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A bstract In the DsTau experiment at the CERN SPS (NA65), an independent and direct way to measure tau neutrino production following high energy proton interactions was proposed. As the main source of tau neutrinos is a decay of D s mesons, produced in proton-nucleus interactions, the project aims at measuring a differential cross section of this reaction. The experimental method is based on a use of high resolution emulsion detectors for effective registration of events with short lived particle decays. Here we present the motivation of the study, details of the experimental technique, and the first results of the analysis of the data collected during test runs, which prove feasibility of the full scale study of the process in future.

The charmless three-body decays B $_{(s}_{)}^{0}$ → K $_{S}^{0}$h $^{+}$h $^{′ −}$(where h $^{(′)}$= π, K) are analysed using a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 3 fb $^{−1}$ . The branching fractions are measured relative to that of the B $^{0}$  → K $_{S}^{0}$π $^{+}$π $^{−}$decay, and are determined to be:$ \\begin{array}{l}\\frac{\\mathrm{\\mathcal{B}}\\left({B}^0\\to {K}_{\\mathrm{S}}^0{K}^{\\pm }{\\pi}^{\\mp}\\right)}{\\mathrm{\\mathcal{B}}\\left({B}^0\\to {K}_{\\mathrm{S}}^0{K}^{+}{\\pi}^{-}\\right)}=0.123\\pm 0.009\\left(\\mathrm{stat}\\right)\\pm 0.015\\left(\\mathrm{syst}\\right),\\hfill \\\ {}\\frac{\\mathrm{\\mathcal{B}}\\left({B}^0\\to {K}_{\\mathrm{S}}^0{K}^{+}{K}^{-}\\right)}{\\mathrm{\\mathcal{B}}\\left({B}^0\\to {K}_{\\mathrm{S}}^0{\\pi}^{+}{\\pi}^{-}\\right)}=0.549\\pm 0.018\\left(\\mathrm{stat}\\right)\\pm 0.033\\left(\\mathrm{syst}\\right),\\hfill \\\ {}\\frac{\\mathrm{\\mathcal{B}}\\left({B}_s^0\\to {K}_{\\mathrm{S}}^0{\\pi}^{+}{\\pi}^{-}\\right)}{\\mathrm{\\mathcal{B}}\\left({B}^0\\to {K}_{\\mathrm{S}}^0{\\pi}^{+}{\\pi}^{-}\\right)}=0.191\\pm 0.027\\left(\\mathrm{stat}\\right)\\pm 0.031\\left(\\mathrm{syst}\\right)\\pm 0.011\\left({f}_s/{f}_d\\right),\\hfill \\\ {}\\frac{\\mathrm{\\mathcal{B}}\\left({B}_s^0\\to {K}_{\\mathrm{S}}^0{K}^{\\pm }{\\pi}^{\\mp}\\right)}{\\mathrm{\\mathcal{B}}\\left({B}^0\\to {K}_{\\mathrm{S}}^0{\\pi}^{+}{\\pi}^{-}\\right)}=1.70\\pm 0.07\\left(\\mathrm{stat}\\right)\\pm 0.11\\left(\\mathrm{syst}\\right)\\pm 0.10\\left({f}_s/{f}_d\\right),\\hfill \\\ {}\\frac{\\mathrm{\\mathcal{B}}\\left({B}_s^0\\to {K}_{\\mathrm{S}}^0{K}^{+}{K}^{-}\\right)}{\\mathrm{\\mathcal{B}}\\left({B}^0\\to {K}_{\\mathrm{S}}^0{\\pi}^{+}{\\pi}^{-}\\right)}\\in \\left[0.008-0.051\\right]\\kern0.5em \\mathrm{at}\\kern0.5em 90\\%\\kern0.5em \\mathrm{confidence}\\kern0.5em \\mathrm{level},\\hfill \\end{array} $where f $_{s}$/f $_{d}$represents the ratio of hadronisation fractions of the B $_{s}^{0}$and B $^{0}$mesons.

The TT-PET collaboration is developing a small animal TOF-PET scanner based on monolithic silicon pixel sensors in SiGe BiCMOS technology. The demonstrator chip, a small-scale version of the final detector ASIC, consists of a 3 x 10 pixel matrix integrated with the front-end, a 50 ps binning TDC and read out logic. The chip, thinned down to 100 m and backside metallized, was operated at a voltage of 180 V. The tests on a beam line of minimum ionizing particles show a detection efficiency greater than 99.9 % and a time resolution down to 110 ps.

In the DsTau experiment at the CERN SPS, an independent and direct way to measure tau neutrino production following high energy proton interactions was proposed. As the main source of tau neutrinos is a decay of Ds mesons, produced in proton-nucleus interactions, the project aims at measuring a differential cross section of this reaction. The experimental method is based on a use of high resolution emulsion detectors for effective registration of events with short lived particle decays. Here we present the motivation of the study, details of the experimental technique, and the first results of the analysis of the data collected during test runs, which prove feasibility of the full scale study of the process in future.

This paper reports on the characterisation with Transient Current Technique measurements of the charge collection and depletion depth of a radiation-hard high-voltage CMOS pixel sensor produced at ams AG. Several substrate resistivities were tested before and after proton irradiation with two different sources: the 24 GeV Proton Synchrotron at CERN and the 16.7 MeV Cyclotron at Bern Inselspital.

