CMS-BPH-21-006 ; CERN-EP-2022-270 | ||
Measurement of the B0s→μ+μ− decay properties and search for the B0→μ+μ− decay in proton-proton collisions at √s= 13 TeV | ||
CMS Collaboration | ||
20 December 2022 | ||
Phys. Lett. B 842 (2023) 137955 | ||
Abstract: Measurements are presented of the B0s→μ+μ− branching fraction and the B0s effective lifetime, as well as results of a search for the B0→μ+μ− decay in proton-proton collisions at √s= 13 TeV at the LHC. The analysis is based on data collected with the CMS detector in 2016-2018 corresponding to an integrated luminosity of 140 fb−1. The branching fraction of the B0s→μ+μ− decay and the effective B0s meson lifetime are the most precise single measurements to date. No evidence for the B0→μ+μ− decay has been found. All results are found to be consistent with the standard model predictions and previous measurements. | ||
Links: e-print arXiv:2212.10311 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; Physics Briefing ; CADI line (restricted) ; |
Figures & Tables | Summary | Additional Figures | References | CMS Publications |
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Figures | |
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Figure 1:
Distributions of the dMVA output for the 2016a (left), 2016b (center), and 2017-2018 (right) data and the corresponding MC samples. The blue squares represent the weighted simulated distributions using the XGBOOST reweighting method. In the lower panel, the blue squares and red points are the ratio of the data to weighted and not weighted simulated distribution respectively. The MC distributions are normalized to the total number of events in data. |
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Figure 1-a:
Distributions of the dMVA output for the 2016a data and the corresponding MC samples. The blue squares represent the weighted simulated distributions using the XGBOOST reweighting method. In the lower panel, the blue squares and red points are the ratio of the data to weighted and not weighted simulated distribution respectively. The MC distributions are normalized to the total number of events in data. |
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Figure 1-b:
Distributions of the dMVA output for the 2016b data and the corresponding MC samples. The blue squares represent the weighted simulated distributions using the XGBOOST reweighting method. In the lower panel, the blue squares and red points are the ratio of the data to weighted and not weighted simulated distribution respectively. The MC distributions are normalized to the total number of events in data. |
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Figure 1-c:
Distributions of the dMVA output for the 2017-2018 data and the corresponding MC samples. The blue squares represent the weighted simulated distributions using the XGBOOST reweighting method. In the lower panel, the blue squares and red points are the ratio of the data to weighted and not weighted simulated distribution respectively. The MC distributions are normalized to the total number of events in data. |
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Figure 2:
The distribution of the B meson pT after the sPlot background subtraction in data (points with error bars) and simulation (hatched histogram) for B+→J/ψK+ (left) and B0s→μ+μ− (right) events. The MC distributions are normalized to the total number of events in data. |
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Figure 2-a:
The distribution of the B meson pT after the sPlot background subtraction in data (points with error bars) and simulation (hatched histogram) for B+→J/ψK+ events. The MC distributions are normalized to the total number of events in data. |
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Figure 2-b:
The distribution of the B meson pT after the sPlot background subtraction in data (points with error bars) and simulation (hatched histogram) for B0s→μ+μ− events. The MC distributions are normalized to the total number of events in data. |
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Figure 3:
The projections on the dimuon mass axis of the fit to the branching fraction for the dMVA> 0.99 (left) and 0.99 >dMVA> 0.90 (right) categories. The solid blue curves represent the corresponding projections of the final fit model, while the individual components of the fit are represented by the dashed curves (backgrounds) and hatched histograms (signals). |
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Figure 3-a:
The projection on the dimuon mass axis of the fit to the branching fraction for the dMVA> 0.99 category. The solid blue curves represent the corresponding projections of the final fit model, while the individual components of the fit are represented by the dashed curves (backgrounds) and hatched histograms (signals). |
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Figure 3-b:
The projection on the dimuon mass axis of the fit to the branching fraction for the 0.99 >dMVA> 0.90 category. The solid blue curves represent the corresponding projections of the final fit model, while the individual components of the fit are represented by the dashed curves (backgrounds) and hatched histograms (signals). |
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Figure 4:
The profile likelihood as a function of B0s→μ+μ− (left) and B0→μ+μ− (middle) decay branching fractions in 1D (top and middle plots) and in 2D (lower plot). The contours in 2D enclose the regions with 1-5σ coverage, where 1, 2, and 3σ regions correspond to 68.3, 95.4, and 99.7% confidence levels, respectively. |
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Figure 4-a:
The profile likelihood as a function of the B0s→μ+μ− decay branching fraction in 1D. |
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Figure 4-b:
The profile likelihood as a function of the B0→μ+μ− decay branching fraction in 1D. |
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Figure 4-c:
The profile likelihood as a function of B0s→μ+μ− and B0→μ+μ− decay branching fractions in 2D. The contours enclose the regions with 1-5σ coverage, where 1, 2, and 3σ regions correspond to 68.3, 95.4, and 99.7% confidence levels, respectively. |
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Figure 5:
The upper limits on the B0→μ+μ− decay branching fraction using the CLs method. The dashed line represents the expected median value of the quantity 1−CL for the background-only hypothesis, while the solid line shows the observed value. The shaded region indicates the ±1σ band. |
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Figure 6:
The UML fit projection on the decay time axis for the signal region 5.28 <mμ+μ−< 5.48 GeV. |
Tables | |
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Table 1:
Selection requirements for the three decay channels used in the signal yield and normalization fits. Addition selection requirements are applied for the B+→J/ψK+ control sample used in systematic studies. |
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Table 2:
Efficiency corrections for the B0s→μ+μ− decays derived using two different methods: the efficiency ratio between data and simulation, and the XGBOOST reweighting in B+→J/ψK+ events. The quoted uncertainties are statistical only. |
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Table 3:
Summary of the systematic uncertainties for the B0s→μ+μ− and B0→μ+μ− branching fraction measurements. |
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Table 4:
Summary of the systematic uncertainties in the B0s→μ+μ− effective lifetime measurement (in ps) in four data-taking periods. |
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Table 5:
The expected event yields for B0s→μ+μ− (N(B0s)), B0→μ+μ− (N(B0)), the combinatorial background (N (comb) ), the peaking background (N (peak)), and the semileptonic background (N (semi)) are summarized for each category (post-fit). The total expected and observed event yields are given in N (total) and Data column, respectively. Regions 0 and 1 refer to the ranges of 0.0-0.7 and 0.7-1.4, respectively, for the |η| of the most forward muon. The uncertainties are statistical only. |
Summary |
Measurements of the branching fraction (B) of the B0s→μ+μ− decay and the effective B0s meson lifetime in this decay based on a data set of proton-proton collisions at √s= 13 TeV corresponding to an integrated luminosity of 140 fb−1 have been presented and found to be: B(B0s→μ+μ−)= [ 3.83+0.38−0.36 (stat) +0.19−0.16 (syst) +0.14−0.13 (fs/fu) ] × 10−9, τ= 1.83 +0.23−0.20 (stat) +0.04−0.04 (syst) ps. Both measurements are the most precise single measurements to date and consistent with the standard model (SM) predictions and previous measurements within one standard deviation. The relative total uncertainty in B is reduced from 23 to 11% compared with the previous CMS measurement [6], based on 2011-2012 and partial 13 TeV data sets, while the central value is found to be somewhat higher. The new analysis applied to the 2016 data used in Ref. [6] yields a central value similar to the original measurement, indicating that the shift in the central value is driven mostly by the new data. The search for the B0→μ+μ− decay has not revealed a significant event excess with