Search for long-lived neutral particles produced in $pp$ collisions at $\sqrt{s} = 13$ TeV decaying into displaced hadronic jets in the ATLAS inner detector and muon spectrometer

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Search for long-lived neutral particles produced in $pp$ collisions at $\sqrt{s} = 13$ TeV decaying into displaced hadronic jets in the ATLAS inner detector and muon spectrometer 28 November 2019
Contact: ATLAS Exotics conveners
e-print arXiv:1911.12575	pdf from arXiv
Inspire record	-
Figures Tables Auxiliary Material	-
Abstract
A search is presented for pair-production of long-lived neutral particles using 33 fb$^{-1}$ of $\sqrt{s} = 13$ TeV proton-proton collision data, collected during 2016 by the ATLAS detector at the LHC. This search focuses on a topology in which one long-lived particle decays in the ATLAS inner detector and the other decays in the muon spectrometer. Special techniques are employed to reconstruct the displaced tracks and vertices in the inner detector and in the muon spectrometer. One event is observed that passes the full event selection, which is consistent with the estimated background. Limits are placed on scalar boson propagators with masses from 125 GeV to 1000 GeV decaying into pairs of long-lived hidden-sector scalars with masses from 8 GeV to 400 GeV. The limits placed on several low-mass scalars extend previous exclusion limits in the range of proper lifetimes $c \tau$ from 5 cm to 1 m.
Figures
Figure 01: Diagram for a Higgs boson or heavy scalar Φ decaying into displaced hadronic jets via a hidden sector. png (12kB) pdf (17kB)
Figure 02a: Distributions of (a) n_trk and (b) m_IDVx for simulated signal MC and data background samples. The vertices shown are required to pass all selection requirements outlined in Table 4 except the one displayed in the plot. The dashed lines and arrows indicate the selection requirement on the parameter shown. The last bin includes overflow. png (97kB) pdf (17kB)
Figure 02b: Distributions of (a) n_trk and (b) m_IDVx for simulated signal MC and data background samples. The vertices shown are required to pass all selection requirements outlined in Table 4 except the one displayed in the plot. The dashed lines and arrows indicate the selection requirement on the parameter shown. The last bin includes overflow. png (113kB) pdf (22kB)
Figure 03a: IDVx selection efficiency as a function of the radial decay position for several (a) 125 GeV H → ss and (b) Φ → ss mass points with m_s = 50 GeV. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. In each figure, the IDVx selection efficiency for one signal MC sample is shown before and after the requirement of the material veto to demonstrate the impact it has on the IDVx selection efficiency. png (145kB) pdf (26kB)
Figure 03b: IDVx selection efficiency as a function of the radial decay position for several (a) 125 GeV H → ss and (b) Φ → ss mass points with m_s = 50 GeV. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. In each figure, the IDVx selection efficiency for one signal MC sample is shown before and after the requirement of the material veto to demonstrate the impact it has on the IDVx selection efficiency. png (169kB) pdf (28kB)
Figure 04a: CL_S upper limits at 95 CL on the branching ratio B_{H → ss} for (a) m_H = 125 GeV, and on the cross section times branching ratio σ × B_{φ → ss} for (b) m_Φ = 200 – 400 GeV, and (c) m_Φ = 600 – 1000 GeV. png (145kB) pdf (16kB)
Figure 04b: CL_S upper limits at 95 CL on the branching ratio B_{H → ss} for (a) m_H = 125 GeV, and on the cross section times branching ratio σ × B_{φ → ss} for (b) m_Φ = 200 – 400 GeV, and (c) m_Φ = 600 – 1000 GeV. png (155kB) pdf (16kB)
Figure 04c: CL_S upper limits at 95 CL on the branching ratio B_{H → ss} for (a) m_H = 125 GeV, and on the cross section times branching ratio σ × B_{φ → ss} for (b) m_Φ = 200 – 400 GeV, and (c) m_Φ = 600 – 1000 GeV. png (163kB) pdf (16kB)
Figure 05a: Combined limits from this analysis (ID) and the CR and MS analyses for m_H = 125 GeV decaying into (a) 15, (b) 25, (c) 40, and (d) 55 GeV mass scalars. The expected limit is shown as a dashed line with shading for the ± 1σ error band and the observed limit is shown with a solid line. The combination of the CR and MS analysis used both the MS1 and MS2 channels for m_H = 125 GeV, but due to orthogonality considerations only the MS2 channel was used when performing the combination with the ID analysis. The MS analysis did not place limits on the 55 GeV LLP mass point (d) so the combined limits use the results of the ID and CR analyses only. png (158kB) pdf (18kB)
