Fit to the Jpsi pi pi invariant mass distributions to determine the yields of X(3872) in pPb/Pbp at 8.16 TeV. The invariant mass is reconstructed using the StrippingHeavyIonDiMuonJpsi2MuMu line from stripping 30r2 and 30r3 for Pbp and pPb, respectively. Jpsi candidates are selected from dimuons within \pm 3sigma of the Jpsi peak and combined with two opposite-sign pions that originate from the same vertex. Using the DecayTreeFitter, X(3872) candidates are reconstructed by refitting the four tracks with the constriants of a common vertex and constraining the dimuon mass to the known Jpsi mass. Candidates are required to have transverse momentum above 5 GeV/c.

Plot | Description |
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The Jpsi pi pi invariant mass spectrum from pPb data recorded at 8.16 TeV. The solid black line shows the total fit, which is composed of a third order Chebychev polynomial representing the background (red dashed line) and a Gaussian representing the $\chi_{c1}$(3872) resonance (blue shaded area). The signal significance is 3.9$\sigma$. | |

The Jpsi pi pi invariant mass spectrum from Pbp data recorded at 8.16 TeV. The solid black line shows the total fit, which is composed of a third order Chebychev polynomial representing the background (red dashed line) and a Gaussian representing the $\chi_{c1}$(3872) resonance (blue shaded area). The signal significance is 2.6$\sigma$. |

Fit to the di-muon invariant mass distributions to determine the yields of Jpsi, Psi(2S) and non-reson backgrounds. The selection of the di-muon candidates include StrippingHeavyIonDiMuonJpsi2MuMuLine in Stripping35a, muon pT>700 MeV, muon 2.0<eta<4.5, dimuon system pT<1 GeV, delta-phi of the two muons greater than 0.9*pi, requiring nLongTracks=2, and a Herschel ln(chi2_hrc)<8.35 with a 90% signal efficiency.

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Fit to the di-muon mass distribution to determine the fractions of $\jpsi$,$\psitwos$ and non-resonant events. The black dots are the data points, the blue line is the result of the fit described in the text. The green line is the $\jpsi$ contribution, the red line is the $\psitwos$ contribution, and the yellow fill is the non resonance background contribution. | |

Fit to the di-muon mass to determine the fractions of $\jpsi$,$\psitwos$ and non-resonant events for rapidity bin $2.0<y < 2.5$. | |

Fit to the di-muon mass to determine the fractions of $\jpsi$,$\psitwos$ and non-resonant events for rapidity bin $2.5<y < 3.0$. | |

Fit to the di-muon mass to determine the fractions of $\jpsi$,$\psitwos$ and non-resonant events for rapidity bin $3.0<y < 3.5$. | |

Fit to the di-muon mass to determine the fractions of $\jpsi$,$\psitwos$ and non-resonant events for rapidity bin $3.5<y < 4.0$. | |

Fit to the di-muon mass to determine the fractions of $\jpsi$,$\psitwos$ and non-resonant events for rapidity bin $4.0<y < 4.5$. |

Invariant mass distribution of $\mu^+\mu^-$ in the full 2018 PbPb datasets. Data are reconstructed up to 10000 nVeloClusters which correspond to a lower bound of $\sim 60\%$ in centrality. The following selection is used: JpsiToMuMu stripping line (S35) with the standard selection based on J/$\psi$ analysis note (see LHCb-ANA-2016-067) and a luminous region cut as well to reduce SMOG contamination (see details in the next description's plot). There are around 1800 J/$\psi$ signal candidates.

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PbPb Plots | |

Invariant mass distribution of $\K^{\mp} \pi^{\pm}$ in the full 2018 PbPb datasets. Data are reconstructed up to 10000 nVeloClusters which correspond to a lower bound of $\sim 60\%$ in centrality. The following $D^0$ selection is applied: HeavyIonOpenCharmD02kpiLine stripping line (S35), and $D^0$ standard selection in pPb (see CERN-LHCb-ANA-2016-012) is applied, together with a cut on the luminous region in order to reduce SMOG contamination : $ \abs{ z_{PV} }$ < 200 mm, 0.35 < $\rho$ <1.1 mm with $\rho =︎\sqrt{x_{PV}^2 + y_{PV}^2), based on the J/$\psi$ analysis note in 2015 PbPb collisions (see LHCb-ANA-2016-067). There are around 83000 $D^0$ signal candidates | |

Invariant mass distribution of $\K^{\pm} \pi^{\mp} \pi^{\mp}$ in the full 2018 PbPb datasets. Data are reconstructed up to 10000 nVeloClusters which correspond to a lower bound of $\sim 60\%$ in centrality. The following $D^+$ selection is applied: HeavyIonOpenCharmDp2KHHLine stripping line (S35), and $D^0$ standard selection in pPb (see CERN-LHCb-ANA-2016-012) is applied, together with a cut on the luminous region in order to reduce SMOG contamination : $ \abs{ z_{PV} }$ < 200 mm, 0.35 < $\rho$ <1.1 mm with $\rho =︎\sqrt{x_{PV}^2 + y_{PV}^2), based on the J/$\psi$ analysis note in 2015 PbPb collisions (see LHCb-ANA-2016-067). There are around 8900 $D^+$ signal candidates | |

