An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Notulae to the Italian flora of algae, bryophytes, fungi and lichens: 10

In this contribution, new data concerning red algae, bryophytes, fungi and lichens of the Italian flora are presented. It includes new records and confirmations for the algal genus Thorea, for the bryophyte genera Ephemerum, Hedwigia, Pogonatum, Riccia, Sphagnum, and Tortella, the fungal genera Pileolaria and Sporisorium, and the lichen genera Bacidia, Cerothallia, Chaenotheca, Cladonia, Halecania, Lecanora, Phylloblastia, Physcia, Protoparmelia, Pycnora, Segestria, and Sphaerophoru

An embedding technique to determine ττ\tau\tau backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model $\tau\tau$ backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed $\mu\mu$ events and replaced with simulated tau leptons with the same kinematic properties. In this way a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at $\sqrt{s}=$ 13 TeV corresponding to an integrated luminosity of 41.5 fb$^{-1}$

Measurement of exclusive ρ(770)0\rho(770)^0 photoproduction in ultraperipheral pPb collisions at sNN=\sqrt{s_\mathrm{NN}} = 5.02 TeV

Exclusive $\rho^0$(770) photoproduction is measured for the first time in ultraperipheral pPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV with the CMS detector. The cross section $\sigma (\gamma$p $\to$ $\rho^0$(770)p) is 11.2 $\pm$ 1.4 (stat) $\pm$ 1.0 (syst) $\mu$b at $\langle W_{\gamma\mathrm{p}}\rangle =$ 92.6 GeV for photon-proton centre-of-mass energies $W_{\gamma\mathrm{p}}$ between 29 and 213 GeV. The differential cross section d$\sigma/$d$|t|$ is measured in the interval 0.025$< |t| < 1$ GeV$^{2}$ as a function of $W_{\gamma\mathrm{p}}$, where $t$ is the squared four-momentum transfer at the proton vertex. The results are compared with previous measurements and theoretical predictions. The measured cross section $\sigma (\gamma$ p$\to \rho^0$(770)p) has a power-law dependence on the photon-proton centre-of-mass, consistent with electron-proton collision measurements performed at HERA. The $W_{\gamma\mathrm{p}}$ dependence of the exponential slope of the differential cross section d$\sigma/$d$|t|$ is also measured and is consistent with the previous measurements