Figure 05b: Combined limits from this analysis (ID) and the CR and MS analyses for m_H = 125 GeV decaying into (a) 15, (b) 25, (c) 40, and (d) 55 GeV mass scalars. The expected limit is shown as a dashed line with shading for the ± 1σ error band and the observed limit is shown with a solid line. The combination of the CR and MS analysis used both the MS1 and MS2 channels for m_H = 125 GeV, but due to orthogonality considerations only the MS2 channel was used when performing the combination with the ID analysis. The MS analysis did not place limits on the 55 GeV LLP mass point (d) so the combined limits use the results of the ID and CR analyses only. png (169kB) pdf (18kB)
Figure 05c: Combined limits from this analysis (ID) and the CR and MS analyses for m_H = 125 GeV decaying into (a) 15, (b) 25, (c) 40, and (d) 55 GeV mass scalars. The expected limit is shown as a dashed line with shading for the ± 1σ error band and the observed limit is shown with a solid line. The combination of the CR and MS analysis used both the MS1 and MS2 channels for m_H = 125 GeV, but due to orthogonality considerations only the MS2 channel was used when performing the combination with the ID analysis. The MS analysis did not place limits on the 55 GeV LLP mass point (d) so the combined limits use the results of the ID and CR analyses only. png (174kB) pdf (18kB)
Figure 05d: Combined limits from this analysis (ID) and the CR and MS analyses for m_H = 125 GeV decaying into (a) 15, (b) 25, (c) 40, and (d) 55 GeV mass scalars. The expected limit is shown as a dashed line with shading for the ± 1σ error band and the observed limit is shown with a solid line. The combination of the CR and MS analysis used both the MS1 and MS2 channels for m_H = 125 GeV, but due to orthogonality considerations only the MS2 channel was used when performing the combination with the ID analysis. The MS analysis did not place limits on the 55 GeV LLP mass point (d) so the combined limits use the results of the ID and CR analyses only. png (162kB) pdf (18kB)
Figure 06a: Combined limits from this analysis (ID) and the CR and MS analyses for benchmark models with m_Φ=200 GeV decaying into (a) 25 and (b) 50 GeV mass scalars. The expected limit is shown as a dashed line with shading for the ± 1σ error band and the observed limit is shown with a solid line. png (166kB) pdf (19kB)
Figure 06b: Combined limits from this analysis (ID) and the CR and MS analyses for benchmark models with m_Φ=200 GeV decaying into (a) 25 and (b) 50 GeV mass scalars. The expected limit is shown as a dashed line with shading for the ± 1σ error band and the observed limit is shown with a solid line. png (182kB) pdf (19kB)
Tables
Table 01: Track parameter requirements for inside-out standard and large-radius tracks. png (14kB) pdf (36kB)
Table 02: Track parameter requirements for the reconstruction of displaced vertices in the ID. png (19kB) pdf (37kB)
Table 03: MSVx selection requirements. png (17kB) pdf (41kB)
Table 04: IDVx selection requirements. png (17kB) pdf (39kB)
Table 05: Total and relative efficiency for each selection requirement for the several signal MC mass points. Here, `Pass trigger' refers to passing the Muon RoI Cluster trigger and passing the veto on the CR triggers, `Good MSVx' includes all the MSVx selection requirements described in Table 3 as well as being matched to the muon RoI cluster and `IDVx' includes all selection requirements in Table 4 except those on n_trk and m_IDVx, which are listed separately. All efficiencies are computed using signal MC samples with a mean lab-frame decay length of 5 m, the proper lifetime of each mass point is listed in the table. png (50kB) pdf (44kB)
Table 06: The data events used in the background estimation. These events include the background events, whose selection is defined in the text, divided into all background events ($\mathit{Bkg}$), and those that contain at least one IDVx that passes the full IDVx requirements ($\mathit{Bkg}+\mathit{IDVx}$). The other events making up the plane are the signal region events ($\mathit{Sig}$), and events that pass all signal region requirements except for the inclusion of an IDVx ($\mathit{Sig}–\mathit{IDVx}$). png (13kB) pdf (44kB)
Table 07: The events used for the validation of the background estimation, alongside the events used for the background estimate. The $\mathit{Bkg},2\mathit{{-}trk}$ and $\mathit{Val},2\mathit{{-}trk}$ validation regions contain ID vertices that have n_trk = 2. The $\mathit{Trig},3\mathit{{-}trk}$ and $\mathit{Trig}$ validation regions are events that pass the Muon RoI Cluster trigger but are agnostic to the presence of MS vertices. The $\mathit{Bkg},3\mathit{{-}trk}$ and $\mathit{Trig},3\mathit{{-}trk}$ validation regions contain ID vertices with 1 GeV < m_IDVx < 3 GeV and n_trk = 3. png (23kB) pdf (57kB)