Invariant mass distribution of $\K^{\pm} \K^{\mp} \pi^{\mp}$ in the full 2018 PbPb datasets. Data are reconstructed up to 10000 nVeloClusters which correspond to a lower bound of $\sim 60\%$ in centrality. The following $D_s^+$ selection is applied: HeavyIonOpenCharmDs2KKHLine stripping line (S35), and $D^0$ standard selection in pPb (see CERN-LHCb-ANA-2016-012) is applied, together with a cut on the luminous region in order to reduce SMOG contamination : $ \abs{ z_{PV} }$ < 200 mm, 0.35 < $\rho$ <1.1 mm with $\rho =︎\sqrt{x_{PV}^2 + y_{PV}^2), based on the J/$\psi$ analysis note in 2015 PbPb collisions (see LHCb-ANA-2016-067). There are around 1700 $D_s^+$ signal candidates | |

Invariant mass distribution of $\K^p \pi^- p$ (and charge-conjugate) in the full 2018 PbPb datasets. Data are reconstructed up to 10000 nVeloClusters which correspond to a lower bound of $\sim 60\%$ in centrality. The following $\Lamdba_c$ selection is applied: HeavyIonOpenCharmLc2PKpiLine stripping line (S35), and $D^0$ standard selection in pPb (see CERN-LHCb-ANA-2016-012) is applied, together with a cut on the luminous region in order to reduce SMOG contamination : $ \abs{ z_{PV} }$ < 200 mm, 0.35 < $\rho$ <1.1 mm with $\rho =︎\sqrt{x_{PV}^2 + y_{PV}^2), based on the J/$\psi$ analysis note in 2015 PbPb collisions (see LHCb-ANA-2016-067). There are around 600 $\Lamdba_c$ signal candidates | |

pPb Plots | |

Distribution of the mass difference $\Delta M \equiv M(\mumu\g) - M(\mumu) $ for converted photons reconstructed from downstream track electrons in 2016 $p$Pb collisions at forward rapidity (integrated luminosity $\mathcal{L} = 13.6 \pm 0.3 \ \mub^{-1}$), integrated in $\pt$ and over $1.5 < y* < 4.0$. The distribution is fitted with a combination of Gaussian functions for the signal peaks and a 3rd degree Chebyshev polynomial for background. The following $\chicJ$ selection was applied: HeavyIonDiMuonJpsi2MuMuLine stripping line (S30r3), mass of the electron-positron pair $M_{ee} < 200 \text{ MeV}/c^{2}$, transverse momentum of the electron-positron pair $\pt^{ee} > 50 \text{ MeV}/c$; $\chicJ$, $\jpsi$, and $\mupm$ required to be within $2.0 < \eta < 4.0$; $\epm$ and $\g$ within $2.0 < \eta < 5.0$. The shown distribution also satisfies $\pt^{\g} > 600 \text{ MeV}/c$ and $3054 < M_{\jpsi} < 3138 \text{ MeV}/c^{2}$. Only events with at least one primary vertex were considered. | |

Distribution of the mass difference $\Delta M \equiv M(\mumu\g) - M(\mumu) $ for calorimetric photons in 2016 $p$Pb collisions at forward rapidity (integrated luminosity $\mathcal{L} = 13.6 \pm 0.3 \ \mub^{-1}$). The distribution is integrated over $1.5 < y* < 4.0$ and for $\pt^{\jpsi} > 3 \text{ GeV}/c$. The distribution is fitted with a combination of Gaussian functions describing the signal and a Mass-Difference Background Distribution. The following $\chicJ$ selection was applied: HeavyIonDiMuonJpsi2MuMuLine stripping line (S30r3), ECAL selection $E_{\rm HCAL}/E_{\rm ECAL}<0.3$, CL$>0.5$, and measured transverse momentum of the photon $\pt^{\g} > 300 \text{ MeV}/c$; $\chicJ$, $\jpsi$, and $\mupm$ required to be within $2.0 < \eta < 4.0$; $\g$ within $2.0 < \eta < 5.0$. The shown distribution also satisfies $\pt^{\g} > 600 \text{ MeV}/c$, $3054 < M_{\jpsi} < 3138 \text{ MeV}/c^{2}$, and $\pt^{\jpsi} > 3 \text{ GeV}/c$. Only events with at least one primary vertex were considered. |

Plot | Description |
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The Jpsi pi pi invariant mass spectrum from Pbp data recorded at 8.16 TeV. The solid black line shows the total fit, which is composed of a third order Chebychev polynomial representing the background (red dashed line) and a Gaussian representing the $\chi_{c1}$(3872) resonance (blue shaded area). | |

The Jpsi pi pi invariant mass spectrum from pPb data recorded at 8.16 TeV. The solid black line shows the total fit, which is composed of a third order Chebychev polynomial representing the background (red dashed line) and a Gaussian representing the $\chi_{c1}$(3872) resonance (blue shaded area). |

-- BenjaminAudurier - 2019-10-14

This topic: LHCb > LHCbPhysics > IonsFixedTarget > LHCbPlotsQM2019

Topic revision: r11 - 2019-10-31 - BenjaminAudurier

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