Production of inclusive charmonia in pp collisions at center-of-mass energy of $\sqrt{s}$ = 13 TeV and p-Pb collisions at center-of-mass energy per nucleon pair of $\sqrt{s_{\rm NN}}$ = 8.16 TeV is studied as a function of charged-particle pseudorapidity density with ALICE. Ground and excited charmonium states (J/$\psi$, $\psi$(2S)) are measured from their dimuon decays in the interval of rapidity in the center-of-mass frame $2.5 < y_{\rm cms} < 4.0$ for pp collisions, and $2.03 < y_{\rm cms} < 3.53$ and $-4.46 < y_{\rm cms} < -2.96$ for p-Pb collisions. The charged-particle pseudorapidity density is measured around midrapidity ($|\eta|<1.0$). In pp collisions, the measured charged-particle multiplicity extends to about six times the average value, while in p-Pb collisions at forward (backward) rapidity a multiplicity corresponding to about three (four) times the average is reached. The $\psi$(2S) yield increases with the charged-particle pseudorapidity density. The ratio of $\psi$(2S) over J/$\psi$ yield does not show a significant multiplicity dependence in either colliding system, suggesting a similar behavior of J/$\psi$ and $\psi$(2S) yields with respect to charged-particle pseudorapidity density. Results for the $\psi$(2S) yield and its ratio with respect to J/$\psi$ agree with available model calculations.
Ratio of measured PSI(2S) cross section in charged-particle multiplicity intervals and integrated in multiplicity.
Ratio of measured PSI(2S) cross section in charged-particle multiplicity intervals and integrated in multiplicity.
Ratio of measured PSI(2S) cross section in charged-particle multiplicity intervals and integrated in multiplicity.
The production of J/$\psi$ is measured as a function of charged-particle multiplicity at forward rapidity in proton$-$proton (pp) collisions at center-of-mass energies $\sqrt{s} =$ 5.02 and 13 TeV. The J/$\psi$ mesons are reconstructed via their decay into dimuons in the rapidity interval (2.5 $< y <$ 4.0), whereas the charged-particle multiplicity density (${\rm d}N_{\rm{ch}}/{\rm d}\eta$) is measured at midrapidity $(|\eta| < 1)$. The production rate as a function of multiplicity is reported as the ratio of the yield in a given multiplicity interval to the multiplicity-integrated one. This observable shows a linear increase with charged-particle multiplicity normalized to the corresponding average value for inelastic events (${{\rm d}N_{\rm ch}/{\rm d}\eta}/{\langle {\rm d}N_{\rm ch}/{\rm d}\eta \rangle}$), at both the colliding energies. Measurements are compared with available ALICE results at midrapidity and theoretical model calculations. First measurement of the mean transverse momentum ($\langle p_{\mathrm{T}}\rangle$) of J/$\psi$ in pp collisions exhibits an increasing trend as a function of ${{\rm d}N_{\rm ch}/{\rm d}\eta}/{\langle {\rm d}N_{\rm ch}/{\rm d}\eta \rangle}$ showing a saturation towards high charged-particle multiplicities.
Measurements of the associated production of a W boson and a charm (c) quark in proton-proton collisions at a centre-of-mass energy of 8 TeV are reported. The analysis uses a data sample corresponding to a total integrated luminosity of 19.7 fb$^{-1}$ collected by the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm quark jets are selected using distinctive signatures of charm hadron decays. The product of the cross section and branching fraction $\sigma$(pp $\to$ W + c + X) $\mathcal{B}$(W $\to$$\ell\nu$), where $\ell$ = e or $\mu$, and the cross section ratio $\sigma$(pp $\to$ W$^+$ + c + X) / $\sigma$(pp $\to$ W$^-$ + $\mathrm{\bar{c}}$ + X) are measured inclusively and differentially as functions of the pseudorapidity and of the transverse momentum of the lepton from the W boson decay. The results are compared with theoretical predictions. The impact of these measurements on the determination of the strange quark distribution is assessed.
Signal yields after background subtraction, efficiency*acceptance correction factors, and cross section measurements for the four channels (W decay to muon or electron and charm identification via muon or secondary vertex inside a jet).
