Recognition: unknown
New Predictions for the Lifetimes of Doubly Heavy Baryons and the B_c Meson
Pith reviewed 2026-05-08 17:22 UTC · model grok-4.3
The pith
Including NNLO corrections to leading terms and full NLO spectator contributions revises the predicted lifetimes and establishes hierarchies for doubly heavy baryons and the B_c meson.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
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 MS-bar, 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(Ξ⁰
What carries the argument
The heavy quark expansion applied to inclusive decay widths of systems with two heavy quarks, with higher-order perturbative corrections added to the dimension-three and dimension-six operators.
Load-bearing premise
The heavy quark expansion remains valid and its perturbative series converges for doubly heavy baryons, with no important missing contributions that would change the results.
What would settle it
A measurement of the Ξ_cc^{++} lifetime that lies well outside the predicted range in the kinetic scheme, including theoretical uncertainties, would settle whether the updated predictions hold.
read the original abstract
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, $\Upsilon$ 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 $\tau(\Xi^0_{bb})<\tau(\Xi^-_{bb})\simeq\tau(\Omega^-_{bb})$, $\tau(\Xi^+_{cc})<\tau(\Omega^+_{cc})<\tau(\Xi^{++}_{cc})$, $\tau(\Xi^0_{bc})\lesssim\tau(\Omega^0_{bc})<\tau(\Xi^+_{bc})$ for $S_{bc}=0$, and $\tau(\Xi^{\prime\, 0}_{bc})<\tau(\Omega^{\prime\, 0}_{bc})<\tau(\Xi^{\prime\, +}_{bc})$ for $S_{bc}=1$. We also revisit the $B_c$ lifetime and discuss the impact of the newly included Darwin term.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript presents updated predictions for the lifetimes of all weakly decaying doubly heavy baryons (bb, cc, and bc) as well as the B_c meson. It incorporates NNLO corrections to the leading dimension-three contribution, NLO corrections to the chromomagnetic operator, and the complete set of known NLO corrections to dimension-six heavy-light spectator operators (including penguins). Results are compared across the MS-bar, kinetic, and Υ mass schemes, with separate hierarchies given for bc baryons under both S_bc=0 and S_bc=1 diquark spin assignments, and the impact of the Darwin term on the B_c lifetime is revisited.
Significance. If the heavy-quark expansion remains valid and the included perturbative corrections are complete, the work supplies valuable, state-of-the-art benchmarks that can be tested against future LHCb and other experimental data on doubly heavy states. The systematic inclusion of NNLO and full known NLO terms, together with scheme comparisons, represents a clear advance over prior calculations and helps quantify perturbative uncertainties.
major comments (2)
- [Numerical results for cc and bc baryons] In the numerical results for cc and bc baryons (section presenting the hierarchies τ(Ξ^+_cc) < τ(Ω^+_cc) < τ(Ξ^{++}_cc) and the S_bc=0,1 patterns): no explicit estimate or bound is supplied for the size of omitted dimension-7 and higher operators. With Λ_QCD/m_c ≃ 0.3–0.4 for charm-containing systems, these terms can enter at the 10–30 % level and are capable of rearranging the reported lifetime orderings.
- [B_c lifetime discussion] In the discussion of the B_c lifetime and the Darwin term: the manuscript states that the newly included term is discussed, yet no quantitative breakdown of its contribution, no comparison table to previous predictions, and no error budget are provided, leaving the size of the update unclear.
minor comments (2)
- [Abstract] The abstract refers to 'the complete set of currently known NLO corrections' without citing the specific references or listing the included penguin and other operators; a short table or explicit enumeration in the text would improve clarity.
- [Abstract and results] Notation for the primed bc states (Ξ′ bc, Ω′ bc) is used in the abstract and hierarchies without a brief reminder of the S_bc=0 versus S_bc=1 assignment; a one-sentence definition at first use would aid readability.
