Figure | Caption |
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The mean of the average impact parameter in the transverse plane $d_{xy}$ as a function of processed luminosity. Only tracks with transverse momentum $p_{T}$ > 3 GeV are considered. The vertical black lines indicate the first processed run for 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate a change in the pixel tracker calibration. The blue points correspond to the results with the alignment constants used during data-taking, the red points to the 2016, 2017 and 2018 End-Of-Year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), and the green points to the results obtained in the Run-2 Legacy alignment procedure. During the LHC shutdown in winter 2016/17, the inner component (pixel detector) of the CMS tracking detector was replaced. The first few inverse picobarns of the 2017 pp collision run have been devoted to the commissioning of the new detector, resulting in sub-optimal tracking performance. This is visible in degraded impact parameter bias around the 36 fb${}^{\text{-1}}$ mark. Apart from this short period, aligning the tracker improves the mean of this distribution. Short IOVs with suboptimal configuration of the pixel local reconstruction (e.g. different high-voltage settings, inconsistent local reconstruction with alignment) can give rise to isolated peaks in the trends, especially during data taking. The suboptimal performance of the alignment during data taking at the beginning of 2018 is caused by the fact that the alignment was not updated by the prompt calibration loop (PCL). |
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The mean of the average impact parameter in the longitudinal plane $d_{z}$ as a function of processed luminosity. Only tracks with transverse momentum $p_{T}$ > 3 GeV are considered. The vertical black lines indicate the first processed run for 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate a change in the pixel tracker calibration. The blue points correspond to the results with the alignment constants used during data-taking, the red points to the 2016, 2017 and 2018 End-Of-Year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), and the green points to the results obtained in the Run-2 Legacy alignment procedure. During the LHC shutdown in winter 2016/17, the inner component (pixel detector) of the CMS tracking detector was replaced. The first few inverse picobarns of the 2017 pp collision run have been devoted to the commissioning of the new detector, resulting in sub-optimal tracking performance. This is visible in degraded impact parameter bias around the 36 fb${}^{\text{-1}}$ mark. Apart from this short period, aligning the tracker improves the mean of this distribution. Short IOVs with suboptimal configuration of the pixel local reconstruction (e.g. different high-voltage settings, inconsistent local reconstruction with alignment) can give rise to isolated peaks in the trends, especially during data taking. The suboptimal performance for the alignment during data taking at the beginning of 2016 is due to relative misalignment of the two half-barrels of the pixel detector along the z-direction. This was not corrected by the alignment in the prompt calibration loop (PCL), which was not active in that period. |
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The RMS of the average impact parameter in the transverse plane $d_{xy}$ in bins of the track azimuth $\phi$, as a function of processed luminosity. Only tracks with transverse momentum $p_{T}$ > 3 GeV are considered. The vertical black lines indicate the first processed run for 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate a change in the pixel tracker calibration. The blue points correspond to the results with the alignment constants used during data-taking, the red points to the 2016, 2017 and 2018 End-Of-Year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), and the green points to the results obtained in the Run-2 Legacy alignment procedure. During the LHC shutdown in winter 2016/17, the inner component (pixel detector) of the CMS tracking detector was replaced. The first few inverse picobarns of the 2017 pp collision run have been devoted to the commissioning of the new detector, resulting in sub-optimal tracking performance. This is visible in degraded impact parameter bias around the 36 fb${}^{\text{-1}}$ mark. Apart from this short period, aligning the tracker improves the mean of this distribution. Short IOVs with suboptimal configuration of the pixel local reconstruction (e.g. different high-voltage settings, inconsistent local reconstruction with alignment) can give rise to isolated peaks in the trends, especially during data taking. The suboptimal performance of the alignment during data taking at the beginning of 2018 is caused by the fact that the alignment was not updated by the prompt calibration loop (PCL). The slopes for the alignment during data taking visible between two pixel calibration updates are due to radiation effects, causing rapid changes of the Lorentz drift. This effect can only be corrected by aligning with a finer granularity than the automated alignment (PCL) implements. |
