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bhadron species  average lifetime  lifetime ratio 
B^{0}  1.517 ± 0.004 ps  
B^{+}  1.638 ± 0.004 ps  B^{+}/B^{0} = 1.076 ± 0.004 
B_{s}^{0}  1.520 ± 0.005 ps  B_{s}^{0}/B^{0} = 1.0032 ± 0.0032 
B_{s}_{L}  1.429 ± 0.006 ps  
B_{s}_{H}  1.622 ± 0.008 ps  
B_{c}^{+}  0.510 ± 0.009 ps  
Λ_{b}  1.471 ± 0.009 ps  Λ_{b}/B^{0} = 0.969 ± 0.006 
Ξ_{b}^{−}  1.572 ± 0.040 ps  
Ξ_{b}^{0}  1.480 ± 0.030 ps  Ξ_{b}^{0}/Ξ_{b}^{−} = 0.929 ± 0.028 
Ω_{b}^{−}  1.64 +0.18 −0.17 ps  Ω_{b}^{−}/B^{0} = 1.08 +0.12 −0.11 
The tables below give a number of effective B_{s} lifetime averages, measured from single exponential fits of the proper time distributions of B_{s} decays to a number of interesting final states. In general each final state may be a different mixture of the two B_{s} mass eigenstates, and hence the effective lifetime falls somewhere between 1/Γ_{L} and 1/Γ_{H}. The "B_{s} → flavour specific" lifetime is measured mainly with B_{s} → D_{s} lepton X decays; it is used as input to extract the long and short lifetimes of the B_{s} system (see next section). The "B_{s} → J/ψ φ" lifetime is an average of the results from single exponential fits. Nowadays, the time dependence and the angular dependence of the B_{s} → J/ψ φ decays is analysed in a more sophisticated way in order to extract separately the long and short lifetimes (see further below). The B_{s} → μ^{+}μ^{} effective lifetime is expected to be equal to the long lifetime in the Standard Model, but could be a mixture.
mixture of the two B_{s} mass eigenstates 
effective lifetime from single exponential fits 
B_{s} → flavour specific  1.527 ± 0.011 ps 
B_{s} → J/ψφ  1.480 ± 0.007 ps 
B_{s} → μ^{+}μ^{}  1.79 ± 0.17 ps 
The two tables below report effective B_{s} lifetime averages for final states that are either pure CPeven or pure CPodd eigenstates. If the corresponding B_{s} decays are dominated by a single weak phase and if CP violation can be neglected, then the effective lifetime for decays to CPeven (CPodd) eigenstates corresponds to 1/Γ_{L} (1/Γ_{H}). These averages are used as constraints in the fit to determine Γ_{s} and ΔΓ_{s} (see further below).
CPeven final states  effective lifetime from single exponential fits 
B_{s} → J/ψη, D_{s}^{+}D_{s}^{−}  1.437 ± 0.014 ps 
CPodd final states  effective lifetime from single exponential fits 
B_{s} → J/ψf_{0}(980), J/ψπ^{+}π^{−}  1.646 ± 0.013 ps 
Combined result on the relative decay width difference in the B^{0} system:
s×ΔΓ_{d}/Γ_{d} = 0.001 ± 0.010  from DELPHI, BABAR, Belle, ATLAS, CMS and LHCb 
The quantity s = sign(Re(λ_{CP})), where λ_{CP} = (q/p)×A_{CP}/A_{CP} refers to a CPeven final state (e.g. J/ψK_{L}), is predicted to be equal to s= +1 to a high degree of confidence from the Standard Model fits to all available constraints on the unitarity triangle.
