CMS-BPH-17-005 ; CERN-EP-2020-070 | ||
Observation of the B0s→X(3872)ϕ decay | ||
CMS Collaboration | ||
10 May 2020 | ||
Phys. Rev. Lett. 125 (2020) 152001 | ||
Abstract: Using a data sample of proton-proton collisions at √s= 13 TeV, corresponding to an integrated luminosity of 140 fb−1 collected by the CMS experiment in 2016-2018, the B0s→X(3872)ϕ decay is observed. Decays into J/ψπ+π− and K+K− are used to reconstruct, respectively, the X(3872) and ϕ. The ratio of the product of branching fractions B(B0s→X(3872)ϕ)B(X(3872)→J/ψπ+π−) to the product B(B0s→ψ(2S)ϕ)B(ψ(2S)→J/ψπ+π−) is measured to be (2.21 ± 0.29 (stat) ± 0.17 (syst))%. The ratio B(B0s→X(3872)ϕ)/B(B0→X(3872)K0) is found to be consistent with one, while the ratio B(B0s→X(3872)ϕ)/B(B+→X(3872)K+) is two times smaller. This suggests a difference in the production dynamics of the X(3872) in B0 and B0s meson decays compared to B+. The reported observation may shed new light on the nature of the X(3872) particle. | ||
Links: e-print arXiv:2005.04764 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; |
Figures & Tables | Summary | Additional Figures | References | CMS Publications |
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Figures | |
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Figure 1:
The observed J/ψπ+π− (left) and K+K− (right) invariant mass distributions for the B0s→ψ(2S)ϕ candidates are shown by the points, with the vertical bars representing the statistical uncertainties. The projections of the 2D fit and its various components are shown by the lines. |
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Figure 1-a:
The observed J/ψπ+π− invariant mass distribution for the B0s→ψ(2S)ϕ candidates is shown by the points, with the vertical bars representing the statistical uncertainties. The projections of the 2D fit and its various components are shown by the lines. |
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Figure 1-b:
The observed K+K− invariant mass distribution for the B0s→ψ(2S)ϕ candidates is shown by the points, with the vertical bars representing the statistical uncertainties. The projections of the 2D fit and its various components are shown by the lines. |
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Figure 2:
The observed J/ψπ+π− (left) and K+K− (right) invariant mass distributions for the B0s→X(3872)ϕ candidates are shown by the points, with the vertical bars representing the statistical uncertainties. The projections of the 2D fit and its various components are shown by the lines. |
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Figure 2-a:
The observed J/ψπ+π− invariant mass distribution for the B0s→X(3872)ϕ candidates is shown by the points, with the vertical bars representing the statistical uncertainties. The projections of the 2D fit and its various components are shown by the lines. |
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Figure 2-b:
The observed K+K− invariant mass distribution for the B0s→X(3872)ϕ candidates is shown by the points, with the vertical bars representing the statistical uncertainties. The projections of the 2D fit and its various components are shown by the lines. |
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Figure 3:
Background-subtracted ψ(2S)ϕ (left) and X(3872)ϕ (right) invariant mass distributions obtained by sPlot weighting. The result of each fit and its components are shown by the lines. |
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Figure 3-a:
Background-subtracted ψ(2S)ϕ invariant mass distribution obtained by sPlot weighting. The result of each fit and its components are shown by the lines. |
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Figure 3-b:
Background-subtracted X(3872)ϕ invariant mass distribution obtained by sPlot weighting. The result of each fit and its components are shown by the lines. |
Tables | |
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Table 1:
Relative systematic uncertainties in the ratio R. |
Summary |
In summary, using a data sample corresponding to an integrated luminosity of 140 fb−1 of proton-proton collisions collected by the CMS experiment at √s= 13 TeV in 2016--2018, the B0s→X(3872)ϕ decay is observed for the first time. The comparison with similar decays of B0 and B+ mesons indicates that the X(3872) formation in B meson decays is different from ψ(2S) formation, suggesting that X(3872) is not a pure charmonium state and supporting similar conclusions derived from other experimental measurements [2, 5, 8–12]. This observation may shed new light on the nature of the X(3872) particle. |
Additional Figures | |
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Additional Figure 1:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(K+K−): (a) left ϕ sideband, (b) ϕ signal region, (c) right ϕ sideband. The projections of the two dimensional fit and its various components are shown by the lines explained in the legend in (b). |
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Additional Figure 1-a:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(K+K−): left ϕ sideband. |
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Additional Figure 1-b:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(K+K−): ϕ signal region. The projection of the two dimensional fit and its various components are shown by the lines explained in the legend. |
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Additional Figure 1-c:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(K+K−): right ϕ sideband. |
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Additional Figure 2:
The observed K+K− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(J/ψπ+π−): (a) left ψ(2S) sideband, (b) ψ(2S) signal region, (c) right ψ(2S) sideband. The projections of the two dimensional fit and its various components are shown by the lines explained in the legend in (b). |
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Additional Figure 2-a:
The observed K+K− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(J/ψπ+π−): left ψ(2S) sideband. |
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Additional Figure 2-b:
The observed K+K− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(J/ψπ+π−): ψ(2S) signal region. The projection of the two dimensional fit and its various components are shown by the lines explained in the legend. |
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Additional Figure 2-c:
The observed K+K− invariant mass distribution for the selected B0s→ψ(2S)ϕ candidates in three ranges of m(J/ψπ+π−): right ψ(2S) sideband. |
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Additional Figure 3:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(K+K−): (a) left ϕ sideband, (b) ϕ signal region, (c) right ϕ sideband. The projections of the two dimensional fit and its various components are shown by the lines explained in the legend in (b). |
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Additional Figure 3-a:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(K+K−): left ϕ sideband. |
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Additional Figure 3-b:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(K+K−): ϕ signal region. right ϕ sideband. The projection of the two dimensional fit and its various components are shown by the lines explained in the legend. |
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Additional Figure 3-c:
The observed J/ψπ+π− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(K+K−): right ϕ sideband. |
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Additional Figure 4:
The observed K+K− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(J/ψπ+π−): (a) left X sideband, (b) X signal region, (c) right X sideband. The projections of the two dimensional fit and its various components are shown by the lines explained in the legend in (b). |
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Additional Figure 4-a:
The observed K+K− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(J/ψπ+π−): left X sideband. |
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Additional Figure 4-b:
The observed K+K− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(J/ψπ+π−): X signal region. The projection of the two dimensional fit and its various components are shown by the lines explained in the legend. |
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Additional Figure 4-c:
The observed K+K− invariant mass distribution for the selected B0s→X(3872)ϕ candidates in three ranges of m(J/ψπ+π−): right X sideband. |
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Additional Figure 5:
Comparison of the branching fractions B(B→J/ψh) for B+, B0, and B0s decays. The values are taken from Ref. [4]. |
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Additional Figure 6:
Comparison of the branching fractions B(B→ψ(2S)h) for B+, B0, and B0s decays. The values are taken from Ref. [4]. |
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Additional Figure 7:
Comparison of the branching fraction products B(B→X(3872)h)×B(X(3872)→J/ψπ+π−) for B+, B0 [4], and B0s decays, where the last result by CMS is highlighted in red. |
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