Pour la seconde fois, les élections européennes en France se déroulaient dans le cadre de huit « grandes régions ». Ces « circonscriptions » ont fait l’objet de fort peu de commentaires, aussi bien ...de la part des politistes que des géographes. Les élections européennes de 2009 sont l’occasion d’observer s’il existe ou non un effet « macro-régional ». En effet, prévues à l’origine pour « territorialiser » la campagne électorale des députés européens, ces « nouvelles » circonscriptions soulèven...
Cross sections for midrapidity production of direct photons in p+p collisions at the Relativistic Heavy Ion Collider (RHIC) are reported for transverse momenta of 3 < pT < 16 GeV/c. Next-to-leading ...order perturbative QCD (pQCD) describes the data well for pT >5 GeV/c, where the uncertainties of the measurement and theory are comparable. We also report on the effect of requiring the photons to be isolated from parton jet energy. The observed fraction of isolated photons is well described by pQCD for pT >7 GeV/c.
The XMM-LSS survey Valtchanov, I.; Pierre, M.; Willis, J. ...
Astronomy & astrophysics,
08/2004, Volume:
423, Issue:
1
Journal Article
Peer reviewed
Open access
We present five newly found galaxy clusters at $z>0.6$ from the XMM Large-Scale Structure Survey (XMM-LSS). All five objects are extended X-ray sources in the XMM images. For three of them we have ...sufficient spectroscopically confirmed member galaxies that an estimate of the velocity dispersion is possible: XLSSC 001 at $z=0.613$ and $\sigma_V=867^{+80}_{-60}$ km s-1, XLSSC 002 at $z=0.772$ and $\sigma_V=524^{+267}_{-116}$ km s-1 and XLSSC 003 at $z=0.839$ and $\sigma_V=780^{+137}_{-75}$ km s-1. These three clusters have X-ray bolometric luminosities $L_{\rm X} \sim 1{-}3 \times 10^{44}$ erg s-1 and temperatures $2{-}4$ keV, and consequently are less massive than previously known clusters at similar redshifts, but nevertheless they follow the low redshift scaling relations between $L_{\rm X}, T$ and $\sigma_v$, within the limits of the measurement errors. One of the clusters, XLSSC 004, is detected independently as an overdensity of galaxies of a colour $R-z'=1.4$ that matches the redshift of the central galaxy $z=0.87$, although it cannot unambiguously be confirmed by the spectroscopic observations alone. The highest redshift candidate cluster pertaining to this paper, XLSSC 005, is most likely a double cluster complex at a redshift around unity, associated with an extended X-ray source with probable substructure.
Emission source functions are extracted from correlation functions constructed from charged pions produced at mid-rapidity in Au+Au collisions at sqrt(s_NN)=200 GeV. The source parameters extracted ...from these functions at low k_T, give first indications of a long tail for the pion emission source. The source extension cannot be explained solely by simple kinematic considerations. The possible role of a halo of secondary pions from resonance emissions is explored.
Correlations between p and p¯ at transverse momenta typical of enhanced baryon production in Au+Au collisions are reported. The PHENIX experiment has measured same and opposite sign baryon pairs in ...Au+Au collisions at sNN=200 GeV. Correlated production of p and p¯ with the trigger particle from the range 2.5<pT<4.0 GeV/c and the associated particle with 1.8<pT<2.5 GeV/c is observed to be nearly independent of the centrality of the collisions. Same sign pairs show no correlation at any centrality. The conditional yield of mesons triggered by baryons (and anti-baryons) and mesons in the same pT range rises with increasing centrality, except for the most central collisions, where baryons show a significantly smaller number of associated mesons. These data are consistent with a picture in which hard scattered partons produce correlated p and p¯ in the pT region of the baryon excess.
Cannabis, status in 2001-2002 Noirfalise, A; Gosset, Ch; Maisse, L
Revue médicale de Liège
57, Issue:
11
Journal Article
Peer reviewed
Even though its use becomes common, cannabis remains a narcotic, the risks of which are nowadays better known. Its therapeutic value still needs to be scientifically demonstrated.
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