Measured production cross sections $\sigma(W^+ + \overline{c})$, $\sigma(W^- + c)$ and their ratio.
Measured diferential cross sections $\sigma(W^- + c) + \sigma(W^+ + \overline{c})$ as a function of the absolute value of the pseudorapidity of the lepton from the W decay.
The production of $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ resonances has been measured in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval $-$0.5 $<$$y$$<$ 0 and the transverse momentum spectra are measured for various multiplicity classes up to $p_{\rm T}$ = 20 GeV/$c$ for $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $p_{\rm T}$ = 16 GeV/$c$ for $\mathrm{\phi(1020)}$. The $p_{\rm T}$ -integrated yields and mean transverse momenta are reported and compared with previous results in pp, p-Pb and Pb-Pb collisions. The $x_{\mathrm{T}}$ scaling for $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ resonance production is newly tested in p-Pb collisions and found to hold in the high-$p_{\rm T}$ region at LHC energies. The nuclear modification factors ($R_{\rm pPb}$) as a function of $p_{\rm T}$ for $\mathrm{K}^{*0}$ and $\mathrm{\phi}$ at $\sqrt{s_{NN}}$ = 8.16 TeV are presented along with the new $R_{\rm pPb}$ measurements of $\mathrm{K}^{*0}$, $\mathrm{\phi}$ , $\Xi$, and $\Omega$ at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. At intermediate $p_{\rm T}$ (2-8 GeV/$c$), $R_{\rm pPb}$ of $\Xi$, $\Omega$ show a Cronin-like enhancement, while $\mathrm{K}^{*0}$ and $\mathrm{\phi}$ show no or little nuclear modification. At high $p_{\rm T}$ ($>$ 8 GeV/$c$), the $R_{\rm pPb}$ values of all hadrons are consistent with unity within uncertainties. The $R_{\rm pPb}$ of $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ at $\sqrt{s_{\rm NN}}$ = 8.16 and 5.02 TeV show no significant energy dependence.
$p_{\mathrm T}$-differential yield of $\frac{\mathrm{K^{*0}} + \overline{\mathrm{K^{*0}}}}{2}$ in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}~=~$8.16 TeV (NSD).
$p_{\mathrm T}$-differential yield of $\frac{\mathrm{K^{*0}} + \overline{\mathrm{K^{*0}}}}{2}$ in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}~=~$8.16 TeV (Multiplicity class 0-5%).
$p_{\mathrm T}$-differential yield of $\frac{\mathrm{K^{*0}} + \overline{\mathrm{K^{*0}}}}{2}$ in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}~=~$8.16 TeV (Multiplicity class 5-10%).
Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. The observation of a new type of hadronic state, a doubly charmed tetraquark containing two charm quarks, an anti-$u$ and an anti-$d$ quark, is reported using data collected by the LHCb experiment at the Large Hadron Collider. This exotic state with a mass of about 3875 MeV$/c^2$ manifests itself as a narrow peak in the mass spectrum of $D^0D^0\pi^+$ mesons just below the $D^{*+}D^0$ mass threshold. The near threshold mass together with a strikingly narrow width reveals the resonance nature of the state.
Distribution of $D^0 D^0 \pi^+$ mass where the contribution of the non-$D^0$ background has been statistically subtracted. Uncertainties on the data points are statistical only and represent one standard deviation, calculated as a sum in quadrature of the assigned weights from the background-subtraction procedure.
Distribution of $D^0 D^0 \pi^+$ mass where the contribution of the non-$D^0$ background has been statistically subtracted by assigning the a weight to every candidate.
