290 research outputs found

    A study of the centrally produced baryon-antibaryon systems in pp interactions at 450 GeV/c

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    A study of the centrally produced ppbar, ppbarpi, ppbarpipi and lambda lambda channels has been performed in pp collisions using an incident beam momentum of 450 GeV/c. No significant new structures are observed in the mass spectra, however, important new information on the production dynamics is obtained. A systematic study of the production properties of these systems has been performed and it is found that these systems are not produced dominantly by double Pomeron exchange.Comment: 13 pages, Latex, 4 Figure

    A study of pseudoscalar states produced centrally in pp interactions at 450 GeV/c

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    A study has been made of pseudoscalar mesons produced centrally in pp interactions. The results show that the eta and etaprime appear to have a similar production mechanism which differs from that of the pi0. The production properties of the eta and etaprime are not consistent with what is expected from double Pomeron exchange. In addition the production mechanism for the eta and etaprime is such that the production cross section are greatest when the azimuthal angle between the pT vectors of the two protons is 90 degrees.Comment: 11 pages, Latex, 3 Figure

    Activated T cells recruit exosomes secreted by dendritic cells via LFA-1

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    Contains fulltext : 79542.pdf (publisher's version ) (Closed access)Dendritic cells (DCs) are known to secrete exosomes that transfer membrane proteins, like major histocompatibility complex class II, to other DCs. Intercellular transfer of membrane proteins is also observed during cognate interactions between DCs and CD4(+) T cells. The acquired proteins are functional and play a role in regulation of immune responses. How membrane protein transfer is achieved and regulated is unclear. Here we show that T cells can recruit major histocompatibility complex class II-containing DC exosomes secreted in the extracellular milieu during cognate DC-T-cell interactions. Recruitment of these exosomes required T-cell activation and was dependent on leukocyte function-associated antigen-1 (LFA-1) rather than on T-cell receptor specificity. Indeed, inducing a high-affinity state of LFA-1 on resting T cells was sufficient to provoke exosome binding. These results imply that DC exosomes secreted in the extracellular milieu during cognate T-cell-DC interactions are targeted to T cells activated in that microenvironment

    A partial wave analysis of the centrally produced K+K- and K0K0 systems in pp interactions at 450 GeV/c and new information on the spin of the fJ(1710)

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    A partial wave analysis of the centrally produced K+K- and K0K0 channels has been performed in pp collisions using an incident beam momentum of 450 GeV/c. An unambiguous physical solution has been found in each channel. The striking feature is the observation of peaks in the S-wave corresponding to the f0(1500) and fJ(1710) with J = 0. The D-wave shows evidence for the f2(1270)/a2(1320), the f2(1525) and the f2(2150) but there is no evidence for a statistically significant contribution in the D-wave in the 1.7 GeV mass region.Comment: 15 pages, Latex, 5 Figure
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