The timedependent and tagged angular analyses of the B_{s} → J/ψ φ decay by ATLAS, CMS, CDF and D0, as well as those of the B_{s} → J/ψKK and B_{s} → ψ(2S)φ decays by LHCb, provide information on Γ_{s}, ΔΓ_{s} and the weak phase φ_{s}^{ccs}, defined as the phase difference between the mixing amplitude and the b→ccs decay amplitude of the B_{s} meson. Combined values of the average decay width Γ_{s} and the decay width difference ΔΓ_{s} are obtained from of a multidimensional fit of the experimental results, extracting several other physics parameters in addition to Γ_{s}, ΔΓ_{s} and φ_{s}^{ccs}. The φ_{s}^{ccs}average is given further below. The correlation matrix between all physics parameters in each analysis is taken into account. Due to tensions between analyses for some of the measured parameters, scale factors are applied on their errors. The scale factors are calculated per parameter, in one dimension, using the PDG prescription. For example the scale factors of the errors of Γ_{s}, ΔΓ_{s} and φ_{s}^{ccs} are 2.45 , 1.84 and 1.00 , respectively. The scale factors are applied in a way that preserves the total correlation matrix of each analysis. The following additional constraints are then applied, using effective lifetime measurements:
Fit results from ATLAS, CDF, CMS, D0 and LHCb data 
without constraint from effective lifetime measurements 
with constraints I and II 
with constraints I, II and III 
Γ_{s}  0.6627 ± 0.0033 ps^{−1}  0.6575 ± 0.0025 ps^{−1}  0.6581 ± 0.0022 ps^{−1} 
1/Γ_{s}  1.509 ± 0.008 ps  1.521 ± 0.006 ps  1.520 ± 0.005 ps 
τ_{Short} = 1/Γ_{L}  1.425 ± 0.008 ps  1.430 ± 0.007 ps  1.429 ± 0.006 ps 
τ_{Long} = 1/Γ_{H}  1.603 ± 0.013 ps  1.624 ± 0.009 ps  1.622 ± 0.008 ps 
ΔΓ_{s}  +0.078 ± 0.006 ps^{−1}  +0.084 ± 0.005 ps^{−1}  +0.083 ± 0.005 ps^{−1} 
ΔΓ_{s}/Γ_{s}  +0.118 ± 0.009  +0.127 ± 0.007  +0.127 ± 0.007 
correlation ρ(Γ_{s}, ΔΓ_{s})  −0.24  −0.02  +0.03 
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Δm_{d} = 0.5069 ± 0.0019 ps^{−1}  from timedependent measurements at ALEPH, DELPHI, L3, OPAL, CDF, D0, BABAR, BELLE, LHCb 
χ_{d} = 0.182 ± 0.015  from timeintegrated measurements at ARGUS and CLEO 
Assuming no CP violation in the mixing and no width difference in the B^{0} system, and using the B^{0} lifetime average of 1.517 ± 0.004 ps (the experimental average listed above), all above measurements can be combined to yield the following world averages:
Δm_{d} =
0.5069
±
0.0019
ps^{−1}
x_{d} = 0.7697 ± 0.0035 χ_{d} = 0.1860 ± 0.0011 
from all ALEPH, DELPHI, L3, OPAL, CDF, D0, BABAR, BELLE, LHCb, ARGUS and CLEO measurements 
The plot shows the LEP and Tevatron averages, as well as all individual measurements listed as quoted by the BABAR, BELLE, BELLE II and LHCb experiments; they might assume different physics inputs. The averages (which take into account all known correlations) are quoted after adjusting the individual measurements to the common set of physics inputs. The χ_{d} average from ARGUS and CLEO is converted to a Δm_{d} measurement assuming no CP violation, no width difference in the B^{0} system and a B^{0} lifetime of 1.517 ± 0.004 ps.
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The plot shows the
LEP and Tevatron averages, as well as the averages
quoted by the other experiments
(or computed by the working group after adjusting the individual results to the common set of inputs);
they might assume different physics inputs. The global averages are quoted
after adjusting the all individual measurements to the common set of physics
inputs. The χ_{d} average from ARGUS and CLEO is converted to a Δm_{d} measurement
assuming no CP violation, no width difference in the B^{0} system and a
B^{0} lifetime of
1.517
±
0.004
ps.
Δm_{s} = 17.765 ± 0.006 ps^{−1}  CDF, LHCb, CMS 
With a mean B^{0}_{s} lifetime of 1/Γ_{s} = 1.520 ± 0.005 ps, a decay width difference of ΔΓ_{s} = +0.083 ± 0.005 ps^{−1} and the assumption of no CP violation in B^{0}_{s} mixing, this leads to
x_{s} = 26.99 ± 0.09 
χ_{s} = 0.499318 ± 0.000005 
The plot shows the different Δm_{s} measurement and their average.
The parameters q/p, A_{SL} and Re(ε_{B})/(1+ε_{B}^{2}) are thus equivalent. There is CP violation in the mixing if q/p is different from 1, i.e. A_{SL} is different from 0.
Averages are given below separately for the B^{0} and the B_{s} systems. Two sets of averages are given for the B^{0} system in the first table: a first set using only measurements performed at Υ(4S) machines, and a second set using all measurements (excluding those that assume no CP violation in B_{s} mixing). The second table presents an average for the B_{s} system. Measurements performed at high energy that do not separate the B^{0} and B_{s} contributions are no longer used to obtain the final averages (at this time, the only measurements at high energy used in the averages are from D0 and LHCb).
