252 research outputs found
The Outsider and Sunk Cost Effects on 'Dango' in Public Procurement Bidding: An Experimental Analysis.
This paper presents the result of experiments for finding some insight into an effect of the new bidding system in Japanese public construction works procurement on bidders' collusion, which is called 'dango'. We focused on an effect of the entry of an outsider who is not a dango member. The main conclusion of the experiments is that an outsider, a subject who is not allowed to communicate with other subjects, has a robust effect to prevent other subjects from colluding and to make the winning price decrease considerably.CONSTRUCTION ; PRICES ; BIDDING
Measurements of double-helicity asymmetries in inclusive production in longitudinally polarized collisions at GeV
We report the double helicity asymmetry, , in inclusive
production at forward rapidity as a function of transverse momentum
and rapidity . The data analyzed were taken during
GeV longitudinally polarized collisions at the Relativistic Heavy Ion
Collider (RHIC) in the 2013 run using the PHENIX detector. At this collision
energy, particles are predominantly produced through gluon-gluon
scatterings, thus is sensitive to the gluon polarization
inside the proton. We measured by detecting the decay
daughter muon pairs within the PHENIX muon spectrometers in the
rapidity range . In this kinematic range, we measured the
to be ~(stat)~~(syst). The
can be expressed to be proportional to the product of the
gluon polarization distributions at two distinct ranges of Bjorken : one at
moderate range where recent RHIC data of jet and
double helicity spin asymmetries have shown evidence for significant gluon
polarization, and the other one covering the poorly known small- region . Thus our new results could be used to further
constrain the gluon polarization for .Comment: 335 authors, 10 pages, 4 figures, 3 tables, 2013 data. Version
accepted for publication by Phys. Rev. D. Plain text data tables for the
points plotted in figures for this and previous PHENIX publications are (or
will be) publicly available at http://www.phenix.bnl.gov/papers.htm
meson production in Au collisions at GeV
The PHENIX experiment has measured meson production in Au
collisions at GeV using the dimuon and dielectron decay
channels. The meson is measured in the forward (backward) -going
(Au-going) direction, () in the transverse-momentum
() range from 1--7 GeV/, and at midrapidity in the
range below 7 GeV/. The meson invariant yields and
nuclear-modification factors as a function of , rapidity, and centrality
are reported. An enhancement of meson production is observed in the
Au-going direction, while suppression is seen in the -going direction, and
no modification is observed at midrapidity relative to the yield in
collisions scaled by the number of binary collisions. Similar behavior was
previously observed for inclusive charged hadrons and open heavy flavor
indicating similar cold-nuclear-matter effects.Comment: 484 authors, 16 pages, 12 figures, 6 tables. v1 is the version
accepted for publication in Phys. Rev. C. Data tables for the points plotted
in the figures are given in the paper itsel
Single electron yields from semileptonic charm and bottom hadron decays in AuAu collisions at GeV
The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured
open heavy-flavor production in minimum bias AuAu collisions at
GeV via the yields of electrons from semileptonic decays
of charm and bottom hadrons. Previous heavy-flavor electron measurements
indicated substantial modification in the momentum distribution of the parent
heavy quarks due to the quark-gluon plasma created in these collisions. For the
first time, using the PHENIX silicon vertex detector to measure precision
displaced tracking, the relative contributions from charm and bottom hadrons to
these electrons as a function of transverse momentum are measured in AuAu
collisions. We compare the fraction of electrons from bottom hadrons to
previously published results extracted from electron-hadron correlations in
collisions at GeV and find the fractions to be
similar within the large uncertainties on both measurements for
GeV/. We use the bottom electron fractions in AuAu and along
with the previously measured heavy flavor electron to calculate the
for electrons from charm and bottom hadron decays separately. We find
that electrons from bottom hadron decays are less suppressed than those from
charm for the region GeV/.Comment: 432 authors, 33 pages, 23 figures, 2 tables, 2011 data. v2 is version
accepted for publication by Phys. Rev. C. Plain text data tables for the
points plotted in figures for this and previous PHENIX publications are (or
will be) publicly available at http://www.phenix.bnl.gov/papers.htm
Inclusive cross section and double-helicity asymmetry for production at midrapidity in collisions at GeV
PHENIX measurements are presented for the cross section and double-helicity
asymmetry () in inclusive production at midrapidity from
collisions at ~GeV from data taken in 2012 and 2013 at
the Relativistic Heavy Ion Collider. The next-to-leading-order
perturbative-quantum-chromodynamics theory calculation is in excellent
agreement with the presented cross section results. The calculation utilized
parton-to-pion fragmentation functions from the recent DSS14 global analysis,
which prefer a smaller gluon-to-pion fragmentation function. The
results follow an increasingly positive asymmetry trend with
and with respect to the predictions and are in excellent
agreement with the latest global analysis results. This analysis incorporated
earlier results on and jet , and suggested a positive
contribution of gluon polarization to the spin of the proton for the
gluon momentum fraction range . The data presented here extend to a
currently unexplored region, down to , and thus provide additional
constraints on the value of . The results confirm the evidence for
nonzero using a different production channel in a complementary
kinematic region.Comment: 413 authors, 8 pages, 4 figures. v2 is version accepted as PRD Rapid
Communication. Plain text data tables for the points plotted in figures for
this and previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
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