arXiv subjects

Lovro Dulibić

Publications and source records attributed to Lovro Dulibić.

4 recordsLinked to original sources

arXiv2026

New Predictions for the Lifetimes of Doubly Heavy Baryons and the $B_c$ Meson

We present updated predictions for the lifetimes of all weakly decaying doubly heavy baryons, including $bb$, $cc$, and $bc$ baryons, as well as for the $B_c$ meson. The analysis includes NNLO corrections to the leading dimension-three contribution, NLO corrections to the chromomagnetic term, and the complete set of currently known NLO corrections to the dimension-six heavy-light quark spectator contributions, including penguin terms. We also compare the results in the $\overline{\rm MS}$, kinetic, and, where applicable, $Υ$ mass schemes. For the $bc$ baryons, we present predictions for both possible ground-state diquark-spin assignments, $S_{bc}=0$ and $S_{bc}=1$. In the kinetic scheme we obtain the lifetime hierarchies $τ(Ξ^0_{bb})<τ(Ξ^-_{bb})\simeqτ(Ω^-_{bb})$, $τ(Ξ^+_{cc})<τ(Ω^+_{cc})<τ(Ξ^{++}_{cc})$, $τ(Ξ^0_{bc})\lesssimτ(Ω^0_{bc})<τ(Ξ^+_{bc})$ for $S_{bc}=0$, and $τ(Ξ^{\prime\, 0}_{bc})<τ(Ω^{\prime\, 0}_{bc})<τ(Ξ^{\prime\, +}_{bc})$ for $S_{bc}=1$. We also revisit the $B_c$ lifetime and discuss the impact of the newly included Darwin term.

hep-ph↗

arXiv2026

Revisiting lifetimes of doubly charmed baryons

We present updated predictions for lifetimes of doubly charmed baryons, within the heavy quark expansion, including available NLO $α_s$ contributions and newly-computed terms in the $1/m_c$ series. Our improved results confirm the expected hierarchy $$τ(Ξ_{cc}^{+}) < τ(Ω_{cc}^{+}) < τ(Ξ_{cc}^{++}) \,, $$ while the predicted lifetime $τ(Ξ_{cc}^{++}) = 0.32 \pm 0.05 ^{+0.08}_{-0.07} \,\textrm{ps} $ is consistent with the recent LHCb determination. We provide predictions for the lifetime ratios of the $Ξ_{cc}^{+}$ and $Ω_{cc}^+$ baryons relative to the $Ξ_{cc}^{++}$ baryon, namely $τ(Ξ_{cc}^{+})/τ(Ξ_{cc}^{++})=0.22\pm 0.05\pm 0.04$ and $τ(Ω_{cc}^{+})/τ(Ξ_{cc}^{++})=0.52\pm 0.13^{+0.03}_{-0.02}$.

hep-ph↗

arXiv2025

Nonperturbative Dynamics in D-meson Mixing

Theoretical predictions for the $D^0\overline{D^0}$ mixing parameters fall significantly short of experimental measurements, with discrepancies spanning several orders of magnitude. This gap is mainly due to the Glashow-Iliopoulos-Maiani (GIM) mechanism, which suppresses leading-order contributions by high powers of $m_s/m_c$. However, higher-order corrections and nonperturbative effects could reduce this suppression, especially through flavor $SU(3)_F$ symmetry breaking. In this work, we investigate the long-distance contributions from QCD condensates, including, for the first time, the effects of mixed quark-gluon and four-quark condensates. Our results show an increase in the predicted values of $D^0\overline{D^0}$ mixing parameters by two orders of magnitude compared to perturbative NLO result, providing valuable insights into nonperturbative QCD dynamics. Although the theoretical estimates still fall below experimental values, this study represents an important step toward narrowing the gap between theory and observation, highlighting the significance of higher-order $1/m_c$ QCD effects in understanding $D^0\overline{D^0}$ mixing.

hep-ph↗

arXiv2024

$D^0\overline{D^0}$ mixing from nonlocal condensate contributions

A significant discrepancy, spanning multiple orders of magnitude, exists between the leading order contribution to the $D^0\overline{D^0}$ mixing parameters and experimental values. This is largely due to the Glashow-Iliopoulos-Maiani (GIM) mechanism, which results in substantial suppression of the theoretical predictions. To bridge this gap, various efforts have been made to account for higher-order terms and nonperturbative effects, which, although suppressed in the operator product expansion (OPE), could potentially lead to a larger contribution by weakening the GIM cancellation through flavour SU(3) symmetry breaking. In this work, we compute the long-distance contributions of nonlocal QCD condensates within different models and, for the first time, determine the impact of the mixed condensate. Although our results still fall short of the experimental value, they represent an improvement over current theoretical estimates by an order of magnitude.

hep-ph↗