CPviolating observable in B^{0} mixing  
q/p =
1.0009
±
0.0013
A_{SL} = −0.0019 ± 0.0027 Re(ε_{B})/(1+ε_{B}^{2}) = −0.0005 ± 0.0007 
from measurements at the Υ(4S) 
q/p =
1.0010
±
0.0008
A_{SL} = −0.0021 ± 0.0017 Re(ε_{B})/(1+ε_{B}^{2}) = −0.0005 ± 0.0004 
world average 
CPviolating observable in B_{s} mixing  
q/p =
1.0003
±
0.0014
A_{SL} = −0.0006 ± 0.0028 
world average 
The above world averages A_{SL}(B^{0}) = −0.0021 ± 0.0017 and A_{SL}(B_{s}) = −0.0006 ± 0.0028 are obtained from a twodimensional fit of the CLEO, BABAR, Belle, D0 and LHCb results: the correlation coefficient between them is found to be −0.054 . This is illustrated in the plot below, where the black ellipse represents the world average. The orange vertical band shows the Bfactory average of A_{SL}(B^{0}) (measurements performed by CLEO, BABAR and Belle at the Υ(4S)), the two brown ellipses the D0 measurements, and the green ellipse the LHCb measurements; the grey ellipse is an average including only untagged B^{0}_{(s)} → D^{(*)}_{(s)} μ X decays measured by D0 and LHCb. The white point close to (0,0) is the Standard Model prediction [J. Albrecht, F. Bernlochner, A. Lenz, and A. Rusov, arXiv:2402.04224]. The prediction and world average are consistent with each other at the level of 0.5 σ.
CP violation in B_{s} mixing is caused by the weak phase difference
φ_{12}=arg[−M_{12}/Γ_{12}],
where M_{12} and Γ_{12}
are the offdiagonal elements of the mass and decay matrices. The tangent of this phase difference
can be estimated (approximately) as A_{SL}(B_{s}) Δm_{s}/ΔΓ_{s}=
−0.1
±
0.6
using the above averages of A_{SL}(B_{s}), Δm_{s} and
ΔΓ_{s}.
Combined result from CDF, D0, ATLAS, CMS and LHCb data (complete list of inputs and references) 

φ_{s}^{ccs}  −0.040 ± 0.016 
φ_{s}^{J/ψφ}  −0.050 ± 0.017 
The plots below show some of the results of the multidimensional fits, including all on the left and only the B_{s} → J/ψφ analyses on the right. The plots on the top show, in the (φ_{s}^{ccs}, ΔΓ_{s}) plane, the individual 68% confidencelevel contours of ATLAS, CMS, CDF, D0 and LHCb, their combined contour (black solid line and shaded area), as well as the Standard Model predictions (very thin white rectangle). The prediction for φ_{s}^{ccs} is taken as the indirect determination of −2β_{s} via a global fit to experimental data within the Standard Model, −2β_{s} = −0.0376 ^{ +0.0006 }_{ −0.0005 } [J. Charles et al. (CKMfitter), Phys. Rev. D91, 073007 (2015), updated with Summer 2023 results] and −0.0367 ± 0.0010 [M. Bona et al. (UTfit), Rend. Lincei Sci. Fis. Nat. 34, 27 (2023), updated with Summer 2023 results], while the Standard Model prediction for ΔΓ_{s} is +0.091 ±0.015 ps^{−1} [J. Albrecht, F. Bernlochner, A. Lenz, and A. Rusov, arXiv:2402.04224]. The combined result is consistent with these predictions. The plots on the bottom show, in the (Γ_{s}, ΔΓ_{s}) plane, the individual 68% confidencelevel contours of ATLAS, CMS, CDF, D0 and LHCb, their combined contour (black solid line and shaded area), as well as the Standard Model prediction for ΔΓ_{s} (horizontal gray band). Because of tensions between the measurements, the errors on Γ_{s} and ΔΓ_{s} have been scaled by the indicated factors (the ellipses representing the results of each experiment are shown before scaling, while the combined ellipses include the scale factors).
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Top right plot in several formats:
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Bottom left plot in several formats:
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Bottom right plot in several formats:
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A complete list of inputs and references from CDF, D0, ATLAS, CMS and LHCb,
as well as the results for φ_{s}^{ccs} and
ΔΓ_{s} from the mutlidimensional fit of all b→ccs results,
is available here.
Please refer to our latest updates performed in 2020.
The bhadron fractions in Υ(4S) decays and in Υ(5S) decays are maintained by the "B to charm" HFLAV subgroup.
The bhadron fractions in Z decays have been stable over many years, without new measurements becoming available.
The fractions of bhadron produced at highenergy colliders
were computed under the assumption that they are the
same in Z decays at LEP, in pp collisions at the Tevatron (√s=1.8−2 TeV)
or in protonproton collisions at the LHC (√s=7−13 TeV).
While this assumption was plausible in the past, it is now known since several years that it is incorrect.
The available data show that the fractions depend on the kinematics of the produced b hadron.
Both CDF and LHCb reported a transversemomentum (p_{T} ) dependence of the fractions, with the
fraction of Λ_{b} baryons observed at low p_{T}
being enhanced with respect to that seen at LEP at higher p_{T}.
Other dependences (e.g. on pseudorapidity) are also expected.