53,258 research outputs found
Non-perturbative approach for the time-dependent symmetry breaking
We present a variational method which uses a quartic exponential function as
a trial wave-function to describe time-dependent quantum mechanical systems. We
introduce a new physical variable which is appropriate to describe the
shape of wave-packet, and calculate the effective action as a function of both
the dispersion and . The effective potential
successfully describes the transition of the system from the false vacuum to
the true vacuum. The present method well describes the long time evolution of
the wave-function of the system after the symmetry breaking, which is shown in
comparison with the direct numerical computations of wave-function.Comment: 8 pages, 3 figure
Supersolid Helium at High Pressure
We have measured the pressure dependence of the supersolid fraction by a
torsional oscillator technique. Superflow is found from 25.6 bar up to 136.9
bar. The supersolid fraction in the low temperature limit increases from 0.6 %
at 25.6 bar near the melting boundary up to a maximum of 1.5% near 55 bar
before showing a monotonic decrease with pressure extrapolating to zero near
170 bar.Comment: 4 pages, 4 figure
Higgs Boson Production from Black Holes at the LHC
If the fundamental Planck scale is near a TeV, then TeV scale black holes
should be produced in proton-proton collisions at the LHC where \sqrt{s} = 14
TeV. As the temperature of the black holes can be ~ 1 TeV we also expect
production of Higgs bosons from them via Hawking radiation. This is a different
production mode for the Higgs boson, which would normally be produced via
direct pQCD parton fusion processes. In this paper we compare total cross
sections and transverse momentum distributions d\sigma/dp_T for Higgs
production from black holes at the LHC with those from direct parton fusion
processes at next-to-next-to-leading order and next-to-leading order
respectively. We find that the Higgs production from black holes can be larger
or smaller than the direct pQCD production depending upon the Planck mass and
black hole mass. We also find that d\sigma/dp_T of Higgs production from black
holes increases as a function of p_T which is in sharp contrast with the pQCD
predictions where d\sigma/dp_T decreases so we suggest that the measurement of
an increase in d\sigma/dp_T as p_T increases for Higgs (or any other heavy
particle) production can be a useful signature for black holes at the LHC.Comment: 20 pages latex, 5 figures, To appear in Phys. Rev.
Observation of the Cabibbo-suppressed charmed baryon decay Λ_c^+→pφ
We report the observation of the Cabibbo-suppressed decays Λ_c^+→pK^-K^+ and Λ_c^+→pφ using data collected with the CLEO II detector at CESR. The latter mode, observed for the first time with significant statistics, is of interest as a test of color suppression in charm decays. We have determined the branching ratios for these modes relative to Λ_c^+→pK^-π^+ and compared our results with theory
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