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The RMS of the average impact parameter in the longitudinal plane $d_{z}$ in bins of the track azimuth $\phi$, as a function of processed luminosity. Only tracks with transverse momentum $p_{T}$ > 3 GeV are considered. The vertical black lines indicate the first processed run for 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate a change in the pixel tracker calibration. The blue points correspond to the results with the alignment constants used during data-taking, the red points to the 2016, 2017 and 2018 End-Of-Year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), and the green points to the results obtained in the Run-2 Legacy alignment procedure. During the LHC shutdown in winter 2016/17, the inner component (pixel detector) of the CMS tracking detector was replaced. The first few inverse picobarns of the 2017 pp collision run have been devoted to the commissioning of the new detector, resulting in sub-optimal tracking performance. This is visible in degraded impact parameter bias around the 36 fb${}^{\text{-1}}$ mark. Apart from this short period, aligning the tracker improves the mean of this distribution. Short IOVs with suboptimal configuration of the pixel local reconstruction (e.g. different high-voltage settings, inconsistent local reconstruction with alignment) can give rise to isolated peaks in the trends, especially during data taking. |
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The RMS of the average impact parameter in the transverse plane $d_{xy}$ in bins of the track pseudorapidity $\eta$, as a function of processed luminosity. Only tracks with transverse momentum $p_{T}$ > 3 GeV are considered. The vertical black lines indicate the first processed run of the 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate a change in the pixel tracker calibration. The blue points correspond to the results with the alignment constants used during data-taking, the red points to the 2016, 2017 and 2018 End-Of-Year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), and the green points to the results obtained in the Run-2 Legacy alignment procedure. During the LHC shutdown in winter 2016/17, the inner component (pixel detector) of the CMS tracking detector was replaced. The first few inverse picobarns of the 2017 pp collision run have been devoted to the commissioning of the new detector, resulting in sub-optimal tracking performance. This is visible in degraded impact parameter bias around the 36 fb${}^{\text{-1}}$ mark. Apart from this short period, aligning the tracker improves the mean of this distribution. Short IOVs with suboptimal configuration of the pixel local reconstruction (e.g. different high-voltage settings, inconsistent local reconstruction with alignment) can give rise to isolated peaks in the trends, especially during data taking. |
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The RMS of the average impact parameter in the longitudinal plane $d_{z}$ in bins of the track pseudorapidity $\eta$, as a function of processed luminosity. Only tracks with transverse momentum $p_{T}$ > 3 GeV are considered. The vertical black lines indicate the first processed run of the 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate a change in the pixel tracker calibration. The blue points correspond to the results with the alignment constants used during data-taking, the red points to the 2016, 2017 and 2018 End-Of-Year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), and the green points to the results obtained in the Run-2 Legacy alignment procedure. During the LHC shutdown in winter 2016/17, the inner component (pixel detector) of the CMS tracking detector was replaced. The first few inverse picobarns of the 2017 pp collision run have been devoted to the commissioning of the new detector, resulting in sub-optimal tracking performance. This is visible in degraded impact parameter bias around the 36 fb${}^{\text{-1}}$ mark. Apart from this short period, aligning the tracker improves the mean of this distribution. Short IOVs with suboptimal configuration of the pixel local reconstruction (e.g. different high-voltage settings, inconsistent local reconstruction with alignment) can give rise to isolated peaks in the trends, especially during data taking. |
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Barycentre position of the barrel pixel detector as a function of the integrated luminosity, determined as the centre-of-gravity of barrel pixel modules only. The vertical black solid lines indicate the first processed run of the 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate changes in the pixel calibration. The blue line corresponds to the results with the alignment constants used during data taking, the red line corresponds to the results with alignment constants during the 2016, 2017 and 2018 End-of-year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), the green line corresponds to the results with alignment constants as obtained in the Run-2 Legacy alignment procedures. Large position differences at the beginning of 2017 and 2018 data taking periods are caused by the fact that the pixel detector was extracted during the shutdowns and then re-installed, in occasion of the Phase-1 upgrade in 2017, and for module replacements in 2018. |