The production cross-sections of $J/\psi$ mesons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=5$ TeV are measured using a data sample corresponding to an integrated luminosity of $9.13\pm0.18~\text{pb}^{-1}$, collected by the LHCb experiment. The cross-sections are measured differentially as a function of transverse momentum, $p_{\text{T}}$, and rapidity, $y$, and separately for $J/\psi$ mesons produced promptly and from beauty hadron decays (nonprompt). With the assumption of unpolarised $J/\psi$ mesons, the production cross-sections integrated over the kinematic range $0<p_{\text{T}}<20~\text{GeV}/c$ and $2.0<y<4.5$ are $8.154\pm0.010\pm0.283~\mu\text{b}$ for prompt $J/\psi$ mesons and $0.820\pm0.003\pm0.034~\mu\text{b}$ for nonprompt $J/\psi$ mesons, where the first uncertainties are statistical and the second systematic. These cross-sections are compared with those at $\sqrt{s}=8$ TeV and $13$ TeV, and are used to update the measurement of the nuclear modification factor in proton-lead collisions for $J/\psi$ mesons at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\text{NN}}}=5$ TeV. The results are compared with theoretical predictions.
Double-differential production cross-sections for prompt $J/\psi$ mesons in ($p_\text{T},y$) intervals. The first uncertainties are statistical, the second are correlated systematic uncertainties shared between intervals, the third are uncorrelated systematic uncertainties, and the last are correlated between $p_\text{T}$ intervals and uncorrelated between $y$ intervals.
Double-differential production cross-sections for nonprompt $J/\psi$ mesons in ($p_\text{T},y$) intervals. The first uncertainties are statistical, the second are correlated systematic uncertainties shared between intervals, the third are uncorrelated systematic uncertainties, and the last are correlated between $p_\text{T}$ intervals and uncorrelated between $y$ intervals.
Single-differential production cross-sections for prompt $J/\psi$ mesons as a function of $p_\text{T}$. The first uncertainties are statistical, the second are correlated systematic uncertainties shared between intervals, and the last are uncorrelated systematic uncertainties.
A measurement of the top quark mass is performed using a data sample enriched with single top quark events produced in the $t$ channel. The study is based on proton-proton collision data, corresponding to an integrated luminosity of 35.9 fb$^{-1}$, recorded at $\sqrt{s}$ = 13 TeV by the CMS experiment at the LHC in 2016. Candidate events are selected by requiring an isolated high-momentum lepton (muon or electron) and exactly two jets, of which one is identified as originating from a bottom quark. Multivariate discriminants are designed to separate the signal from the background. Optimized thresholds are placed on the discriminant outputs to obtain an event sample with high signal purity. The top quark mass is found to be 172.13 $^{+0.76}_{-0.77}$ GeV, where the uncertainty includes both the statistical and systematic components, reaching sub-GeV precision for the first time in this event topology. The masses of the top quark and antiquark are also determined separately using the lepton charge in the final state, from which the mass ratio and difference are determined to be 0.9952 $^{+0.0079}_{-0.0104}$ and 0.83 $^{+1.79}_{-1.35}$ GeV, respectively. The results are consistent with $CPT$ invariance.
Top quark mass measured inclusive of lepton flavor and charge. The uncertainties are given in two parts, the first part is the combination of statistical (stat) and profiled (prof) uncertainties and the second part is for the experimental (ext) uncetrinaties.
The top quark mass measured inclusive of lepton flavor and charge. The uncertainties are given in two parts, the first is the combination of statistical (stat) and profiled systematic (prof) uncertainties and the second is the externalized systematic (ext) uncertainties.
Top quark mass measured inclusive of lepton flavor and for positively charged lepton.
The energy deposited at very forward rapidities (very forward energy) is a powerful tool for characterising proton fragmentation in pp and p$-$Pb collisions. The correlation of very forward energy with particle production at midrapidity provides direct insights into the initial stages and the subsequent evolution of the collision. Furthermore, the correlation with the production of particles with large transverse momenta at midrapidity provides information complementary to the measurements of the underlying event, which are usually interpreted in the framework of models implementing centrality-dependent multiple parton interactions. Results about very forward energy, measured by the ALICE zero degree calorimeters (ZDCs), and its dependence on the activity measured at midrapidity in pp collisions at $\sqrt{s}=13$ TeV and in p$-$Pb collisions at $\sqrt{s_{\rm{NN}}}=8.16$ TeV are discussed. The measurements performed in pp collisions are compared with the expectations of three hadronic interaction event generators: PYTHIA 6 (Perugia 2011 tune), PYTHIA 8 (Monash tune), and EPOS LHC. These results provide new constraints on the validity of models in describing the beam remnants at very forward rapidities, where perturbative QCD cannot be used.
