Rubin-LSST

Abstract:

Double diffraction differential cross sections in pp collisions at √s = 1800 and 630 GeV were measured. Results were compared with data at √s = 200 and 900 GeV and with predictions based on Regge theory and factorization. A factorization breakdown comparable in magnitude to that observed in single diffraction dissociation was found. The data are in agreement with the renormalized gap probability model.

Abstract:

We present HST WFPC2 I band imaging for a sample of 9 Hyperluminous Infrared Galaxies spanning a redshift range 0.45 < z < 1.34. Three of the sample have morphologies showing evidence for interactions, six are QSOs. Host galaxies in the QSOs are reliably detected out to z ~ 0.8. The detected QSO host galaxies have an elliptical morphology with scalelengths spanning 6.5 < r_{e}(Kpc) < 88 and absolute k corrected magnitudes spanning -24.5 < M_{I} < -25.2. There is no clear correlation between the IR power source and the optical morphology. None of the sources in the sample, including F15307+3252, show any evidence for gravitational lensing. We infer that the IR luminosities are thus real. Based on these results, and previous studies of HLIRGs, we conclude that this class of object is broadly consistent with being a simple extrapolation of the ULIRG population to higher luminosities; ULIRGs being mainly violently interacting systems powered by starbursts and/or AGN. Only a small number of sources whose infrared luminosities exceed 10^{13}Lsun are intrinsically less luminous objects which have been boosted by gravitational lensing.

Abstract:

A study was carried out to search for the decay Υ → γη' with the decay mode η' → ηπ⁺π^- and three decay modes of the η. Using simple, loose selection criteria, no candidates were found and the 90%C C.L. limit of B(Υ → γη') 1.6 × 10^-5 was set.