Table 08: Numbers used in the background estimation method and for the validation of the estimate, for the observed (n_obs) number of events in the $\mathit{Bkg}$, $\mathit{Bkg}+\mathit{IDVx}$, and $\mathit{Sig}–\mathit{IDVx}$ regions, and the predicted (n_pred) and observed numbers of events in the $\mathit{Val},2\mathit{{-}trk}$, $\mathit{Trig},3\mathit{{-}trk}$, and $\mathit{Sig}$ regions. png (14kB) pdf (56kB)
Table 09: Ranges of proper lifetimes excluded at 95% CL for the m_H = 125 GeV benchmark model assuming a 10% branching ratio for H → ss. The m_s = 55 GeV exclusion range uses the results of the ID and CR analyses only. png (9kB) pdf (35kB)
Auxiliary figures and tables
Figure 01a: Comparison of the IDVx reconstruction and selection efficiency for a Higgs boson with a mass of 125 GeV decaying to an LLP with a mass of 8 GeV, using only standard tracking versus using standard and large radius tracking (LRT) for (a) all ID vertices in the signal MC samples and (b) ID vertices passing the full IDVx selection criteria. png (53kB) pdf (20kB)
Figure 01b: Comparison of the IDVx reconstruction and selection efficiency for a Higgs boson with a mass of 125 GeV decaying to an LLP with a mass of 8 GeV, using only standard tracking versus using standard and large radius tracking (LRT) for (a) all ID vertices in the signal MC samples and (b) ID vertices passing the full IDVx selection criteria. png (55kB) pdf (20kB)
Figure 02a: Comparison of the IDVx reconstruction and selection efficiency for a $\Phi$ boson with a mass of 1000 GeV decaying to an LLP with a mass of 150 GeV, using only standard tracking versus using standard and large radius tracking (LRT) for (a) all ID vertices in the signal MC samples and (b) ID vertices passing the full IDVx selection criteria. png (50kB) pdf (19kB)
Figure 02b: Comparison of the IDVx reconstruction and selection efficiency for a $\Phi$ boson with a mass of 1000 GeV decaying to an LLP with a mass of 150 GeV, using only standard tracking versus using standard and large radius tracking (LRT) for (a) all ID vertices in the signal MC samples and (b) ID vertices passing the full IDVx selection criteria. png (52kB) pdf (19kB)
Figure 03a: IDVx selection efficiency as a function of the longitudinal decay position for (a) 125 GeV H → ss and (b) Φ → ss mass points with m_s = 50 GeV. In each figure, the IDVx selection efficiency for one signal MC sample is shown before and after the requirement of the material veto to demonstrate the impact it has on the IDVx selection efficiency. png (134kB) pdf (28kB)
Figure 03b: IDVx selection efficiency as a function of the longitudinal decay position for (a) 125 GeV H → ss and (b) Φ → ss mass points with m_s = 50 GeV. In each figure, the IDVx selection efficiency for one signal MC sample is shown before and after the requirement of the material veto to demonstrate the impact it has on the IDVx selection efficiency. png (156kB) pdf (32kB)
Figure 04a: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Higgs with a mass of 125 GeV decaying to an LLP with a mass of 8 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx selection efficiency is shown in (c) after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (169kB) pdf (28kB)
Figure 04b: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Higgs with a mass of 125 GeV decaying to an LLP with a mass of 8 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx selection efficiency is shown in (c) after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (138kB) pdf (27kB)
Figure 04c: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Higgs with a mass of 125 GeV decaying to an LLP with a mass of 8 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx selection efficiency is shown in (c) after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (170kB) pdf (33kB)
Figure 05a: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Φ with a mass of 400 GeV decaying to an LLP with a mass of 50 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx reconstruction efficiency with no selections imposed is compared to (c) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (159kB) pdf (26kB)
Figure 05b: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Φ with a mass of 400 GeV decaying to an LLP with a mass of 50 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx reconstruction efficiency with no selections imposed is compared to (c) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (135kB) pdf (28kB)
Figure 05c: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Φ with a mass of 400 GeV decaying to an LLP with a mass of 50 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx reconstruction efficiency with no selections imposed is compared to (c) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (160kB) pdf (32kB)
