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Measurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction

The tension between different determinations of the CKM matrix element $|V_{ub}|$ using measurements of either exclusive or inclusive semileptonic decays represents a long-standing puzzle in flavour physics. To resolve this, measurements of new exclusive channels as well as more precise measurements...

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Autor principal: Kirsebom, Veronica Soelund
Lenguaje:eng
Publicado: 2023
Materias:
Acceso en línea:http://cds.cern.ch/record/2864159
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author Kirsebom, Veronica Soelund
author_facet Kirsebom, Veronica Soelund
author_sort Kirsebom, Veronica Soelund
collection CERN
description The tension between different determinations of the CKM matrix element $|V_{ub}|$ using measurements of either exclusive or inclusive semileptonic decays represents a long-standing puzzle in flavour physics. To resolve this, measurements of new exclusive channels as well as more precise measurements are needed. This thesis presents the first measurement of the exclusive semileptonic decay $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ at the LHCb experiment, using data collected during 2018. Profiting from the large number of $B$ mesons produced in $pp$ collisions at the LHC, a precise measurement of the $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction as a function of the dilepton invariant mass squared is performed relative to the decay $B^{+}\to \bar{D^{0}} \mu^{+} \nu_{\mu}$ with $\bar{D^{0}} \to \pi^+ \pi^-$. This measurement will be used to obtain a determination of the $|V_{ub}|$ matrix element from the $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ channel. All steps leading to the final measurement are documented and the current precision of the result is given, with the numerical values of the result still kept blind to avoid accidental biases before the final publication. The measurement presented in this thesis does not only pave the way for obtaining $|V_{ub}|$, but also for measuring the full differential branching fraction that expresses the rich helicity structure of the $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ decay and provides more variables to test the Standard Model and to probe new physics.
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institution Organización Europea para la Investigación Nuclear
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publishDate 2023
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spelling cern-28641592023-07-28T14:09:35Zhttp://cds.cern.ch/record/2864159engKirsebom, Veronica SoelundMeasurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fractionParticle Physics - ExperimentThe tension between different determinations of the CKM matrix element $|V_{ub}|$ using measurements of either exclusive or inclusive semileptonic decays represents a long-standing puzzle in flavour physics. To resolve this, measurements of new exclusive channels as well as more precise measurements are needed. This thesis presents the first measurement of the exclusive semileptonic decay $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ at the LHCb experiment, using data collected during 2018. Profiting from the large number of $B$ mesons produced in $pp$ collisions at the LHC, a precise measurement of the $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction as a function of the dilepton invariant mass squared is performed relative to the decay $B^{+}\to \bar{D^{0}} \mu^{+} \nu_{\mu}$ with $\bar{D^{0}} \to \pi^+ \pi^-$. This measurement will be used to obtain a determination of the $|V_{ub}|$ matrix element from the $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ channel. All steps leading to the final measurement are documented and the current precision of the result is given, with the numerical values of the result still kept blind to avoid accidental biases before the final publication. The measurement presented in this thesis does not only pave the way for obtaining $|V_{ub}|$, but also for measuring the full differential branching fraction that expresses the rich helicity structure of the $B^{+}\to \rho^{0} \mu^{+} \nu_{\mu}$ decay and provides more variables to test the Standard Model and to probe new physics.CERN-THESIS-2023-092oai:cds.cern.ch:28641592023-07-06T13:52:14Z
spellingShingle Particle Physics - Experiment
Kirsebom, Veronica Soelund
Measurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction
title Measurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction
title_full Measurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction
title_fullStr Measurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction
title_full_unstemmed Measurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction
title_short Measurement of the $B^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction
title_sort measurement of the $b^{+}\rightarrow \rho^{0} \mu^{+} \nu_{\mu}$ differential branching fraction
topic Particle Physics - Experiment
url http://cds.cern.ch/record/2864159
work_keys_str_mv AT kirsebomveronicasoelund measurementofthebrightarrowrho0munumudifferentialbranchingfraction