Simulated Author's Rebuttal
We thank the referee for the careful reading of our manuscript and the constructive comments. We address each major point below and have revised the manuscript to incorporate additional estimates and quantitative details as suggested.
read point-by-point responses
-
Referee: [Numerical results for cc and bc baryons] In the numerical results for cc and bc baryons (section presenting the hierarchies τ(Ξ^+_cc) < τ(Ω^+_cc) < τ(Ξ^{++}_cc) and the S_bc=0,1 patterns): no explicit estimate or bound is supplied for the size of omitted dimension-7 and higher operators. With Λ_QCD/m_c ≃ 0.3–0.4 for charm-containing systems, these terms can enter at the 10–30 % level and are capable of rearranging the reported lifetime orderings.
Authors: We agree that an explicit discussion of the potential size of dimension-7 and higher operators is useful, particularly for charm-containing systems. While a full calculation of all such terms lies beyond the present work, we have added a new paragraph to the numerical results section in the revised manuscript. This paragraph estimates the expected magnitude of these contributions using the expansion parameter Λ_QCD/m_Q (approximately 0.1 for bottom and 0.3–0.4 for charm), provides a conservative bound on their impact, and notes that the reported hierarchies for bb states remain robust while those for cc and bc states carry larger theoretical uncertainties that could affect ordering at the 10–20% level. This addition directly addresses the referee's concern without overstating the precision of the current results. revision: yes
-
Referee: [B_c lifetime discussion] In the discussion of the B_c lifetime and the Darwin term: the manuscript states that the newly included term is discussed, yet no quantitative breakdown of its contribution, no comparison table to previous predictions, and no error budget are provided, leaving the size of the update unclear.
Authors: We thank the referee for highlighting this point. In the revised manuscript we have expanded the B_c lifetime section to include a quantitative breakdown of the Darwin term's numerical contribution (both absolute and relative to the total width), a comparison table of our updated prediction against previous results in the literature, and an explicit error budget that separates perturbative, parametric, and higher-order uncertainties. These additions make the size and impact of the update transparent and allow readers to assess the improvement clearly. revision: yes
Circularity Check
No circularity: predictions computed from HQE expansion with external inputs
full rationale
The paper computes lifetime predictions via the heavy-quark expansion, incorporating NNLO corrections to the dimension-3 term, NLO to the chromomagnetic operator, and NLO spectator contributions including penguins. Numerical inputs such as quark masses and matrix elements are taken from external fits or literature, and the hierarchies (e.g., τ(Ξ⁺_cc) < τ(Ω⁺_cc) < τ(Ξ⁺⁺_cc)) emerge from these calculations rather than by redefining or fitting the target observables themselves. No self-definitional loop, fitted-input-as-prediction, or load-bearing self-citation chain is present in the abstract or described methodology; the derivation remains self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption Heavy-quark expansion in 1/m_Q is applicable and sufficiently convergent for doubly heavy baryons
