum can be
described as the interference of continuum and channels, whose relative
phase jumps by at the CM energy, resulting in a minimum shifted from the
photoionization result. We also show that the full calculations reproduce the
dependence of the CM on the macroscopic conditions. We calculate simple phase
matching factors as a function of harmonic order and explain our experimental
and theoretical observation in terms of the effect of phase matching on the
shape of the harmonic spectrum. Phase matching must be taken into account to
fully understand spectral features related to HHG spectroscopy
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