2,723 research outputs found
Cancellation of divergences in unitary gauge calculation of process via one W loop, and application
Following the thread of R. Gastmans, S. L. Wu and T. T. Wu, the calculation
in the unitary gauge for the process via one W loop is
repeated, without the specific choice of the independent integrated loop
momentum at the beginning. We start from the 'original' definition of each
Feynman diagram, and show that the 4-momentum conservation and the Ward
identity of the W-W-photon vertex can guarantee the cancellation of all terms
among the Feynman diagrams which are to be integrated to give divergences
higher than logarithmic. The remaining terms are to the most logarithmically
divergent, hence is independent from the set of integrated loop momentum. This
way of doing calculation is applied to process via one W loop
in the unitary gauge, the divergences proportional to including
quadratic ones are all cancelled, and terms proportional to are
shown to be zero. The way of dealing with the quadratic divergences
proportional to in has subtle implication on the
employment on the Feynman rules especially when those rules can lead to high
level divergences. So calculation without integration on all the
functions until have to is a more proper or maybe necessary way of the
employment of the Feynman rules.Comment: 1 figure, 34 pages (updated
Central-edge asymmetry as a probe of Higgs-top coupling in production at LHC
The Higgs-top coupling plays a central role in the hierarchy problem and the
vacuum stability of the Standard Model (SM). We propose a central-edge
asymmetry () to probe the CP violating Higgs-top coupling in dileptonic
channel of production at the LHC. We demonstrate that
the CP-violating Higgs-top coupling can affect the central-edge asymmetry
through distorting distribution because of the
contribution of new top charge asymmetric term. Since
distribution is frame-independent and has a good discrimination even in boosted
regime, we use the jet substructure technique to enhance the observability of
the dileptonic channel of production. We find that (1) the
significance of dileptonic channel of production can reach
for CP phase when the luminosity fb at 14 TeV LHC. (2) the central-edge asymmetry
show a good discrimination power of CP phase of
interaction, which are -40.26\%, -26.60\%, -9.47\% for , , respectively and are hardly affected by the event selections. Besides,
by performing the binned- analysis of
distribution, we find that the scalar and pseudo-scalar interactions can be
distinguished at 95\% C.L. level at 14 TeV HL-LHC.Comment: minor changes, version accepted by PL
Semileptonic Decays of Meson to a P-Wave Charmonium State or
The semileptonic decays of meson to a P-wave charmonium state
or are computed. The results show that the decays
are sizable so they are accessible in Tevatron and in LHC, especially, with the
detectors LHCB and BTeV in the foreseeable future, and of them, the one to the
charmonium state potentially offers us a novel window to see the
unconfirmed particle. In addition, it is pointed out that since the two
charmonium radiative decays have sizable
branching ratios, the cascade decays of the concerned decays and the charmonium
radiative decays may affect the result of the observing the meson through
the semileptonic decays substantially.Comment: 8 pages, 2 figure
Faithful teleportation with arbitrary pure or mixed resource states
We study faithful teleportation systematically with arbitrary entangled
states as resources. The necessary conditions of mixed states to complete
perfect teleportation are proved. Based on these results, the necessary and
sufficient conditions of faithful teleportation of an unknown state |\phi> in
C^d with an entangled resource {\rho} in C^m \otimes C^d and C^d \otimes C^n
are derived. It is shown that for {\rho} in C^m\otimesC^d, {\rho} must be a
maximally entangled state, while for {\rho} in C^d \otimes C^n, {\rho} must be
a puremaximally entangled state. Moreover, we show that the sender's
measurements must be all projectors of maximally entangled pure states. The
relations between the entanglement of the formation of the resource states and
faithful teleportation are also discussed.Comment: 9 page
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