Doctoral School of Fundamental Sciences

 Juan Sebastian Ordonez Soto

Universidad Nacional de Colombia

MSc. Physics-LHCb member 


Subjects:

  • Study of charmless \(b-\)hadron decays with the LHCb spectrometer
  • Rare radiative decays of \(B\) mesons at LHCb



Université Clermont Auvergne

Clermont-Ferrand, France

June 10th, 2024

Outline

  • Academic Studies
  • Research Experience
    • Summer programs
    • Internships
    • Research assistant
      • Master thesis
      • Other projects
  • Motivation for the thesis
    • Charmless \(b\)-hadron decays
    • Rare radiative decays of \(B\) mesons
  • Questions from the committee

June 10th, 2024

Ecole Doctorale des Sciences Fondamentales (UCA)

J. Ordonez Soto

 

  • Bachelor in Sciences Physics (UNAL) GPA: 4.1/5 (Top 10%)
    • Bachelor thesis in phenomenology of HEP 
    • First place in the UNAL Physics Tournament

 Academic studies

  • ​Master in Sciences Physics (UNAL) GPA: 4.5/5 (Top 5%) 
    • Research assistant in the High Energy Physics (HEP) group of UNAL and affiliated with the LHCb collaboration at CERN
    • Teaching Assistant of different courses:
      • Special Relativity 
      • Complex Analysis for physicists
      • Quantum for everyone and everything 

J. Ordonez Soto

June 10th, 2024

Ecole Doctorale des Sciences Fondamentales (UCA)

  • ​Master in Sciences Physics (UNAL) GPA: 4.5/5 (Top 5%) 
    • Two international Summer Research Programs and three internships
    • Speaker and participant in national and international schools in High Energy Physics:
      • 6a Escola Avançada de Física Experimental, CBPF, Rio de Janeiro, Brasil
      • 5th-8th Colombian Meeting on High Energy Physics, Colombia
      • 1st school of the Colombian Network for High Energy Physics, Tolima, Colombia
      • ​II Joint ICTP-Trieste/SAIFR School in particle Physics, ICTPT-SAIFR, Brasil-Italy

 Academic studies

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

Research experience

Summer programs

  • LHCb, CERN, Geneva, Switzerland
    • ​Lectures on experimental and theoretical particle physics, statistics and computing by top researchers in the fields.
    • Applying machine learning techniques for the event selection optimization of the \(D^{+}\rightarrow K^{-}K^{+}K^{+}\) decay at the LHCb experiment

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

Internships

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

Research experience

Research assistant​ 

Member of the HEP group at UNAL, which is affiliated with the ATLAS and LHCb experiments at CERN

  • Bachelor and master thesis under the supervision of Diego Milanés, a former collaborator of the UCA LPC LHCb team.

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

  • Involved in projects related to the Study of \(B_{c}^{+}\) meson rare decays

Research experience

Cabibbo–Kobayashi–Maskawa (CKM) mixing matrix

\boxed{SU(3)_{c}\otimes SU(2)_{L}\otimes U(1)_{Y}}
  • Weak interaction enables quarks to transform from one type to another (quark mixing)
    • ​\(W^{\pm}\) bosons \(\rightarrow\) Charged Current Interactions
    • ​\(Z^{0}\) boson \(\rightarrow\) Neutral Current Interactions
  • CKM matrix is a unitary matrix which contains information on the strength of the flavor-changing weak interaction
  • It describes the probability of a transition from one flavor \(j\) quark to another flavor \(i\) quark
    •  These transitions are proportional to \(|V_{ij}|^{2}\).

J. Ordonez Soto

June 10th, 2024

Ecole Doctorale des Sciences Fondamentales (UCA)

Research experience

\(CP\) violation

  • The existence of new sources of \(CP\) violation necessary to account for the baryonic asymmetry in the Universe.
  • The \(CP\)-violating phase emerging from the CKM matrix is enough to describe all \(CP\)-violating observables measured so far in particle systems.
  • One of the unitarity conditions of the CKM matrix can  be expressed as a triangle.

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

J. Ordonez Soto

Research experience

\(CP\) violation

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

J. Ordonez Soto

Research experience

\(CP\) violation

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

J. Ordonez Soto

Research experience

Internship: Study of \(B_{c}^{+}\) meson rare decays

\(B_{c}^{+}\) meson 

  1. Search for semileptonic decays with \(c\bar{c}\) in the final state, i.e.,  \(B_{c}^{+}\rightarrow (c\bar{c})l\nu_{l}\)​​
    • Input for: Full width determination and Lepton Flavor Universality ( a symmetry of the SM) test
  2. Search for annihilation channels like \(B_{c}^{+}\rightarrow \phi K^{+}\)
    • ​​First evidence of \(B_{c}^{+}\) annihilation decay  and a potential precision measurement of the \(V_{cb}\) CKM matrix element

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

Semileptonic decay

Annihilation decay

Research experience

Master thesis: Amplitude analysis of three-body hadronic decay of \(D^{+}\) meson

\(D^{+}\) meson 

  • Dalitz plot analysis of the \(D^{+}\rightarrow K^{-}K^{+}K^{+}\) decay using data collected in  \(pp\) collisions at \(\sqrt{s} = 13\) TeV by the LHCb experiment with a total integrated luminosity of 5.6 fb\(^{-1}\).

  • \(D\) mesons are a unique laboratory to study light quark spectroscopy. Three-body decay of these mesons exhibit rich interference between intermediate states.
  • Offer rich phenomenology, including unique sensitive to \(CP\) violation and charm mixing.

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

Research experience

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

LHCb internal

LHCb internal

LHCb internal

Research experience

Motivation for the thesis subjects

Subject 1: Study of charmless \(b\)-hadron decays

  • Dalitz plot analysis of the \(B^{0}\rightarrow K_{S}^{0}\pi^{+}\pi^{-}\) decay using data collected in  \(pp\) collisions at \(\sqrt{s} = 13\) TeV by the LHCb experiment during Run 2.
  • The \(B^{0}\rightarrow K_{S}^{0}\pi^{+}\pi^{-}\) decay is dominated by \(b \rightarrow q\bar{q}s\) quark transitions, which proceeds via loop diagrams.
  • Three-body charmless neutral \(B\) decays are rich laboratories for studying \(CP\) violation, strong interaction, constrains in the CKM triangle, etc.

J. Ordonez Soto

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

Motivation for the thesis subjects

Subject 2: Rare radiative \(b\)-hadron decays

  • The physics content is similar, with possible New Physics spectrum allowed to propagate inside the loops, but in this case with electromagnetic states.

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

J. Ordonez Soto

  • Interesting \(B\) meson decays produce one or several neutral pions (\(\pi^{0}\)) in the final-state, which decay mainly into two photons: \(\pi^{0}\rightarrow \gamma\gamma\)
    • Experimental complicated, but possible with the LHCb detector
    • Similar signature to radiative decays
  • Many possible channels of interest!

Thank you for your attention.

Ecole Doctorale des Sciences Fondamentales (UCA)

June 10th, 2024

J. Ordonez Soto

Back up

The interview

Members of the jury

  • Pierre Disseix: Physicist working on Optical Spectroscopy of Solids \(\rightarrow\) Physics General questions
  • Julien Donini: Particle Physicist in ATLAS \(\rightarrow\) Physics Technical questions
  • Yanick Heurteaux: Mathematician \(\rightarrow\) General questions + CV questions
  • Dominique Pallin: Director of the Clermont Physics Laboratory \(\rightarrow\) General questions + CV questions
  • Laurent Serlet: Mathematician \(\rightarrow\) General questions + CV questions