Rare Charm Decays at LHCb

Studies of rare decays are an indirect probe of New Physics (NP). This document presents recent measurements of rare decays in the charm sector by the LHCb experiment. The analyses are performed with proton-proton collision data at $\sqrt{s}$ = 7 TeV recorded in 2011.Comment: to appear in the proceedings of The 6th International Workshop on Charm Physics (CHARM 2013

Search for the Standard Model Higgs Boson at LEP

Preliminary results from the four LEP experiments using data collected at 189 GeV have shown no evidence for the Standard Model Higgs boson. The preliminary 95% confidence level lower limits on the SM Higgs boson mass from ALEPH, DELPHI, OPAL, and L3 are 90.4 GeV, 94.1 GeV, 95.5 GeV, and 95.2 GeV, respectively. When LEP finishes in the year 2000, each experiment expects to collect 200 pb-1 of data at 200 GeV. These data will allow the discovery of the SM Higgs boson with a mass lower than about 105 GeV. Assuming that no new evidence for the SM Higgs boson is found, the mass exclusion limit would be approximately 110 GeV.Comment: 5 pages with 4 figures Submitted to UCLS/DPF 99 Conference Proceeding

A Multi-coloured survey of NGC 253 with XMM-Newton

There is a large body of work that has used the excellent Chandra observations of nearby galaxies with neglible low mass X-ray binary (LMXB) populations. This has culminated in a ``Universal'' X-ray luminosity function (XLF) for high mass X-ray binaries (HMXBs). However, a number of methods have been used to convert from source intensities to luminosities when creating these XLFs. We have taken advantage of the XMM-Newton observations of the nearby starbursting spiral galaxy NGC 253 to test some of these methods. We find the luminosities derived from these various methods to vary by a factor of $\sim$3. We also find the most influential factor in the conversion from intensity to luminosity to be the absorption. We therefore conclude that a more consistent approach is required for determining the true Universal XLF for HMXBs. Ideally, this would involve individual spectral fitting of each X-ray source. Certainly, the line-of-sight absorption should be determined from the observations rather than assuming Galactic absorption. We find the best approach for obtaining an XLF from low-count data to be the splitting of the X-ray sources into two or more intensity intervals, and obtaining a conversion from intensity to flux for each group from spectral modelling of the summed spectrum of that group.Comment: To appear in the proceedings of "X-rays from Nearby Galaxies", 4-7 Septembeer 2007, 4 page