4,518 research outputs found
Methanol as a tracer of fundamental constants
The methanol molecule CH3OH has a complex microwave spectrum with a large
number of very strong lines. This spectrum includes purely rotational
transitions as well as transitions with contributions of the internal degree of
freedom associated with the hindered rotation of the OH group. The latter takes
place due to the tunneling of hydrogen through the potential barriers between
three equivalent potential minima. Such transitions are highly sensitive to
changes in the electron-to-proton mass ratio, mu = m_e/m_p, and have different
responses to mu-variations. The highest sensitivity is found for the mixed
rotation-tunneling transitions at low frequencies. Observing methanol lines
provides more stringent limits on the hypothetical variation of mu than ammonia
observation with the same velocity resolution. We show that the best quality
radio astronomical data on methanol maser lines constrain the variability of mu
in the Milky Way at the level of |Delta mu/mu| < 28x10^{-9} (1sigma) which is
in line with the previously obtained ammonia result, |Delta mu/mu| < 29x10^{-9}
(1\sigma). This estimate can be further improved if the rest frequencies of the
CH3OH microwave lines will be measured more accurately.Comment: 7 pages, 1 table, 1 figure. Accepted for publication in Ap
Enhancement of the electric dipole moment of the electron in PbO
The a(1) state of PbO can be used to measure the electric dipole moment of
the electron d_e. We discuss a semiempirical model for this state, which yields
an estimate of the effective electric field on the valence electrons in PbO.
Our final result is an upper limit on the measurable energy shift, which is
significantly larger than was anticipated earlier: .Comment: 4 pages, revtex4, no figures, submitted to PR
Electric dipole moment enhancement factor of thallium
The goal of this work is to resolve the present controversy in the value of
the EDM enhancement factor of Tl. We have carried out several calculations by
different high-precision methods, studied previously omitted corrections, as
well as tested our methodology on other parity conserving quantities. We find
the EDM enhancement factor of Tl to be equal to -573(20). This value is 20%
larger than the recently published result of Nataraj et al. [Phys. Rev. Lett.
106, 200403 (2011)], but agrees very well with several earlier results.Comment: 5 pages; v2: link to supplemental material adde
Correlations of two photons at hadron colliders
We study the Bose-Einstein correlations of two photons and their coherent
properties that can provide the information about the space-time structure of
the emitting source through the Higgs-boson decays into two photons. We argue
that such an investigation could probe the Higgs-boson mass. The model is
rather sensitive to the temperature of the environment and to the external
distortion effect in medium.Comment: 10 pages, 1 figur
Using Molecules to Measure Nuclear Spin-Dependent Parity Violation
Nuclear spin-dependent parity violation arises from weak interactions between
electrons and nucleons, and from nuclear anapole moments. We outline a method
to measure such effects, using a Stark-interference technique to determine the
mixing between opposite-parity rotational/hyperfine levels of ground-state
molecules. The technique is applicable to nuclei over a wide range of atomic
number, in diatomic species that are theoretically tractable for
interpretation. This should provide data on anapole moments of many nuclei, and
on previously unmeasured neutral weak couplings
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