- ad hoc to paper All relevant NLO and NNLO operator contributions have been identified and computed
Reference graph
Works this paper leans on
-
[1]
Shifman and M.B
M.A. Shifman and M.B. Voloshin,Preasymptotic Effects in Inclusive Weak Decays of Charmed Particles,Sov. J. Nucl. Phys.41(1985) 120
1985
-
[2]
J. Chay, H. Georgi and B. Grinstein,Lepton energy distributions in heavy meson decays from QCD,Phys. Lett. B247(1990) 399
1990
- [3]
-
[4]
Lenz,Lifetimes and heavy quark expansion,Int
A. Lenz,Lifetimes and heavy quark expansion,Int. J. Mod. Phys. A30(2015) 1543005 [1405.3601]
-
[5]
J. Albrecht, F. Bernlochner, A. Lenz and A. Rusov,Lifetimes of b-hadrons and mixing of neutral B-mesons: theoretical and experimental status,Eur. Phys. J. ST233(2024) 359 [2402.04224]
- [6]
-
[7]
J. Gratrex, A. Lenz, B. Melić, I. Nišandžić, M.L. Piscopo and A.V. Rusov,Quark-hadron duality at work: lifetimes of bottom baryons,JHEP04(2023) 034 [2301.07698]
- [8]
-
[9]
J. Gratrex, B. Melić and I. Nišandžić,Lifetimes of singly charmed hadrons,JHEP07(2022) 058 [2204.11935]
-
[10]
V.V. Kiselev, A.K. Likhoded and A.I. Onishchenko,Lifetimes ofΞ+ bc andΞ 0 bc baryons,Eur. Phys. J. C16(2000) 461 [hep-ph/9901224]
-
[11]
A.K. Likhoded and A.I. Onishchenko,Lifetimes of doubly heavy baryons,hep-ph/9912425
work page internal anchor Pith review arXiv
-
[12]
V.V. Kiselev and A.K. Likhoded,Baryons with two heavy quarks,Phys. Usp.45(2002) 455 [hep-ph/0103169]
-
[13]
A.V. Berezhnoy, A.K. Likhoded and A.V. Luchinsky,Doubly heavy baryons at the LHC, Phys. Rev. D98(2018) 113004 [1809.10058]
-
[14]
H.-Y. Cheng and Y.-L. Shi,Lifetimes of Doubly Charmed Baryons,Phys. Rev. D98(2018) 113005 [1809.08102]
-
[15]
H.-Y. Cheng and F. Xu,Lifetimes of doubly heavy baryonsBbb andB bc,Phys. Rev. D99 (2019) 073006 [1903.08148]
-
[16]
G.-H. Yang, E.-P. Liang, Q. Qin and K.-K. Shao,Inclusive weak-annihilation decays and lifetimes of beauty-charmed baryons,Phys. Rev. D106(2022) 093013 [2208.06834]
-
[17]
Revisiting lifetimes of doubly charmed baryons
L. Dulibić, J. Gratrex, B. Melić and I. Nišandžić,Revisiting lifetimes of doubly charmed baryons,JHEP07(2023) 061 [2305.02243]
work page internal anchor Pith review Pith/arXiv arXiv 2023
-
[18]
Z.S. Brown, W. Detmold, S. Meinel and K. Orginos,Charmed bottom baryon spectroscopy from lattice QCD,Phys. Rev. D90(2014) 094507 [1409.0497]. [19]LHCbcollaboration,Observation of the doubly charmed baryonΞ ++ cc ,Phys. Rev. Lett.119 (2017) 112001 [1707.01621]. – 49 – [20]LHCbcollaboration,Measurement of the Lifetime of the Doubly Charmed BaryonΞ ++ cc , P...
-
[19]
M. Beneke and G. Buchalla,TheBc Meson Lifetime,Phys. Rev. D53(1996) 4991 [hep-ph/9601249]
-
[20]
J. Aebischer and B. Grinstein,Standard Model prediction of the Bc lifetime,JHEP07(2021) 130 [2105.02988]
-
[21]
Banerjeeet al.(Heavy Flavor Averaging Group (HFLAV)), Phys
