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| CMS-PAS-BPH-15-009 | ||
| Angular analysis of the decay ${\mathrm B^{+} \to \mathrm K^{*+} \mu^{+} \mu^{-}}$ in proton-proton collisions at $\sqrt{s}= $ 8 TeV | ||
| CMS Collaboration | ||
| July 2020 | ||
| Abstract: Angular distributions of the decay ${\mathrm B^{+} \to \mathrm K^{*+} \mu^{+} \mu^{-}}$ are studied using events collected with the CMS detector from $\sqrt{s}= $ 8 TeV proton-proton collisions, corresponding to an integrated luminosity of 20.0 fb$^{-1}$. The forward-backward asymmetry of the muons and the longitudinal polarization of the $\mathrm K^{*+}$ meson are determined for an integrated sample and as a function of the dimuon invariant mass squared. These are the first results from this exclusive decay mode and are in agreement with standard model predictions. | ||
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Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, JHEP 04 (2021) 124. The superseded preliminary plots can be found here. |
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| Figures | |
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Figure 1:
The signal efficiency as a function $\cos\theta _{\mathrm{K}} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 1-a:
The signal efficiency as a function $\cos\theta _{\mathrm{K}} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 1-b:
The signal efficiency as a function $\cos\theta _{\mathrm{K}} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 1-c:
The signal efficiency as a function $\cos\theta _{\mathrm{K}} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 1-d:
The signal efficiency as a function $\cos\theta _{\mathrm{K}} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 2:
The signal efficiency as a function $\cos\theta _{\ell} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 2-a:
The signal efficiency as a function $\cos\theta _{\ell} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 2-b:
The signal efficiency as a function $\cos\theta _{\ell} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 2-c:
The signal efficiency as a function $\cos\theta _{\ell} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 2-d:
The signal efficiency as a function $\cos\theta _{\ell} $ for different ${q^2}$ ranges. The vertical bars indicate the statistical uncertainty. The curves show the fitted result, as described in the text. |
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Figure 3:
The fitted $\mathrm{B^{+}}$ invariant mass, $\mathrm {m}$, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 3-a:
The fitted $\mathrm{B^{+}}$ invariant mass, $\mathrm {m}$, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 3-b:
The fitted $\mathrm{B^{+}}$ invariant mass, $\mathrm {m}$, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 3-c:
The fitted $\mathrm{B^{+}}$ invariant mass, $\mathrm {m}$, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 3-d:
The fitted $\mathrm{B^{+}}$ invariant mass, $\mathrm {m}$, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 4:
The fitted angular variable $\cos\theta _{\mathrm{K}}$, for each ${q^2}$ range from the three dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 4-a:
The fitted angular variable $\cos\theta _{\mathrm{K}}$, for each ${q^2}$ range from the three dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 4-b:
The fitted angular variable $\cos\theta _{\mathrm{K}}$, for each ${q^2}$ range from the three dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 4-c:
The fitted angular variable $\cos\theta _{\mathrm{K}}$, for each ${q^2}$ range from the three dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 4-d:
The fitted angular variable $\cos\theta _{\mathrm{K}}$, for each ${q^2}$ range from the three dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars represent the statistical uncertainty. |
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Figure 5:
The fitted angular variable $\cos\theta _{\ell} $, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars on the points represent the statistical uncertainty. |
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Figure 5-a:
The fitted angular variable $\cos\theta _{\ell} $, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars on the points represent the statistical uncertainty. |
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Figure 5-b:
The fitted angular variable $\cos\theta _{\ell} $, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars on the points represent the statistical uncertainty. |
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Figure 5-c:
The fitted angular variable $\cos\theta _{\ell} $, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars on the points represent the statistical uncertainty. |
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Figure 5-d:
The fitted angular variable $\cos\theta _{\ell} $, for each ${q^2}$ range from the three-dimensional fit to the data. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. The vertical bars on the points represent the statistical uncertainty. |
