3,824 research outputs found
Angular distribution and forward-backward asymmetry of the Higgs-boson decay to photon and lepton pair
The Higgs-boson decay h -> gamma l+ l- for various lepton states l = (e, mu,
tau) is analyzed. The differential decay width and forward-backward asymmetry
are calculated as functions of the dilepton invariant mass in a model where the
Higgs boson interacts with leptons and quarks via a mixture of scalar and
pseudoscalar couplings. These couplings are partly constrained from data on the
decays to leptons, h -> l+ l-, and quarks h -> q \bar{q} (where q = (c, b)),
while the Higgs couplings to the top quark are chosen from the two-photon and
two-gluon decay rates. Nonzero values of the forward-backward asymmetry will
manifest effects of new physics in the Higgs sector. The decay width and
asymmetry integrated over the dilepton invariant mass are also presented.Comment: 9 pages, 4 figures, SVJour3 class; v2: minor changes in text,
references updated and extended, corresponds to journal versio
Review of information systems of analytical analysis of data research of Ternopil state agricultural experiment station IKSHP NAAS of Ukraine
Testing Lorentz Invariance by Comparing Light Propagation in Vacuum and Matter
We present a Michelson-Morley type experiment for testing the isotropy of the
speed of light in vacuum and matter. The experiment compares the resonance
frequency of a monolithic optical sapphire resonator with the resonance
frequency of an orthogonal evacuated optical cavity made of fused silica while
the whole setup is rotated on an air bearing turntable once every 45 s.
Preliminary results yield an upper limit for the anisotropy of the speed of
light in matter (sapphire) of \Delta c/c < 4x10^(-15), limited by the frequency
stability of the sapphire resonator operated at room temperature. Work to
increase the measurement sensitivity by more than one order of magnitude by
cooling down the sapphire resonator to liquid helium temperatures (LHe) is
currently under way.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
Test of the isotropy of the speed of light using a continuously rotating optical resonator
We report on a test of Lorentz invariance performed by comparing the
resonance frequencies of one stationary optical resonator and one continuously
rotating on a precision air bearing turntable. Special attention is paid to the
control of rotation induced systematic effects. Within the photon sector of the
Standard Model Extension, we obtain improved limits on combinations of 8
parameters at a level of a few parts in . For the previously least
well known parameter we find . Within the Robertson-Mansouri-Sexl test theory, our measurement
restricts the isotropy violation parameter to
, corresponding to an eightfold improvement with
respect to previous non-rotating measurements.Comment: 4 pages, 3 figures, to appear in Phys. Rev. Let
Quasiclassical and Quantum Systems of Angular Momentum. Part II. Quantum Mechanics on Lie Groups and Methods of Group Algebras
In Part I of this series we presented the general ideas of applying
group-algebraic methods for describing quantum systems. The treatment was there
very "ascetic" in that only the structure of a locally compact topological
group was used. Below we explicitly make use of the Lie group structure. Basing
on differential geometry enables one to introduce explicitly representation of
important physical quantities and formulate the general ideas of quasiclassical
representation and classical analogy
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