S. Banerjee et al.,Averages ofb-hadron,c-hadron, andτ-lepton properties as of 2023,Phys. Rev.D113(2026) 012008 [2411.18639]
-
[22]
Weak Decays Beyond Leading Logarithms
G. Buchalla, A.J. Buras and M.E. Lautenbacher,Weak decays beyond leading logarithms, Rev. Mod. Phys.68(1996) 1125 [hep-ph/9512380]
work page Pith review arXiv 1996
-
[23]
F. Krinner, A. Lenz and T. Rauh,The inclusive decayb→c¯csrevisited,Nucl. Phys.B876 (2013) 31 [1305.5390]
-
[24]
M. Fael and F. Herren,NNLO QCD corrections to the q2 spectrum of inclusive semileptonic B-meson decays,JHEP05(2024) 287 [2403.03976]
-
[25]
A. Czarnecki, M. Jezabek and J.H. Kuhn,Radiative corrections tob→cτ¯ντ,Phys. Lett. B 346(1995) 335 [hep-ph/9411282]
- [26]
- [27]
-
[28]
Moreno,NLO QCD corrections to inclusive semitauonic weak decays of heavy hadrons up to1/m 3 b,Phys
D. Moreno,NLO QCD corrections to inclusive semitauonic weak decays of heavy hadrons up to1/m 3 b,Phys. Rev. D106(2022) 114008 [2207.14245]
- [29]
- [30]
- [31]
- [32]
-
[33]
Moreno,QCD corrections to the Darwin coefficient in inclusive semileptonicB→Xuℓ¯νl decays,Phys
D. Moreno,QCD corrections to the Darwin coefficient in inclusive semileptonicB→Xuℓ¯νl decays,Phys. Rev. D109(2024) 074030 [2402.13805]. – 50 –
- [34]
-
[35]
A. Lenz and T. Rauh,D-meson lifetimes within the heavy quark expansion,Phys. Rev.D88 (2013) 034004 [1305.3588]
- [36]
-
[37]
M. Ciuchini, E. Franco, V. Lubicz and F. Mescia,Next-to-leading order QCD corrections to spectator effects in lifetimes of beauty hadrons,Nucl. Phys.B625(2002) 211 [hep-ph/0110375]
-
[38]
C.-H. Chang, S.-L. Chen, T.-F. Feng and X.-Q. Li,The Lifetime ofBc meson and some relevant problems,Phys. Rev. D64(2001) 014003 [hep-ph/0007162]
-
[39]
B.M. Dassinger, T. Mannel and S. Turczyk,Inclusive semi-leptonicBdecays to order1/m4 b, JHEP03(2007) 087 [hep-ph/0611168]
- [40]
- [41]
-
[42]
A. Boushmelev, T. Mannel and K.K. Vos,Alternative treatment of the quark mass in the heavy quark expansion,JHEP07(2023) 175 [2301.05607]
- [43]
-
[44]
M. Beneke,Renormalons,Phys. Rept.317(1999) 1 [hep-ph/9807443]
-
[45]
Beneke,Pole mass renormalon and its ramifications,Eur
M. Beneke,Pole mass renormalon and its ramifications,Eur. Phys. J. ST230(2021) 2565 [2108.04861]
- [46]
-
[47]
F. Herren and M. Steinhauser,Version 3 of RunDec and CRunDec,Comput. Phys. Commun.224(2018) 333 [1703.03751]
- [48]
-
[49]
A. Pineda and F.J. Yndurain,Calculation of quarkonium spectrum andmb,m c to orderα 4 s, Phys. Rev. D58(1998) 094022 [hep-ph/9711287]
-
[50]
K. Melnikov and A. Yelkhovsky,Thebquark low scale running mass fromΥsum rules, Phys. Rev. D59(1999) 114009 [hep-ph/9805270]
- [51]
- [52]
-
[53]
Falk and M
A.F. Falk and M. Neubert,Second order power corrections in the heavy quark effective theory
- [54]
-
[55]
Second order power corrections in the heavy quark effective theory. 2. Baryon form-factors,
A.F. Falk and M. Neubert,Second order power corrections in the heavy quark effective theory. 2. Baryon form-factors,Phys. Rev. D47(1993) 2982 [hep-ph/9209269]. [61]HFLA Vcollaboration,Averages of b-hadron, c-hadron, andτ-lepton properties as of 2018, Eur. Phys. J. C81(2021) 226 [1909.12524]