respect to the dominant combinatorial background prediction. The 95% confidence level upper limit on the branching fraction is found to be B(B0→μ+μ−)< 1.9 × 10−10 at 95% CL. More data will be required to establish its existence and compare the result with the SM predictions. Compared with the latest LHCb measurement [8] B(B0s→μ+μ−)= (3.09+0.46−0.43 (stat) +0.15−0.11 (syst) ) × 10−9, our result with the combined systematic uncertainty B(B0s→μ+μ−)= (3.83 +0.38−0.36 (stat) +0.24−0.21 (syst) ) × 10−9, is about 1.2 standard deviations higher. These two measurements will shift the world average from its current value of B(B0s→μ+μ−)= ( 2.69 +0.37−0.35 ) × 10−9 [9] to a larger value, more consistent with the SM prediction, thus reducing the overall tension. The new measurement of the B0s→μ+μ− branching fraction is an important input to the global fits to the flavor data (e.g., Ref. [23]) in light of the reported b→sℓ+ℓ− anomalies (where lepton ℓ= e or μ). The uncertainties in the branching fraction and effective lifetime measurements are dominated by the statistical component, which means that significant improvements can be expected in the precision of future measurements with the LHC Run 3 data. The effective B0s meson lifetime measurement in the B0s→μ+μ− decay has achieved a precision comparable with the lifetime difference between the heavy and light B0s meson mass eigenstates, thus offering sensitivity to potential beyond-the-SM physics effects in the effective lifetime. |
Additional Figures | |
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Additional Figure 1:
Comparison of the B0s→μ+μ− branching fraction measurement with the most recent results and the Standard Model. |
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Additional Figure 2:
Comparison of the B0s→μ+μ− branching fraction measurement with the most recent results and the Standard Model. |
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Additional Figure 3:
Comparison of the B0→μ+μ− branching fraction measurement with the most recent results and the Standard Model. |
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Additional Figure 4:
Comparison of the B0→μ+μ− branching fraction measurement with the most recent results and the Standard Model. |
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Additional Figure 5:
Comparison of the B0s→μ+μ− effective lifetime measurement with the most recent results and the Standard Model. |
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Additional Figure 6:
Comparison of the B0s→μ+μ− effective lifetime measurement with the most recent results and the Standard Model. |
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Additional Figure 7:
The dimuon mass distribution projection for the branching fraction fit for high purity event category. The blue curves represent the corresponding projections of the final fit model. |
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Additional Figure 8:
Simulated B→h+h− mass distribution using the nominal event selection. |
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Additional Figure 9:
The mass distribution of the B+→J/ψK+ decays observed in Run2018 data for events where |ημ|< 0.7. The blue curve shows the result of the unbinned maximum likelihood fit. The signal event yield, extracted from the fit, is used for normalization of the B0s→μ+μ− branching fraction. The selection requirements are optimized for the most precise estimation of the normalization. |
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Additional Figure 10:
The mass distribution of the B+→J/ψK+ decays observed in Run2018 data for events where |ημ1|> 0.7 or |ημ2|> 0.7. The blue curve shows the result of the unbinned maximum likelihood fit. The signal event yield, extracted from the fit, is used for normalization of the B0s→μ+μ− branching fraction. The selection requirements are optimized for the most precise estimation of the normalization. |
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Additional Figure 11:
The mass distribution of the B0s→J/ψϕ(1020) decays observed in Run2018 data for events where |ημ|< 0.7. The blue curve shows the result of the unbinned maximum likelihood fit. The signal event yield, extracted from the fit, is used for normalization of the B0s→μ+μ− branching fraction. The selection requirements are optimized for the most precise estimation of the normalization. |
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Additional Figure 12:
