17,276 research outputs found
Complete Study of Hadroproduction of a Meson Associated with a Prompt
We present the first complete study of and prompt
production from single-parton scattering, including the complete
color-singlet contribution, the
electroweak contribution, the complete
nonrelativistic S-wave and P-wave color-octet contribution as well as the
feeddown contribution. Our study was motivated by the recent evidence reported
by D0 Collaboration of prompt and simultaneous production
at the Tevatron. With our complete evaluation, we are able to refine the
determination of the double parton scattering contribution made by D0
Collaboration. We find that the effective cross section characterizing the
importance of double-parton scatterings is mb at
confidence level from the D0 measurement.Comment: 11 pages, 4 figures, 4 tables; v2: journal version, update the
references and fix a few typo
Split degenerate states and stable p+ip phases from holography
In this paper, we investigate the p+p superfluid phases in the complex
vector field holographic p-wave model. We find that in the probe limit, the
p+p phase and the p-wave phase are equally stable, hence the p and p
orders can be mixed with an arbitrary ratio to form more general p+p
phases, which are also equally stable with the p-wave and p+p phases. As a
result, the system possesses a degenerate thermal state in the superfluid
region. We further study the case with considering the back reaction on the
metric, and find that the degenerate ground states will be separated into
p-wave and p+p phases, and the p-wave phase is more stable. Finally, due to
the different critical temperature of the zeroth order phase transitions from
p-wave and p+p phases to the normal phase, there is a temperature region
where the p+p phase exists but the p-wave phase doesn't. In this region we
find the stable p+p phase for the first time.Comment: 16 pages, 5 figures; typos correcte
Observation of recoil-induced resonances and electromagnetically induced absorption of cold atoms in diffuse light
In this paper we report an experiment on the observation of the
recoil-induced resonances (RIR) and electromagnetically induced absorption
(EIA) of cold Rb87 atoms in diffuse light. The pump light of the RIR and the
EIA comes from the diffuse light in an integrating sphere, which also serves
the cooling light. The probe light beam is a weak laser split from the cooling
laser in order to keep the cooling and probe lasers correlated. We measured the
RIR and the EIA signal varying with the detuning of the diffuse laser light,
and also measured the temperature of the cold atoms at the different detunings.
The mechanism of RIR and EIA in the configuration with diffuse-light pumping
and laser probing is discussed, and the difference of nonlinear spectra of cold
atoms between in diffuse-light cooling system and in optical molasses as well
as in a magneto-optical trap (MOT) are studied.Comment: 9 pages, 6 figure
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