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Barycentre position of the barrel pixel detector as a function of the integrated luminosity, determined as the centre-of-gravity of barrel pixel modules only. The vertical black solid lines indicate the first processed run of the 2016, 2017 and 2018 data-taking period, respectively. The vertical dotted lines indicate changes in the pixel calibration. The blue line corresponds to the results with the alignment constants used during data taking, the red line corresponds to the results with alignment constants during the 2016, 2017 and 2018 End-of-year (EOY) re-reconstruction (notice there is no EOY re-reconstruction for the last 33 fb${}^{\text{-1}}$ of data-taking in 2018), the green line corresponds to the results with alignment constants as obtained in the Run-2 Legacy alignment procedures. Large position differences at the beginning of 2017 and 2018 data taking periods are caused by the fact that the pixel detector was extracted during the shutdowns and then re-installed, in occasion of the Phase-1 upgrade in 2017, and for module replacements in 2018. |
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Average rates of cosmic ray data (in Hz) recorded by the CMS tracker during the years 2016, 2017 and 2018, calculated including all commissioning and interfill runs. Events are required to have at least one track with a minimum of 7 hits, and at least two hits measured in either pixel detector or stereo strip modules (2D measurement). For the event rate (first bin), tracks are reconstructed by at least one out of three reconstruction algorithms ( CMS Collaboration, Alignment of the CMS Silicon Tracker during Commissioning with Cosmic Rays.(2010) J. Inst. 5 T03009
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Observed movements in x direction of the two barrel pixel half cylinders as a function of processed luminosity from the prompt calibration loop. Error bars represent the statistical uncertainties of the measurement. The vertical black solid lines indicate the first processed run for 2016, 2017 and 2018 data-taking period, respectively. Vertical dashed lines illustrate updates of the pixel calibration. The two horizontal lines show the threshold for a new alignment to be triggered. The grey bands at the beginning of each year indicate runs, where the automated updates of the alignment were not active. Missing points, especially at the beginning of 2018, correspond to periods where the automated alignment was not fully functional. |
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Observed movements in x direction of the two barrel pixel half cylinders from the prompt calibration loop. The two vertical lines show the threshold for a new alignment to be triggered. The filled entries~(Updates inactive) correspond to runs in early 2016, 2017 and 2018, where the automated updates of the alignment were not active. For both half cylinders the fraction of runs, where a new alignment was triggered by the movement in x direction, is displayed. In this fraction the filled entries are not taken into account. |
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Distribution of median residuals in the local-x(x') coordinate for different components of the tracker system. The derived MC object (MC) is compared to three representative Data IOVs (18 July, 18 August, 05 October) to assess its validity as final geometry. The study corresponds to the MC scenario derived for 2017. The larger width of the MC distribution in the forward pixel is driven by the systematic misalignment of 30 $\mu$m in the global z-direction that was applied to the forward pixel to achieve a better description of the data (see $ \left<d_z\right> $ vs. $ \eta $ plot). |
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Distribution of median residuals in the local-x(x') coordinate for different components of the tracker system. The derived MC object (MC) is compared to three representative Data IOVs (18 July, 18 August, 05 October) to assess its validity as final geometry. The study corresponds to the MC scenario derived for 2017. |
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Distribution of mean impact parameter in the transverse plane $d_{xy}$ and in the longitudinal plane $d_{z}$ as a function of two angular variables $\phi$ and $\eta$. The derived MC object (MC) is compared to three representative Data IOVs (18 July, 18 August, 05 October) to assess its validity as final geometry. The study corresponds to the MC scenario derived for 2017. In the attempt of mimicking the observed behaviour in data in the $ \left<d_z\right> $ vs. $ \eta $ plot, a systematic misalignment of 30 $ \mu $m in the global z-direction was applied to the forward pixel endcaps. |
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Difference in impact parameter in the longitudinal and transverse plane between two halves of cosmic tracks. The derived MC object (MC) is compared to three representative Data IOVs (18 July, 18 August, 05 October) to assess its validity as final geometry. The study corresponds to the MC scenario derived for 2017. |