The mass distribution of the B0s→J/ψϕ(1020) decays observed in Run2018 data for events where |ημ1|> 0.7 or |ημ2|> 0.7. The blue curve shows the result of the unbinned maximum likelihood fit. The signal event yield, extracted from the fit, is used for normalization of the B0s→μ+μ− branching fraction. The selection requirements are optimized for the most precise estimation of the normalization. |
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Additional Figure 13:
Ratios of the decay time efficiencies for the tight (dMVA> 0.99) and loose (dMVA> 0.90) selections observed in Run2016a Data and MC simulations for B+→J/ψK+ decays. The difference between the two ratios is used to correct the decay time efficiency for B0s→μ+μ− decays. |
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Additional Figure 14:
Ratios of the decay time efficiencies for the tight (dMVA> 0.99) and loose (dMVA> 0.90) selections observed in Run2016b Data and MC simulations for B+→J/ψK+ decays. The difference between the two ratios is used to correct the decay time efficiency for B0s→μ+μ− decays. |
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Additional Figure 15:
Ratios of the decay time efficiencies for the tight (dMVA> 0.99) and loose (dMVA> 0.90) selections observed in Run2017 Data and MC simulations for B+→J/ψK+ decays. The difference between the two ratios is used to correct the decay time efficiency for B0s→μ+μ− decays. |
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Additional Figure 16:
Ratios of the decay time efficiencies for the tight (dMVA> 0.99) and loose (dMVA> 0.90) selections observed in Run2018 Data and MC simulations for B+→J/ψK+ decays. The difference between the two ratios is used to correct the decay time efficiency for B0s→μ+μ− decays. |
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Additional Figure 17:
The pointing angle distribution for 2017--2018 data and corresponding MC simulation. The blue histogram represent the reweighted MC simulation using the XGBoost reweighting method. |
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Additional Figure 18:
The impact parameter significance distribution for 2017--2018 data and corresponding MC simulation. The blue histogram represent the reweighted MC simulation using the XGBoost reweighting method. |
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Additional Figure 19:
The impact parameter distribution for 2017--2018 data and corresponding MC simulation. The blue histogram represent the reweighted MC simulation using the XGBoost reweighting method. |
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Additional Figure 20:
3D view of a B0s→μ+μ− candidate in Run 2 data. The two red lines correspond to the two muons from the decay. Other curved lines represent charged tracks originating from the same primary vertex as the B candidate. Tracks from other interactions in the event have been removed for clarity. |
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Additional Figure 21:
The rho-phi projection of a B0s→μ+μ− candidate in Run 2 data. The two red lines correspond to the two muons from the decay. Other curved lines represent charged tracks originating from the same primary vertex as the B candidate. Tracks from other interactions in the event have been removed for clarity. |
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Additional Figure 22:
The rho-phi projection of a B0s→μ+μ− candidate in Run 2 data zoomed in on the inner tracker regions. The two red lines correspond to the two muons from the decay. Other curved lines represent charged tracks originating from the same primary vertex as the B candidate. Tracks from other interactions in the event have been removed for clarity. |
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Additional Figure 23:
The rho-phi proejction of a B0s→μ+μ− candidate in Run 2 data zoomed in on the innermost detector regions. The two red lines correspond to the two muons from the decay. Other curved lines represent charged tracks originating from the same primary vertex as the B candidate. Tracks from other interactions in the event have been removed for clarity. |
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Additional Figure 24:
Comparison of the pointing angle distributions for B+→J/ψK+ and B0s→μ+μ− decays in MC simulated data using the nominal event selection. |
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Additional Figure 25:
Comparison of the pointing angle distributions for B+→J/ψK+ and B0s→μ+μ− decays in MC simulated data with the kaon pT> 3.0 GeV. |
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Additional Figure 26:
Comparison of the pointing angle distributions for B+→J/ψK+ and B0s→μ+μ− decays in MC simulated data with the kaon pT< 1.5 GeV. |