Figure 06a: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Φ with a mass of 1000 GeV decaying to an LLP with a mass of 150 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx reconstruction efficiency with no selections imposed is compared to (c) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (158kB) pdf (26kB)
Figure 06b: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Φ with a mass of 1000 GeV decaying to an LLP with a mass of 150 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx reconstruction efficiency with no selections imposed is compared to (c) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (138kB) pdf (27kB)
Figure 06c: The impact of the IDVx selections on the selection efficiency for the MC signal sample with a Φ with a mass of 1000 GeV decaying to an LLP with a mass of 150 GeV. The IDVx reconstruction efficiency with no selections imposed is compared to (a) the IDVx selection efficiency after the imposition of the selection on the distance of the IDVx from the PV, the selection on the χ²/n_DoF of the IDVx, or the imposition of the material veto. The IDVx reconstruction efficiency with no selections imposed is compared to (b) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, on the mass of the IDVx, or on the mass of the IDVx and the number of tracks associated to the IDVx. The IDVx reconstruction efficiency with no selections imposed is compared to (c) the IDVx selection efficiency after the imposition of the selection on the number of tracks associated to the IDVx, the selection on the mass of the IDVx, the selection on the χ²/n_DoF of the IDVx, and the IDVx selection efficiency when all selections are applied. The dashed vertical red lines indicate the main radial material layers in the inner detector that are included in the material veto. png (162kB) pdf (32kB)
Figure 07: The $F$, $F$_{2-$\mathit{trk}$}, and $F$_{3-$\mathit{trk}$} factors used in the background estimation and the two sets of validation regions, with the exception of $F$^{$\mathit{Sig.}$}, which corresponds to the single event observed in the signal region. The $F$_{2-$\mathit{trk}$}, and $F$_{3-$\mathit{trk}$} factors are the $F$ factors used to calculate the predicted number of events in the 2-track and 3-track validation regions. The $F$, $F$_{2-$\mathit{trk}$}, and $F$_{3-$\mathit{trk}$} factors are compared when calculated using the background events, as in $F$_{2-$\mathit{trk}$}^{$\mathit{Bkg.}$} = N_{$\mathit{Bkg}$,2-$\mathit{trk}$}/N_{$\mathit{Bkg}$}, or with signal-like events, as in $F$_2-trk^{$\mathit{Sig.}$} = $N$_{$\mathit{Val}$,2-trk}/$N$_{$\mathit{Sig-IDVx}$}. The solid blue lines represent the $F$, $F$_{2-$\mathit{trk}$}, and $F$_{3-$\mathit{trk}$} factors ±25, to demonstrate that all variations, not considering statistical uncertainties, fall within 25%. Error bars represent the statistical uncertainties only. png (28kB) pdf (14kB)
Figure 08a: Two dimensional distributions of m_IDVx and IDVx n_trk are shown for ID vertices in events that pass all signal selection criteria other than the requirements on the IDVx n_trk and m_IDVx. These distributions are shown for events in data and in the signal MC samples with a Higgs boson decaying to an LLP with a mass of (a) 25 GeV or (b) 40 GeV. The vertices in data are displayed as numbers overlaid on the signal MC IDVx distribution. The final signal region is denoted by vertical and horizontal red lines. The number of events in data in the final signal region is 1, which is consistent with the predicted number of background events, 1.16 ± 0.18 (stat.) ± 0.29 (syst.). The yield in the signal region for the signal MC samples is estimated assuming the gluon-gluon fusion production cross section for the Higgs boson and a 10 branching ratio for the Higgs boson decay to the hidden sector. png (92kB) pdf (14kB)
Figure 08b: Two dimensional distributions of m_IDVx and IDVx n_trk are shown for ID vertices in events that pass all signal selection criteria other than the requirements on the IDVx n_trk and m_IDVx. These distributions are shown for events in data and in the signal MC samples with a Higgs boson decaying to an LLP with a mass of (a) 25 GeV or (b) 40 GeV. The vertices in data are displayed as numbers overlaid on the signal MC IDVx distribution. The final signal region is denoted by vertical and horizontal red lines. The number of events in data in the final signal region is 1, which is consistent with the predicted number of background events, 1.16 ± 0.18 (stat.) ± 0.29 (syst.). The yield in the signal region for the signal MC samples is estimated assuming the gluon-gluon fusion production cross section for the Higgs boson and a 10 branching ratio for the Higgs boson decay to the hidden sector. png (93kB) pdf (14kB)
