A search for the lepton flavor violating $\tau$$\to$ 3$\mu$ decay is performed using proton-proton collision events at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2017-2018, corresponding to an integrated luminosity of 97.7 fb$^{-1}$. Tau leptons produced in both heavy-flavor hadron and W boson decays are exploited in the analysis. No evidence for the decay is observed. The results of this search are combined with an earlier null result based on data collected in 2016 to obtain a total integrated luminosity of 131 fb$^{-1}$. The observed (expected) upper limits on the branching fraction $\mathcal{B}$($\tau$$\to$ 3$\mu$) at confidence levels of 90 and 95% are 2.9 $\times$ 10$^{-8}$ (2.4 $\times$ 10$^{-8}$) and 3.6 $\times$ 10$^{-8}$ (3.0 $\times$ 10$^{-8}$), respectively.
Expected and observed upper limits on the $\tau\to3\mu$ branching fraction at 90% of confidence level for different categories of the analyis.
Expected and observed upper limits on the $\tau\to3\mu$ branching fraction at 95% of confidence level for the Run2 combination.
The measurements of the production of prompt ${\rm D^0}$, ${\rm D^+}$, ${\rm D^{*+}}$, and ${{\rm D^+_s}}$ mesons in proton--proton (pp) collisions at $\sqrt{s}=5.02$ TeV with the ALICE detector at the Large Hadron Collider (LHC) are reported. D mesons were reconstructed at mid-rapidity ($|y|<0.5$) via their hadronic decay channels ${\rm D}^0 \to {\rm K}^-\pi^+$, ${\rm D}^+\to {\rm K}^-\pi^+\pi^+$, ${\rm D}^{*+} \to {\rm D}^0 \pi^+ \to {\rm K}^- \pi^+ \pi^+$, ${\rm D^{+}_{s}\to \phi\pi^+\to K^{+} K^{-} \pi^{+}}$, and their charge conjugates. The production cross sections were measured in the transverse momentum interval $0<p_{\rm T}<36~\mathrm{GeV}/c$ for ${\rm D^0}$, $1<p_{\rm T}<36~\mathrm{GeV}/c$ for ${\rm D^+}$ and ${\rm D^{*+}}$, and in $2<p_{\rm T}<24~\mathrm{GeV}/c$ for ${{\rm D^+_s}}$ mesons. Thanks to the higher integrated luminosity, an analysis in finer $p_{\rm T}$ bins with respect to the previous measurements at $\sqrt{s}=7$ TeV was performed, allowing for a more detailed description of the cross-section $p_{\rm T}$ shape. The measured $p_{\rm T}$-differential production cross sections are compared to the results at $\sqrt{s}=7$ TeV and to four different perturbative QCD calculations. Its rapidity dependence is also tested combining the ALICE and LHCb measurements in pp collisions at $\sqrt{s}=5.02$ TeV. This measurement will allow for a more accurate determination of the nuclear modification factor in p-Pb and Pb-Pb collisions performed at the same nucleon-nucleon centre-of-mass energy.
$p_{\rm T}$-differential cross section of prompt $\rm{D}^{0}$ mesons in pp collisions at $\sqrt{\rm{s_{NN}}}$=5.02 TeV in the rapidity interval $|y|$<0.5. Branching ratio of $\rm{D}^{0}\rightarrow K\pi$ : 0.0389.
$p_{\rm T}$-differential cross section of prompt $\rm{D^{+}}$ mesons in pp collisions at $\sqrt{\rm{s_{NN}}}$=5.02 TeV in the rapidity interval $|y|$<0.5. Branching ratio of $\rm D^{+-}\rightarrow K{\rm{\pi}}{\rm{\pi}}$ : 0.0898.
$p_{\rm T}$-differential cross section of prompt $\rm D^{*}$ mesons in pp collisions at $\sqrt{\rm{s_{NN}}}$=5.02 TeV in the rapidity interval $|y|$<0.5. Branching ratio of $\rm{D}^{*+}\rightarrow \rm{D}^{0}\pi\rightarrow K\pi\pi$ : 0.02633.
The $p_{\rm T}$-differential inclusive production cross sections of the prompt charmed mesons $D^0$, $D^+$, and $D^{*+}$ in the rapidity range |y|<0.5 were measured in proton-proton collisions at $\sqrt{s} = 7$ TeV at the LHC using the ALICE detector. Reconstructing the decays $D^0\rightarrow K^-\pi^+$, $D^+\rightarrow K^-\pi^+\pi^+$, $D^{*+}\rightarrow D^0\pi^+$, and their charge conjugates, about 8,400 $D^0$, 2,900 $D^+$, and 2,600 $D^{*+}$ mesons with 1<$p_{\rm T}$<24 GeV/$c$ were counted, after selection cuts, in a data sample of 3.14x10$^8$ events collected with a minimum-bias trigger (integrated luminosity $L_{\rm int}$ = 5/nb). The results are described within uncertainties by predictions based on perturbative QCD.
Differential cross section for prompt D0 production.
Differential cross section for prompt D0 production.
Differential cross section for prompt D+ production.
We report on a study of the inclusive production properties of DD¯ mesons in pp collisions at 800 GeV/c and compare our results to measurements made at lower energies and to the expectations of the QCD fusion model.
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We report a measurement of the inclusive D/D̄ production cross section in 800 GeV/ c proton-proton interactions. The experiment used the high resolution bubble chamber LEBC exposed to an 800 GeV/ c proton beam at the Fermilab MPS. We obtain σ( D/ D ̄ )=59 −15 +22 μ b (statistical errors), having analysed 25% of the total data sample. Comparison with 400 GeV/ c pp dat a obtained with LEBC at CERN shows a D/D̄ cross section increase by a factor of 1.7 −0.5 +0.7 . This is in good agreement with fusion model calculations.
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