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Title: Towards New Physics Through Precision Measurements in B$$^0_S$$ and $$\tau$$ Decays

Abstract

Despite the correct and consistent description of the elementary particle interactions, there is evidence that the Standard Model (SM) is an incomplete theory. Solving the issues faced by the SM requires the introduction of new interactions and, if such interactions exist, they can be observed as deviations in the SM predictions or forbidden processes. Particularly of interest for this work are the B$$^0_s$$ mesons and $$\tau$$ leptons produced in the DØ and Belle II experiments, respectively, where the luminosity provides the statistics for high precision SM measurements and searches for new physics. In this work, the lifetime measurement of the B$$^0_s$$ meson in the decay channel $$B^0_s \to J/\Psi f_0(980)$$ is reported, which is a CP-odd final state. Using 10.4 fb$$^{-1}$$ of data collected with the DØ detector in Run II of the Tevatron, the lifetime of the CP-odd component of the B$$^0_s$$ meson is measured to be $$\tau(B^0_s)$$ = 1.70$$\pm$$0.14 (stat)$$\pm$$0.05 (syst) ps. This measurement is closely related to the $$B^0_s - \bar{B^0_s}$$ mixing and searches for new CP violation mechanisms. Additionally, the $$\tau$$ lepton physics program of Belle II is reviewed and two sensitivity studies are shown: (i) $$\tau^- \to \eta \pi^-\pi^0 \nu_{\tau}$$, which in the isospin symmetry limit SU(2) is a cross-check of consistency with the cross section $$\sigma(e^+e^- \to \eta \pi^+ \pi^-$$) at low energies; (ii) $$\tau^- \to \eta \pi^- \nu_{\tau}$$, which has never been observed and, given the suppression by G-parity, it allows the searches of scalar and tensor interactions. Estimations from 1 to 20 ab$$^{-1}$$ are shown, corresponding to the integrated luminosity expected during the first years of operation of Belle II.

Authors:
 [1]
  1. CINVESTAV, IPN
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1495350
Report Number(s):
FERMILAB-THESIS-2019-02
1716854
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Hernández Villanueva, Michel Enrique. Towards New Physics Through Precision Measurements in B$^0_S$ and $\tau$ Decays. United States: N. p., 2018. Web. doi:10.2172/1495350.
Hernández Villanueva, Michel Enrique. Towards New Physics Through Precision Measurements in B$^0_S$ and $\tau$ Decays. United States. doi:10.2172/1495350.
Hernández Villanueva, Michel Enrique. Sat . "Towards New Physics Through Precision Measurements in B$^0_S$ and $\tau$ Decays". United States. doi:10.2172/1495350. https://www.osti.gov/servlets/purl/1495350.
@article{osti_1495350,
title = {Towards New Physics Through Precision Measurements in B$^0_S$ and $\tau$ Decays},
author = {Hernández Villanueva, Michel Enrique},
abstractNote = {Despite the correct and consistent description of the elementary particle interactions, there is evidence that the Standard Model (SM) is an incomplete theory. Solving the issues faced by the SM requires the introduction of new interactions and, if such interactions exist, they can be observed as deviations in the SM predictions or forbidden processes. Particularly of interest for this work are the B$^0_s$ mesons and $\tau$ leptons produced in the DØ and Belle II experiments, respectively, where the luminosity provides the statistics for high precision SM measurements and searches for new physics. In this work, the lifetime measurement of the B$^0_s$ meson in the decay channel $B^0_s \to J/\Psi f_0(980)$ is reported, which is a CP-odd final state. Using 10.4 fb$^{-1}$ of data collected with the DØ detector in Run II of the Tevatron, the lifetime of the CP-odd component of the B$^0_s$ meson is measured to be $\tau(B^0_s)$ = 1.70$\pm$0.14 (stat)$\pm$0.05 (syst) ps. This measurement is closely related to the $B^0_s - \bar{B^0_s}$ mixing and searches for new CP violation mechanisms. Additionally, the $\tau$ lepton physics program of Belle II is reviewed and two sensitivity studies are shown: (i) $\tau^- \to \eta \pi^-\pi^0 \nu_{\tau}$, which in the isospin symmetry limit SU(2) is a cross-check of consistency with the cross section $\sigma(e^+e^- \to \eta \pi^+ \pi^-$) at low energies; (ii) $\tau^- \to \eta \pi^- \nu_{\tau}$, which has never been observed and, given the suppression by G-parity, it allows the searches of scalar and tensor interactions. Estimations from 1 to 20 ab$^{-1}$ are shown, corresponding to the integrated luminosity expected during the first years of operation of Belle II.},
doi = {10.2172/1495350},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {12}
}

Thesis/Dissertation:
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