Technical University of Dortmund

About: Technical University of Dortmund is a education organization based out in Dortmund, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Context (language use) & Large Hadron Collider. The organization has 13028 authors who have published 27666 publications receiving 615557 citations. The organization is also known as: Dortmund University & University of Dortmund.

Angular distributions of B̄ → Kl̄l decays

Abstract: We model-independently analyze the angular distributions of → Kl decays, l = e,μ, for low dilepton mass using QCD factorization. Besides the decay rate, we study the forward-backward asymmetry AlFB and a further observable, FlH, which gives rise to a flat term in the angular distribution. We find that in the Standard Model FlH∝ml2, hence vanishing FeH and FμH of around 2% (exact value depends on cuts) with a very small theoretical uncertainty of a few percent. We also give predictions for RK, the ratio of → Kμ to → Kēe decay rates. We analytically show using large recoil symmetry relations that in the Standard Model RK equals one up to lepton mass corrections of the order 10−4 including αs and subleading 1/E power corrections. The New Physics reach of the observables from the → Kl angular analysis is explored together with RK and the s → l and → Xsl branching ratios for both l = e and l = μ. We find substantial room for signals from (pseudo-) scalar and tensor interactions beyond the Standard Model. Experimental investigations of the → Kμ angular distributions are suitable for the LHC environment and high luminosity B factories, where also studies of the electron modes are promising.

Measurement of the $B^0_s \to \mu^+ \mu^-$ branching fraction and search for $B^0 \to \mu^+ \mu^-$ decays at the LHCb experiment

Abstract: A search for the rare decays $B^0_s \to\mu^+\mu^-$ and $B^0 \to\mu^+\mu^-$ is performed at the LHCb experiment. The data analysed correspond to an integrated luminosity of 1 fb$^{-1}$ of $pp$ collisions at a centre-of-mass energy of 7 TeV and 2 fb$^{-1}$ at 8 TeV. An excess of $B^0_s \to\mu^+\mu^-$ signal candidates with respect to the background expectation is seen with a significance of 4.0 standard deviations. A time-integrated branching fraction of ${\cal B}(B^0_s \to\mu^+\mu^-) = (2.9^{+1.1}_{-1.0})\times 10^{-9}$ is obtained and an upper limit of ${\cal B}(B^0 \to\mu^+\mu^-) < 7.4\times 10^{-10}$ at 95% confidence level is set. These results are consistent with the Standard Model expectations.

Search for new high-mass phenomena in the dilepton final state using 36 fb−1 of proton-proton collision data at √s=13 TeV with the ATLAS detector

Abstract: A search is conducted for new resonant and non-resonant high-mass phenomena in dielectron and dimuon fi nal states. The search uses 36 : 1 fb(-1) of proton-proton collision data, collected at root ...