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Additional Figure 27:
The B0→μ+μ− signal significance distribution for 1000 pseudo data experiments generated with the nominal fit configuration. |
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Additional Figure 28:
Comparison of the dMVA distributions for B+→J/ψK+ and B0s→μ+μ− decays in MC simulated data treating B+→J/ψK+ as background. |
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Additional Figure 29:
Comparison of the flight length significance distributions for B+→J/ψK+ and B0s→μ+μ− decays in MC simulated data with the kaon pT< 1.5 GeV. |
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Additional Figure 30:
Comparison of the flight length significance distributions for B+→J/ψK+ and B0s→μ+μ− decays in MC simulated data with the kaon pT< 1.5 GeV scaling the flight length significance by 1.6 for B+→J/ψK+ events. |
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Additional Figure 31:
Distribution of the dimuon mass uncertainty for B0s→μ+μ− decays in MC simulated data. The first peak corresponds to events with both muons in the central part of the detector, the second one has one central and one forward muons and the last one corresponds to events where both muons are forward. |
References | ||||
1 | N. Cabibbo | Unitary symmetry and leptonic decays | PRL 10 (1963) 531 | |
2 | M. Kobayashi and T. Maskawa | CP-violation in the renormalizable theory of weak interaction | Progress of Theoretical Physics 49 (1973) 652 | |
3 | M. Beneke, C. Bobeth, and R. Szafron | Power-enhanced leading-logarithmic QED corrections to Bq→μ+μ− | JHEP 10 (2019) 232 | 1908.07011 |
4 | C. Bobeth and A. J. Buras | Searching for new physics with ¯B(Bs,d→μ¯μ)/ΔMs,d | Acta Phys. Polon. B 52 (2021) 1189 | 2104.09521 |
5 | CMS and LHCb Collaborations | Observation of the rare B0s→μ+μ− decay from the combined analysis of CMS and LHCb data | Nature 522 (2015) 68 | 1411.4413 |
6 | ATLAS Collaboration | Study of the rare decays of B0s and B0 mesons into muon pairs using data collected during 2015 and 2016 with the ATLAS detector | JHEP 04 (2019) 098 | 1812.03017 |
7 | CMS Collaboration | Measurement of properties of B0s→μ+μ− decays and search for B0→μ+μ− with the CMS experiment | JHEP 04 (2020) 188 | CMS-BPH-16-004 1910.12127 |
8 | LHCb Collaboration | Measurement of the B0s→μ+μ− branching fraction and effective lifetime and search for B0→μ+μ− decays | PRL 118 (2017) 191801 | 1703.05747 |
9 | LHCb Collaboration | Measurement of the B0s→μ+μ− decay properties and search for the B0→μ+μ− and B0s→μ+μ−γ decays | PRD 105 (2022) 012010 | 2108.09283 |
10 | LHCb Collaboration | Analysis of neutral B-meson decays into two muons | PRL 128 (2022) 041801 | 2108.09284 |
11 | ATLAS, CMS and LHCb Collaborations | Combination of the ATLAS, CMS and LHCb results on the B0s→μ+μ− decays | Physics Analysis Summary, LHCb-CONF-2020-002, ATLAS-CONF-2020-049 CMS-PAS-BPH-20-003 |
CMS-PAS-BPH-20-003 |
12 | LHCb Collaboration | Differential branching fractions and isospin asymmetries of B→K∗(892)μ+μ− decays | JHEP 06 (2014) 133 | 1403.8044 |
13 | LHCb Collaboration | Angular analysis of the rare decay B0s→ϕμ+μ− | JHEP 11 (2021) 043 | 2107.13428 |
14 | LHCb Collaboration | Measurements of the S-wave fraction in B0→K+π−μ+μ− decays and the B0→K∗(892)(892)0μ+μ− differential branching fraction | JHEP 11 (2016) 047 | 1606.04731 |
15 | LHCb Collaboration | Branching fraction measurements of the rare B0s→ϕμ+μ− and B0s→f′2(1525)μ+μ− decays | PRL 127 (2021) 151801 | 2105.14007 |
16 | LHCb Collaboration | Measurement of CP-averaged observables in the B0→K∗(892)0μ+μ− decay | PRL 125 (2020) 011802 | 2003.04831 |
17 | LHCb Collaboration | Angular analysis of the B+→K∗(892)+μ+μ− decay | PRL 126 (2021) 161802 | 2012.13241 |
18 | LHCb Collaboration | Test of lepton universality with B0→K∗(892)0ℓ+ℓ− decays | JHEP 08 (2017) 055 | 1705.05802 |
19 | LHCb Collaboration | Test of lepton universality in beauty-quark decays | Nature Phys. 18 (2022) 277 | 2103.11769 |
20 | Belle Collaboration | Test of lepton-flavor universality in B→K∗(892)ℓ+ℓ− decays at Belle | PRL 126 (2021) 161801 | 1904.02440 |
21 | Belle Collaboration | Test of lepton flavor universality and search for lepton flavor violation in B→Kℓℓ decays | JHEP 03 (2021) 105 | 1908.01848 |
22 | LHCb Collaboration | Tests of lepton universality using B0→K0Sℓ+ℓ− and B+→K∗(892)+ℓ+ℓ− decays | PRL 128 (2022) 191802 | 2110.09501 |
23 | CMS Collaboration | Angular analysis of the decay B0→K∗(892)0μ+μ− from pp collisions at √s= 8 TeV | PLB 753 (2016) 424 | CMS-BPH-13-010 1507.08126 |