Average signal on A-side vs. C-side ZN in pp collisions at 13 TeV
Average signal on A-side vs. C-side ZP in pp collisions at 13 TeV
Pb-remnant side ZN signal normalized to MB value vs. ZN centrality percentile in p-Pb collisions at 5.02 TeV
A search for lepton-flavor-violating $Z\to e\tau$ and $Z\to\mu\tau$ decays with $pp$ collision data recorded by the ATLAS detector at the LHC is presented. This analysis uses 139 fb$^{-1}$ of Run 2 $pp$ collisions at $\sqrt{s}=13$ TeV and is combined with the results of a similar ATLAS search in the final state in which the $\tau$-lepton decays hadronically, using the same data set as well as Run 1 data. The addition of leptonically decaying $\tau$-leptons significantly improves the sensitivity reach for $Z\to\ell\tau$ decays. The $Z\to\ell\tau$ branching fractions are constrained in this analysis to $\mathcal{B}(Z\to e\tau)<7.0\times10^{-6}$ and $\mathcal{B}(Z\to \mu\tau)<7.2\times10^{-6}$ at 95% confidence level. The combination with the previously published analyses sets the strongest constraints to date: $\mathcal{B}(Z\to e\tau)<5.0\times10^{-6}$ and $\mathcal{B}(Z\to \mu\tau)<6.5\times10^{-6}$ at 95% confidence level.
The best-fit predicted and observed distributions of the combined NN output in the low-$p_\text{T}$-SR for the $e\tau_\mu$ channel. The first and last bin include underflow and overflow events, respectively.
The best-fit predicted and observed distributions of the combined NN output in the low-$p_\text{T}$-SR for the $\mu\tau_e$ channel. The first and last bin include underflow and overflow events, respectively.
The best-fit predicted and observed distributions of the combined NN output in the high-$p_\text{T}$-SR for the $e\tau_\mu$ channel. The first and last bin include underflow and overflow events, respectively.
The production of $\phi$ mesons has been studied in pp collisions at LHC energies with the ALICE detector via the dimuon decay channel in the rapidity region $2.5 < y < 4$. Measurements of the differential cross section ${\rm d}^2\sigma/{\rm d}y {\rm d}p_{\rm T}$ are presented as a function of the transverse momentum ($p_{\rm T}$) at the center-of-mass energies $\sqrt{s}=5.02$, 8 and 13 TeV and compared with the ALICE results at midrapidity. The differential cross sections at $\sqrt{s}=5.02$ and 13 TeV are also studied in several rapidity intervals as a function of $p_{\rm T}$, and as a function of rapidity in three $p_{\rm T}$ intervals. A hardening of the $p_{\rm T}$-differential cross section with the collision energy is observed, while, for a given energy, $p_{\rm T}$ spectra soften with increasing rapidity and, conversely, rapidity distributions get slightly narrower at increasing $p_{\rm T}$. The new results, complementing the published measurements at $\sqrt{s}=2.76$ and 7 TeV, allow one to establish the energy dependence of $\phi$ meson production and to compare the measured cross sections with phenomenological models. None of the considered models manages to describe the evolution of the cross section with $p_{\rm T}$ and rapidity at all the energies.
$\phi$ meson production cross section $\mathrm{d}^2\sigma/(\mathrm{d}y\mathrm{d}p_\mathrm{T})$ as a function of $p_\mathrm{T}$ at $\sqrt{s}=5.02$ TeV at forward rapidity in pp collisions.
$\phi$ meson production cross section $\mathrm{d}^2\sigma/(\mathrm{d}y\mathrm{d}p_\mathrm{T})$ as a function of $p_\mathrm{T}$ at $\sqrt{s}=8$ TeV at forward rapidity in pp collisions.
$\phi$ meson production cross section $\mathrm{d}^2\sigma/(\mathrm{d}y\mathrm{d}p_\mathrm{T})$ as a function of $p_\mathrm{T}$ at $\sqrt{s}=13$ TeV at forward rapidity in pp collisions.
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