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Figure 6:
The angular variable $\cos\theta _{\mathrm{K}}$ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
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Figure 6-a:
The angular variable $\cos\theta _{\mathrm{K}}$ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
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Figure 6-b:
The angular variable $\cos\theta _{\mathrm{K}}$ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
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Figure 6-c:
The angular variable $\cos\theta _{\mathrm{K}}$ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
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Figure 6-d:
The angular variable $\cos\theta _{\mathrm{K}}$ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
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Figure 7:
The angular variable $\cos\theta _{\ell} $ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
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Figure 7-a:
The angular variable $\cos\theta _{\ell} $ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
png pdf |
Figure 7-b:
The angular variable $\cos\theta _{\ell} $ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
png pdf |
Figure 7-c:
The angular variable $\cos\theta _{\ell} $ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
png pdf |
Figure 7-d:
The angular variable $\cos\theta _{\ell} $ for the events in the signal region 5.18 $ < m < $ 5.38 GeV, overlayed with the corresponding signal, background and total pdfs obtained from the final fit, for each ${q^2}$ range. The filled area, dashed lines, and solid lines represent the signal, background, and total contributions, respectively. |
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Figure 8:
The measured values of ${A_\mathrm {FB}}$ and ${F_\mathrm {L}}$ versus ${q^2}$ for ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} \mu^{+} \mu^{-}}$ decays. The statistical (total) uncertainty is shown by inner (outer) vertical bars. The vertical shaded regions correspond to the ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} {\mathrm{J}/\psi} (\mu^{+} \mu^{-})}$ and ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} \psi(\text{2S})(\mu^{+} \mu^{-})}$ dominated regions. The blue band shows the SM predictions for the corresponding ${q^2}$ range. |
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Figure 8-a:
The measured values of ${A_\mathrm {FB}}$ and ${F_\mathrm {L}}$ versus ${q^2}$ for ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} \mu^{+} \mu^{-}}$ decays. The statistical (total) uncertainty is shown by inner (outer) vertical bars. The vertical shaded regions correspond to the ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} {\mathrm{J}/\psi} (\mu^{+} \mu^{-})}$ and ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} \psi(\text{2S})(\mu^{+} \mu^{-})}$ dominated regions. The blue band shows the SM predictions for the corresponding ${q^2}$ range. |
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Figure 8-b:
The measured values of ${A_\mathrm {FB}}$ and ${F_\mathrm {L}}$ versus ${q^2}$ for ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} \mu^{+} \mu^{-}}$ decays. The statistical (total) uncertainty is shown by inner (outer) vertical bars. The vertical shaded regions correspond to the ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} {\mathrm{J}/\psi} (\mu^{+} \mu^{-})}$ and ${\mathrm{B^{+}} \to {{\mathrm{K}} ^{*+}} \psi(\text{2S})(\mu^{+} \mu^{-})}$ dominated regions. The blue band shows the SM predictions for the corresponding ${q^2}$ range. |
| Tables | |
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Table 1:
Sources of systematic uncertainties and the effect on ${A_\mathrm {FB}}$ and ${F_\mathrm {L}}$. The values given are absolute and the ranges indicate the variation over the four ${q^2}$ bins. |
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Table 2:
The signal yield with statistical uncertainty and the fitted ${A_\mathrm {FB}}$ and ${F_\mathrm {L}}$ values with statistical and systematic uncertainties, for each ${q^2}$ range. |
| Summary |
| The first angular analysis of the decay ${\mathrm{B^{+}}\to {\mathrm K^{*+}} \mu^{+} \mu^{-}}$ has been performed using a sample of proton-proton collisions at a center-of-mass energy of 8 TeV. The data were collected with the CMS detector in 2012 and correspond to an integrated luminosity of 20.0 fb$^{-1}$ . For each bin of dimuon invariant mass squared (${q^2} $), a three-dimensional unbinned maximum-likelihood fit was performed to the distributions of the ${\mathrm K^{*+}} \mu^{+}\mu^{-}$ invariant mass and two decay angles. The forward-backward asymmetry, ${A_\mathrm{FB}} $, of the muon system and the longitudinal polarization of ${\mathrm K^{*+}} , {F_\mathrm{L}} $, are extracted from the fit and compared with predictions from a standard model prediction. The results are consistent with standard model expectations. |
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