Abstract Forward top quark pair production is studied in pp collisions in the μeb final state using a data sample corresponding to an integrated luminosity of 1.93 fb−1 collected with the LHCb ...experiment at a centre-of-mass energy of 13 TeV. The cross-section is measured in a fiducial region where both leptons have a transverse momentum greater than 20 GeV and a pseudorapidity between 2.0 and 4.5. The quadrature sum of the azimuthal separation and the difference in pseudorapidities, denoted ΔR, between the two leptons must be larger than 0.1. The b-jet axis is required to be separated from both leptons by a ΔR of 0.5, and to have a transverse momentum in excess of 20 GeV and a pseudorapidity between 2.2 and 4.2. The cross-section is measured to be σtt¯=126±19stat±16syst±5lumifb $$ {\sigma}_{t\overline{t}}=126\pm 19\left(\mathrm{stat}\right)\pm 16\left(\mathrm{syst}\right)\pm 5\left(\mathrm{lumi}\right)\mathrm{f}\mathrm{b} $$ where the first uncertainty is statistical, the second is systematic, and the third is due to the luminosity determination. The measurement is compatible with the Standard Model prediction.
Abstract The inclusive D s ± production asymmetry is measured in pp collisions collected by the LHCb experiment at centre-of-mass energies of s=7 $$ \sqrt{s}=7 $$ and 8 TeV. Promptly produced D s ± ...mesons are used, which decay as D s ± → ϕπ±, with ϕ → K + K −. The measurement is performed in bins of transverse momentum, p T, and rapidity, y, covering the range 2.5 < p T < 25.0 GeV/c and 2.0 < y < 4.5. No kinematic dependence is observed. Evidence of nonzero D s ± production asymmetry is found with a significance of 3.3 standard deviations.
In this work, we measure the branching fraction of B-→τ- ν¯ τ using the full Υ ( 4S ) data sample containing 772×106 B B¯ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- ...collider. Events with B B¯ pairs are tagged by reconstructing one of the B mesons decaying into hadronic final states, and B-→τ- ν¯ τ candidates are detected in the recoil. We discover evidence for B-→τ- ν¯ τ with a significance of 3.0 standard deviations including systematic errors and measure a branching fraction B ( B-→τ- ν¯ τ ) = 0.72-0.25+0.27 ( stat ) ±0.11 ( syst ) ×10-4 .
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Abstract A search for the decay BS0→K¯∗0μ+μ− $$ {B}_S^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-} $$ is presented using data sets corresponding to 1.0, 2.0 and 1.6 fb−1 of integrated luminosity ...collected during pp collisions with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, respectively. An excess is found over the background-only hypothesis with a significance of 3.4 standard deviations. The branching fraction of the BS0→K¯∗0μ+μ− $$ {B}_S^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-} $$ decay is determined to be ℬBs0→K¯∗0μ+μ−=2.9±1.0stat±0.2syst±0.3norm×10−8 $$ \mathrm{\mathcal{B}}\left({B}_s^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-}\right)=\left2.9\pm 1.0\left(\mathrm{stat}\right)\pm 0.2\left(\mathrm{syst}\right)\pm 0.3\left(\mathrm{norm}\right)\right\times {10}^{-8} $$, where the first and second uncertainties are statistical and systematic, respectively. The third uncertainty is due to limited knowledge of external parameters used to normalise the branching fraction measurement.
Abstract The production cross-sections of ϒ(1S), ϒ(2S) and ϒ(3S) mesons in proton-proton collisions at s = 13 $$ \sqrt{s}=13 $$ TeV are measured with a data sample corresponding to an integrated ...luminosity of 277 ± 11 pb−1 recorded by the LHCb experiment in 2015. The ϒ mesons are reconstructed in the decay mode ϒ → μ + μ −. The differential production cross-sections times the dimuon branching fractions are measured as a function of the ϒ transverse momentum, p T, and rapidity, y, over the range 0 < p T < 30 GeV/c and 2.0 < y < 4.5. The ratios of the cross-sections with respect to the LHCb measurement at s = 8 $$ \sqrt{s}=8 $$ TeV are also determined. The measurements are compared with theoretical predictions based on NRQCD.
Preliminary results of an experiment that is aimed at measuring the cross section for the process
e
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e
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K
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K
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at c.m. energies in the range between 1.01 and 2.0 GeV with the aid of the CMD-3 ...detector and which is being performed at the VEPP-2000 collider of the Budker Institute of Nuclear Physics (Novosibirsk, Siberian Branch, Russian Academy of Sciences) are presented.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We search for lepton flavor and lepton number violating τ decays into a lepton (ℓ=electron or muon) and two charged mesons (h,h′=π± or K±), τ−→ℓ−h+h′− and τ−→ℓ+h−h′−, using 671 fb−1 of data collected ...with the Belle detector at the KEKB asymmetric-energy e+e− collider. We obtain 90% C.L. upper limits on the branching fractions in the range (4.4–8.8)×10−8 for τ→ehh′, and (3.3–16)×10−8 for τ→μhh′ processes. These results improve upon previously published upper limits by factors between 1.6 to 8.8.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK
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