20,376 research outputs found
Charmed meson decays to two pseudoscalars
A recent update of data on the decays of , , and to pairs
of light pseudoscalars calls for a renewed analysis of key decay amplitudes and
tests of flavor symmetry. The present data change our previous understanding of
relative phases between amplitudes that describe Cabibbo-favored decays of the
charmed mesons. The new data also seem to favor a smaller octet-singlet mixing
angle for the and mesons when singly-Cabibbo-suppressed
processes are taken into account. We also discuss the effects of the new data
on interference between Cabibbo-favored and doubly-Cabibbo-suppressed decays.Comment: 15 pages, 7 figures, to be submitted to Phys. Rev.
Decay of Spin-One Particle into Two Photons in Presence of Uniform External Magnetic Field
Yang's theorem states that an initial J=1 state cannot decay into two
photons. Because of this result some reactions relating to elementary particles
or atomic transitions can be ruled out. The theorem is not valid in the
presence of background electric or magnetic fields. In this work we show that
the decay of a J=1 particle into two photons is permitted by Bose symmetry and
rotational invariance when the background of the decay process is not pure
vacuum but contains an external classical magnetic/electric field. We also
discuss constraints on these amplitudes from {\bf CP} invariance.Comment: Tex fil
Relative phases in Dalitz plot amplitudes for and
Relative phases of amplitudes for meson decays to a light pseudoscalar
meson and a light vector meson decaying to two pseudoscalar mesons will
lead to characteristic interferences on the three-body Dalitz plot. These
phases may be compared with predictions of a flavor-symmetric treatment which
extracts contributing amplitudes and their relative phases from a fit to decay rates. Good agreement was found previously for the cases of and . The present work is devoted
to the decays and , for which
agreement is not found. Several suggestions are offered for this discrepancy.Comment: 11 pages, 3 figures, to be published in Phys. Rev. D. Additonal
figure, text, and references; minor correction
Options for Energy Efficiency in India and Barriers to Their Adoption: A Scoping Study
We review the economics literature on energy efficiency in India, as a guide for further research in the area. The empirical literature has focused on four questions: How does energy efficiency in India compare with energy efficiency in other countries? What would be the energy savings (and cost savings) from adopting certain energy-efficient technologies? Why are these technologies being -- or not being -- adopted? What policies should be implemented to encourage their adoption? Most of the literature focuses on answers to the first two questions. Studies are needed that quantify factors affecting the rate of diffusion of energy-efficient technologies and rigorously evaluate reforms implemented by the Government of India, beginning in the 1990s, that could affect energy efficiency.energy efficiency, energy use, India
Cross ratios between Dalitz plot amplitudes in three-body decays
A recent study of and
describes a flavor-symmetric approach to calculate relative amplitudes and
phases, for characteristic interferences between decays to a light
pseudoscalar and a light vector , on Dalitz plots for
decays. The flavor-symmetric approach used an earlier fit to decay
rates and was found to agree fairly well with experiments for but not as well for and . The present work extends this investigation to include . We use an SU(3) flavor symmetry relationship between ratios
of Cabibbo-favored (CF) amplitudes in and
ratios of singly- Cabibbo-suppressed (SCS) amplitudes in and . We observe that experimental
values for Dalitz plot cross ratios obey this relationship up to discrepancies
noted previously. The need for an updated Dalitz plot analysis of is emphasized.Comment: 9 pages, one figure. Submitted to Phys. Rev. D (Brief Reports).
Additional comparisons with previous result
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