24 | CMS Collaboration | Measurement of angular parameters from the decay B0→K∗(892)0μ+μ− in proton-proton collisions at √s= 8 TeV | PLB 781 (2018) 517 | CMS-BPH-15-008 1710.02846 |
25 | LHCb Collaboration | Test of lepton universality in b→sℓ+ℓ− decays | 2212.09152 | |
26 | LHCb Collaboration | Measurement of lepton universality parameters in B+→K+ℓ+ℓ− and B0→K∗0ℓ+ℓ− decays | 12, 2022 | 2212.09153 |
27 | Flavour Lattice Averaging Group (FLAG) | FLAG review 2021 | EPJC 82 (2022) 869 | 2111.09849 |
28 | HFLAV Collaboration | Averages of b-hadron, c-hadron, and τ-lepton properties as of 2021 | 2206.07501 | |
29 | Particle Data Group, R. L. Workman, and others | Review of Particle Physics | PTEP 2022 (2022) 083C01 | |
30 | CMS Collaboration | HEPData record for this analysis | link | |
31 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | |
32 | CMS Collaboration | Description and performance of track and primary-vertex reconstruction with the CMS tracker | JINST 9 (2014) P10009 | CMS-TRK-11-001 1405.6569 |
33 | CMS Tracker Group | The CMS Phase-1 pixel detector upgrade | JINST 16 (2021) P02027 | 2012.14304 |
34 | CMS Collaboration | Track impact parameter resolution for the full pseudorapidity coverage in the 2017 dataset with the CMS Phase-1 pixel detector | CMS Detector Performance Report CMS-DP-2020-049, 2020 CDS |
|
35 | CMS Collaboration | Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at √s= 13 TeV | JINST 13 (2018) P06015 | CMS-MUO-16-001 1804.04528 |
36 | CMS Collaboration | Performance of the CMS Level-1 trigger in proton-proton collisions at √s= 13 TeV | JINST 15 (2020) P10017 | CMS-TRG-17-001 2006.10165 |
37 | CMS Collaboration | The CMS trigger system | JINST 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
38 | CMS Collaboration | Precision luminosity measurement in proton-proton collisions at √s= 13 TeV in 2015 and 2016 at CMS | EPJC 81 (2021) 800 | CMS-LUM-17-003 2104.01927 |
39 | CMS Collaboration | CMS luminosity measurements for the 2017 data-taking period at √s= 13 TeV | CMS Physics Analysis Summary, 2018 CMS-PAS-LUM-17-004 |
CMS-PAS-LUM-17-004 |
40 | CMS Collaboration | CMS luminosity measurements for the 2018 data-taking period at √s= 13 TeV | CMS Physics Analysis Summary, 2018 CMS-PAS-LUM-18-001 |
CMS-PAS-LUM-18-001 |
41 | T. Sjöstrand et al. | An introduction to PYTHIA 8.2 | Comput. Phys. Commun. 191 (2015) 159 | 1410.3012 |
42 | CMS Collaboration | Extraction and validation of a new set of CMS PYTHIA 8 tunes from underlying-event measurements | EPJC 80 (2020) 4 | CMS-GEN-17-001 1903.12179 |
43 | GEANT4 Collaboration | GEANT 4---a simulation toolkit | NIM A 506 (2003) 250 | |
44 | D. J. Lange | The EvtGen particle decay simulation package | NIM A 462 (2001) 152 | |
45 | N. Davidson, T. Przedzinski, and Z. Was | PHOTOS interface in C++: technical and physics documentation | Comput. Phys. Commun. 199 (2016) 86 | 1011.0937 |
46 | K. Prokofiev and T. Speer | A kinematic and a decay chain reconstruction library | in Proc. Int. Conf. on Comput. in High-Energy and Nuc. Physics (CHEP '04) link |
|
47 | T. Chen and C. Guestrin | XGBoost: A scalable tree boosting system | in 22nd ACM SIGKDD Int. Conf. on Knowledge Discovery and Data Mining, KDD '16, . ACM, New York Proc. 2 (2016) 785 |
|
48 | M. Pivk and F. R. Le Diberder | sPlot: A statistical tool to unfold data distributions | NIM A 555 (2005) 356 | physics/0402083 |
49 | M. J. Oreglia | A study of the reactions ψ′→γγψ | PhD thesis, Stanford University, SLAC Report SLAC-R-236, 1980 link |
|
50 | CMS Collaboration | Tracking performances for charged pions with Run2 legacy data | CMS Detector Performance Report CMS-DP-2022-012, 2022 CDS |
|
51 | LHCb Collaboration | Precise measurement of the fs/fd ratio of fragmentation fractions and of B0s decay branching fractions | PRD 104 (2021) 032005 | 2103.06810 |
52 | CMS Collaboration | Measurement of the dependence of the hadron production fraction ratio fs/fu on B meson kinematic variables in proton-proton collisions at √s = 13 TeV | Submitted to PRL | CMS-BPH-21-001 2212.02309 |
53 | Belle-II Collaboration | The Belle II physics book | no.~12, 123C01, , . [Erratum: PTEP , 01 ()], 2019 PTEP 2019 (2019) |
1808.10567 |
54 | T. Junk | Confidence level computation for combining searches with small statistics | NIM A 434 (1999) 435 | hep-ex/9902006 |
55 | A. L. Read | Presentation of search results: The CLs technique | JPG 28 (2002) 2693 | |
56 | W. Altmannshofer and P. Stangl | New physics in rare B decays after Moriond 2021 | EPJC 81 (2021) 952 | 2103.13370 |
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Compact Muon Solenoid LHC, CERN |
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