-
[56]
J. Soto and J. Tarrús Castellà,Effective field theory for double heavy baryons at strong coupling,Phys. Rev. D102(2020) 014013 [2005.00551]
-
[57]
J. Soto and J. Tarrús Castellà,Effective QCD string and doubly heavy baryons,Phys. Rev. D 104(2021) 074027 [2108.00496]
-
[58]
Eichten,Narrow Spectra in Heavy Quark Systems,PoSQCHSC24(2025) 143 [2504.19972]
E. Eichten,Narrow Spectra in Heavy Quark Systems,PoSQCHSC24(2025) 143 [2504.19972]
-
[59]
De Rujula, H
A. De Rujula, H. Georgi and S.L. Glashow,Hadron masses in a gauge theory,Phys. Rev. D 12(1975) 147
1975
-
[60]
M. Karliner and J.L. Rosner,Baryons with two heavy quarks: masses, production, decays, and detection,Phys. Rev. D90(2014) 094007 [1408.5877]. [67]Particle Data Groupcollaboration,Review of particle physics,Phys. Rev. D110(2024) 030001
-
[61]
Improved Nonrelativistic QCD for Heavy Quark Physics
G.P. Lepage, L. Magnea, C. Nakhleh, U. Magnea and K. Hornbostel,Improved nonrelativistic QCD for heavy quark physics,Phys. Rev. D46(1992) 4052 [hep-lat/9205007]
work page Pith review arXiv 1992
-
[62]
N. Brambilla, A. Vairo and T. Rosch,Effective field theory Lagrangians for baryons with two and three heavy quarks,Phys. Rev. D72(2005) 034021 [hep-ph/0506065]
-
[63]
Bagan, H.G
E. Bagan, H.G. Dosch, P. Gosdzinsky, S. Narison and J.M. Richard,Hadrons with charm and beauty,
-
[64]
D. Pirjol and N. Uraltsev,Four fermion heavy quark operators and light current amplitudes in heavy flavor hadrons,Phys. Rev. D59(1999) 034012 [hep-ph/9805488]
- [65]
-
[66]
V.V. Kiselev, A.K. Likhoded and A.I. Onishchenko,Lifetimes of doubly charmed baryons: Ξ+ cc andΞ ++ cc ,Phys. Rev. D60(1999) 014007 [hep-ph/9807354]
-
[67]
S.S. Gershtein, V.V. Kiselev, A.K. Likhoded and A.I. Onishchenko,Spectroscopy of doubly charmed baryons:Ξ + cc andΞ ++ cc ,Mod. Phys. Lett. A14(1999) 135 [hep-ph/9807375]
-
[68]
B. Guberina, B. Melic and H. Stefancic,Inclusive decays and lifetimes of doubly charmed baryons,Eur. Phys. J. C9(1999) 213 [hep-ph/9901323]
-
[69]
Study of doubly heavy baryon lifetimes
H.-Y. Cheng and C.-W. Liu,Study of doubly heavy baryon lifetimes,2604.10939. [77]Fermilab Lattice, MILCcollaboration,B- and D-meson decay constants from three-flavor lattice QCD,Phys. Rev. D85(2012) 114506 [1112.3051]
work page internal anchor Pith review Pith/arXiv arXiv 2012
-
[70]
C. McNeile, C.T.H. Davies, E. Follana, K. Hornbostel and G.P. Lepage,High-PrecisionfBs and HQET from Relativistic Lattice QCD,Phys. Rev. D85(2012) 031503 [1110.4510]
- [71]
- [72]
-
[73]
N.H. Christ, J.M. Flynn, T. Izubuchi, T. Kawanai, C. Lehner, A. Soni et al.,B-Meson Decay Constants from 2+1-Flavor Lattice QCD with Domain-Wall Light Quarks and Relativistic Heavy Quarks,Phys. Rev. D91(2015) 054502 [1404.4670]
-
[74]
C. McNeile, C.T.H. Davies, E. Follana, K. Hornbostel and G.P. Lepage,Heavy meson masses and decay constants from relativistic heavy quarks in full lattice QCD,Phys. Rev. D86 (2012) 074503 [1207.0994]. [83]Fla vour Lattice A veraging Group (FLAG)collaboration,FLAG review 2024,Phys. Rev. D113(2026) 014508 [2411.04268]. – 53 –
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.