The ratios of the branching fractions of the decays $\\Lambda_{c}^{+} \\rightarrow p \\pi^{-} \\pi^{+}$, $\\Lambda_{c}^{+} \\rightarrow p K^{-} K^{+}$, and $\\Lambda_{c}^{+} \\rightarrow p \\pi^{-} K^{+}$ with respect to the Cabibbo-favoured $\\Lambda_{c}^{+} \\rightarrow p K^{-} \\pi^{+}$ decay are measured using proton-proton collision data collected with the LHCb experiment at a 7 TeV centre-of-mass energy and corresponding to an integrated luminosity of 1.0 fb$^{-1}$: \\begin{align*} \\frac{\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p \\pi^{-} \\pi^{+})}{\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p K^{-} \\pi^{+})} & = (7.44 \\pm 0.08 \\pm 0.18)\\,\\%, \\frac{\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p K^{-} K^{+})}{\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p K^{-} \\pi^{+})} &= (1.70 \\pm 0.03 \\pm 0.03)\\,\\%, \\frac{\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p \\pi^{-} K^{+})}{\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p K^{-} \\pi^{+})} & = (0.165 \\pm 0.015 \\pm 0.005 )\\,\\%, \\end{align*} where the uncertainties are statistical and systematic, respectively. These results are the most precise measurements of these quantities to date. When multiplied by the world-average value for $\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p K^{-} \\pi^{+})$, the corresponding branching fractions are \\begin{align*} \\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p \\pi^{-} \\pi^{+}) &= (4.72 \\pm 0.05 \\pm 0.11 \\pm 0.25) \\times 10^{-3}, \\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p K^{-} K^{+}) &= (1.08 \\pm 0.02 \\pm 0.02 \\pm 0.06) \\times 10^{-3}, \\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p \\pi^{-} K^{+}) &= (1.04 \\pm 0.09 \\pm 0.03 \\pm 0.05) \\times 10^{-4}, \\end{align*} where the final uncertainty is due to $\\mathcal{B}(\\Lambda_{c}^{+} \\rightarrow p K^{-} \\pi^{+})$.

A search for charmless four-body decays of $\\Lambda_{b}^{0}$ and $\\Xi_{b}^{0}$ baryons with a proton and three charged mesons (either kaons or pions) in the final state is performed. The data sample used was recorded in 2011 and 2012 with the LHCb experiment and corresponds to an integrated luminosity of 3 fb$^{-1}$. Six decay modes are observed, among which $\\Lambda_{b}^{0} \\to pK^{-}\\pi^{+}\\pi^{-}$, $\\Lambda_{b}^{0} \\to pK^{-}K^{+}K^{-}$, $\\Xi_{b}^{0} \\to pK^{-}\\pi^{+}\\pi^{-}$ and $\\Xi_{b}^{0} \\to pK^{-} \\pi^{+}K^{-}$ are established for the first time. Their branching fractions (including the ratio of hadronisation fractions in the case of the $\\Xi_{b}^{0}$ baryon) are determined relative to the $\\Lambda_{b}^{0} \\to \\Lambda_{c}^{+}\\pi^{-}$ decay.

A search for the lepton-flavour violating decays B$_{s}^{0}$ → e$^{±}$μ$^{∓}$ and B$^{0}$ → e$^{±}$μ$^{∓}$ is performed based on a sample of proton-proton collision data corresponding to an integrated luminosity of 3 fb$^{−1}$, collected with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The observed yields are consistent with the background-only hypothesis. Upper limits on the branching fraction of the B$_{s}^{0}$ → e$^{±}$μ$^{∓}$ decays are evaluated both in the hypotheses of an amplitude completely dominated by the heavy eigenstate and by the light eigenstate. The results are $ \\frac{@}{@}\\mathrm{\\mathcal{B}}\\left({B}_s^0\\to {e}^{\\pm }{\\mu}^{\\mp}\\right)<6.3(5.4)\\times 1{0}^{-9} $ and $ \\frac{@}{@}\\mathrm{\\mathcal{B}}\\left({B}_s^0\\to {e}^{\\pm }{\\mu}^{\\mp}\\right)<7.2(6.0)\\times 1{0}^{-9} $ at 95% (90%) confidence level, respectively. The upper limit on the branching fraction of the B$^{0}$ → e$^{±}$μ$^{∓}$ decay is also evaluated, obtaining $ \\frac{@}{@}\\mathrm{\\mathcal{B}}\\left({B}^0\\to {e}^{\\pm }{\\mu}^{\\mp}\\right)<1.3(1.0)\\times 1{0}^{-9} $ at 95% (90%) confidence level. These are the strongest limits on these decays to date.

A search for B$^{+}$ → D$_{s}^{+}$ K$^{+}$K$^{−}$ decays is performed using pp collision data corresponding to an integrated luminosity of 4.8 fb$^{−1}$, collected at centre-of-mass energies of 7, 8 and 13 TeV with the LHCb experiment. A significant signal is observed for the first time and the branching fraction is determined to be $\\mathcal{B}(B^+ \\to D_{s}^+ K^+ K^-) = (7.1\\pm 0.5\\pm 0.6\\pm 0.7) \\times 10^{-6}$ where the first uncertainty is statistical, the second systematic and the third due to the uncertainty on the branching fraction of the normalisation mode $B^+ \\to D^{+}_s \\bar{D}^0$. A search is also performed for the pure annihilation decay $B^+ \\to D_{s}^+ \\phi$. No significant signal is observed and a limit of $\\mathcal{B}(B^+ \\to D_{s}^+ \\phi) < 4.9 \\times 10^{-7} (4.2 \\times 10^{-7})$ is set on the branching fraction at 95% (90%) confidence level.