744 research outputs found
An intron 9 containing splice variant of PAX2
© 2009 Busse et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Inclusive Production Cross Sections from 920 GeV Fixed Target Proton-Nucleus Collisions
Inclusive differential cross sections and
for the production of \kzeros, \lambdazero, and
\antilambda particles are measured at HERA in proton-induced reactions on C,
Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to
GeV in the proton-nucleon system. The ratios of differential
cross sections \rklpa and \rllpa are measured to be and , respectively, for \xf . No significant dependence upon the
target material is observed. Within errors, the slopes of the transverse
momentum distributions also show no significant
dependence upon the target material. The dependence of the extrapolated total
cross sections on the atomic mass of the target material is
discussed, and the deduced cross sections per nucleon are
compared with results obtained at other energies.Comment: 17 pages, 7 figures, 5 table
Deuteron and antideuteron production in Au+Au collisions at sqrt(s_NN)=200 GeV
The production of deuterons and antideuterons in the transverse momentum
range 1.1 < p_T < 4.3 GeV/c at mid-rapidity in Au + Au collisions at
sqrt(s_NN)=200 GeV has been studied by the PHENIX experiment at RHIC. A
coalescence analysis comparing the deuteron and antideuteron spectra with those
of protons and antiprotons, has been performed. The coalescence probability is
equal for both deuterons and antideuterons and increases as a function of p_T,
which is consistent with an expanding collision zone. Comparing (anti)proton
yields p_bar/p = 0.73 +/- 0.01, with (anti)deuteron yields: d_bar/d = 0.47 +/-
0.03, we estimate that n_bar/n = 0.64 +/- 0.04.Comment: 326 authors, 6 pages text, 5 figures, 1 Table. Submitted to PRL.
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
Mid-Rapidity Direct-Photon Production in p+p Collisions at sqrt(s) = 200 GeV
A measurement of direct photons in p+p collisions at sqrt(s)=200 GeV is
presented. A photon excess above background from pi^0 --> gamma+gamma, eta -->
gamma+gamma, and other decays is observed in the transverse momentum range 5.5
< p_T < 7 GeV/c. The result is compared to a next-to-leading-order perturbative
QCD calculation. Within errors, good agreement is found between the QCD
calculation and the measured result.Comment: 330 authors, 7 pages text, RevTeX, 2 figures, 2 tables. Submitted to
Physical Review 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
Suppressed pi^0 Production at Large Transverse Momentum in Central Au+Au Collisions at sqrt(s_NN) = 200 GeV
Transverse momentum spectra of neutral pions in the range 1 < p_T < 10 GeV/c
have been measured at mid-rapidity by the PHENIX experiment at RHIC in Au+Au
collisions at sqrt(s_NN) = 200 GeV. The pi^0 multiplicity in central reactions
is significantly below the yields measured at the same sqrt(s_NN) in peripheral
Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions. For
the most central bin, the suppression factor is ~2.5 at p_T = 2 GeV/c and
increases to ~4-5 at p_T ~= 4 GeV/c. At larger p_T, the suppression remains
constant within errors. The deficit is already apparent in semi-peripheral
reactions and increases smoothly with centrality.Comment: 326 authors, 6 pages text, RevTeX, 3 figures, 2 tables. Submitted to
PRL. 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
Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA
An investigation of the hadronic final state in diffractive and
non--diffractive deep--inelastic electron--proton scattering at HERA is
presented, where diffractive data are selected experimentally by demanding a
large gap in pseudo --rapidity around the proton remnant direction. The
transverse energy flow in the hadronic final state is evaluated using a set of
estimators which quantify topological properties. Using available Monte Carlo
QCD calculations, it is demonstrated that the final state in diffractive DIS
exhibits the features expected if the interaction is interpreted as the
scattering of an electron off a current quark with associated effects of
perturbative QCD. A model in which deep--inelastic diffraction is taken to be
the exchange of a pomeron with partonic structure is found to reproduce the
measurements well. Models for deep--inelastic scattering, in which a
sizeable diffractive contribution is present because of non--perturbative
effects in the production of the hadronic final state, reproduce the general
tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil
J/Psi Production in Au-Au Collisions at sqrt(s_NN) = 200 GeV at the Relativistic Heavy Ion Collider
First results on charm quarkonia production in heavy ion collisions at the
Relativistic Heavy Ion Collider (RHIC) are presented. The yield of J/Psi's
measured in the PHENIX experiment via electron-positron decay pairs at
mid-rapidity for Au-Au reactions at sqrt(s_NN) = 200 GeV are analyzed as a
function of collision centrality. For this analysis we have studied 49.3
million minimum bias Au-Au reactions. We present the J/Psi invariant yield
dN/dy for peripheral and mid-central reactions. For the most central collisions
where we observe no signal above background, we quote 90% confidence level
upper limits. We compare these results with our J/Psi measurement from
proton-proton reactions at the same energy. We find that our measurements are
not consistent with models that predict strong enhancement relative to binary
collision scaling.Comment: 325 authors, 11 pages text, 6 figures, 4 tables, RevTeX 4. Accepted
for publication as a regular article in Physical Review C. This version has
minor changes to respond to referee suggestions. Plain text data tables for
the points plotted in figures for this and previous PHENIX publications are
publicly available at http://www.phenix.bnl.gov/papers.htm
Scaling properties of proton and anti-proton production in sqrt(s_NN) = 200 GeV Au + Au collisions
We report on the yield of protons and anti-protons, as a function of
centrality and transverse momentum, in Au+Au collisions at sqrt(s_NN) = 200 GeV
measured at mid-rapidity by the PHENIX experiment at RHIC. In central
collisions at intermediate transverse momenta (1.5 < p_T < 4.5 GeV/c) a
significant fraction of all produced particles are protons and anti-protons.
