# Model of Block et al.

## References

[1] | BLOCK, M. M., GREGORES, E. M., HALZEN, F. and PANCHERI, G., Phys. Rev. D60 (1999) 054024 |

[2] | BLOCK, M. M., Phys. Rept. 436 (2006) 71-215 |

## Implementation notes

Implemented in class `BHModel`

(see in Doxygen).

There have been two issues discovered when implementing the model.

- The definition of
`N_g`

is inconsistent between [1] and [2]. As confirmed in private communication with the authors, the correct normalisation is such that the average x carried by the gluons is 1/2 - which is the case of the value published in [1]. - Using Eq. (478) from [2] does not give reasonable dsigma/dt. However, if a factor of 1/2 is applied to the r.h.s. (see
`BHModel::chi_without_i`

) the results overlap with the published predictions from the original authors (see a test sheet with Elegent calculations in green). It is possible that the 1/2 factor was omitted due to confusion with the other 1/2 factor mentioned in point 1.

Last modified 5 years ago
Last modified on Oct 8, 2013, 3:55:10 PM