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Projects / Programmes source: ARIS

Lattice QCD study of electroweak transitions between heavy mesons and light hadronic resonances

Research activity

Code Science Field Subfield
1.02.00  Natural sciences and mathematics  Physics   

Code Science Field
1.03  Natural Sciences  Physical sciences 
Keywords
Quantum Field Theory, Elementary Particle Physics, Numerical simulation, Standard Model, lattice QCD, CKM matrix, hadronic physics, hadronic resonances
Evaluation (rules)
source: COBISS
Researchers (5)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  14130  PhD Svjetlana Fajfer  Physics  Researcher  2021 - 2023  393 
2.  24264  PhD Jernej Fesel Kamenik  Physics  Researcher  2021 - 2023  277 
3.  34446  PhD Luka Leskovec  Physics  Head  2021 - 2023  58 
4.  56559  PhD Emmanuel Ortiz Pacheco  Physics  Researcher  2022 - 2023 
5.  15643  PhD Saša Prelovšek Komelj  Physics  Researcher  2021 - 2023  221 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  91,025 
Abstract
The project promises the first calculation of the weak transition between a stable hadron and decaying resonance in lattice Quantum Chromo-Dynamics. We will consider electroweak processes that are sensitive to the quantum effects of undetected elementary particles. Precision studies of such processes are currently the most promising way to find new physics. An example of such decays are the decays of b-quarks. One of the central puzzles in flavor physics concerns the CKM matrix element between the u-quark and the b-quark, V_{ub}. In the standard model, these processes take place at tree level through a W-boson exchange. The new exclusive determinations of V_{ub} will have a major impact on flavor physics. The ideal candidate for a new determination of V_{ub} is the decay of B to the rho(770) together with a lepton and anti-neutrino. Determining this amplitude directly in QCD is essential for further investigation of semileptonic B decays in the electroweak sector of the standard model. The decay of B to rho(770) together with a lepton and anti-neutrino includes the unstable hadron - rho(770), which decays rapidly to a pair of pions. To date, there are no calculations of this amplitude from the first principles that would take into account the unstable nature of the resonance rho(770). The exact calculation of such transition amplitudes, however, must take into account the interaction between the pions in the final state. In this project, we propose the use of lattice QCD to calculate the transition amplitudes and form factors of electroweak decays of heavy mesons into light resonances. To analyze these processes and take into account all possible systematic effects, we use a state-of-the-art methodology that actually treats rho(770) as a resonance. We will first determine the transient amplitudes of the sister decay, D to rho(770) and lepton and anti-neutrino, where the CKM matrix element between the c-quark and d-quark is well known. Comparison with experimental data will allow us to establish the validity of the formalism. We will then apply the analysis to the decay process B to rho(770) and a lepton and anti-neutrino.
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