Figure 09: The yield of K_S⁰ vertices with two large radius tracks as a function of R. Data is normalized to MC by the data/MC ratio of the total number of K_S⁰ vertices reconstructed with two standard tracks. png (36kB) pdf (15kB)
Figure 10a: CL_S limits on B_{H → ss} for a Higgs boson with a mass of 125 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 15 GeV, (c) 25 GeV, (d) 40 GeV, or (e) 55 GeV, assuming σ = σ_ggF. png (55kB) pdf (16kB)
Figure 10b: CL_S limits on B_{H → ss} for a Higgs boson with a mass of 125 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 15 GeV, (c) 25 GeV, (d) 40 GeV, or (e) 55 GeV, assuming σ = σ_ggF. png (108kB) pdf (17kB)
Figure 10c: CL_S limits on B_{H → ss} for a Higgs boson with a mass of 125 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 15 GeV, (c) 25 GeV, (d) 40 GeV, or (e) 55 GeV, assuming σ = σ_ggF. png (58kB) pdf (17kB)
Figure 10d: CL_S limits on B_{H → ss} for a Higgs boson with a mass of 125 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 15 GeV, (c) 25 GeV, (d) 40 GeV, or (e) 55 GeV, assuming σ = σ_ggF. png (61kB) pdf (16kB)
Figure 10e: CL_S limits on B_{H → ss} for a Higgs boson with a mass of 125 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 15 GeV, (c) 25 GeV, (d) 40 GeV, or (e) 55 GeV, assuming σ = σ_ggF. png (60kB) pdf (16kB)
Figure 11a: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 200 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 25 GeV, or (c) 50 GeV. png (53kB) pdf (16kB)
Figure 11b: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 200 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 25 GeV, or (c) 50 GeV. png (53kB) pdf (17kB)
Figure 11c: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 200 GeV decaying to an LLP with a mass of (a) 8 GeV, (b) 25 GeV, or (c) 50 GeV. png (58kB) pdf (17kB)
Figure 12a: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 400 GeV decaying to an LLP with a mass of (a) 50 GeV or (b) 100 GeV. png (57kB) pdf (17kB)
Figure 12b: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 400 GeV decaying to an LLP with a mass of (a) 50 GeV or (b) 100 GeV. png (60kB) pdf (17kB)
Figure 13a: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 600 GeV decaying to an LLP with a mass of (a) 50 GeV or (b) 150 GeV. png (56kB) pdf (17kB)
Figure 13b: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 600 GeV decaying to an LLP with a mass of (a) 50 GeV or (b) 150 GeV. png (61kB) pdf (17kB)
Figure 14a: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 1000 GeV decaying to an LLP with a mass of (a) 50 GeV, (b) 150 GeV, or (c) 400 GeV. png (53kB) pdf (17kB)
Figure 14b: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 1000 GeV decaying to an LLP with a mass of (a) 50 GeV, (b) 150 GeV, or (c) 400 GeV. png (58kB) pdf (17kB)
Figure 14c: CL_S limits on σ × B_{Φ → ss} for a Φ boson with a mass of 1000 GeV decaying to an LLP with a mass of (a) 50 GeV, (b) 150 GeV, or (c) 400 GeV. png (60kB) pdf (17kB)
Figure 15a: Visualizations of the event (Event 1804273557, Run 303338) in the signal region containing an MSVx and an IDVx. The IDVx and associated tracks are in blue, the MSVx is in purple, and the PV is in green. The IDVx is at R = 29.1 mm, z = 143 mm, η = 2.30, and φ = 0.0145. The IDVx has 4 associated tracks and a reconstructed mass of 3.34 GeV. The MSVx is at R = 4.97 m, z = 12.5 m, η = 1.65, and φ = -2.94. The event is depicted in (a) including only the PV, the IDVx and associated tracks, and the MSVx. In (b) all reconstructed tracks in the event with $p$_T > 1 GeV and \|η\| < 2.5 are shown in yellow to demonstrate the challenge of reconstructing and selecting displaced vertices in the ID. png (1019kB) pdf (1MB)
Figure 15b: Visualizations of the event (Event 1804273557, Run 303338) in the signal region containing an MSVx and an IDVx. The IDVx and associated tracks are in blue, the MSVx is in purple, and the PV is in green. The IDVx is at R = 29.1 mm, z = 143 mm, η = 2.30, and φ = 0.0145. The IDVx has 4 associated tracks and a reconstructed mass of 3.34 GeV. The MSVx is at R = 4.97 m, z = 12.5 m, η = 1.65, and φ = -2.94. The event is depicted in (a) including only the PV, the IDVx and associated tracks, and the MSVx. In (b) all reconstructed tracks in the event with $p$_T > 1 GeV and \|η\| < 2.5 are shown in yellow to demonstrate the challenge of reconstructing and selecting displaced vertices in the ID. png (1MB) pdf (2MB)
Table 01: The proper lifetime generated for each the signal MC samples, shown for each mass point and approximate mean lab-frame decay length. png (26kB) pdf (36kB)

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2020-02-17 00:02:15