Erratum to: “Measurement of open beauty production at HERA”


18 October 2001

Physics Letters B 518 (2001) 331–332
www.elsevier.com/locate/npe

Erratum

Erratum to: “Measurement of open beauty production at HERA”
[Phys. Lett. B 467 (1999) 156–164] ✩

H1 Collaboration
Received 13 August 2001

We have miscalculated the theoretical value of the
muon production cross section from b decay in [1].
The cross section in the visible region derived from
the NLO QCD calculation of [2] should be 0.054 ±
0.009 nb (instead of 0.104 ± 0.017 nb given in [1])
to be compared to the measured value of 0.176 ±
0.016+0.026−0.017 nb which is unchanged. This amended
theoretical value is now computed using the Peterson
fragmentation parameterisation described in [1]. The
LO calculation of this cross section gives 0.036 nb
(instead of 0.069 nb given in [1]) compared to the
value of 0.038 nb computed from the AROMA Monte
Carlo [3] which is unchanged. Here the updated value
of 10.95% is used for the semi-leptonic branching ra-
tio for the primary admixture of b hadrons [4]. The
total number of decay muons in the visible region
also includes a fraction of 14% due to secondary de-
cays. The changes enter the extrapolations to the full
phase space and so other amendments are necessary.
Despite the large factors involved we give the corre-
sponding numbers for completeness. The total elec-
troproduction cross section (Q2 < 1 GeV2) should be
14.8 ± 1.3+3.3−2.8 nb (instead of 7.1 nb) and the total pho-
toproduction cross section at W = 180 GeV should be
206 ± 19+46−40 nb (instead of 111 nb). The value of the
latter quantity has been amended in Fig. 1 which re-
places Fig. 4 of [1].

Apart from the amended numbers given above the
conclusions of the paper are unchanged.

✩ PII of original article: S0370-2693(99)01099-0.

Fig. 1. The total photoproduction cross section, σ (γp → bb̄X). The
horizontal error bar represents the range of the measurement. The
solid curve shows the expectation of the FMNR NLO QCD calcu-
lation (full line) with mb = 4.75 GeV and the MRSG and GRV-HO
structure functions for the proton and the photon, respectively. The
shaded area corresponds to the uncertainty if the factorisation scale
changes by a factor of 2. A change of the renormalisation scale by
a factor of 2 leads to a similar result. The dashed line represents
the prediction of the FMNR NLO QCD calculation if the MRST [5]
structure function for the proton is used.

References

[1] C. Adloff et al., H1 Collaboration, Phys. Lett. B 467 (1999)
156, hep-ex/9909029.

[2] S. Frixione, M.L. Mangano, P. Nason, G. Ridolfi, Phys. Lett.
B 348 (1995) 633, hep-ph/9412348.

PII: S 0 3 7 0 - 2 6 9 3 ( 0 1 ) 0 1 0 3 5 - 8
 2001 Elsevier Science B .V. Open access under CC BY license.0370-2693/01/

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332 Physics Letters B 518 (2001) 331–332

[3] G. Ingelman, J. Rathsman, G.A. Schuler, Comput. Phys.
Commun. 101 (1997) 135, hep-ph/9605285.

[4] D.E. Groom et al., Particle Data Group Collaboration, Eur.
Phys. J. C 15 (2000) 1.

[5] A.D. Martin, R.G. Roberts, W.J. Stirling, R.S. Thorne, Eur.
Phys. J. C 4 (1998) 463, hep-ph/9803445.