They show a centrality-scaling behavior different from that of pions. The
p-bar/pion and p/pion ratios are enhanced compared to peripheral Au+Au, p+p,
and electron+positron collisions. This enhancement is limited to p_T < 5 GeV/c
as deduced from the ratio of charged hadrons to pi^0 measured in the range 1.5
< p_T < 9 GeV/c.Comment: 325 authors, 6 pages text, 4 figures, RevTeX 4. Minor changes to text
and figures to meet PRL length restrictions; no changes to figures;
resubmitted to PRL. 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
A Detailed Study of High-pT Neutral Pion Suppression and Azimuthal Anisotropy in Au+Au Collisions at \sqrt{s_{NN}} = 200 GeV
Measurements of neutral pion production at midrapidity in sqrt(s_NN) = 200
GeV Au+Au collisions as a function of transverse momentum, p_T, collision
centrality, and angle with respect to reaction plane are presented. The data
represent the final pi^0 results from the PHENIX experiment for the first RHIC
Au+Au run at design center-of-mass-energy. They include additional data
obtained using the PHENIX Level-2 trigger with more than a factor of three
increase in statistics over previously published results for p_T > 6 GeV/c. We
evaluate the suppression in the yield of high-p_T pi^0's relative to point-like
scaling expectations using the nuclear modification factor R_AA. We present the
p_T dependence of R_AA for nine bins in collision centrality. We separately
integrate R_AA over larger p_T bins to show more precisely the centrality
dependence of the high-p_T suppression. We then evaluate the dependence of the
high-p_T suppression on the emission angle \Delta\phi of the pions with respect
to event reaction plane for 7 bins in collision centrality. We show that the
yields of high-p_T pi^0's vary strongly with \Delta\phi, consistent with prior
measurements. We show that this variation persists in the most peripheral bin
accessible in this analysis. For the peripheral bins we observe no suppression
for neutral pions produced aligned with the reaction plane while the yield of
pi^0's produced perpendicular to the reaction plane is suppressed by more than
a factor of 2. We analyze the combined centrality and \Delta\phi dependence of
the pi^0 suppression in different p_T bins using different possible
descriptions of parton energy loss dependence on jet path-length averages to
determine whether a single geometric picture can explain the observed
suppression pattern.Comment: 330 authors, pages text, RevTeX4, figures, tables. Submitted to
Physical Review 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
Physical activity, suicidal ideation, suicide attempt and death among individuals with mental or other medical disorders: A systematic review of observational studies
A growing body of research has demonstrated the potential role for physical activity as an intervention across mental and other medical disorders. However, the association between physical activity and suicidal ideation, attempts, and deaths has not been systematically appraised in clinical samples. We conducted a PRISMA 2020-compliant systematic review searching MEDLINE, EMBASE, and PsycINFO for observational studies investigating the influence of physical activity on suicidal behavior up to December 6, 2023. Of 116 eligible full-text studies, seven (n = 141691) were included. Depression was the most frequently studied mental condition (43%, k = 3), followed by chronic pain as the most common other medical condition (29%, k = 2). Two case-control studies examined suicide attempts and found an association between physical activity and a reduced frequency of such attempts. However, in studies examining suicidal ideation (k = 3) or suicide deaths (k = 2), no consistent associations with physical activity were observed. Overall, our systematic review found that physical activity may be linked to a lower frequency of suicide attempts in non-prospective studies involving individuals with mental disorders
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